Occurrence and immunogenicity of proteinases from Legionella species.

Proteinases produced by various Legionella species were studied by means of caseinate precipitation. Proteinase production was particularly high in strains of Legionella pneumophila (serogroups 1-6), much lower in other Legionella species, and absent in Legionella micdadei strain Tatlock. Immunoglobulins against proteinases of Legionella pneumophila (serogroup 1, strain Philadelphia 1) inhibited the proteinase activity of all strains of Legionella pneumophila, Legionella bozemanii, Legionella dumoffi and Legionella gormanii. There was no cross-reactivity between these antibodies and proteinases from bacteria belonging to other genera. Antibodies against Legionella pneumophila proteinases were not found in human convalescent sera. The proteinases of Legionella species could possibly be associated with pathogenicity factors.