A kinetic and quantitative analysis of antibody and protein synthesis during the primary response to keyhole limpet haemocyanin.

Rabbits were injected with alum-precipitated keyhole limpet haemocyanin. On various days after immunization popliteal lymph node cells were prepared for synthesis of antibody as well as non-antibody proteins by incorporation of C-amino acids. Antibody and proteins were characterized by gel filtration, radio-immunoelectrophoretic and zone electrophoretic analyses of the culture media. Some `natural' antibody appeared to be synthesized by lymph node cells from uninjected animals. The first definite increase in numbers of nucleated lymph node cells and in antibody synthesis occurred on the third day after immunization. The peak of cell numbers and antibody synthesis was attained on the sixth day after antigenic stimulation. The antigen-stimulated cells also synthesized increased amounts of non-antibody proteins, including IgM and IgG, and proteins tentatively identified as α macroglobulin, α globulin and a microglobulin. Most of the radioactive protein which was synthesized following injection of antigen was demonstrably not antibody. Both IgM and IgG antibody were synthesized at all times, but relatively more radioactivity was incorporated into IgM antibody on day 3 and into IgG antibody on day 6 after immunization.