ANALYSIS OF THE VARIABILITY IN EXPRESSION OF MYCOPLASMA-GALLISEPTICUM SURFACE-ANTIGENS

The in vitro expression of surface epitopes for different strains of Mycoplasma gallisepticum (MG) was studied with a panel of monoclonal antibodies (mAbs) using indirect colony immunostaining and Western blot (WB) analyses. Immunostaining of colonies with mAbs showed that five epitopes had different degrees of variable expression, while one epitope 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 expressed epitopes were associated with more than one protein and not all mAb-defined proteins were responsible for the immunostaining of intact MG colonies. The ability of MG to variably express their surface epitopes maybe the mechanism utilized by the microorganism to avoid the host immune response.