Immune Cells Play Key Role in Early Breast Cancer Metastasis Even Before a Tumor Develops

Mount Sinai researchers have discovered that normal immune cells called macrophages, which reside in healthy breast tissue surrounding milk ducts, play a major role in helping early breast cancer cells leave the breast for other parts of the body, potentially creating metastasis before a tumor has even developed, according to a study published in Nature Communications.

The macrophages play a role in mammary gland development by regulating how milk ducts branch out through breast tissue. Many studies have also proven the importance of macrophages in metastasis, but until now, only in models of advanced large tumors. By studying human samples, mouse tissues, and breast organoids, which are miniaturized and simplified versions of breast tissue produced in the lab, the new research found that in very early cancer lesions, macrophages are attracted to enter the breast ducts where they trigger a chain reaction that brings early cancer cells out of the breast, said lead researcher Julio Aguirre-Ghiso, PhD, Professor of Oncological Sciences, Otolaryngology, Medicine, Hematology and Medical Oncology at The Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai.

This research shows that macrophages’ relationship with normal breast cells is co-opted by early cancer cells that activate the cancer-causing HER2 gene, helping in this newly-discovered role of these immune cells. The findings from this study could eventually help pinpoint biomarkers to identify cancer patients who may be at risk of carrying potential metastatic cells due to these macrophages and potentially lead to the development of novel therapies that prevent early cancer metastasis.

Early treatment of high-risk patients may prevent the formation of deadly metastasis better than the current standard of treating metastatic disease only once it has occurred, said key researcher Miriam Merad, MD, PhD, Director of the Precision Immunology Institute and the Human Immune Monitoring Center and co-leader of the Cancer Immunology program at The Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai.

“Our study challenges the dogma that early diagnosis and treatment means sure cure,” Dr. Aguirre-Ghiso said. “In this study and in our previous studies, we present mechanisms governing early dissemination.  This work further sheds light onto the mysterious process of early dissemination and cancer of an unknown primary tumor.”

Researchers hope to build on this study by identifying which macrophages specifically control early dissemination. They also hope to further detail how early disseminated cancer cells interact with macrophages in the lungs where metastases eventually form and how this interaction can be targeted to prevent metastasis.

“Here, we have identified how macrophages and early cancer cells form a ‘microenvironment of early dissemination’ and show that by disrupting this interaction we can prevent early dissemination and ultimately deadly metastasis,” said Dr. Merad. “This sheds light onto the mysterious process of early dissemination and for patients who have metastasis cancer that came from an unknown source.”

Immune Cells Produce Wound Healing Factor, Could Lead To New IBD Treatment

Specific immune cells have the ability to produce a healing factor that can promote wound repair in the intestine, a finding that could lead to new, potential therapeutic treatments for inflammatory bowel disease (IBD), according to a new research study.

The research team, led by Georgia State University and the University of Michigan, wanted to understand how a wound heals in the intestine because in IBD, which includes Crohn’s disease and ulcerative colitis, damage to the intestinal epithelial barrier allows bacteria in the intestine to go across the barrier and stimulate the body’s immune system. This can lead to excessive inflammation and IBD. Efficient repair of the epithelial barrier is critical for suppressing inflammation and reestablishing intestinal homeostasis.

In this study, the researchers found that a specific population of immune cells called macrophages have the ability to secrete or produce a protective or healing factor known as Interleukin-10 (IL-10), which can interact with receptors on intestinal epithelial cells to promote wound healing. The findings are published in The Journal of Clinical Investigation.

“Understanding how wounds can be healed is believed to be very important and a potential therapeutic avenue for the treatment of inflammatory bowel disease,” said Dr. Tim Denning, associate professor in the Institute for Biomedical Sciences at Georgia State. “In this study, we tried to understand some of the cellular mechanisms that are required for optimal wound healing in the intestine. To do this, we used a cutting-edge system, a colonoscope with biopsy forceps, to create a wound in mice. This is analogous to colonoscopies in humans. This cutting-edge system allowed us to begin to define what cells and factors contribute to wound healing in the mouse model.”

The researchers used a small, fiber optic camera and forceps to pinch the mouse’s intestine and take a small biopsy, just as how colonoscopies are done in humans. This small pinch created a wound, which the researchers observed as it healed. The study compared intestinal wound healing in two groups of mice: 1) typical mice (wild type) found in nature and 2) mice genetically deficient in the healing factor IL-10, specifically in macrophages, which impairs their ability to have normal wound repair.

The team also analyzed the effects of IL-10 on epithelial wound closure in vitro using an intestinal epithelial cell line.

They concluded that macrophages are a main source of IL-10 in the wound bed, and IL-10 stimulates in vitro intestinal epithelial wound healing and increases in expression during in vivo intestinal epithelial wound repair. In vitro, exposure to IL-10 increased wound repair within 12 hours and the response was further enhanced after 24 hours.

