Accession Number : AD0427619


Title :   QUANTITATIVE ASSAY OF PSITTACOSIS VIRUS BY THE FLUORESCENT CELL-COUNTING TECHNIQUE


Descriptive Note : Technical manuscript


Corporate Author : ARMY BIOLOGICAL LABS FREDERICK MD


Personal Author(s) : Hahon, Nicholas ; Nakamura, Robert M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/427619.pdf


Report Date : Dec 1963


Pagination or Media Count : 24


Abstract : The studies described indicate that the fluorescent cell-counting technique provides a rapid, precise, reproducible, and sensitive procedure for the assay of infective particles of psittacosis virus. The efficiency of virus adsorption onto coverslip cultures of McCoy cells was markedly increased by the use of centrifugal force; assay values were 1.0 log higher than those obtained after stationary incubation. With the former procedure, the rate of cell-virus contact was independent of the volume of inoculum. Incubation for 20 to 22 hours was optimal for enumerating fluorescent viral particles in stained cell cultures. Virus assay values were not affected unduly by the incubation of infected cell cultures at temperatures ranging from 32 to 39 C. The number of fluorescent cell-infecting units was a linear function of virus concentration; the distribution of infected cells on coverslip cultures was random. The reduction of cell-infecting units of psittacosis virus by dilutions of specific antiserum suggests the possible usefulness of the procedure for detecting and measuring levels of serum-neutralizing antibody. The demonstration that the concentration of psittacosis virus in aerosols can be determined within 24 hours exemplifies the rapidity and applicability of the fluorescent cell-counting technique.


Descriptors :   *COUNTING METHODS , *VIRUSES , MEASUREMENT , FLUORESCENCE , BIOASSAY


Subject Categories : Microbiology


Distribution Statement : APPROVED FOR PUBLIC RELEASE