PASSIVE IMMUNOTHERAPY FOR RETROVIRAL DISEASE - INFLUENCE OF MAJOR HISTOCOMPATIBILITY COMPLEX TYPE AND T-CELL RESPONSIVENESS

Administration of virus-specific antibodies is known to be an effectiv e early treatment for some viral infections. Such immunotherapy probab ly acts by antibody-mediated neutralization of viral infectivity and i s often thought to function independently of T-cell-mediated immune re sponses. In the present experiments, we studied passive antibody thera py using Friend murine leukemia virus complex as a model for an immuno suppressive retroviral disease in adult mice. The results showed that antibody therapy could induce recovery from a well-established retrovi ral infection. However, the success of therapy was dependent on the pr esence of both CD4(+) and CD8(+) T lymphocytes. Thus, cell-mediated re sponses were required for recovery from infection even in the presence of therapeutic levels of antibody. The major histocompatibility type of the mice was also an important factor determining the relative succ ess of antibody therapy in this system, but it was less critical for l ow-dose than for high-dose infections. Our results imply that limited T-cell responsiveness as dictated by major histocompatibility genes an d/or stage of disease may have contributed to previous immunotherapy f ailures in AIDS patients. Possible strategies to improve the efficacy of future therapies are discussed.