Anti-MHC immunity detected prior to intentional alloimmunization. IV. Natural monoclonal H-2-specific antibodies.

Naturally occurring H-2-specific antibodies can be detected rather frequently in sera of non-alloimmunized mice by sufficiently sensitive techniques (Cerny-Provaznik et al., 1985a; Cerny-Provaznik & Ivanyi, 1985). In this report, we summarize our experiences with the preparation of monoclonal anit-H-2 antibodies obtained from hybridization experiments from non-alloimmunized mice. From a total of 30 spleen cell hybridization experiments, we could isolate only four anti-H-2 monoclonal antibodies (mAB). Two of the mAB are described in this report. Monoclonal antibody By-2 is anti-Kf and mAB By-3 is anti-Db, Ds. We investigated which conditions favour the isolation of monoclonal H-2-specific antibodies from non-alloimmunized mice. The presence of naturally occurring serum antibodies, the age of the spleen donor mouse or non-specific B cell stimulation were not critical for the isolation of natural anti-H-2 mAB. We hypothesise that the 'natural' H-2-specific antibodies represent compartments of the B cell repertoire which were triggered by modified or aberrant self-MHC expression.

Natural autoreactive H-2-specific serum antibodies in a group of BALB/cBy (H-2d) mice.

Natural autoreactive H-2-specific antibodies were detected by lymphocytotoxic test in sera of 15 BALB/cBy (H-2d) mice maintained in the same cage. The antibodies could be detected only for a short period of time; they reacted strongly with H-2d and H-2s and weakly with H-2k,q,r cells. Such antibodies could not be identified in sera of other groups of mice of the same strain maintained in the same environment. All serum-positive mice had a shorter life span than control mice. However, neither a real link between the antibodies and the disease nor a clear understanding of the disease was achieved.