Cell Surveillance Model for Lymphocyte Cooperation

Surface Antigens of Immunocompetent Cells

“…In the latter case a soluble mediator induced by activated T cells may be involved, and would be obtained by reexposing sensitized T cells to their sensitizing antigen (35) or else by exposing T cells to nonspecific mitogens or to H-2 antigens (32, 38, 39). It should be noted, that the observation on the phenomenon of nonspecific B cell activation by allogeneic cells, suggesting that a graft-vs.-host but not a host-vs.-graft reaction is needed (32,34), speak against a primary role for soluble factors.…”

“…Although these findings appear to establish a specific memory function of T cells, it should be realized that nonspecific enhancement of B cell function has also been accomplished by a variety of means in vivo (31)(32)(33)(34) and in vitro (33,(35)(36)(37)(38)(39). It is, therefore, important to study the reconstituting effect of various doses of cells sensitized to other antigens on the response of anti-0-treated SE-immune spleen cells.…”

Immunodeviation by Passive Antibody, an Expression of Selective Immunodepression

“…Carrier and hapten determinants are unrelated, separate determinants (14, 17); this conclusion is strongly favored by experiments where tolerance to the carrier reduces the response to the hapten (13,18,19). Carrier and hapten determinants must be on the same molecule (14,17,20), although recent reports challenge this conclusion (21)(22)(23)(24).…”

“…In order to be activated, the B cell apparently needs more than one signal: two or more molecules of antigen cross-linked by anticarrier antibody (25) or by anticarrier T cells, these being then linked to the B cell through the antigen (26). In some instances, however, the second signal does not originate in the antigen under study; T cells might act on B cells either directly as in the allogeneic effect (22,23) or through the liberation of a mediator induced by their interaction with any antigen to which they are sensitized (21,24). These interpretations must be accepted with caution, inasmuch as they are inferred from complex systems in which cross-reactivity between antigens might furthermore exist.…”

Immunological Tolerance in Bone Marrow-Derived Lymphocytes

“…Indeed the original observation that this phenomenon could convert a normally strong tolerogenic molecule such as DNP-D-GL into an immunogenic signal (1) provided the strongest early evidence that the allogeneic T cells were reacting directly with DNP-specific B lymphocytes, a point which has since been directly substantiated (7,15,16). Moreover, Osborne and Katz have recently shown that an appropriately timed allogeneic effect can provide the necessary helper influence for generating primary antibody responses of the IgG class to DNP-D-GL (9).…”