“Basically, you have a wound, and you have an immune cell that comes in,” Denning said. “That’s the macrophage. The macrophage can produce a factor (IL-10), and that factor can then cause the cells that are around the wound to start closing the wound.”

In addition, the researchers defined some of the signaling pathways that IL-10 uses to orchestrate wound repair. They found IL-10 promotes intestinal epithelial wound repair through the activation of cAMP response element-binding protein (CREB) signaling at the sites of injury, followed by synthesis and secretion of the WNT1-inducible signaling protein 1 (WISP-1).

“The implications are that understanding these cells, the factors and the pathways may offer us the ability to modulate this pathway during inflammatory bowel disease, which could lead to treatment and promote healing and recovery from inflammatory bowel disease,” Denning said. “There are different ways we think about it, but perhaps we could deliver the beneficial compounds (IL-10 and the downstream signaling pathways) to those patients, orally or even intravenously, or somehow drive the natural production of those compounds.”

Experimental HIV vaccine regimen is well-tolerated, elicits immune responses

Results from an early-stage clinical trial called APPROACH show that an investigational HIV vaccine regimen was well-tolerated and generated immune responses against HIV in healthy adults. The APPROACH findings, as well as results expected in late 2017 from another early-stage clinical trial called TRAVERSE, will form the basis of the decision whether to move forward with a larger trial in southern Africa to evaluate vaccine safety and efficacy among women at risk of acquiring HIV.

The APPROACH results will be presented July 24 at the 9th International AIDS Society Conference on HIV Science in Paris.

The experimental vaccine regimens evaluated in APPROACH are based on “mosaic” vaccines designed to induce immunological responses against a wide variety of HIV subtypes responsible for HIV infections globally. Different HIV subtypes, or clades, predominate in various geographic regions around the world. The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, funded pre-clinical development of these vaccines. Together with other partners, NIAID supported the APPROACH trial, which is sponsored by Janssen Vaccines & Prevention B.V., part of the Janssen Pharmaceutical Companies of Johnson & Johnson. The manufacture and clinical development of the mosaic vaccines are led by Janssen.

“A safe and effective HIV vaccine would be a powerful tool to reduce new HIV infections worldwide and help bring about a durable end to the HIV/AIDS pandemic,” said NIAID Director Anthony S. Fauci, M.D. “By exploring multiple promising avenues of vaccine development research, we expand our opportunities to achieve these goals.”

APPROACH involved nearly 400 volunteers in the United States, Rwanda, Uganda, South Africa and Thailand who were randomly assigned to receive one of seven experimental vaccine regimens or a placebo. APPROACH found that different mosaic vaccine regimens were well-tolerated and capable of generating anti-HIV immune responses in healthy, HIV-negative adults. Notably, the vaccine regimen that was most protective in pre-clinical studies in animals elicited among the greatest immune responses in the study participants. However, further research will be needed because the ability to elicit anti-HIV immune responses does not necessarily indicate that a candidate vaccine regimen can prevent HIV acquisition.

According to the researchers, the findings from APPROACH, as well as from animal studies, support further evaluation of a lead candidate regimen in a clinical trial to assess its safety and efficacy. Plans for such a clinical trial to be conducted in southern Africa are in development, with projected enrollment of 2,600 healthy, HIV-negative women. Should the larger trial move forward, it is expected to begin enrollment in late 2017 or early 2018.

In APPROACH, study participants received four vaccinations over 48 weeks: two doses of an initial, or “prime,” vaccine, followed by two doses of a booster vaccine. The experimental regimens all incorporated the same vaccine components in the prime vaccination, known as Ad26.Mos.HIV. The vaccine uses a strain of common-cold virus (adenovirus serotype 26, or Ad26), engineered so that it does not cause illness, as a vector to deliver three mosaic antigens created from genes from many HIV variants. The booster vaccination included various combinations of the Ad26.Mos.HIV components or a different mosaic component, called MVA-Mosaic, and/or two different doses of clade C HIV gp140 envelope protein containing an aluminum adjuvant to boost immune responses.

The Ad26-based mosaic vaccines were initially developed by the laboratory of NIAID grantee Dan H. Barouch, M.D., Ph.D., and Janssen. In pre-clinical studies, regimens incorporating these mosaic vaccines protected monkeys against infection with an HIV-like virus called simian human immunodeficiency virus (SHIV). The most effective prime-boost regimen reduced the risk of infection per exposure to SHIV by 94 percent and resulted in 66 percent complete protection after six exposures. Researchers identified and characterized the vaccine-induced immune responses that correlated with this protection.

“The promising, early-stage results from the APPROACH study support further evaluation of these candidate vaccines to assess their ability to protect those at risk of acquiring HIV,” said Dr. Barouch, a principal investigator for APPROACH. He also is director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston and professor of medicine at Harvard Medical School.

