Warren symposium follows legacy of geneticist giant

If we want to understand how the brain creates memories, and how genetic disorders distort the brain’s machinery, then the fragile X gene is an ideal place to start. That’s why the Stephen T. Warren Memorial Symposium, taking place November 28-29 at Emory, will be a significant event for those interested in neuroscience and genetics. Stephen T. Warren, 1953-2021 Warren, the founding chair of Emory’s Department of Human Genetics, led an international team that discovered Read more

Mutations in V-ATPase proton pump implicated in epilepsy syndrome

Why and how disrupting V-ATPase function leads to epilepsy, researchers are just starting to figure Read more

Tracing the start of COVID-19 in GA

At a time when COVID-19 appears to be receding in much of Georgia, it’s worth revisiting the start of the pandemic in early 2020. Emory virologist Anne Piantadosi and colleagues have a paper in Viral Evolution on the earliest SARS-CoV-2 genetic sequences detected in Georgia. Analyzing relationships between those virus sequences and samples from other states and countries can give us an idea about where the first COVID-19 infections in Georgia came from. We can draw Read more
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Immunology

Dissecting a pediatric autoimmune disease

When a child is just learning to play sports, swim or even simply get dressed on her own, it can be heartbreaking to see that she is already being affected by symptoms of arthritis: swelling, limping, and/or restricted range of motion.

At the recent research retreat held by the Emory–Children’s Pediatric Research Center, rheumatologist Sampath Prahalad described his efforts to define the genetics and contributing factors for juvenile idiopathic arthritis (JIA).

Sampath Prahalad, MD

A challenge in this area is determining what makes juvenile idiopathic arthritis both different from other autoimmune diseases such as lupus or type I diabetes and what makes the disease appear early in life, decades before adult-onset rheumatoid arthritis usually appears.

Determining genetic and other risk factors for the disease can help increase understanding of the mechanisms of disease, leading to better treatments, and knowing how the cheap oakley disease develops can improve diagnosis. On this second point, we asked Prahalad two questions about his work:

What proportion of patients come to you because there is a suspected genetic connection?

Most come because of symptoms of rheumatic disease. I would estimate about 20 percent of our referrals come because of a mild symptom or abnormal lab test plus a family cheap oakley sunglasses history of autoimmunity, which prompts the PCP to seek a rheumatology evaluation. Less than 2 percent come purely for a family history of autoimmunity where they are concerned the child also has it.

Under what circumstances would a doctor seek to determine a genetic risk score for a child?

We know that twins, siblings and children of individuals with an autoimmune disease have a higher risk of the condition. So a genetic risk score could help identify those at risk for closer follow up or further evaluation. Conceivably in a child with symptoms suspicious for an autoimmune disease but not definitive, a genetic risk score could help increase the probability of being able to diagnose a specific condition.

Prahalad and colleagues published a paper in the June issue of Arthritis & Rheumatism investigating the applicability of a genetic risk score for JIA involving variations in four genes. In their study looking at 155 children with JIA and 684 controls, individuals with a risk score in the top fifth have odds of childhood-onset disease 12 times of those in the bottom fifth.

A key passage from the discussion of the Arthritis & Rheumatism paper indicates that genetic factors specific for childhood onset remain to be found.

Studying children has the advantage of focusing more on the influence of genetic factors compared to the influence of environmental factors, such as smoking. Notably, the magnitude and direction of the association between childhood-onset RA [rheumatoid arthritis] and TNFAIP3, STAT4, and PTPN22 variants were similar to those observed in RA. The observation that the selected variants did not have an elevated OR in childhood-onset RA as compared to RA suggests that there are other variants still to be investigated that may influence the risk of childhood-onset RA.

Prahalad says he wants to find out whether genetic http://www.gooakley.com/ factors contributing to childhood onset are simply cumulatively more intense, and thus drive the appearance of the disease earlier, or whether they are active in a childhood-specific context.

Notably, many of the genetic risk factors identified so far are shared with other autoimmune diseases. A recent Nature Genetics paper, which Prahalad contributed to, used a customized “Immunochip” to find several new risk factors for JIA.

