Serum and fecal specimens were collected from vaccinees receiving Sabin vaccine. Whey was separated from mother's milk collected from those who received Salk vaccine at their late pregnancy. Each specimen was tested for antibody to poliovirus type 2 (MEF 1) and the antibody-positive specimens were pooled separately with respect to serum, whey and stool extract. From each of three pools, the globulin fraction was precipitated at half saturation of (NH₄) ₂SO₄. IgG/IgA ratios of globulin fractions from serum, stool and whey were 12.53, 4.06, and 0.76, respectively, but they showed no distinction in kinetics and in avidity of the neutralizing antibody for the poliovirus. The neutralization by each of the globulin fractions followed the first order reaction. The salting-out globulin fractions were subjected to Geon 72S block electrophoresis and to step-wise elution with phosphate buffers of pH 7.5, 6.4, and 4.7 through a DEAE-cellulose column. The elutes were pooled into Fr. I, Fr. II, and Fr. III at three peaks in optical density at 280mμ. Whey Fr. II showed two peaks, Fr. II-1 and Fr. II-2, and the latter was found by ultracentrifugal analysis to contain 11S secretory IgA exclusively. Stool Fr. II was proved by immunophoretic and thin-layer chromatographic analyses to contain IgA. The modes of kinetic neutralization of poliovirus type 2 with serum IgG (Fr. I), secretory IgA from whey (Fr. II-2) and stool extract (Fr. II) were very much similar. However, stool Fr. I showed pronounced deviation from linearity. It was confirmed by serological analysis that this fraction was composed of degraded products of the IgA molecule, Fab or the like. In conclusion, the mode of neutralization of poliovirus type 2 was not different between serum IgG and secretory IgA derived from whey and stool extract.

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Variola virus growth and hyperplastic focus formation in HeLa cells cultured at temperatures higher than 37C were studied. Virus growth was inhibited by 98% at 37.5C, whereas the efficiency of focus formation was not changed. At 38.0C the growth of virus was almost completely inhibited, while the number of foci formed was reduced only to 30 to 50% of those formed at 37C. At temperatures higher than 38.5C both virus growth and focus formation were completely inhibited.
The interaction between variola virus and HeLa cells leading to focus formation was then analysed by exposing the infected cultures to 40C for a limited period of time at various intervals after infection. Virus adsorption and penetration into HeLa cells were rather accelarated at 40C. Shifting the incubation temperature of the infected cultures from 37C to 40C at any time after infection resulted in interruption of the virus growth. It was also indicated that 30 to 36 hr at 37C were necessary for visible foci to develop even after the shift up, suggesting that micro-foci completed during this period and that subsequent cell aggregation took place at 40C. Shift down experiments from 40C to 37C indicated that initial incubation at 40C for longer than 36 hr impaired greatly the efficiency of focus formation after shift down, probably due to the thermal degradation of penetrated virus.

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Blood-fed mosquitoes were collected by various methods at Itakura Village of Gunma Prefecture, Japan. The blood meals were identified by precipitin tests. Over 1, 300 Aedes vexans were tested and they reacted primarily with antisera to cattle or pigs. In a few cases there were reactors to a ciconiiformes antiserum possibly representing Black-crowned Night Heron (Nycticorax nycticorax) feedings. Multiple feedings by A. vexans were not commonly detected in the abdominal contents of single mosquitoes. The feeding patterns of Anopheles sinensis and Culex tritaeniorhynchus were similar to that of A. vexans. Culex pipiens had fed mostly on chickens. The Blackcrowned Night Heron was focussed to be a probable transporter of non-JE (Japanese encephalitis) arboviruses which have been isolated sporadically from A. vexans in the collection area.

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Antibody-eliciting capacity of peritoneal macrophages obtained from the immunologically mature adult as well as immature, five-day-old, suckling rats was studied. Sheep red blood cells were used as the test antigen and the antibody-forming activity was assessed by the number of hemolytic plaque-forming cells per unit number of spleen cells or the hemagglutinin titer of the serum or both. It was shown that transplantation of the SRBC-containing macrophages derived from adult rats elicited the apparently normal antibody response in adult rats but not in the immunologically deficient suckling animals. It was also found that the macrophages of the suckling rats were capable of ingesting SRBC and of transferring the antibody-eliciting capacity when transplanted into normal adult rats after ingestion of the antigen. It was concluded from these results that maturation of the phagocytic as well as antigen-processing capacity of macrophages preceded the differentiation of immunologically competent, antigen-reactive cells or the precursor of antibody-forming cells or both.

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