Following the third vaccination, most APPROACH participants had developed antibody and cellular immune responses against HIV. The different boost vaccines altered the magnitude and character of these immune responses, with the regimen that showed greatest protection in monkey studies also eliciting among the greatest immune responses in humans. The anti-HIV immune responses increased after the fourth vaccination.

The researchers conclude that further evaluation of this approach would use a regimen comprising two Ad26 mosaic primes and two boosts with Ad26 mosaic and clade C gp140. The ongoing TRAVERSE trial is comparing Ad26-based regimens containing three mosaic antigens (trivalent) with Ad26-based regimens containing four mosaic antigens (tetravalent). Results from TRAVERSE are expected in late 2017.

Nanoparticles Reprogram Immune Cells to Fight Cancer

Researchers at Fred Hutchinson Cancer Research Center have developed biodegradable nanoparticles that can be used to genetically program immune cells to recognize and destroy cancer cells — while the immune cells are still inside the body.

In a proof-of-principle study to be published April 17 in Nature Nanotechnology, the team showed that nanoparticle-programmed immune cells, known as T cells, can rapidly clear or slow the progression of leukemia in a mouse model.

“Our technology is the first that we know of to quickly program tumor-recognizing capabilities into T cells without extracting them for laboratory manipulation,” said Fred Hutch’s Dr. Matthias Stephan, the study’s senior author. “The reprogrammed cells begin to work within 24 to 48 hours and continue to produce these receptors for weeks. This suggests that our technology has the potential to allow the immune system to quickly mount a strong enough response to destroy cancerous cells before the disease becomes fatal.”

Cellular immunotherapies have shown promise in clinical trials, but challenges remain to making them more widely available and to being able to deploy them quickly. At present, it typically takes a couple of weeks to prepare these treatments: the T cells must be removed from the patient and  genetically engineered and grown in special cell processing facilities before they are infused back into the patient. These new nanoparticles could eliminate the need for such expensive and time consuming steps.

Although his T-cell programming method is still several steps away from the clinic, Stephan imagines a future in which nanoparticles transform cell-based immunotherapies — whether for cancer or infectious disease — into an easily administered, off-the-shelf treatment that’s available anywhere.

“I’ve never had cancer, but if I did get a cancer diagnosis I would want to start treatment right away,” Stephan said. “I want to make cellular immunotherapy a treatment option the day of diagnosis and have it able to be done in an outpatient setting near where people live.”

The body as a genetic engineering lab

Stephan created his T-cell homing nanoparticles as a way to bring the power of cellular cancer immunotherapy to more people.

In his method, the laborious, time-consuming T-cell programming steps all take place within the body, creating a potential army of “serial killers” within days.

As reported in the new study, Stephan and his team developed biodegradable nanoparticles that turned T cells into CAR T cells, a particular type of cellular immunotherapy that has delivered promising results against leukemia in clinical trials.

The researchers designed the nanoparticles to carry genes that encode for chimeric antigen receptors, or CARs, that target and eliminate cancer. They also tagged the nanoparticles with molecules that make them stick like burrs to T cells, which engulf the nanoparticles. The cell’s internal traffic system then directs the nanoparticle to the nucleus, and it dissolves.

The study provides proof-of-principle that the nanoparticles can educate the immune system to target cancer cells. Stephan and his team designed the new CAR genes to integrate into chromosomes housed in the nucleus, making it possible for T cells to begin decoding the new genes and producing CARs within just one or two days.

Once the team determined that their CAR-carrying nanoparticles reprogrammed a noticeable percent of T cells, they tested their efficacy. Using a preclinical mouse model of leukemia, Stephan and his colleagues compared their nanoparticle-programming strategy against chemotherapy followed by an infusion of T cells programmed in the lab to express CARs, which mimics current CAR-T-cell therapy.

The nanoparticle-programmed CAR-T cells held their own against the infused CAR-T cells. Treatment with nanoparticles or infused CAR-T cells improved survival 58 days on average, up from a median survival of about two weeks.

The study was funded by Fred Hutch’s Immunotherapy Initiative, the Leukemia & Lymphoma Society, the Phi Beta Psi Sorority, the National Science Foundation and the National Cancer Institute.

Next steps and other applications

Stephan’s nanoparticles still have to clear several hurdles before they get close to human trials. He’s pursuing new strategies to make the gene-delivery-and-expression system safe in people and working with companies that have the capacity to produce clinical-grade nanoparticles. Additionally, Stephan has turned his sights to treating solid tumors and is collaborating to this end with several research groups at Fred Hutch.

And, he said, immunotherapy may be just the beginning. In theory, nanoparticles could be modified to serve the needs of patients whose immune systems need a boost, but who cannot wait for several months for a conventional vaccine to kick in.

