Investigations of a killed dermatophyte cell-wall vaccine against infection with Microsporum canis in cats.

A laboratory-prepared killed Microsporum canis cell-wall vaccine was evaluated under conditions simulating an accidental infection of a cattery, by inoculating eight- to nine-week-old cats with the vaccine or with a placebo control. The vaccinated cats developed high titres of anti-dermatophyte IgG as measured by an ELISA, and a small cell-mediated response against M canis as measured by a lymphocyte blastogenesis assay, using a whole fungus extract. After being inoculated the cats were challenged by the introduction of an infected cat into the same room. All the vaccinated and control cats became culture-positive for M canis within four weeks of the introduction of the infected cat. Four of the six control cats and all the vaccinated cats developed lesions consistent with dermatophytosis within 16 weeks after exposure to the infected cat.