Life cycle of goat pneumonitis agent, strain Nagano, in L cell culture was described. The developmental cycle occurs in four stages, as generally observed with PLT group of agents: (i) penetration of invaded elementary bodies into the cytoplasm. (ii) transformation of the elementary bodies to the initial bodies occurs by the 8th hour after inoculation. (iii) Initial bodies begin to multiply between the 11th and 12th hours as observed by appearance of the “diplococci-like” forms. Thereafter they multiply at an exponential rate, and (iv) highly infective mature particles are formed after the 21st hour. The life cycle is complete in 48 hours. The results are well accounted for as that the invaded elementary bodies transform directly to the initial bodies, the vegetative forms, from which highly infective elementary bodies are developed. Which rules out the possibility that the multiplication of the agent might occur at a (hypothetical) preliminary virus-like phase, before the formation of the initial bodies.
Purification of the receptor for Japanese encehaplitis virus (JEV) prepared from mouse brain tissue was performed successfully by differential centrifugation, digestion with trypsin, precipitation by streptomycin and centrifugation in D2O. The receptor, which was purified about 2, 000 times from crude extract, had a single peak with a S20°W of about 110 Svedberg units and a buoyant density of 1.06. The purified receptor was found to be composed of lipid and small amounts of carbohydrate and protein. Receptor activity was inactivated by phospholipase C and D, but not proteolytic enzymes such as trypsin and α-chymotrypsin. Interaction of the receptor with JEV proceeded in two stages, reversible and then irreversible. Reversibly attached virus could be dissociated from the receptor by treatment with streptomycin or hydrogen bond dissociating agents such as LiCl and NaCl. The action of the purified receptor was highly specific in a sense that it was effective in inhibiting hemagglutination or infectivity of Arboviruses, but not other viruses so far examined.