“We hope that this can be used for infectious diseases like hepatitis or HIV,” Stephan said.  This method may be a way to “provide patients with receptors they don’t have in their own body,” he explained.  “You just need a tiny number of programmed T cells to protect against a virus.”

Georgia State Researcher Gets $4.1 Million Federal Grant to Develop Drug to Combat Ebola Virus

Dr. Christopher Basler, a professor in the Institute for Biomedical Sciences at Georgia State University, director of the university’s Center for Microbial Pathogenesis and a Georgia Research Alliance Eminent Scholar in Microbial Pathogenesis, has received a five-year, $4.1 million federal grant to develop a drug targeting Ebola virus.

“We still lack any approved drugs to treat Ebola virus infection,” Basler said. “Ebola remains a significant concern. The outbreak in West Africa from 2014 to 2016 drives home the significance of Ebola as a public health threat. We need vaccines and drugs to treat the infections. There’s been more progress on the vaccine front than treatment, but hopefully, we’ll come up with new strategies that may lead to new drugs.”

The Ebola virus outbreak in West Africa was the largest known occurrence of the disease and resulted in more than 28,000 infections and 11,000 deaths, according to the World Health Organization. History shows that Ebola virus periodically reemerges.

“I think given the history, we can expect Ebola virus and other related viruses to come back,” Basler said. “To me, that drives home the importance of having ways to respond.”

The grant from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, will support Basler’s work to target the viral machinery that Ebola uses to make new copies of its genome, a critical function for the virus to grow and spread. The goal is to find drug compounds that block the growth of Ebola virus.

“One of the complications with Ebola is that you need special high containment labs to work with the live virus,” Basler said. “So our strategy was to try to break the virus down into its different functions in a way that you could study them without creating any infectious material. We’ll define compounds that will inhibit the function of the system that enables growth of the virus and then later test them against the actual live virus.”

Basler is collaborating on the project with Dr. Megan Shaw of the Icahn School of Medicine at Mt. Sinai, Drs. Sumit Chanda and Anthony Pinkerton of Sanford Burnham Prebys Medical Discovery Institute and Dr. Robert Davey of Texas Biomedical Research Institute.

The four institutions will identify inhibitors of the viral machinery, confirm inhibition against live Ebola virus, determine how the drug candidates block the viral machinery and develop additional tests to identify drug candidates that will inhibit not only Ebola virus, but also other related and deadly viruses, such as Marburg virus.

“These are generally all quite deadly viruses, so you would like to have drugs that work not only against Ebola virus but all of its family members,” Basler said. “We’re trying to find things that we’re calling panfiloviral drugs that will target all members of the family. If we find those, those would be our top candidates. The next step would require different funding, but we’d want to test the best candidates in animal models to see if these can prevent Ebola virus disease.”

“GRA congratulates Dr. Basler on his recent achievement,” said Michael Cassidy, president and chief executive officer of the Georgia Research Alliance. “His research has the potential to protect us from the world’s most threatening viruses. We are pleased to have participated with Georgia State University in recruiting him to Georgia and to have this important work take place in our state.”

Cytotoxins Contribute to Virulence of Deadly Epidemic Bacterial Infections

Beginning in the mid-1980s, an epidemic of severe invasive infections caused by Streptococcus pyogenes (S. pyogenes), also known as group A streptococcus (GAS), occurred in the United States, Europe, and elsewhere. The general public became much more aware of these serious and sometimes fatal infections, commonly known as the “flesh-eating disease.” Potent cytotoxins produced by this human pathogen contribute to the infection. A new study in The American Journal of Pathology reports that the bacteria’s full virulence is dependent on the presence of two specific cytotoxins, NADase (SPN) and streptolysin O (SLO).

Bacteria produce cytotoxins that can cause cell death and result in infections of the deep fascia and other tissues, including necrotizing fasciitis. “Our research revealed that the most severe form of the disease requires two cytotoxins. If either one or both are missing, the infection is much less dangerous,” explained lead investigator James M. Musser, MD, PhD, chairman of the Department of Pathology and Genomic Medicine at Houston Methodist Research Institute (Houston, TX).

To evaluate how the toxins SPN and SLO act together, investigators used mice infected with genetically altered S. pyogenes strains that produced either, both, or neither of the toxins. They found that mutant strains lacking either SPN or SLO or both do not cause the most severe forms of necrotizing fasciitis, necrotizing myositis, bacteremia, and other soft tissue infections. Production of both toxins was required for full infection virulence.

Resistance to bacterial infections depends in part on innate immunity conferred by white blood cells, including polymorphonuclear leukocytes (primarily neutrophils). The researchers found evidence that infections with SPN- and SLO-deficient S. pyogenes could be controlled better because they were less likely to resist the bactericidal effects of human polymorphonuclear leukocytes.

