Protein and antigen variability among strains of Mycoplasma arthritidis.

Six strains of Mycoplasma arthritidis isolated from different host tissues were examined for differences in their proteins and antigens by using one- and two-dimensional electrophoretic techniques as well as immunoblotting. One-dimensional electrophoresis revealed differences in concentrations of individual bands, but not differences in the overall banding pattern. By two-dimensional electrophoretic analysis, 25 proteins were identified as strain-variable whereas the majority of protein spots was strain-constant (about 195 after IEF-2D-PAGE and 145 after NEPHGE-2D-PAGE). Immunoblot analysis using an antiserum against the type-strain of Mycoplasma arthritidis (PG 6) revealed size-heterogeneity of antigens of all six strains. An epitopic relationship between these size-variant antigens could be demonstrated by using monospecific antibodies produced against some of these antigens of Mycoplasma arthritidis. Furthermore, we describe a highly variable antigen of Mycoplasma arthritidis similar to that shown previously in Mycoplasma pulmonis.