ON THE NATURE OF SPECIFIC FACTORS AND THE INTEGRATION OF THEIR SIGNALS BY MACROPHAGES

Abstract

ABSTRACT Antigen specific helper and suppressor factors have a similar structure, which has two major sections, a ‘variable region', determining antigen specificity which is probably controlled by Immunoglobulin V H genes, with which it shares idiotype and framework determinants. Specific factors also have a ‘constant region’ which does not vary between strains or with the antigenic specificity of the factors, which are defined by rabbit anti-helper or anti-suppressor antisera. This region determines the biological function of the molecule. Anti-la antisera react with factors, but the nature and function of la molecules on T cell factors is unclear. The model of specific factor structure, with C and V regions resembles that of immunoglobulin, and it is thus possible that the C region of factors like the V region is Ig linked. Because there are multiple T cells, helping and suppressing antibody responses specifically, it seems improbable that all of these cells could interact directly with rare antigen-specific B cells. Thus we propose that macrophage presenting cells are the key to the integration of signals for immune induction and regulation for both T and B cells. Since Ir genes have been identified in the macrophage presenting cells interacting with both T and B cells, this suggests that macrophage Ia antigens are of importance in the integration of triggering signals for the lymphoid pool.