Non-genetic risk factors: At the retreat, Mina Rohani Pichavant, a researcher working with Prahalad, had a poster discussing her preliminary data on the types of microorganisms found in the intestines of JIA patients. Previous studies in adults with rheumatoid arthritis have shown a link between intestinal bugs and disease risk, but this area of research is new for JIA. There are also connections between gum disease and JIA.

Posted on July 5, 2013 by Quinn Eastman in Immunology Leave a comment

A model for fetal hemolytic disease

Part of standard prenatal care for a pregnant woman is to test her blood for antibodies against the red blood cells of her baby, such as anti-Rhesus D antibodies. An incompatibility can result in hemolytic disease, where the mother’s antibodies attack fetal red blood cells. The development of a therapy for Rhesus D incompatibility was one of the major success stories of medical research in the 1960s.

Jeanne Hendrickson, MD

Although Rhesus D is the most common troublemaker, other anti-red blood cell antibodies such as those against the Kell protein can also cause hemolytic disease of the fetus. The origin is often from sensitization related to previous blood transfusions. At a recent seminar, pediatric hematologist Jeanne Hendrickson described a recent case that illustrates how serious this condition can be. Hendrickson is associate medical director of Children’s Healthcare of Atlanta’s Blood and Tissue Bank, and an assistant professor in pediatrics and pathology at Emory.

Early in her second pregnancy, a woman had developed anti-Kell antibodies, causing the baby to develop anemia and the early stages of fetal heart failure. Several intrauterine transfusions, which carry a risk of miscarriage, were required. At one point, Hendrickson says, the mother was in the http://www.raybani.com/ hospital for a week while doctors looked for compatible blood. When the baby was born, he was very pale and continues to need medical care, because anti-Kell antibodies interfere with red blood cell development.

Unfortunately, there is nothing analogous to RhoGam (the standard therapy for Rhesus D) for this situation. Today, 6 out of 1000 pregnancies are affected by red blood cell immunization. And despite its success, Hendrickson says some mystery remains about exactly how RhoGam works.

First author Sean Stowell, MD, PhD

First author Sean Stowell, MD, PhD

She and her colleagues have a new paper in the journal Blood describing an animal model for hemolytic disease of the fetus and newborn involving anti-Kell antibodies. Postdoc Sean Stowell is the first author Ray Ban outlet of the paper. This is the first animal model of anti-red blood cell antibodies generated through pregnancy – previous rabbit experiments dating back to the 1950s involved transfusions and/or immunizations.

The model uses mice that have been engineered to produce a human form of Kell protein on their red blood cells. When male mice positive for this extra gene mate with females who don’t have it, the litters are smaller and some of the pups are anemic or stillborn. The authors say that the model could provide a platform for studying how anti-red blood cell antibodies develop, as well as potential therapies.

Another recent paper from Stowell and Hendrickson describes a similar mouse model involving anti-red blood cell antibodies that develop because of transfusions rather than pregnancy. Between 3 and 5 percent of patients who get a blood transfusion will develop antibodies against Ray Ban online something on the red blood cells they received, making future transfusions possibly more problematic.

At the seminar, we learned that Hendrickson will be moving to Yale University later this summer. We wish her good luck at her new job.

 

 

 

 

Posted on July 3, 2013 by Quinn Eastman in Immunology Leave a comment

A Human Vaccine Project?

Emory Vaccine Center director Rafi Ahmed, is a co-author on a recent Science paper advocating a “Human Vaccines Project”. Wayne Koff, chief scientific officer of IAVI (International Aids Vaccine Initiative) is lead author and several other vaccine experts are co-authors.

The idea behind a “Human Vaccine Project” is to combine efforts at developing vaccines for major (but very different) diseases such as influenza, dengue, HIV, hepatitis C, tuberculosis and malaria, with the rationale that what scientists working on those diseases have in common is the Ray Ban outlet challenge of working with the human immune system.

Technology has advanced to the point where whole genome-type approaches can be brought to bear on vaccine problems. The authors cite work by Bali Pulendran’s laboratory on “systems vaccinology” and their analysis of the yellow fever vaccine as an example.

One major puzzle confronting vaccine designers is to coax the immune system into producing broadly neutralizing antibodies against a rapidly mutating virus, whether it is Gafas Ray Ban outlet influenza or HIV. Our own Cynthia Derdeyn has been analyzing this problem through painstaking work following how the immune system pursues a twisting and turning HIV.