According to the Centers for Disease Control and Prevention, approximately 700 to 1,100 cases of necrotizing fasciitis caused by group A streptococcus have occurred yearly since 2010. Although the disease primarily affects the young and old and those with underlying chronic conditions, it may also develop in healthy individuals. Transmission occurs person-to-person, many times through a break in the skin.

“We do not have a Group A strep vaccine that works right now,” commented Dr. Musser. “The information we gained from this research may help to develop more effective therapeutics, such as inhibitors of these two toxins, or even a vaccine.”

Patients with Severe Chronic Rhinosinusitis Show Improvement with Verapamil Treatment

A small clinical trial at Massachusetts Eye and Ear found that patients with chronic rhinosinusitis (CRS) with nasal polyps improved with Verapamil therapy

A clinical trial studying the use of Verapamil (a drug currently in use for cardiovascular disease and cluster headache) in alleviating chronic rhinosinusitis (CRS) with nasal polyps revealed significant improvement in the symptoms of this subset of patients. It is the first study of its kind to explore treatment for CRS by inhibiting P-glycoprotein, a protein pump within the nasal lining that Mass. Eye and Ear researchers previously identified as a mechanism for these severe cases of CRS marked by the presence of nasal polyps. The clinical trial results, published online today in the Journal of Allergy and Clinical Immunology: In Practice, suggest that Verapamil represents a promising novel therapy for the treatment of CRS with nasal polyps.

“Recently, we became aware that some of the inflammation in CRS with nasal polyps is generated by the nasal lining itself, when a particular protein pump (P-glycoprotein) is overexpressed and leads to the hyper-secretion of inflammatory cytokines,” said senior author Benjamin S. Bleier, M.D., a sinus surgeon at Mass. Eye and Ear and an assistant professor of otolaryngology at Harvard Medical School. “Verapamil is a first-generation inhibitor that is well-established in blocking P-glycoprotein. In some patients with CRS with nasal polyps, we saw dramatic improvement in their symptom scores.”

One of the more prevalent chronic illnesses in the United States, CRS has been known to cause significant quality of life detriments to affected patients, who often cannot breathe or sleep easily due to obstructed nasal and sinus passages. The presence of nasal polyps represents a particularly severe presentation of the disease. Current treatment strategies (most often long-term steroid use) are plagued by difficult side effects and fail to target an underlying source of the disease.

Motivated by their previous finding of the presence of P-glycoprotein overexpression in the nasal lining of patients with CRS with nasal polyps, the study authors conducted a randomized, double-blind, placebo-controlled clinical trial studying the use of low-dose Verapamil in 18 patients with CRS with nasal polyps. An analysis of these patients demonstrated improved outcomes for those in the Verapamil group in relation to those in the placebo group. However, the researchers also observed that the treatment effect was significantly limited among patients with higher body mass indices. Future studies are being planned to determine if a higher dose of Verapamil may be needed to be therapeutic for some patients.

“Chronic rhinosinusitis with nasal polyps is among our most challenging diagnoses to treat, because these patients essentially have chronic, lifelong inflammation that needs chronic, lifelong treatment,” said Dr. Bleier. “We observed no significant side effects at the doses we used, and we are very encouraged by the results of this first step toward a more targeted therapy for our patients.”

‘Collateral’ Lethality May Offer New Therapeutic Approach for Cancers of the Pancreas, Stomach and Colon

Cancer cells often delete genes that normally suppress tumor formation. These deletions also may extend to neighboring genes, an event known as “collateral lethality,” which may create new options for development of therapies for several cancers.

Scientists at The University of Texas MD Anderson Cancer Center have discovered that during early cancer development when a common tumor suppressor known as SMAD4 is deleted, a nearby metabolic enzyme gene called malic enzyme 2 (ME2) also is eradicated, suggesting the possibility of malic enzyme inhibitors as a novel therapy approach. Study findings were published in the Jan. 18 online issue of Nature.

“In an effort to expand therapeutic strategies beyond oncogenic targets to those not directly linked to cancer development, we have identified collateral lethal vulnerability in pancreatic cancers that can be targeted pharmacologically in certain patient populations,” said Prasenjit Dey, Ph.D., postdoctoral fellow in Cancer Biology and co-author of the Nature article. “Genomic data across several cancers further suggest this therapeutic strategy may aid many cancer patients, including those with stomach and colon cancers.”

Collateral lethality occurs when tumor suppressor genes are deleted, a nearly universal occurrence in cancer. Correspondingly, a large number of genes with no direct role in tumor progression also are deleted as a result of their proximity to tumor suppressor genes.

SMAD4 is deleted in one-third of pancreatic cancers. The research team found that when the SMAD4 gene is eradicated in mice, it also results in depletion of ME2 levels. The genetic depletion of ME3, a sister gene to ME2, sets off a complex chain of events that ultimately regulates an amino acid group called branched chain amino acid (BCAA), which are crucial to cancer’s ability to thrive. Thus, if a therapy could be developed that inhibits ME3, it might prevent ME2-deleted tumor growth.

