The immune response to agents that cause acute and chronic diseases

Recent advances in lymphocyte technology allow production of large amounts of homogenous T cells which create immunoregulatory peptides. This means that it is now possible to define and purify nontoxic peptides that either specifically turn off or turn on immune responses. For example, monoclonal peptides synthesized by inducer cells each activates a different target cell to divide or differentiate. One activates stem cells to differentiate into red cells and white cells [27], another stimulates B cells to secrete antibody [21], and another induces mast cells to divide [26] and perhaps to differentiate. More recent work has shown that some inducer peptides may "fine tune" the immune response: Certain types of inducer clones, for example, selectively stimulate production of IgA. Peptides that mediate the activity of these clones are the subject of intense analysis of because these monoclonal substances offer the possibility of stimulating rapid induction of IgA after infection by microbes that enter through mucosal of the gut, bladder or lungs. This type of antibody (IgA) is the body's key defense against infections by these microbes: Development of a rapid and specific IgA response is the most important factor in the outcome of infections by viruses such as genital herpes type II and infections by intracellular bacterial pathogens that are currently resistant to treatment by antibiotics. Perhaps the most informative point that has come from these studies is that each peptide that has been isolated from T cell clones exerts powerful regulatory effects on either the intensity or type of the immune response. The hope is that some of these immunoregulatory molecules or their analogs can be used as potent therapeutic agents for some chronic diseases. Since purified inducer and suppressive peptides will be available in large amounts within the next several years, it will not be long before this strategy can be thoroughly evaluated.