Immunoprecipitation of Triton X-100-solubilized Mycoplasma mycoides proteins

Mycoplasma mycoides subsp. mycoides (PG1 and strain Y) proteins were solubilized in Triton X-100, and the antigenic proteins were precipitated from this complex mixture by addition of antiserum and then separated by two-dimensional gel electrophoresis. Of the 300 proteins solubilized, about 10 were precipitated. Proteins of PG1, a slow-growing, small colony (SC) strain, were precipitated by antiserum to PG1 and by antiserum to strain Y, a fast-growing, large colony (LC) strain. Similarly, strain Y proteins were precipitated by antiserum to PG1 and by antiserum to strain Y. The few proteins precipitated in this way gave similar patterns after two-dimensional gel electrophoresis indicating that many of the dominant protein antigens of PG1 and strain Y are shared. Antiserum to Mycoplasma mycoides subsp. capri (PG3) also precipitated some proteins of strain Y. Antiserum to Mycoplasma gallisepticum gave no reaction with any M. mycoides antigens. It was concluded that, in addition to the polysaccharide antigens, there are proteins in M. mycoides that are antigenic and that some of these are found in both the SC and LC strains of subsp. mycoides and also in subsp. capri.