Production of auto-anti-idiotype antibody during the normal immune response. XIV. Evidence for the antigen-independent operation of the idiotype network.

We have previously shown that that idiotype (Id) repertoire expressed by old mice is different from that of young mice after immunization with trinitrophenylated Ficoll. Older mice also produce more auto-anti-Id antibodies than do young mice. Mice surviving a normally lethal dose of radiation (800 rads) as result of partial shielding of their bone marrow slowly recover immune function, after the repopulation of their peripheral lymphoid system by bone marrow precursor cells. Aged mice subjected to such a procedure produce low auto-anti-Id responses, like those of young mice. However, transfer of splenic T cells from old donors into such mice increases the magnitude of the auto-anti-Id response. In the present studies, we show that the age-related shift in Id expression is also determined by the age of the donor T cells. Furthermore, we show in serial cell transfer studies that the peripheral T-cell population of old mice modifies the level of the auto-anti-Id response in the absence of antigen. The results thus provide evidence for the normal, in vivo, operation of an Id-anti-Id network between B and T lymphocytes.