“Our work suggests a mechanism for cell lethality involving the regulation of BCAAs as crucial elements in pancreatic cancer by regulating ME3,” said Ronald DePinho, M.D., professor of Cancer Biology, senior author of the Nature paper and president of MD Anderson. “We propose that highly specific ME3 inhibitors could provide an effective therapy for many cancer patients, but more research must be done.”

Researchers Discover a New Gatekeeper Role for Thymic Dendritic Cells in Controlling T Cell Release into the Bloodstream

Better Understanding of Cell’s Role Could Lead to New Strategies to Treat Autoimmune Diseases, Cancer

Newswise — Oakland, CA (December 6, 2016) – A team of scientists led by Julie Saba, MD, PhD at UCSF Benioff Children’s Hospital Oakland, has unveiled a novel role of thymic dendritic cells, which could result in new strategies to treat conditions such as autoimmune diseases, immune deficiencies, prematurity, infections, cancer, and the loss of immunity after bone marrow transplantation.

The study “Dendritic cell sphingosine-1-phosphate lyase regulates thymic egress,” appeared in the ‘Journal of Experimental Medicine’ (October 17, 2016 issue), published by Rockefeller University Press.

T lymphocytes are blood cells that carry out the main functions of our immune system. Dendritic cells and B lymphocytes are other types of immune cells that present foreign substances (such as microbial proteins) and “self” substances from our own tissues to T lymphocytes. In this way, T lymphocytes are “educated” to distinguish between self and non-self, so they can mount an immune response to pathogens but recognize and remain tolerant of one’s own bodily tissues. When this system fails to operate properly, autoimmune disease and immune deficiencies can result.

T lymphocytes undergo maturation in the thymus, a small gland located just above the heart, and are then released into the bloodstream. T lymphocyte egress from the thymus is essential for immune surveillance and to fight various types of infections. Sphingosine-1-phosphate (S1P) is a lipid molecule found at high levels in the blood and low levels in most tissues. Mature T cells produce a cell surface receptor that recognizes S1P, allowing the S1P chemical gradient to attract them into the bloodstream once they have completed their education in the thymus. However, the precise mechanisms that control T lymphocyte egress are not fully understood.

Thymic dendritic cells have a well-established role in antigen presentation and immune tolerance in the body. In addition to this role, dendritic cells also act as metabolic gatekeepers of lymphocyte trafficking. The team showed that thymic dendritic cells take up S1P, a blood borne lipid mediator, and metabolize it through the actions of an enzyme called S1P lyase, generating a localized S1P gradient that facilitates T lymphocyte egress into the blood In light of the fact that dendritic cells are known to continually traffic throughout the body surveying for the presence of infectious agents, the team’s observations raise the possibility that dendritic cells could potentially control the release of T lymphocytes in response to various disease states or conditions. These findings provide a deeper understanding of how the body regulates lymphocyte trafficking.

“T cells are needed to orchestrate the body’s immune response against pathogenic organisms and also against cancer cells,” says UCSF Benioff Oakland’s Dr. Julie Saba, one of the study’s authors. “In addition to natural T cells, genetically engineered T cells are being used in revolutionary ways to treat cancer. However, conditions such as chronic infection, aging, cancer and bone marrow transplantation can reduce T cell output from the thymus, compromising immune function. By learning what controls T cell output, we hope to be able to restore T cell production when it is low and provide more T cells for therapeutic purposes. ”

In addition to Saba, other co-authors are Jesus Zamora-Pineda, Ashok Kumar, Jung H. Suh, and Meng Zhang,

The research is supported by the (CA129438) and Swim Across America funds (to J.D. Saba). Confocal images were acquired at the Children’s Hospital Oakland Research Institute Microimaging Facility supported by an NIH grant (S10RR025472) and the Children’s Hospital Branches, Inc. S1P measurements were obtained using the Children’s Hospital Oakland Research Institute Mass Spectrometry Facility supported by an NIH Health grant (S10OD018070).

About UCSF Benioff Children’s Hospital Oakland
UCSF Benioff Children’s Hospital Oakland (formerly Children’s Hospital & Research Center Oakland) is a premier, not-for-profit medical center for children in Northern California, and is the only hospital in the East Bay 100% devoted to pediatrics. UCSF Benioff Children’s Hospital Oakland affiliated with UCSF Benioff Children’s Hospital San Francisco on January 1, 2014. UCSF Benioff Children’s Hospital Oakland is a national leader in many pediatric specialties including cardiology, hematology/oncology, neonatology, neurosurgery, endocrinology, urology, orthopedics, and sports medicine. The hospital is one of only five ACS Pediatric Level I Trauma Centers in the state, and has one of largest pediatric intensive care units in Northern California. UCSF Benioff Children’s Hospital Oakland is also a leading teaching hospital with an outstanding pediatric residency program and a number of unique pediatric subspecialty fellowship programs.

