Development of local morphological changes after intradermal inoculation of Q-fever chemovaccine

Development of morphological changes was studied in the site of intradermal inoculation of Q-fever chemovaccine. The chemovaccine was obtained by trichloroacetic acid extraction from Coxiella burnetii, strain Nine mile, phase I cells. The effect of two vaccine doses (0.2 mg and 1.0 mg) was compared in two groups of guinea pigs (each consisting of 21 animals). After inoculation of 1.0 mg vaccine abscesses formed in the dermis and in subcutaneous tissue along with dystrophic changes of skeletal muscles. Reparation of these lesions progressed sufficiently slowly and was not completed before 60 days after vaccine inoculation. The regeneration of skeletal muscles was of budding type. After inoculation of 0.2 mg of chemovaccine minimal lesions occurred in the subcutaneous tissue only. However, already within 48 hr this vaccine dose evoked a strong reparation response. Interesting was the finding of Kurloff cells in the haemorrhagic foci. The results suggest that the low-reactogenic chemovaccine dose of 0.2 mg might be sufficiently immunogenic after subcutaneous administration.