An interesting related tidbit:

There are hints that the reverse engineering of vaccines has taken a leap forward in the case of RSV (respiratory syncytial virus): Scientists at Scripps Research Institute have designed vaccine components by computer and have used them to provoke neutralizing antibodies in monkeys.

Also check out Mike King’s feature in Emory Health on HIV vaccine research.

Posted on June 20, 2013 by Quinn Eastman in Immunology Leave a comment

Detecting clandestine chlamydia

In recent years public health authorities have raised concern that many strains of Chlamydia trachomatis, a bacterium that is the most common cause of sexually transmitted infections around the world, can be missed by conventional genetic tests. A mutation in part of its genomc can make Chlamydia undetectable by the most commonly used tests.

Microfluidic

The Chlamydia tests are performed in a microfluidic cassette platform and data is returned about an hour after sample collection. In comparison, standard tests take a day or longer.

Most infections are asymptomatic but left untreated, Chlamydia infection can lead to pelvic inflammatory disease, infertility and ectopic pregnancy. It is also a Ray Ban online leading cause of blindness in developing countries.

Microbial geneticist Tim Read at Emory has been collaborating with Deborah Dean at Children’s Hospital Oakland and the Massachusetts firm NetBio to develop a fast, accurate and sensitive genetic test for Chlamydia.

“We used tools that were developed initially to answer basic scientific questions,” Read says. “We compared multiple genomes of C. trachomatis to find targets that would work across a broad selection of bacterial strains.”

Read more

Posted on April 16, 2013 by Quinn Eastman in Immunology Leave a comment

Old drug = new treatment for parasitic skin disease?

A coal-tar dye first produced in the 19th century, gentian violet is available over the counter as an antifungal agent.

Dermatologist Jack Arbiser has been a champion of the inexpensive drug gentian violet for skin diseases. He recently teamed up with collaborators in Brazil to find that gentian violet is active against leishmaniasis, a disfiguring skin disease found in many tropical and subtropical countries.

Caused by protozoan parasites and transmitted by sand flies, leishmaniasis’ most common form produces skin sores but can also affect the nose and mouth and even vital organs. The World Health Organization has identified Kabul, Afghanistan as a world hot spot for leishmaniasis.

In the journal PLOS One, Ana Paula Fernandes and colleagues at the Federal University of Minas Gerais showed that gentian violet and related compounds are active against Leishmania species in animal models.

Conventionallly, therapy for leishmaniasis has involved antimony compounds, but resistance is growing. More recently, clinicians have used the drugs miltefosine and amphotericin against leishmaniasis, but severe side effects have been reported.

“Because it has a http://www.troakley.com/ proven safety record, gentian violet might be a useful treatment that can be used in developing countries as well as by US troops serving in Afghanistan,” Arbiser says.

Arbiser also recently published a case report on the use of gentian violet, in combination with the immune modulator imiquimod, to treat melanoma.

Posted on January 31, 2013 by Quinn Eastman in Immunology Leave a comment

Emory scientists co-signers of H5N1 flu letter

Emory influenza researchers Richard Compans, Anice Lowen and John Steel are co-signers of a statement announcing the end of a self-imposed moratorium on H5N1 avian flu research.

Last year, an international group of researchers called for the moratorium after public concern over studies of H5N1 transmissibility in ferrets, a model for spread of infection between humans. The group of researchers has now recommended ending the moratorium, citing safeguards and safety review procedures put in place by the National Institutes of Health and authorities in other countries. From the letter published today in Science and Nature:

In January 2012, influenza virus researchers from around the world announced a voluntary pause of 60 days on any research involving highly pathogenic avian influenza H5N1 viruses leading to the generation of viruses that are more transmissible in mammals. We declared a pause to this important research to provide time to explain the public-health benefits cheap oakley of this work, to describe the measures in place to minimize possible risks, and to enable organizations and governments around the world to review their policies (for example on biosafety, biosecurity, oversight, and communication) regarding these experiments.

…Thus, acknowledging that the aims of the voluntary moratorium have been met in some countries and are close to being met in others, we declare an end to the voluntary moratorium on avian flu transmission studies.

