Primary and Secondary Immune Responses of the Marine Toad (<em>Bufo marinus</em>) to Bacteriophage f2.

The primary and secondary immune responses of toads (Bufo marinus) were studied using the bacteriophage f2 as antigen. Antibodies were identified in the serum 2 weeks after primary immunization and peak antibody levels were reached at 6 weeks. Although both IgM and IgG antibodies can be found in toad serum, most of the antibody activity in our animals persisted in the IgM fraction until 8 weeks after immunization. When a second injection of antigen was given 4 weeks after primary immunization, there was a marked increase in the total serum antibody activity and IgG antibodies were found as early as 4 weeks after the second injection of antigen. These observations suggest that the toad, B. marinus, is capable of a true secondary response to the bacteriophage f2. [ABSTRACT FROM AUTHOR]