Boston, MA, October 2, 2001—Researchers at HAI have provided new evidence that developing subtype-specific HIV-1 vaccine based on population-distinct surface proteins known as CTL is a sound approach for the design of an effective vaccine against AIDS. The research on this study "Identification of Human Immunodeficiency Virus Type 1 Subtype C Gag-, Tat-, Rev-, and Nef-Specific Elispot-Based Cytotoxic T-Lymphocyte Responses for AIDS Vaccine Design" appears in the October issue of the Journal of Virology."
The researchers have identified and characterized profiles of CTL epitopes, proteins on the cell surface that bind with antibody. These proteins have the ability to kill virus-infected cells and are key to the body’s immune response to control HIV infection. The researchers’ will next use the CTL epitopes or CTL epitope-rich regions found to enhance the immune system’s ability to attack infected cells in vaccine designs underway at the Institute.
By analyzing the cumulative HIV-1C specific CTL responses of HIV-infected donors in Botswana, the study indicated that the characteristics of the virus that cause the HIV-1 epidemic in a certain geographic area and the genetic background of the population might affect the CTL responses in people receiving the vaccine.
"In the past, most CTL studies have been performed on HIV-1B samples, the subtype predominant in North America and Europe," says Vladimir Novitsky, research scientist at HAI and lead investigator in the study. "A limited number of studies have targeted HIV-1 subtype C, the subtype responsible for the severe epidemic occurring in southern Africa. Our initial results further support the need to develop different vaccines to fight the different strains of HIV circulating in Africa and around the world."
Soon after infection by HIV, the immune system of most individuals mounts a CTL response against the virus. This leads to a period of stability, during which the virus appears to be contained. Although in most instances this containment fails and the infection intensifies, HIV-infected individuals who thrive for long periods may have a different CTL response—leading researchers to conclude that accounting for the CTL response is critical to any successful vaccine design.
"The results support the critical role of CTL in HIV infection. Our work will continue to examine the ways in which CTL responses are sometimes restricted and how epitopes can activate a strong immune response in HIV-infected individuals—both critical to better understanding of the disease pathogenesis and vaccine development at the Institute," says Richard Marlink, executive director of HAI.
HAI is a research and education institution dedicated to discovering and fostering solutions to the HIV and AIDS epidemic.
