Specimens from men with acute non-gonococcal urethritis were tested to determine their microbial content and then given intra-urethrally to male chimpanzees. Two animals received ureaplasmas only and one became infected. The second did so when given a different strain. Both developed a polymorphonuclear leukocyte (PMNL) response. Two chimpanzees received a mixture of ureaplasmas and Chlamydia trachomatis and there was a suggestion that the ureaplasmas delayed or suppressed the chlamydial response. The latter, that is urethral infection with a pronounced PMNL response, was most clearly seen in a chimpanzee given C. trachomatis only. No inflammation was detected in two chimpanzees acting as controls. Three of five chimpanzees given ureaplasmas genitally, and one that had them endogenously, had them transiently in the oropharynx about 2 weeks later. The occurrence of ureaplasmas in the conjunctiva of three chimpanzees inoculated at this site was also transient and without inflammation. The possibility that Mycoplasma genitalium might have been in the inocula and caused urethral inflammation was discounted largely because no animal had antibody to this mycoplasma.
INTRODUCTIONThe pathogenicity of several micro-organisms, for example Chlamydia trachomatis (Jacobs et al., 1978), Ureaplasma urealyticum (Taylor- Robinson et al., 1974) and Mycoplasma genitalium for the genital tract of male chimpanzees has been investigated. All of these micro-organisms were reported to have produced a polymorphonuclear leukocyte (PMNL) response, apart from U. urealyticum. However, subsequently, several references have been made to ureaplasmas causing such a response (Taylor-Robinson et al., 1983; Taylor-Robinson, 1984a, b) but without supportive data. Confirmation of this claim was the aim of the study reported here.
METHODSInocula. Nasopharyngeal swabs were inserted into the urethra of men with acute non-gonococcal urethritis seen at the Genitourinary Medicine Clinic of St Mary's Hospital, Paddington, London, UK. Each swab was expressed in 2 ml sucrose-phosphate transport medium (Taylor-Robinson & Furr, 1981) and this was divided into two aliquots, each of which was stored in liquid nitrogen. The first was examined for ureaplasmas, Mycoplasma hominis and C. trachomatis (see below) and the second, judged from these examinations not to contain these micro-organisms, or to contain one or more of them, was kept for chimpanzee inoculation. The numerical identities of animals and their inocula are shown in Table 1.Chimpanzees and experimental procedures. The chimpanzees (Pan troglodytes) had been captive for several years, housed at Meloy Laboratories, Rockville, MD, USA, under conditions that met or exceeded all relevant requirements at the time (late 1970s) and the protocols were reviewed by the relevant animal use committees. Some laboratory studies were done in the Laboratory of Infectious Diseases, National Institutes of Health, MD, USA, and others at the Clinical Research Centre, Harrow, Middlesex, UK.Of eight male chimpanzees (25-...