Ciliostatic, hemagglutinating, and proteolytic activities in a cell extract of Mycoplasma pneumoniae

An extract of Mycoplasma pneumoniae, prepared from glass-grown organisms by extraction with 2 M NaCl, followed by freeze-thaw, ultracentrifugation, dialysis, and lyophilization, yielded approximately 20% of the total mycoplasmal protein. The extract contained at least 20 protein bands on sodium dodecyl sulfate-polyacrylamide gels and 2 to 5% carbohydrate and inhibited 70 to 100% of the ciliary activity of hamster tracheal organ cultures (ciliostasis). The extent of ciliostasis was dependent on the concentration of the extract. The extract also produced hemagglutination of human O-positive erythrocytes and showed proteolytic activity with a synthetic tetrapeptide substrate, S-2222. These in vitro tissue-damaging activities may be associated with the virulence of the mycoplasmas and with the pathogenesis of M. pneumoniae disease.