EFFECT OF DIFFERENT CONDITIONS ON PRECIPITATION IN AGAR BETWEEN MAREK'S DISEASE ANTIGEN AND ANTIBODY

SUMMARY Experiments were designed to determine the optimum conditions or reagents for precipitation in agar between Marek's disease cell-culture antigen and antibody in chicken serums. The effects of various agar concentrations and sources, NaCI concentration, buffers, pH, and incubation time and temperature were evaluated with undiluted and serially diluted serums and a standard antigen. The diluted serums were more sensitive to changes in conditions of precipitation than the undiluted serums. Minor variations in factors studied, except for NaCl concentration, did not greatly affect the sensitivity of the reaction. Physiologic salt concentration (0.85%) was greatly inferior to 8% NaCl concentration. The turbidity of high concentrations of agar tended to obscure the precipitin lines partially. The optimum conditions were 1% special agar-Noble, 8% NaCl, NaK phosphate buffer, pH 7.4, and incubation at 37 C for 72 hours.