Isotype responses of mice to tetanus-toxoid preparations.

The development of anti-tetanus antibodies in CBA/Ca and Balb/c mice immunised with two tetanus-toxoid preparations has been investigated by sensitive enzyme-linked immunoassays. These studies revealed the presence in both strains of mice of naturally occurring antibodies to tetanus toxoid. These were of the IgM, IgA and, to a lesser extent, the IgG3 isotypes. Differences in the responses of mice to the two toxoid preparations were noted; the purer preparation elicited a more rapid and pronounced response. Both strains of mice exhibited similar isotype responses.