Dan Vergano has a more extensive story in USA Today.

Compans is professor of microbiology and immunology at Emory University School of Medicine and scientific director of Emory’s Influenza Pathogenesis and Immunology Research Center. Lowen and Steel are assistant professors of microbiology and immunology at Emory and IPIRC investigators.

Posted on January 23, 2013 by Quinn Eastman in Immunology Leave a comment

Playing tetherball with HIV

Raise your hand if you played tetherball in grade school. Paul Spearman and his colleagues have a new paper in the journal Cell Host & Microbe probing a protein called “tetherin” that keeps HIV ensnared within cells it is infecting.

The paper includes electron microscopy images that make it possible to imagine a tiny cord attached to a nascent HIV particle within the cell. In these images, we don’t see the tetherin protein directly. However, we do see gold beads, bound to antibodies against the tetherin protein, which indicate where the protein is. The microscopy was performed at Emory’s Robert P. Apkarian Integrated Electron Microscopy Core.

Tetherin is a so-called “restriction factor,” one of several proteins within the cell that interfere with parts of the viral life

The black dots are antibody-linked gold beads, which indicate where the tetherin is. The larger globules are viral capsids.

cycle. Other restriction factors include enzymes that strip the viral RNA or impede the assembly of the viral capsid. Tetherin also interferes with a variety of other viruses such as Ebola.

Some viral proteins such as HIV’s Vpu or Nef fight back against the action of tetherin. Tracking how this kind of arms race has developed can help scientists follow how HIV evolved from similar retroviruses that infect non-human primates. In addition, knowing how tetherin works could be important in efforts to eradicate potential reservoirs of HIV in infected individuals, and in understanding how the virus is transmitted from person to person.

In their paper, first author Hin Chu and Spearman wanted to determine why infection looks different in two different cell types vulnerable to HIV. In T cells, HIV assembly occurs near the membrane, but in macrophages, HIV assembly occurs in an internal compartment.

“The reason that there is a large, internal collection of HIV particles in macrophages is hotly debated,” Spearman explains. “Some see this as a reservoir of virus that is available to spread to other cells, others would say this is a dead-end compartment. We found that the compartment basically goes away when we deplete tetherin, so tetherin is essential to the existence of the virus-containing compartment.”

Chu and his co-workers examined what happened in macrophages when they used a tool called “RNA interference” to turn off the tetherin gene.

Hin Chu

“We found that cell-cell transmission was enhanced when we depleted tetherin. My interpretation is that when tetherin is upregulated in macrophages, viral particles are rapidly internalized and are not transmitted.”

“Another significant finding is that Vpu doesn’t work well in macrophages. If we can determine why it doesn’t work well in this cell type, it will help us understand how Vpu does work so efficiently in other cells such as T cells. Macrophages are one of the most important cell types infected by HIV, so these questions are likely to be very important in how virus spreads and is maintained in infected individuals.”

Spearman is chief research officer for Children’s Healthcare of Atlanta and director of the Children’s Center for Vaccines and Immunology, within the Emory-Children’s Pediatric Research Center. He is also professor and vice chair of research in pediatrics at Emory. Hin Chu is a graduate student in the Microbiology and Molecular Genetics program.

Posted on September 13, 2012 by Quinn Eastman in Immunology 1 Comment

Present at the creation: immunology from chickens to lampreys

You can get far in biology by asking: “Which came first, the chicken or the egg?” Max Cooper discovered the basis of modern immunology by asking basic questions.

Cooper was selected for the 2012 Dean’s Distinguished Faculty Lecture and Award, and on Thursday evening dazzled an Emory University School of Medicine audience with a tour of his scientific career. He joined the Emory faculty in 2008 as a Georgia Research Alliance Eminent Scholar.

Max Cooper, MD

Cooper’s research on the development of the immune system, much of it undertaken before the era of cloned genes, formed the underpinnings of medical advances ranging from bone marrow transplants to monoclonal antibodies. More recently, his research on lampreys’ divergent immune systems has broadened our picture of how adaptive immunity evolved.

Cooper grew up in Mississippi and was originally trained as a pediatrician, and became interested in inherited disorders that disabled the immune system, leaving children vulnerable to infection. He joined Robert Good’s laboratory at the University of Minnesota, where he began research on immune system development in chickens.

