Navigation Links
Research on AIDS vaccine a wealth of information

Fresh inputs on the manner of T-cells enabling immunity and furthering chances of survival especially with a virus similar to AIDS will go a long way in measuring the efficiency of AIDS vaccine. A boon for scientists during clinical trials //.

Led by researchers at Beth Israel Deaconess Medical Center (BIDMC) and the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, the findings appear in the June 9 issue of the journal Science.

'Over the last decade, we have created AIDS vaccines that generate T-cell populations that can combat HIV,' explains lead author Norman Letvin, M.D., chief of the Division of Viral Pathogenesis at BIDMC, professor of Medicine at Harvard Medical School, and investigator at the NIAID VRC. 'These latest findings now provide us with an important new way of looking at subpopulations of CD4 helper T-cells and suggest how they may be used as a marker to gauge the efficacy of these vaccines.'

The work was spearheaded by Letvin and his colleagues at the VRC, which is dedicated to improving global human health through the rigorous pursuit of effective vaccines for human diseases such as AIDS. Since it was first identified 25 years ago, the human immunodeficiency virus (HIV) has proven extraordinarily difficult to control. Attempts to develop an HIV vaccine that triggers the production of antibodies -- the mechanism responsible for vaccine protection against other viruses including polio and hepatitis B -- have been unsuccessful.

'HIV mutates so quickly it can evade antibody immunity,' explains Letvin. Instead, Letvin and other scientists in this field have focused their work on developing a vaccine that confers cellular immunity, so that a group of T-cells induced by a vaccine recognizes the cells that have been infected by HIV and then destroys them so that the virus cannot continue replicating.

'Wh ile this vaccine approach cannot actually prevent an infection, it can tamp down the AIDS virus, resulting in the development of a much milder form of the disease in vaccinated monkeys that subsequently become infected,' he adds. 'We know this because the loss of helper T-cells is much less dramatic, the amount of virus replication is much less and the infected animals go on to live longer.'

Until now, the success or failure of this type of T-cell vaccine has been determined by measures of virus levels and total counts of CD4+ helper T-cells, which are indicative of infection control in monkeys infected with the AIDS virus.

As in previous studies, this new research found that among monkeys infected with the simian immunodeficiency virus (SIV) -- 24 of which were vaccinated and six of which were not -- the immunity generated by the vaccine controlled infection for approximately 100 days before levels of virus increased and T-cell counts dropped.

But instead of ending the experiment at this point -- assuming that the vaccine conferred protection for only 100 days -- Letvin and his VRC colleagues decided to follow the monkeys for an additional 750 days, a total of 850 days or nearly three years.

'We found that the vaccinated monkeys lived significantly longer than the unvaccinated monkeys following infection and that levels of memory CD4+ cells remained significantly higher in the vaccinated animals,' explains Letvin. 'This suggests that the initial protection that the vaccine provides in the early weeks following infection gives the monkeys a long-term survival advantage, and that this protection is associated with a significantly higher level of memory CD4+ cells.'

In another aspect of the study, Letvin and his colleagues at the VRC found that measurements of a subset of memory CD4+ T cells -- central memory CD4+ T cells -- could help predict how the vaccinated monkeys would fare over the long run.

'This second finding provides us with an important marker to use in gauging the vaccine's performance,' says Letvin. 'By measuring the levels of central memory cells in blood samples taken from participants in human clinical trials [to test the AIDS vaccine] scientists would be able to predict how well the vaccine would work over time.'

More than 30 million individuals -- a majority in the world's developing nations -- have died of AIDS since it was first identified 25 years ago.

'This research underscores the importance of the preservation of memory CD4+ T cells for the long-term health of the HIV-infected individual,' says Letvin. 'It also suggests that the measurement of this cell in the blood of vaccinated individuals who subsequently become infected with HIV may provide an important predictor of vaccine efficacy.'

Study coauthors include BIDMC investigators Yue Sun, M.D., Darci Gorgone, M.A., Adam Buzby, A.B., Jorn Schmitz, M.D., and Brianne Barker, A.B.; John Mascola, M.D., Ling Xu, M.D., Zhi-yong Yang, M.D., Bimal Chakrabarti, M.D., Srinivas Rao, D.V.M., Ph.D., and Gary Nabel, M.D., Ph.D., of the NIAID VRC; David Montefiori, Ph.D., of Duke University Medical Center; and Fred Bookstein, Ph.D., of the University of Washington, Seattle and the University of Vienna, Austria.

(Source:Eureka)
'"/>




Related medicine news :

1. Kidney Stones - Interesting New Research implicates bacteria as its cause
2. Researchers urge caution in using ear tube surgery
3. Paracetamol May Cause Live Damage Warns Consumer Education and Research Centre
4. Researchers Scale to assess the Severity of Epilepsy in Kids
5. Research of Ritalin
6. Researchers trick Alzheimers Enzyme
7. Researchers find new HIV hiding place
8. A Compilation of recent Diabetes Research articles
9. Research on causes for falling helps develop preventive strategies
10. New standards for Human Research Safety
11. Research on Celiac Disease in children
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/25/2016)... ... , ... The temporary closing of Bruton Memorial Library on June 21 due to a possible ... often overlooked aspect of head lice: the parasite’s ability to live away from a human ... but a necessary one in the event that lice have simply gotten out of control. ...
(Date:6/25/2016)... ... , ... First Choice Emergency Room , the largest network of independent ... Director of its new Mesquite-Samuell Farm facility. , “We are pleased to announce ... Dr. James M. Muzzarelli, Executive Medical Director of First Choice Emergency Room. , ...
(Date:6/25/2016)... ... June 25, 2016 , ... Dr. Calvin Johnson has ... he has implemented orthobiologic procedures as a method for treating his patients. The ... first doctors to perform the treatment. Orthobiologics are substances that orthopaedic surgeons use ...
(Date:6/25/2016)... Montreal, Canada (PRWEB) , ... June 25, 2016 , ... ... the pursuit of success. In terms of the latter, setting the bar too high ... low, risk more than just slow progress toward their goal. , Research from ...
(Date:6/24/2016)... ... 2016 , ... Those who have experienced traumatic events may suffer from a ... such as drug or alcohol abuse, as a coping mechanism. To avoid this pain ... following a traumatic event. , Trauma sufferers tend to feel a range of emotions, ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... June 23, 2016 Research and Markets ... Issue 52" report to their offering. ... treatment creates a favourable commercial environment for MedImmune to enter. ... base that will serve to drive considerable growth for effective ... serve to cap sales considerably, but development is still in ...
(Date:6/23/2016)... and BOGOTA, Colombia , June 23, 2016  Astellas today announced the establishment of Astellas ... Brasil as the company,s second affiliate in Latin America . ... ... of Astellas Farma Colombia ... ...
(Date:6/23/2016)... -- Research and Markets has announced the ... (United States, China, Japan, Brazil, United Kingdom, Germany, France, ... Surgical Procedure Volumes: ... provides surgical procedure volume data in a geographic context. ... analysis of growth drivers and inhibitors, including world population ...
Breaking Medicine Technology: