Study finds ‘important implications’ to understanding immunity against COVID-19

New research from Emory University indicates that nearly all people hospitalized with COVID-19 develop virus-neutralizing antibodies within six days of testing positive. The findings will be key in helping researchers understand protective immunity against SARS-CoV-2 and in informing vaccine development. The test that Emory researchers developed also could help determine whether convalescent plasma from COVID-19 survivors can provide immunity to others, and which donors' plasma should be used. The antibody test developed by Emory and validated Read more

Emory plays leading role in landmark HIV prevention study of injectable long-acting cabotegravir

Emory University played a key role in a landmark international study evaluating the safety and efficacy of the long-acting, injectable drug, cabotegravir (CAB LA), for HIV prevention. The randomized, controlled, double-blind study found that cabotegravir was 69% more effective (95% CI 41%-84%) in preventing HIV acquisition in men who have sex with men (MSM) and transgender women who have sex with men when compared to the current standard of care, daily oral emtricitabine/tenofovir disoproxil fumarate Read more

Yerkes researchers find Zika infection soon after birth leads to long-term brain problems

Researchers from the Yerkes National Primate Research Center have shown Zika virus infection soon after birth leads to long-term brain and behavior problems, including persistent socioemotional, cognitive and motor deficits, as well as abnormalities in brain structure and function. This study is one of the first to shed light on potential long-term effects of Zika infection after birth. “Researchers have shown the devastating damage Zika virus causes to a fetus, but we had questions about Read more

Mehul Suthar

Study finds ‘important implications’ to understanding immunity against COVID-19

New research from Emory University indicates that nearly all people hospitalized with COVID-19 develop virus-neutralizing antibodies within six days of testing positive. The findings will be key in helping researchers understand protective immunity against SARS-CoV-2 and in informing vaccine development.

The test that Emory researchers developed also could help determine whether convalescent plasma from COVID-19 survivors can provide immunity to others, and which donors’ plasma should be used.

The antibody test developed by Emory and validated with samples from diagnosed patients has demonstrated that not all antibody tests are created equal – and that neutralizing antibodies, which provide immunity, have specific characteristics. Emory’s study focused on those neutralizing antibodies, which can stop the virus from infecting other cells.

The findings are now available on MedRxiv, the preprint server for health sciences, and are not yet peer-reviewed.

In the study, researchers looked at antibodies against the receptor-binding domain (RBD), part of the spike protein on the outside of the virus. The RBD is what grips on to human cells and allows the virus to enter them. The researchers focused on antibodies against the RBD because the sequence of the RBD in SARS-CoV-2 distinguishes it from other coronaviruses that cause the common cold.

The receptor-binding domain, or RBD, is what grips on to human cells and allows the virus to enter them.

The initial 44 patient blood samples used in this study were from patients being treated for COVID-19 at Emory University Hospital and Emory University Hospital Midtown.

“These findings have important implications for our understanding of protective immunity against SARS-CoV-2, the use of immune plasma as a therapy, and the development of much-needed vaccines,” says Mehul S. Suthar, PhD, co-lead author and assistant professor of pediatrics at Emory University School of Medicine and Emory Vaccine Center. This study serves as the initial step in a much larger serology effort.

Read more

Posted on by Wayne Drash in Immunology Leave a comment

Zika virus blindfolds immune alarm cells

Important immune alarm cells — dendritic cells — are fighting Zika virus with an arm tied behind their backs, scientists from Emory Vaccine Center report.

Dendritic cells are “sentinel” cells that alert the rest of the immune system when they detect viral infection. When Zika virus infects them, it shuts down interferon signaling, one route for mustering the antiviral troops. However, another antiviral pathway called RIG-I-like receptor (RLR) signaling is left intact and could be a target for immunity-boosting therapies, the researchers say.

Mehul Suthar, PhD in the lab with graduate students Kendra Quicke and James Bowen

The findings were published on Feb. 2 in PLOS Pathogens.

Zika was known to disrupt interferon signaling, but Emory researchers have observed that it does so in ways that are distinct from other related flaviviruses, such as Dengue virus and West Nile virus. The findings give additional insight into how Zika virus is able to counter human immune defenses. Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Antiviral success makes some immune cells stickier

As they succeed in clearing a viral infection from the body, some virus-hunting T cells begin to stick better to their target cells, researchers from Emory Vaccine Center and Georgia Tech have discovered.

The increased affinity helps the T cells kill their target cells more efficiently, but it depends both on the immune cells’ anatomic location and the phase of the infection.

The results were published this week in the journal Immunity.

Arash Grakoui, PhD

Arash Grakoui, PhD

After the peak of the infection, cells within the red pulp of the spleen or in the blood displayed a higher affinity for their targets than those within the white pulp. However, the white pulp T cells were more likely to become long-lasting memory T cells, critical for vaccines.

“These results provide a better understanding of how memory precursor populations are established and may have important implications for the development of efficacious vaccines,” the scientists write.

In the mouse model the researchers were using, the differences in affinity were only detectable a few days after the non-lethal LCMV viral infection peaks. How the differences were detected illustrates the role of serendipity in science, says senior author Arash Grakoui, PhD.

Typically, the scientists would have taken samples only at the peak (day 7 of the infection) and weeks later, when memory T cells had developed, Grakoui says. In January 2014, the weather intervened during one of these experiments. Snow disrupted transportation in the Atlanta area and prevented postdoctoral fellow Young-Jin Seo, PhD from taking samples from the infected mice until day 11, which is when the differences in affinity were apparent.

Seo and Grakoui collaborated with graduate student Prithiviraj Jothikumar and Cheng Zhu, PhD at Georgia Tech, using a technique Zhu’s laboratory has developed to measure the interactions between T cells and their target cells. Co-author Mehul Suthar, PhD performed gene expression analysis.

Read more

Posted on by Quinn Eastman in Immunology Leave a comment