Lethatlity of and Elicitation of Protective Antibody by Vibrio parahaemolyticus ATTC 17803
The LD50 of Vibrio parahaemolyticus ATCC 17803 for 13- to 18-g male mice, strain ICR, as determined by the 50% endpoint method, was found to be an estimated 7 x 107 CFU, when administered intraperitoneally in 0.5 ml of 24-h broth culture, O. D. 0.5 at 650 nm, diluted to 10-0.72. The elicitation of protective antibody by this bacterium in male New Zealand White rabbits was demonstrated by testing control, baseline, and hyperimmune rabbit sera for their protective effect against 2 LD50 of the bacterium administered intraperitoneally in 13- to 18-g male mice, strain ICR. A comparison of these sera showed that there was a highly significant difference, at the 0.01 level, between the protection conferred by the hyperimmune sera and the protection conferred by the baseline or control area. Significant protection was demonstrated by hperimmune sera at dilutions as high as 1/32. Comparison of results of in vitro tests for preciptins and agglutinins in hyperimmune rabbit sera with results of in vivo tests for protective effect of hyperimmune rabbit sera led to a tentative conclusion that this passive protection afforded by the hyperimmune rabbit sera is probably conferred more by precipitins than by agglutinins.
Western Kentucky University, Bacterial Infections and Mycoses, Biology, Diseases, Medical Immunology
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