title: Complement-dependent stimulation of normal lymphocytes by immune complexes.
abstract: Normal rabbit lymphocytes were stimulated to proliferate in vitro by antibody-antigen complexes. Stimulation was dependent upon C activity. Heat-inactivation or zymosan-treatment of the serum used in culture caused a 75 to 100% loss of responsiveness to the complexes. Serum-free culture or cultures with less than 1% serum supported only low levels of stimulation, but responsiveness reappeared proportionally with increased serum concentration. The low level dose-dependent responses seen in the absence of active C may have been due to C carried over with the cells or to stimulation independent of C. Aggregated rabbit gamma-globulin tested over a broad dose range failed to stimulate normal lymphocytes more than minimally whether or not C was present. Stimulation with immune complexes was sustained by C4-deficient guinea pig serum, indicating participation of the alternative C pathway. Normal rabbit lymphocytes from peripheral blood, bone marrow, spleen, and lymph node proliferated in response to rabbit antibody-antigen complexes. Normal thymocytes were consistently unresponsive to the complexes.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D001853:Bone Marrow / Q000276:immunology; D003165:Complement System Proteins; D006358:Hot Temperature; D008198:Lymph Nodes / Q000276:immunology; D008213:Lymphocyte Activation; D011817:Rabbits; D013154:Spleen / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology; D015054:Zymosan / Q000494:pharmacology; D005719:gamma-Globulins / Q000494:pharmacology
chemical_list: D000936:Antigen-Antibody Complex; D005719:gamma-Globulins; D003165:Complement System Proteins; D015054:Zymosan