Occurrence and immunogenicity of proteinases fromLegionella species

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