Specific in vivo and in vitro antibody response to tetanus toxoid immunization.

Booster immunization of normal individuals with soluble tetanus toxoid (TT) produced significant levels of plasma anti-tetanus IgG and IgM detectable by an enzyme linked immunosorbent assay (ELISA). Similar changes in circulating anti-TT antibody were found in mice following primary immunization. There was. however, no correlation observed between circulating anti-TT antibody response and the proliferative response of peripheral blood mononuclear cells exposed to soluble TT in the immunized individuals. The capacity of the peripheral blood mononuclear cells to produce specific anti-TT antibody in vitro was evaluated using a new microculture antibody synthesis enzyme-linked assay (MASELA). It was observed that the production of specific antibody in vitro correlated with the circulating anti-TT antibody level and not with the proliferative response. Peripheral blood mononuclear cells from these recently secondary immunized individuals produced greater specific anti-TT antibody when cultured in TT coated plastic wells than did controls. The potential utility of this technique in assessing response to immunization and basic immune competence is discussed.