Serologic crossreactions among primate immunoglobulins

We have generated and characterized 50 murine monoclonal antibodies (mAb) specific for baboon IgG. We examined crossreactivity of these mAb to baboon IgM and immunoglobulin (Ig) of various other primates including human, chimpanzee, rhesus monkey, cynomologous monkey, and African green monkey. Those mAB that crossreacted with human IgG were further examined using myeloma proteins for specificity to human Ig subclasses. One mAB crossreacted with all four human IgG subclasses and with human IgM. We further analyzed this reactivity utilizing Bence Jones proteins representative of various l ight (L) chain germline gene family products. This mAB reacted with Bence Jones proteins indicating the recognition of a kappa (κ) L chain specificity associated with the κi, κiii, and κIV subgroups, but not with κII. Based on the differences between κII germ line gene encoded L chains and the other κ L chain subgroups, we ascribe this reactivity to six amino acids that define a discontinuous epitope.