Immunoregulatory effects of covalent antigen-antibody complexes. IV. Priming and tolerance in T-dependent responses.

Stable, covalently bonded, monomeric complexes of rabbit anti-NAP (4-azido-2-nitrophenyl) antibodies and NAP-bovine pancreatic ribonuclease (RNase), when injected into mice, prime the subsequent response to a soluble challenge of RNase. This effect is shown to be dependent on an intact Fc portion of the rabbit antibody and not simply due to foreign determinants recognized on the latter. A study of the kinetics of elimination of radioiodinated complexes from the serum indicates that the generation of a primary anti-rabbit IgG response and subsequent clearance of the complex leads to priming of the anti-RNase response. If mice are previously rendered tolerant to rabbit IgG or the complexes are ultracentrifuged, the priming to RNase is often abolished and tolerance may be induced.