L-forms of Pseudomonas aeruginosa. 3. The serological cross-reactions among stable L-forms of Pseudomonas aeruginosa, L-form of Streptococcus pyogenes and mycoplasmas.

The serological cross-reactions among stable L-forms of Pseudomonas aeruginosa, or of Streptococcus pyogenes and mycoplasmas were investigated in passive hemagglutination (PHA) and agar gel diffusion tests. (1) PHA active fraction which reacts most strongly with homologous serum was obtained from the sodium dodecyl sulfate soluble fraction of L-form membrane after disruption by Braun cell homogenizer. (2) Antiserum prepared against L-forms in rabbits showed high-level stimulation of PHA antibodies, while it showed little stimulation of agglutinating antibodies. (3) In PHA and agar gel diffusion tests, antiserum to L-form of P. aeruginosa strain IFO-3,455 reacted with L-form of strain N-10, which is serologically different in serotype from strain IFO-3,455. Furthermore, the two L-forms of P. aeruginosa cross-reacted with a L-form of S. pyogenes. 4) L-forms of P. aeruginosa and S. pyogenes did not react with five strains of mycoplasmas in PHA and agar gel diffusion tests.