Cellular and humoral immune responses in mice. II. Effect of intraperitoneal or subcutaneous injection of carrier of anti-hapten antibody and delayed hypersensitivity responses.

The subcutaneous (s.c.) injection of sheep red blood cells (SRBC) without adjuvant into mice preferentially induced delayed hypersensitivity (DH) reaction, as measured by footpad swelling, while intraperitoneal (i.p.) measured by the haemagglutinin test. Under these conditions, the properties of the helper activities of thymus-derived (T) cells for humoral responses were examined, in association with the features of the DH response, by measuring the anti-hapten and anticarrier antibody responses after a booster injection of trinitrophenylated (TNP) SRBC and by changing the combination of doses and injections routes of the carrier and the hapten-carrier conjugates. When mice were presensitized with i.p. injections of SRBC and boosted with i.p. injections of TNP-SRBC, the anti-TNP antibody production was maximally enhanced by presensitization with a low dose of SRBC, and gradually abolished with higher doses of SRBC for pre-sensitization. In the latter case, anti-SRBC antibody production was increases with increasing doses of SRBC..