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We recently reported the cultivation in organ cultures of a virus, B814, which caused colds in volunteers but could not be detected or propagated in tissue cultures (Tyrrell and Bynoe, 1965). Hamre and Procknow (1966) have discovered a new virus in the respiratory tract of six students suffering from colds. There was a slight viral cytopathic effect in tissue cultures of human embryo kidney cells, but the virus was subsequently adapted to the WI-38 strain of human embryo fibroblasts. Both of these viruses were ether-labile but apparently unrelated serologically to any known myxoviruses. It now appears that they are morphologically identical and indistinguishable from the viruses of avian infectious bronchitis (Almeida and Tyrrell, 1967), and mouse hepatitis (Tyrrell and Almeida, 1967). The particles are 80-120 rxifx in diameter, pleomorphic, and sur rounded by a fringe of club-shaped projections about 20 m/x in length. Recently, further viruses of this morphological type have been isolated in organ cultures by Mclntosh et al. (1967). We have now given the prototype strain, 229-E, of Hamre and Procknow to volunteers in order to determine whether it causes colds and to study serum neutralizing antibody during infections with viruses of this type.
Bradburne et al. (Sat,) studied this question.