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 SlgA. This enhanced response, as compared to SlgA alone, was analysed with mouse polyclonal anti-α chain antibodies (Ab). A kinetic study showed an early rise (between days 14 and 21) of the antibody response against the discontinuous epitopes of SlgA while the anti-lgA response increase was delayed. Induction of hybridomas with an IC consisting in SlgA containing an excess of anti-α chain Ab, increased 10-fold the number of positive wells.

Moreover, two of these MAb were specific for weakly immunogenic epitopes. One recognized only SlgA (anti-C), i.e. the association between the α chain and the secretory component (SC), while the other mainly combined to lgA dimers (anti-P). Both these MAb will be useful tools for structural studies and for the dosage of secretory Ab.