The distribution and effect ofChlamydia trachomatis in CBA mice inoculated genitally, intra-articularly or intravenously

Abstract

A “fast” egg-killing human strain ofChlamydia trachomatis was inoculated into normal CBA and congenic CBA/nu mice, which have an impairment of T-cell function and do not produce anti-chlamydial antibodies. The mice were inoculated by the intra-uterine, intra-articular, or intravenous routes. Some of the mice were first treated with progesterone, which allows successful chlamydial infection of the mouse genital tract when the organisms are introduced genitally. Mice were sacrificed up to 27 days after inoculation. Homogenates of joints, genital tract, spleen, liver, kidneys, eyes and lungs were prepared and tested for chlamydiae in cycloheximide-treated McCoy cell cultures.

Chlamydiae were detected in the genital tracts and spleens, but not in the joints, of mice inoculated via the intra-uterine route. They were found in the joints and spleens of mice inoculated intra-articularly, and were detected also in spleens and, from the 4th to 6th day after inoculation, in joints of mice given the organisms intravenously. These results were obtained irrespective of whether or not the mice had received progesterone. The numbers of chlamydiae in the spleens and joints of the nude mice were larger and they persisted longer than in the corresponding immunocompetent animals, although this was not true for chlamydiae in the genital tract of mice inoculated via the intra-uterine route.

Compartmentalisation of chlamydiae was evident although the spleen was infected consistently irrespective of the route of inoculation and, as mentioned, chlamydiae were found transiently in the joints following intravenous inoculation. This suggests that chlamydiae might also enter the human joint. However, the observations in mice have not, so far, been helpful in establishing the mechanism of human arthritis thought to be chlamydial because none of the mice given chlamydiae extra-articularly developed arthritis either in the presence or the absence of antibody.