IMMUNE-COMPLEXES AS IMMUNIZING AGENTS TO INCREASE THE NUMBER OF MONOCLONAL-ANTIBODY PRODUCING HYBRIDS AND TO DEVIATE THE RESPONSE TO POORLY IMMUNOGENIC EPITOPES

The use of immune complexes (IC) in an antibody excess, as immunizing agent, led to a large increase in the mouse polyclonal response to human SIgA. This enhanced response, as compared to SIgA alone, was analysed with mouse polyclonal anti-alpha-chain antibodies (Ab). A kinetic study showed an early rise (between days 14 and 21) of the antibody response against the discontinuous epitopes of SIgA while the anti-IgA response increase was delayed. Induction of hybridomas with an IC consisting in SIgA containing an excess of anti-alpha-chain Ab, increased 10-fold the number of positive wells. Moreover, two of these MAb were specific for weakly immunogenic epitopes. One recognized only SIgA (anti-C), i.e. the association between the alpha-chain and the secretory component (SC), while the other mainly combined to IgA dimers (anti-P). Both these MAb will be useful tools for structural studies and for the dosage of secretory Ab.