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A strain of human cytomegalovirus called Towne was isolated in WI-38 human fibrolast cell cultures from the urine of an infected infant. It was then passaged 125 times in WI-38, including three clonings, and a pool was prepared in the same cell substrate for use as a potential live attenuated vaccine. The Towne virus has a broad antigenicity and cross-reacts with the AD-169 strain. Several markers of the Towne virus were found which differentiated it from fresh isolates. One of these was resistance of the former to trypsin. The Towne virus was tested for freedom from oncogenicity or other harmful effects in preparation for tests in humans.

Extract: High passage Cendehill strain of rubella virus, possesing in vivo and in vitro characteristics of an attenuated virus, was tested for efficacy in 28 seronegative infants, 3 to 23 months old. Thirteen seronegative infants received one subcutaneous injection of 0.5 ml of the vaccine preparation containg 103.7plaque-forming units (PFU) per ml. Fifteen seronegative infants served as controls for viral spread and were kept in intimate contact with the vaccinees for a period of 6 weeks.All thirteen vaccines developed high levels of hemagglutination-inhibiting antibodies, from 1/128 to 1/2048, confirming the immunogenicity of the vaccine. No clinical reactions were observed in the vaccinees. The fifteen contacts remained seronegative, indicating that no viral spread occurred from the vaccinees to the susceptible contacts.The present clinical trial provides evidence that high-passage Cendehill strain presents characteristics of immunogenicity, nonreactogenicity and noncommunicability, making it a prospective candidate for a live attenuated rubella virus vaccine.Speculation: When the results of preliminary immunization trials with the attenuated Cendehill strain of rubella virus are confirmed in larger groupt, this strain may meet all the criteria required for a safe and efficient immunizing agent against rubella.

A live attenuated influenza virus (“Ann” strain) derived from A/England/878/69 was given intranasally to a group of volunteers, most of whom had already circulating antibodies against H3N2viruses at the time of inoculation. There was a fourfold or higher increase of circulating hemagglutination-inhibiting antibodies in those volunteers who had relatively low initial titers. The response was lower in those with initially higher serum titers. The pattern of the serum neutralizing antibody response was very similar. The geometric means of the antineuraminidase antibodies were 67 and 118 pre- and postvaccination, respectively. All subjects showed a rise in local neutralizing antibodies in their nasal secretions with geometric means of 4 and 17 pre- and postvaccination, respectively. The levels of local antineuraminidase antibodies also rose in most subjects. In addition to the response to the homologous virus type, the antibody formation to the recent A/England/42/72 was measured in the sera and nasal secretions of some subjects. There was a clearcut response in most of the sera and in all of the secretions examined. The stimulation of circulating lymphocytes was measured in 6 volunteers. All volunteers showed a temporary stimulation. The stimulation index ranged between 2.5 and 28.5.

Ligated intestinal loops of mice were found suitable for the assay of heat-stable enterotoxin produced by enteropathogenic Escherichia colistrains of porcine origin; loops inoculated with heat-labile enterotoxin failed to react.