Perspective on molecular immunology and modulation of immune responses.

Despite enormous advances made in recent years, there remain fundamental and fascinating unanswered questions in immunology. They would include the mechanism of tolerance, the biological significance of the major histocompatibility complex (MHC) restriction, generation of diversity in T cells, control of V region and isotype selection in B cells, how immune response genes work and how important their function is in man, among others. With the advent of monoclonal antibodies and recombinant DNA technologies, together with greater understanding of immunological interactions within the network and of the intracellular networks between membrane-associated receptors and cell function, a variety of immunological strategies are available for modulating immune responses in man. Some nonspecific strategies include immunomodulatory lymphokines, receptor modulation, and development of agonists and antagonists for important receptors. In addition, there is great potential for immunologically specific strategies for intervention, including the use of idiotypes and anti-idiotypes and genetic engineering of antibodies. Ultimately, there is the possibility of predicting antigenic epitopes likely to engage the cellular and humoral arms of the immune response on the basis of protein or DNA sequences. The potential of exploring these developments for new diagnostic tests and vaccines is emphasized here, as is the unpredictable importance of seemingly nonrelevant fundamental science in producing many of the tools for intervention, now and in the future.