Cell surface associated gamma globulin in lymphocytes. V. Detection of early cytophilic complexes reacting with T- and B-lymphocytes.

Abstract

Serum collected from mice 6 hr after immunization with soluble antigens in Freund9s complete adjuvant was able to induce various changes of the bone marrow-derived (B)-cell (γ globulin-carrying) and thymus-derived (T)-cell (θ-carrying) populations when incubated with spleen cells from unimmunized mice. First there was an overall increase (by 25%) of all the γ globulin-carrying cells. This increase could be accounted for by an identical increase of the cells carrying γ G (7S γ2a) globulin on their surface. At the same time the cell population normally carrying γ F (7S γ1) globulin decreased. These changes were detected by the reverse immune cytoadherence technique (RICA) with highly specific hybrid antibodies which detect one class of mouse γ globulins. Second, the treated spleen cells show a decrease of the T-cell population as detected by an anti-ϑ serum. This decrease was of a similar magnitude as the increase of the γ G -carrying cells and involved about 40% of the ϑ-carrying cells. Thus the serum reproduces in vitro all the phenomena previously described as taking place in the spleen 6 hr after immunization. When the 6-hr serum from mice injected with radioactively labeled bovine serum albumin was fractionated on a Sephadex G-200 column, all the activities described above were reproduced by a fraction containing 7S γ globulin and antigen. The presence in this fraction of a complex of the antigen with mouse immunoglobulin was confirmed by autoradiography. It is quite possible that the alterations in the populations of B- and T-cells described are due to the interactions of such a complex with these cells in the spleen cell suspension.