Studies of Polyoma Virus

[摘要] Several variables inherent in the assay of the polyoma virus by hemagglutination (HA) and of antibody to the virus by hemagglutination-inhibition (HI) tests were studied at 2°C with guinea pig erythrocytes.Hemagglutination was not detected in 125 mM sucrose containing less than 15 mM of NaCl. Peak titers were obtained at NaCl concentrations of 50–300 mM. MgCl2 (10–75 mM) and CaCl2 (10–50 mM) in veronal buffered saline did not enhance or inhibit hemagglutination. A detailed study of the effects of hydrogen ion concentration in the pH range 6.0–8.2 revealed that higher titers were obtained at pH 7 to 8, particularly at pH 7.8.Hemagglutination and complement fixation studies of crude virus, as well as products and byproducts of various purification procedures, revealed good correspondence between HA and CF titers of virus preparations. The HA assay was 30–40 times more sensitive than the CF assay. In view of the absence of nonhemagglutinating antigens, HA as well as CF assays could be used for the measurement of viral mass.At 55° and 65° C the kinetics of thermal inactivation were found to be pseudo-first order. A rate constant of 10-3 sec-1 was found at 68°C. The energy of activation in the range 55° to 75°C was 80 kcal/mole.Studies of the relationship between the serum HI titer and the concentration of virus in the assay revealed that increase in virus concentrations beyond 16–32 HA units did not affect serum titers. At lesser concentrations the serum titers increased, but less rapidly than the decrease of virus in the test system.Sera from inoculated and uninoculated hamsters were assayed by HI and CF with crude and partially purified antigens. For sera with high and moderate levels of activity good correspondence of HI and CF titers, with an average ratio of 5.5, was established. At low levels of activity, the ratios varied considerably, particularly with sera from uninoculated animals which showed HI activity in the absence of CF. The HI titers of such sera dropped significantly in assays with virus obtained from DEAE cellulose column chromatography.

[学科分类] 生物科学（综合）