A 41-KDA VARIABLE SURFACE PROTEIN OF MYCOPLASMA-GALLISEPTICUM HAS A COUNTERPART IN MYCOPLASMA-IMITANS AND MYCOPLASMA-IOWAE

Mycoplasma gallisepricum, M. imitans and M. iowae are three morphologi cally similar avian Mycoplasma species, and M. gallisepticum and M. im itans have been shown to be antigenically related. Using a monoclonal antibody that binds to the previously described size- and phase-varian t integral membrane surface protein PvpA of M. gallisepticum, we have identified in all three avian Mycoplasma species a 41-kDa surface anti gen, which in M. gallisepticum and M. imitans was identified as periph eral membrane protein undergoing variation in expression among clonal isolates. Southern blot analysis using the pupil gene as a probe demon strated sequence homology with M. imitans and M. iowae genomic DNA and suggested that a pupil-related gene that may encode the 41-kDa produc t exists in these two Mycoplasma species. These studies establish (i) that M. iowae is antigenically related to M. gallisepticum and M. imit ans, (ii) that the three species share non-ribosomal gene sequences, a nd (iii) that peripheral membrane proteins contribute to Mycoplasma su rface variation.