Days are not far when researchers will be successful in developing a vaccine for HIV, so far there is no vaccine available against HIV, in last few years HIV vaccine research has seen many setbacks and failures, researchers too have learned from those failures, we too strongly believe that a vaccine for HIV is just not a dream but it is a possibility. HIV vaccine will be of great importance when combined with other drugs. A hope comes from the fact that there lies a region on HIV which do not show much variation which is known as cd4 binding site, developing proteins similar to those regions which can be used to evoke B cells for production of antibodies against HIV which can neutralize HIV virus and thus can be used as vaccine against HIV.
The process of developing a vaccine for HIV is not less than solving a puzzle, where it is required to unwind lot of facts about the process and mechanism with which HIV infect and replicate in human body, the enzyme systems and the genetic constitution of each and every HIV strains, and finding how HIV antigens are recognized by human immune system, how genes code for proteins which can neutralize HIV virus, and how to present these proteins to human immune system so that it can stimulate the production of antibodies against incoming HIV virus which they can neutralize by binding with it, so that, those proteins can be used as vaccine.
Scientists at Vaccine Research Center (VRC) and the National Institute of Allergy and Infectious Diseases (NIAID) which is a part of National Institutes of Health, are successful in finding the facts about how some HIV neutralizing antibodies are developed in human body, they have found the map or route with which human B cells can develop a immune response which can trigger production of antibodies against HIV virus which can successfully neutralize HIV virus by binding with it.
One of the interesting fact about this discovery is that variation in genetic material of HIV occurs due to greater degree of mutation in HIV in all strains, which is a biggest hurdle in developing an effective vaccine against HIV, which makes virus to change its genes which are then difficult to recognize by human body in event of encounter with HIV virus. A hope comes from the fact that there lies a region on HIV which do not show much variation which is known as cd4 binding site.
Last year VRC scientists discovered three antibodies of which two antibodies can stop HIV from infecting humans by neutralizing HIV virus, these antibodies can stop almost ninety percent of known HIV strains from infecting humans.
These antibodies were named as VRC01, VRC02 and VRC03 , these antibodies against HIV were found in blood sample of North American named as donor 45 , further in a new study researchers found antibodies similar to VRC01 in the blood donated by two Africans which were already infected with HIV they were called as donor 74 and donor 0219.
Scientists found that the genes which code for VRC01 protein are present over DNA in B cells, which are responsible for imparting immunity our body. These gens are responsible for coding VRC01 like proteins which can neutralize HIV virus.
Scientists studied the gens responsible for coding VRC01 by method known as deep sequencing, this method is used first time in HIV vaccine research to find the path way of evolution of the antibody response to HIV virus to genetic level. Scanning of B-cell DNA libraries of donor 45 and donor 74 was done, and the genes which code for HIV neutralizing antibodies were grouped at one place.
Further researchers studied the gene segment which coded for the part of VRC01-like antibody which binds to HIV virus and neutralize. Study of sequence in new found relative genes which code VRC01 discovered how step by step changes in the sequence turned it to into a mature form. A vaccine which evoke VRC01-like antibodies is required to coax the B-cell DNA of immature antibodies to evolve along one of these pathways.
Researchers are now focused on developing proteins which will guide B Cells step by step , guide them towards develop a immune response for formation of antibodies against HIV which can neutralize HIV virus in the same manner as that of VRC01 antibodies.
Authored by: B V Waghmare.