title: Enhancement of B lymphocyte secretory differentiation by a Ly 1+,2-,Qa-1+ helper T cell subset that sees both antigen and determinants on immunoglobulin.
abstract: The question of how many helper T cells are required for producing optimal antibody responses and what function each of the candidate helper cells performs are subjects of intense interest (and controversy) to the majority of immunologists. Our manuscript directly demonstrates for the first time that B cell clone growth and secretory differentiation are controlled by two distinct classes of helper T cells which can be discriminated from one another by profiles of their expressed cell surface alloantigens. There is a significant amount of inferential evidence that two types of helper T cells are required to interact with B cells and antigen in order to induce maximal antibody responses. In all reports, classical MHC-restricted, carrier-specific helper T cells (TH 1) had to interact with hapten-specific B cells via carrier-hapten bridges before the second helper cell (TH 2) could act. In contrast to the TH 1 cells, TH 2 cells have been reported neither to be MHC-restricted nor to require carrier-hapten bridges in their interaction with hapten-specific B cells. That certain isotype-, allotype-, or idiotype-expressing portions of the antigen-induced antibody response are preferentially enhanced in the presence of and depleted in the absence of the appropriate TH 2 cells has led to the suggestion that such TH 2 cells interact with B cells through receptors specific for determinants expressed on B cell surface immunoglobulin molecules. That TH 2 cells recognize autologous immunoglobulin determinants is also indirectly supported by their reported absence in appropriately immunized mice which were deficient in the relevant immunoglobulin during ontogeny [e.g. all TH 2 cells in anti-mu-treated mice; T15-specific TH 2 cells in (CBA/N X BALB/c)F1 male Xid mice which lack T15+ B cells]. It has been suggested that TH 2 cells recognize not only autologous immunoglobulin determinants but also "nominal" antigen since they have been reported to be dependent on antigen priming and reexposure to the priming antigen. However, to establish firmly that a TH 2 cell expresses receptors for both antigen and Ig determinants, one must isolate that helper cell by virtue of its receptor for one of these two moieties and show that the isolated cell has receptors for the other. We have done this, as well as showing that the Ig-recognizing, carrier-immune T cell selectively enhanced B cell secretory differentiation while having no effect on clonal expansion.(ABSTRACT TRUNCATED AT 400 WORDS)
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000950:Antigens, Ly; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation; D015395:Histocompatibility Antigens Class I; D007136:Immunoglobulins / Q000276:immunology; D051379:Mice; D010954:Plasmacytoma / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000145:classification / Q000276:immunology*
chemical_list: D000950:Antigens, Ly; D015395:Histocompatibility Antigens Class I; D007136:Immunoglobulins; C032907:Q surface antigens