107 The modern methods for HIV/AIDS vaccine evaluation

The spread of HIV/AIDS increases worldwide, a safe and efficacious vaccine remains the cornerstone for a prevention strategy to stop HIV-1 epidemic. Both humoral (neutralizing antibodies) and cellular (CTL) responses are able to control HIV infection. Non-neutralizing HIV-specific antibodies could play an important role in preventing or controlling HIV infection. These antibodies can bind to infected cells and recruit innate immune effector cells, such as natural killer (NK) cells, to lyse infected cells through antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cell-mediated virus inhibition (ADCVI). The measurement of immune responses directed specifically against the HIV is critical for understanding the interplay between the virus and the host immune system. By characterizing the immunological correlates of protection against HIV infection, such measurements will aid in the development of efficacious prophylactic vaccine. To improve vaccine antigens and adjuvant, it is also necessary to asses a similarity of vaccine—and virus—induced immune responses. The evaluation of antigen-specific humoral response includes measurement amount and specificity of vaccine-induced antibodies (in ELISA or WB), their neutralizing activity and ADCC or ADCVI. ELISPOT, intracellular cytokine flow cytometry assays and Luminex are the most common assays to determine CTL response. They all determine immune response by the detection of the cytokines (IFN-gamma, TNF-alpha, IL2) secreted by cells upon antigen-stimulation. MHC tetramer binding assay measures the absolute number of cells that recognize a particular epitope without providing any information regarding the functionality of the cells.