Henry H. Bloom

Recovery of PPLO of atypical pneumonia on artificial agar medium.

Summary Naturally occurring Eaton PPLO was shown to propagate on an agaryeast extract-horse serum medium. The agent was recovered directly on agar from 12 of 13 serologically positive patients with pneumonia. Eaton PPLO was not recovered from 14 serologically negative pneumonia patients. All Eaton PPLO isolates produced small homogenously granular colonies which could be easily differentiated from the usual “fried egg” or “nippled” colonies produced by non-Eaton oral PPLO. The distinctive colonial morphology of Eaton PPLO may ultimately prove useful for its presumptive identification.

Antibodies to Mouse Hepatitis Viruses in Human Sera.

Summary Human sera frequently react with mouse hepatitis viruses in CF and neutralization tests; available evidence indicates that the reacting factor is a specific antiviral antibody. Antibody responses were observed in several population groups, particularly in Marine recruits during winter. The agent responsible for the antibody is not known. We thank Mr. Worth I. Capps for devoted assistance in the performance of neutralization tests and preparation of CF antigens.

Growth of Laboratory and Naturally Occurring Strains of Eaton Agent in Monkey Kidney Tissue Culture.

Summary An egg adapted strain of Eaton agent multiplied in rhesus monkey kidney tissue culture. Antigen concentration within the cells was insufficient to permit visualization by immunofluorescence. An eclipse phase was demonstrated during replication in monkey kidney cells. In a simultaneous test monkey kidney culture was found to be as sensitive as embryonated eggs for recovery of naturally occurring strains of Eaton agent. Fourteen strains were recovered in tissue culture from 17 patients with pneumonia.

Pathogenicity of Coxsackie A-21 Virus for Suckling Mice:

Summary The production of a myopathy and paralysis in mice inoculated with tissue culture passaged Coxsackie A-21 virus was directly related to the inoculum dose and extent of virus multiplication. The virus yield from paralyzed mice was usually about 106 7 TCD50 or greater per mouse. Four strains of naturally occurring virus did not produce paralysis of suckling mice but virus multiplication occurred in mice with 2 of the 4 strains. Serial passage of Coxsackie A-21 virus in HEK cell cultures did not alter its virulence for suckling mice. The histopathologic changes associated with Coxsackie A-21 virus infection in mice were characterized by a waxy degeneration of the skeletal musculature which was generally confined to the lower extremities.

Characterization of Two Newly Recognized Rhinovirus Serotypes of Human Origin.

Summary Two new viruses, 1505 and 8213, were recovered from the human oro-pharynx in two separate epidemiological studies. The viruses were found possess characteristics of agents in the rhinovirus subgroup of picornaviruses: small size (15-30 mμ), RNA core, ether stability, inactivation at pH 3.0. Both 1505 and 8213 viruses were tested by neutralization tests against 85 previously described rhinovirus serotypes and 11 possible candidate rhinoviruses, and both were found to be distinct antigenically from all ninety-six. Addendum; Following the completion of this study, the two rhinovirus strains were assigned serotype numbers by the participants in the WHO-NIAID Rhinovirus Collaborative Nomenclature Program. Rhinovirus strain 1505 was designated rhinovirus 48 and rhinovirus strain 8213 was designated rhinovirus 49.

Multiplication and Cytopathology of Coxsackie A-21 Virus in Rotated and Stationary Tissue Culture

Summary Rotation of HEp-2 tissue cultures infected with Coxsackie A-21 virus enhanced the production and rapidity of appearance of CPE. In comparable stationary cultures the formation of CPE was delayed and often it was not demonstrable. Although the rate of virus replication was slightly faster in the rotated cultures the amounts of virus produced in both systems were similar.

Serologic Response in Man to Varying Amounts of Inactivated Epidemic Typhus Vaccine.

Summary Three hundred and sixty-nine Marine Corps recruits, initially without either complement fixing or toxin neutralizing epidemic typhus antibodies, were studied to determine their antibody response to subcutaneous injection of decreasing doses of commercially produced epidemic typhus vaccine administered in 1 or 2 doses of 1 ml each. When immunized with either 1 or 2 doses of undiluted vaccine or with 1 dose of vaccine diluted 1:2 or 1:4 91 to 100% of the 194 marines responded by developing either complement fixing or toxin neutralizing antibodies, or both. About 1/3 of 116 marines who received 1 dose of vaccine diluted 1:16 or 1:64 developed these antibodies. A single dose of vaccine diluted 1:256 elicited demonstrable antibodies in 15% or 9 of 59 men. These results suggested that the amount of antigen contained in 2.0 ml of vaccine required in the basic course of the immunization regimen was more than was needed to accomplish reasonable antibody responses in man. Accordingly, the primary immunization regimen for epidemic typhus for military personnel in the United States was changed in 1963 from 2 1-ml doses of vaccine given 7 to 10 days apart to a single 0.5 ml dose on entrance into military service and another 0.5 ml dose of vaccine at the time of overseas assignment.