Chondroitin sulfates used as adjuvants for antibody formation and as mitogens for B cells

The effects of chondroitin sulfates (ChS) A and C on antibody formation in mice and chickens and on proliferation of murine B cells in vitro were determined. Simultaneous injection of ChS with sheep erythrocytes (SRBC) caused enhanced antibody production as measured by plaque-forming cells per spleen on day 5 after antigen and by serum agglutinin titers. ChS.C was more active than ChS.A and intravenous (i.v.) injection was far more effective, requiring 100-fold lower doses, than intraperitoneal (i.p.) injection. Responses of chickens could be enhanced by i.v., but not by i.p., injection of ChS.C with SRBC. Simultaneous injection of ChS.C with trinitrophenylated Ficoll had no effect, but injection of ChS.C 2 days after this antigen significantly increased the responses. Although ChS.C and ChS.A both caused proliferation of normal and athymic mouse spleen cells, the concentrations required for this effect in vitro were much higher than those needed for the in vivo effect. ChS.C caused only a slight increase in delayed hypersensitivity to a contact sensitizer.