Mysterious DNA modification important in fly brain

Drosophila, despite being a useful genetic model of development, have very little DNA methylation on C. What they do have is methylation on A (technically, N6-methyladenine), although little was known about what this modification did for Read more

Where it hurts matters in the gut

What part of the intestine is problematic matters more than inflammatory bowel disease subtype (Crohn’s vs ulcerative colitis), when it comes to genetic activity signatures in pediatric Read more

Overcoming cisplatin resistance

Cisplatin was known to damage DNA and to unleash reactive oxygen species, but the interaction between cisplatin and Mek1/cRaf had not been observed Read more

neutralizing antibodies

HIV vaccine news: a glass half full

This week, researchers from Yerkes and Emory Vaccine Center led by Cindy Derdeyn published a paper that I first thought was disturbing. It describes how monkeys vaccinated against HIV’s relative SIV (simian immunodeficiency virus) still become infected when challenged with the virus. Moreover, it’s not clear whether the vaccine-induced antibodies are exerting any selective pressure on the virus that gets through.

But then I realized that this might be an example of “burying the lead,” since we haven’t made a big hoopla about the underlying vaccine studies, conducted by Rama Amara. Some of these studies showed that a majority of monkeys can be protected from repeated viral challenge. The more effective vaccine regimens include adjuvants such as the immune-stimulating molecules GM-CSF or CD40L (links are the papers on the protective effects). Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Key to universal flu vaccine: embrace the unfamiliar

Vaccine researchers have developed a strategy aimed at generating broadly cross-reactive antibodies against the influenza virus: embrace the unfamiliar.

In recent years, researchers interested in a “universal flu vaccine” identified a region of the viral hemagglutinin protein called the stem or stalk, which doesn’t mutate and change as much as other regions and could be the basis for a vaccine that is protective against a variety of flu strains.

In an Emory Vaccine Center study, human volunteers immunized against the avian flu virus H5N1 readily developed antibodies against the stem region of the viral hemagglutinin protein. In contrast, those immunized with standard seasonal trivalent vaccines did not, instead developing most of their antibodies against the more variable head region. H5N1, regarded as a potential pandemic strain, is not currently circulating in the United States and the volunteers had not been exposed to it before.

The results were published Monday, August 25 in PNAS.

The key to having volunteers’ bodies produce antibodies against the stem region seemed to be their immune systems’ unfamiliarity with the H5N1 type of virus, says lead author Ali Ellebedy, PhD, postdoctoral fellow in the laboratory of Rafi Ahmed, PhD, director of Emory Vaccine Center and a Georgia Research Alliance Eminent Scholar.

Note: for a counterpoint, check out this 2013 Science Translational Medicine paper on how vaccination that induces anti-stem antibodies contributes to enhanced respiratory disease in pigs.

Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Unexpected effect on flu immunity

Immunologists reported recently that the drug rapamycin, normally used to restrain the immune system after organ transplant, has the unexpected ability to broaden the activity of a flu vaccine.

The results, published in Nature Immunology, indicate that rapamycin steers immune cells away from producing antibodies that strongly target a particular flu strain, in favor of those that block a wide variety of strains. The results could help in the effort to develop a universal flu vaccine.

This study was inspired by a 2009 Nature study from Koichi Araki and Emory Vaccine Center director Rafi Ahmed, reports Jon Cohen in Science magazine. Read more

Posted on 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 by Quinn Eastman in Immunology Leave a comment

What if HIV was just another virus

Imagine that HIV was a “normal” virus. An infection begins and the body responds, without getting trapped in a cycle where CD4+ T cells are consumed and the immune system is crippled.

SIV can infect sooty mangabeys but it doesn't cripple their immune systems.

The attractiveness of this idea explains some of why scientists are interested in sooty mangabeys and other non-human primates. HIV’s relative SIV can infect them, but they usually don’t develop immunodeficiency.

At last week’s AIDS Vaccine 2010 conference, Cynthia Derdeyn reported her laboratory’s recent results investigating sooty mangabeys, which don’t develop high levels of neutralizing antibodies against SIV when infected. Derdeyn’s group at Emory Vaccine Center and Yerkes National Primate Research Center studies how HIV and SIV evade the immune system.

Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Re-energizing AIDS vaccine research

Emory President James Wagner welcomed participants Wednesday to the AIDS Vaccine 2010 conference in Atlanta, hosted by the Global HIV Vaccine Enterprise and locally hosted by the Emory Center for AIDS Research.

“Only occasionally are there scientific challenges that unite people powerfully towards a common goal,” Wagner said. “We are proud for the role we’ve been able to play in the pursuit of vaccine research. I am particularly pleased that so many students and young investigators have been able to participate in this conference.”

John Mascola from the Vaccine Research Center at the NIH gave the day’s first scientific talk, describing the discovery of broadly cross-reactive neutralizing antibodies to HIV and the ability to isolate those antibodies. This is the kind of recent discoveries that has re-energized the HIV vaccine research community.

Bette Korber of the Los Alamos National Laboratory noted that HIV mutations that escape immune response in some infected people are frequently susceptible in others. New “mosaic vaccines” can expand the breadth and depth of these immune responses, she said. She also described the effort underway in her laboratory to re-examine results of an earlier vaccine trial, VAX004, in light of new analytic strategies.

Giuseppe Pantaleo of the Centre Hospitalier Universitaire Vaudois in Lausanne, Switzerland expressed the need to implement adaptive clinical trial study design. This theme — the need to examine clinical trial results early and often, and then adapt, rather than waiting for all results at the very end of a years-long trial — has been echoed often at the conference.

At a midday press briefing, Peter Kwong of the NIH Vaccine Research Center discussed his research with broadly neutralizing antibodies, one of which attacks the initial site of vital attachment to CD4 T cells.

Hendrik Streek from Harvard’s Ragon Institute described how vaccines induce antibody and CD4 response and contraction. Even though CD4 cells are the ones attacked during HIV infection, Streek believes CD4 responses may be a missing link to effective vaccine development

Alan Bernstein, executive director of the Global HIV Vaccine Enterprise, led a discussion of the new Enterprise Scientific Strategic Plan. Less than two out of five people who need treatment for HIV are receiving it, said Bernstein, which underscores the importance of an effective vaccine.

The new plan arrives at a time of great momentum and excitement in the field. A year of important advances has included discoveries about broadly neutralizing antibodies, new technologies, and a vaccine that demonstrated an immune response. The plan emphasizes novel clinical trials design, a strong commitment and engagement by many partners, and expanded diversity of funding by many stakeholders.

Jose Esparza, senior advisor on HIV vaccines to the Bill & Melinda Gates Foundation, emphasized the need to rapidly capitalize on new science, and said HIV vaccines are one of the foundation’s top priorities. High risk, high reward projects will be funded through the Gates Grand Challenges Explorations grants.

Posted on by Holly Korschun in Immunology Leave a comment