In the early 1960s, Cooper explained, scientists thought that all immune cells developed in one place: the thymus. Working with Good, he showed that there are two lineages of immune cells in chickens: some that develop in the thymus (T cells) and other cells responsible for antibody production, which develop in the bursa of Fabricius (B cells). [On Thursday, he evoked chuckles by noting that a critical discovery that drove his work was published in the journal Poultry Science after being rejected by Science.]

Cooper moved on to the University of Alabama, Birmingham, and there made several discoveries related to how B cells develop. A collaboration with scientists at University College, London led to the identification of the places where B cells develop in mammals: fetal liver and adult bone marrow.

Cooper’s research on lampreys began in Alabama and has continued after he came to Emory in 2008. Primitive lampreys are thought to be an early offshoot on the evolutionary tree, before sharks, the first place where an immune system resembling those of mammals and birds is seen. Lampreys’ immune cells produce “variable lymphocyte receptors” that act like our antibodies, but the molecules look very different in structure. These molecules were eventually crystallized and their structure probed, in collaboration with Ian Wilson in San Diego.

Lampreys have variable lymphocyte receptors, which resemble our antibodies in function but not in structure

Cooper said he set out to figure out “which came first, T cells or B cells?” but ended up discovering something even more profound. He found that lampreys also have two separate types of immune cells, and the finding suggests that the two-arm nature of the immune system may have preceded the appearance of the particular features that mark those cells in evolution.

 

 

 

Posted on April 23, 2012 by Quinn Eastman in Immunology 1 Comment

Fertility: a new frontier in treating those with HIV

HIV

Not long ago, physicians who treated those with HIV focused only on helping their patients stay well. Today some physicians are also beginning to focus on helping those patients conceive.

“Most of the patients who are now diagnosed with HIV are in their reproductive years, and as many as a third express a desire to have children,” says Emory reproductive endocrinologist Vitaly Kushnir, MD.

This emerging area of treatment has been made possible thanks to the growing effectiveness of a combination of drugs known as Highly Active Antiretroviral Therapy, or HAART, used for years to treat retroviruses, including HIV.

“Now that people with HIV are living longer, fertility and HIV is an emerging area of interest,” says Kushnir. “Several studies have indicated that HIV drugs if given early in the course of the disease can reduce the risk of transmission from an HIV-positive person to an HIV-negative person.”

But researchers and physicians know very little yet about how treatments for HIV, the virus itself, and the comorbidities associated with HIV affect fertility. So, Kushnir and his colleague, Emory pathologist William Lewis, MD, decided it was time to explore existing data on how HIV and its treatment affect fertility, especially in women. Their review paper on the subject appears in the August 2011 issue of Fertility and Sterility.

Because there are safety concerns and legal restrictions on fertility treatments in couples in which one partner is HIV positive and the other is not, treatment options often are limited.

“This is becoming more and more of an issue,” says Kushnir. “It’s probably time for us to have a more open discussion about the access these patients have to fertility treatment. I think the current system probably discourages these patients from pursuing treatments that are a lot safer than trying to get pregnant on their own.”

Posted on August 4, 2011 by admin in Immunology Leave a comment

Excitement building over potential for universal flu vaccine

Francis Collins, director of the National Institutes of Health, made a splash last week predicting the arrival of a universal flu vaccine in the next five years.

Francis Collins told USA Today he is "guardedly optimistic" about the possibility of long-term vaccination that could replace seasonal flu shots.

His prediction came at the same time as a report in Science identifying an antibody that can protect against several strains of the flu virus. Taking a look at the Science paper, how the scientists found the “super antibody” seems remarkably similar to how Emory’s Jens Wrammert, Rafi Ahmed and colleagues found a similar broadly protective antibody. Their results were published in the Journal of Experimental Medicine in January.

In both cases, the researchers started with someone who had been infected with the 2009 H1N1 swine origin flu virus, sifted through the antibodies that person produced and found some that reacted against several varieties of the flu virus. There must be something special about that 2009 pandemic strain!

Posted on August 2, 2011 by Quinn Eastman in Immunology Leave a comment
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