UCSF Benioff Children’s Hospital Oakland’s research arm, Children’s Hospital Oakland Research Institute (CHORI), is internationally known for its basic and clinical research. CHORI is at the forefront of translating research into interventions for treating and preventing human diseases. CHORI has 250 members of its investigative staff, a budget of about $50 million, and is ranked among the nation’s top ten research centers for National Institutes of Health funding to children’s hospitals. For more information, go to www.childrenshospitaloakland.org and www.chori.org.

FDA Approves Vaccine for Cholera

In a milestone that was years in the making, a vaccine to prevent cholera, invented and developed by researchers at the University of Maryland School of Medicine’s Center for Vaccine Development, was approved today by the U.S. Food and Drug Administration (FDA).

The vaccine, Vaxchora, is the only approved vaccine in the U.S. for protection against cholera. Its licensure allows for use in people traveling to regions in which cholera is common, including travelers, humanitarian aid workers, and the military.

PaxVax, a global biotechnology company based in California, received marketing approval from the FDA for Vaxchora, a single-dose oral, live attenuated cholera vaccine that is indicated for use in adults 18 to 64 years of age. Vaxchora is the only vaccine available in the U.S. for protection against cholera and the only single-dose vaccine for cholera currently licensed anywhere in the world.

The vaccine was invented in the 1980s at Center for Vaccine Development (CVD). Since 2009, CVD researchers have worked closely with PaxVax to develop the vaccine and secure FDA licensure approval.

“This important FDA decision is the culmination of years of dedicated work by many researchers,” said Myron M. Levine, MD, DTPH, the Simon and Bessie Grollman Distinguished Professor at the University of Maryland School of Medicine (UM SOM). “For travelers to the many parts of the world where cholera transmission is occurring and poses a potential risk, this vaccine helps protect them from this disease. It is a wonderful example of how public-private partnerships can develop medicines from bench to bedside.” Dr. Levine is co-inventor of the vaccine, along with James B. Kaper, PhD, Professor and Chairman of the UM SOM Department of Microbiology and Immunology, and the senior associate dean for academic affairs at the school.

Cholera is an acute intestinal diarrheal infection acquired by ingesting contaminated food or water. Globally, cholera cases have increased steadily since 2005 and, millions of people are affected by this disease each year. Cholera can cause severe dehydration and death in less than 24 hours, if left untreated. While some cholera cases are rarely acquired in the U.S. from ingestion of uncooked seafood from the Gulf of Mexico, the vast majority of cases of domestic cholera cases occur in travelers to areas with epidemic or endemic cholera (for example, parts of Africa, Asia, or the Caribbean). A report from the U.S. Centers for Disease Control and Prevention suggests that the true number of cholera cases in the U.S. is at least 30 times higher than observed by national surveillance systems. The currently recommended intervention to prevent infection is to avoid contaminated water and food. But studies have shown that 98 percent of travelers do not follow these precautions.

Vaxchora is expected to be commercially available later this year. The FDA approval is based on results from a phase 1 safety and immunogenicity trial, a phase 3 efficacy trial, and a phase 3 trial to test manufacturing consistency. The first two of these trials were led by Wilbur H. Chen, MD, MS, associate professor of medicine at UM SOM, and chief of the CVD’s Adult Clinical Studies section. The pivotal efficacy trial, which demonstrated protection from cholera of more than 90 percent at 10 days and 80 percent at 3 months after vaccination, is the first instance the FDA has based the decision to approve a product on a human experimental challenge model. Therefore, the licensure of Vaxchora marks a significant regulatory milestone. The most common adverse reactions to Vaxchora in the clinical trials were tiredness, headache, abdominal pain, nausea/vomiting, lack of appetite and diarrhea.

Cholera is chiefly a disease of poverty, poor sanitation, and lack of access to safe drinking water, so the global health burden of cholera rests on those populations residing in vulnerable developing countries. The World Health Organization estimates the burden of cholera to be between 1.4 and 4.3 million cases per year globally. Dr. Chen said that the next steps for this cholera vaccine are to explore formulations that could be developed into successful strategies to prevent and control cholera in countries where cholera is common. These future activities would involve immunizing young children in developing countries; this group has the highest risk of dying from cholera.

“The FDA approval of a new vaccine for a disease for which there has been no vaccine available is an extremely rare event. The approval of Vaxchora is an important milestone for PaxVax and we are proud to provide the only vaccine against cholera available in the U.S.,” said Nima Farzan, chief executive officer and president of PaxVax. “We worked closely with the FDA on the development of Vaxchora and credit the agency’s priority review program for accelerating the availability of this novel vaccine. In line with our social mission, we have also begun development programs focused on bringing this vaccine to additional populations such as children and people living in countries affected by cholera.”

