Human Immunodeficiency Virus Specific T-Cell Immunity in Seropositive, Asymptomatic Individuals.

摘要

In HIV infections, three relevant effector mechanisms have been identified: neutralizing antibodies, HIV-specific cytotoxic T lymphocytes (CTLs), and antibody-dependent cell-mediated cytotoxicity (ADCC) (Seligmann et al. 1987). Each of these mechanisms is dependent on the function of CD4(+) T-helper (TH) cells, and, in theory, abnormal TH-cell activity would effectively impair the ability to generate an appropriate effector immune response. Previous work from Lane and colleagues (Lane and Fauci 1985) suggests that one of the earliest immunological abnormalities to appear in HIV-infected individuals is anergy, i.e., lack of response to recall antigens. Patients with advanced HIV disease cannot be primed to de novo antigens, suggesting profound TH-cell dysfunction. Taking these observations together, one could speculate that the defective TH-cell response seen in seropositive individuals is responsible for the loss of protective immunity. Once the TH-cell compartment becomes nonfunctional, specific antibody responses decline and CTL activity wanes. HIV infection of CD4(+) lymphocytes and monocytes ensues and virus spreads unabated in the absence of an effective immune response. Our objective was to study the HIV-specific T-cell response in seropositive individuals. Evaluation of HIV-specific cellular responses should provide insight into the pathogenesis of HIV infection and the role of protective immunity during the natural course of the disease. (aw)