Diversity of age-dependent changes of antibody formation and of tolerance decrease.

Age-dependent changes in immune response and in tolerance occur at different rates in inbred mice of different genetic backgrounds. The change in tolerizability is connected with the change in the balance of the suppressor helper circuit; the change in B-cells, at least in C57BL/6 mice, appears to be also due to a regulatory change. Changes in immune responsiveness and tolerance inducibility appear to vary independently of one another.