Effect of age on ease of B-cell tolerance induction

It was shown in intact mice, and in lethally irradiated, thymectomized recipients of peripheral B cells from donors of various ages, that the ease of B-cell tolerance induction with the dinitrophenyl derivative of the copolymer of d-glutamic acid and d-lysine decreases with age. That is, the B-cell population of 6- to 7-month-old BALB/c mice is more resistant to tolerance induction than is the B-cell population of $\text{1}\text{1}\text{2}$- to 2-month-old mice and the B-cell population of 10- to 11-month-old mice is highly resistant to tolerance induction. This age-related resistance of the peripheral B-cell population to tolerance induction might, at least in part, account for the increased incidence of autoantibodies in aged animals. However, the increased resistance to tolerance induction appears to occur at an earlier age than the increased incidence of autoantibodies. This suggests that changes in ease of tolerance induction may not be the sole factor responsible for the increase in autoantibodies in aged animals. Evidence is also presented for an age-related decrease in the function of the B-cell population with respect to the response to a T-dependent antigen.