“This approval is an excellent example of how our researchers are entering into public-private partnerships to help further science in tangible ways,” said UM SOM Dean E. Albert Reece, MD, PhD, MBA, who is also the vice president for Medical Affairs, University of Maryland, and the John Z. and Akiko K. Bowers Distinguished Professor. “This vaccine shows once again that work by scientists here has an impact not only nationally, but globally.”

Novel Metagenomics Pathogen Detection Tool Could Change How Infectious Diseases Are Diagnosed

Scientists at the University of Utah, ARUP Laboratories, and IDbyDNA, Inc., have developed ultra-fast, meta-genomics analysis software called Taxonomer that dramatically improves the accuracy and speed of pathogen detection. In a paper published today in Genome Biology, the collaborators demonstrated the ability of Taxonomer to analyze the sequences of all nucleic acids in a clinical specimen (DNA and RNA) and to detect pathogens, as well as profile the patient’s gene expression, in a matter of minutes.

Infectious diseases are one of the biggest killers in the world. Almost 5 million children under age 5 die each year from infectious diseases worldwide, yet many infections are treatable if the pathogen culprit can be quickly and accurately identified.

“In the realm of infectious diseases, this type of technology could be as significant as sequencing the human genome,” says co-author Mark Yandell, PhD, professor of human genetics at the University of Utah (U of U), H.A. & Edna Benning Presidential Endowed Chair holder, co-director of the USTAR Center for Genetic Discovery, and co-founder of IDbyDNA. “Very few people have inherited genetic disease. But at some point, everyone gets sick from infections.”

It is difficult for infectious pathogens to hide when their genetic material is laid bare. Taxonomer opens up an entirely new approach for infectious disease diagnosis, driven by sophisticated genomic analysis and computational technologies. After a patient’s sample is sequenced, the data are uploaded via the internet to Taxonomer. In less than one minute, the tool displays a thumbnail inventory of all pathogens in the sample, including viruses, bacteria, and fungi. The interactive, real-time user interface of Taxonomer is powered by the IOBIO system developed by the laboratory of Gabor Marth, DSc, professor of human genetics at the U of U and co-Director of the USTAR Center for Genetic Discovery.

“Our benchmark analyses show Taxonomer being ten to a hundred times faster than similar tools,” says co-author Robert Schlaberg, MD, Dr Med, MPH, a medical director at ARUP Laboratories and cofounder of IDbyDNA. Schlaberg was awarded a $100,000 grant from the Bill and Melinda Gates Foundation to apply Taxonomer toward decreasing high mortality rates of children with infectious diseases in resource-limited settings.

Schlaberg points out that current diagnostic testing still relies heavily on growing cultures of suspected pathogens in the laboratory, which is often inconclusive and time consuming. Even with much faster tests like PCR, the number of pathogens that can be detected is limited.

Schlaberg explains that Taxonomer can identify an infection without the physician having to decide what to test for, something a PCR-based test cannot do. In other words, a doctor doesn’t have to suspect the cause of a patient’s infection, but can instead simply ask, “What does my patient have?” and Taxonomer will identify the pathogens.

In the new study, Taxonomer was put to the test with real-world cases using data published by others and samples provided by ARUP Laboratories and the Centers for Disease Control and Prevention (CDC). Taxonomer determined that some patients who exhibited Ebola-like symptoms in the recent African outbreak did not have Ebola but severe bacterial infections that likely caused their symptoms. “This technology can be applied whenever we don’t know the cause of the disease, including the detection of sudden outbreaks of disease. It is very clear we urgently need more accurate diagnostics to greatly enhance the ability of public health response and clinical care,” says Seema Jain, MD, medical epidemiologist at the CDC.

Another unique feature of Taxonomer is its ability to delve into human gene expression profiling, which provides information on how or if the patient’s body is reacting to an infection. “As a clinician, this gives you a better idea, when we identify a pathogen whether it is really the cause of the disease,” says Carrie L. Byington, MD, professor of pediatrics of the U of U and co-director of the Center for Clinical and Translational Science. “This tool will also allow us to determine if the patient is responding to a bacterial or viral infection when we don’t find a pathogen or when we find multiple potential causes.” She says that she sees the exceptional value of this tool for treating children, who experience more life-threatening infections early in life. “Seeing how a host [patient] reacts is extremely valuable; I believe this is a paradigm shift in how we diagnose people. It is why I wanted to be involved.”

In a previous paper published in the Journal of Clinical Microbiology, Schlaberg and his collaborators demonstrated that high-throughput sequencing in combination with Taxonomer can reliably detect pathogens, and identify previously missed pathogens, in patient samples. “Taxonomer provides a critical step forward, as it is extremely fast, accurate, and easy enough to use for implementation in diagnostic laboratories,” says Schlaberg.