INTEREST OF IMMUNOMODULATION AS A MEAN TO IMPROVE THE PREPARATION OF POLYCLONAL AND MONOCLONAL-ANTIBODY REAGENTS

Immunomodulation by monoclonal antibodies (mAbs) was investigated in m ice in order to improve the preparation of antibody reagents. Three di fferent types of representative immunogens were chosen: a human solubl e protein (secretory immunoglobulin A, SIgA), a bacterial polysacchari de from E. coli K1 and an envelope protein from the hepatitis B virus. These Ag are all of importance for diagnosis and exhibit different le vels of immunogenicity. Antibody-mediated enhancement was observed aga inst restricted and defined regions of each immunogen i.e.: the Fab ep itopes of SIgA, the preS1 domain of the HBV envelope and associated ce ll wall components of the capsular PS. The epitopes which were enhance d appeared to be different from those recognized by the modulating mAb . Negative modulations were also observed. Moreover, new epitopes seem ed to be generated, In both cases the level and direction of the modul ation were irrespective of isotypy and affinity of the mAbs. Interesti ngly the positive modulatory effect was found to be correlated with an in vitro assay based on the binding of immune complex to antigen-pres enting cells.