ANALYSIS OF THE VARIABILITY IN EXPRESSION OF MYCOPLASMA-GALLISEPTICUMSURFACE-ANTIGENS

The in vitro expression of surface epitopes for different strains of M ycoplasma gallisepticum (MG) was studied with a panel of monoclonal an tibodies (mAbs) using indirect colony immunostaining and Western blot (WB) analyses. Immunostaining of colonies with mAbs showed that five e pitopes had different degrees of variable expression, while one epitop e was permanently expressed in vitro. Colonies that failed to express the studied epitopes had the potential of phenotypically switching the expression of these epitopes in vitro. Variable and permanently expre ssed epitopes were associated with more than one protein and not all m Ab-defined proteins were responsible for the immunostaining of intact MG colonies. The ability of MG to variably express their surface epito pes maybe the mechanism utilized by the microorganism to avoid the hos t immune response.