SENSITIZATION OF RABBITS BY INTRADERMAL INJECTION OF HEAT-KILLED LACTOBACILLI OF HUMAN ORAL ORIGIN

¹ Walter G. Zoller Memorial Dental Clinic and Department of Bacteriology and Parasitology, University of Chicago, Chicago, Ill.

1. The repeated injection of heat-killed lactobacilli of human oral origin into the skin of rabbits elicits a hypersensitivity which can be demonstrated by intradermal and intracorneal injection of nontoxic cellular carbohydrate extracted from these organisms. The skin reaction is of the delayed type.

2. The reactivity increased progressively until 4 to 6 successive intradermal inoculations of vaccine had been made and then diminished in intensity and duration.

3. Type specific precipitins were not demonstrable in the sera of the sensitized animals by ordinary in vitro precipitation tests, but lactobacilli were usually agglutinated by these sera in low titre.