Strain differences in the behavior of TRIC agnets in cell cultures

Laboratory procedures for the isolation of chlamydia trachomatis from the human genital tract

The technique of isolating Chlamydia trachomatis from the human gential tract by centrifuging clinical specimens on to cell monolayers with subsequent incubation has been improved and simplified. Gentamicin in the media was found to be superior to streptomycin in reducing bacterial contamination of specimens. The infectivity of chlamydial suspensions of laboratory cultured material was significantly reduced by storage at +4 degrees C for more than 48 hours, and by immediate freezing to -70 degrees C. When compared with immediate processing of the specimens, freezing to -70 degrees C was found to reduce the isolation rate of C.trachomatis from men with non-gonococcal urethritis (NGU) by approximately 20%. McCoy cells pretreated with idoxuridine were compared with irradiated McCoy cells for the isolation of C. trachomatis from clinical specimens. There was no significant difference in sensitivity between the two systems, but the former is considerably simpler. The effect of the centrifugal force used for inoculating specimens on to the cell monolayers on the isolation rate of C. trachomatis was studied in groups of men with NGU. Maximal isolation rates were obtained with forces of about 3000 G, which were not significantly raised by further increasing the force used. It is suggested that the isolation of C. trachomatis from the genital tract is now well within the capacity of any laboratory equipped with simple cell culture facilities.

Chlamydin trachomatis in cell culture. I. Comparison of efficiencies of infection in several chemically defined media, at various pH and temperature values, and after exposure to diethylaminoethyl-dextran

Three chemically defined cell culture media, Eagle minimum essential medium (MEM) with Earle basal salt solution, Eagle MEM with Hanks basal salt solution, and a modified Eagle MEM, were tested and found capable of supporting the development of Chlamydia trachomatis in (60)Co-treated McCoy cells. The enhancement of trachoma infection by diethylaminoethyl-dextran (DEAE-D) was greater at pH values closer to neutrality than at any other pH values measured at the start of the experiments. Centrifugation of the trachoma inoculum onto cell monolayers at 33 C increased the number of inclusions when compared to centrifugation at 20 C. When the inoculum was centrifuged onto cell monolayers and subsequent incubation was at temperatures ranging from 34 to 39 C, the greatest number of inclusions was observed after incubation from 35 through 37 C. Enhancement of the trachoma infection by DEAE-D was tested at temperatures ranging from 35 to 37 C. These cultures had three- to fivefold increases in inclusions when compared to previously reported experiments in which DEAE-D-treated cultures were incubated at 34 C.

The development of TRIC organisms in cell cultures during multiple infection

The relationship between multiplicity of infection and the yield of organisms and of polysaccharide was studied in BHK 21 cells infected with TRIC organisms. Although an increase in the multiplicity of infection resulted in an increase in the absolute number of organisms per culture, there was a decrease in relation to the number of infecting organisms. The amount of polysaccharide produced was independent of multiplicity of infection; it was not limited by the concentration of glucose in the medium. Polysaccharide leaked from cells and was slowly broken down in the culture medium.