Isolation of TRIC

The technique of cultivation ofTRIC agent, and other Chlamydia (Bedsonia) by centrifugation onto irradiated McCoy cells, developed by Gordon, Magruder, Quan, and Arm (i 963), Magruder, Gordon, Quan, and Dressler (i963), and Gordon, Dressler, and Quan (I967), has been used to recover laboratory-adapted isolates of TRIC agent from the infected eyes of simians (Gordon and others, I963) and of man (Magruder and others, I963). Studies recently completed in this laboratory on clinical specimens from genital or genitally-related ocular infections in London showed that isolation in irradiated McCoy cells is more sensitive for the detection and isolation of chlamydial agents than cultivation in the yolk sac of embryonated hen's eggs or inclusion-finding in Giemsa-stained scrapings (Gordon, Harper, Quan, Treharne, Dwyer, and Garland, I969; Dunlop, Hare, Darougar, Jones, and Rice, I969). It was also shown that TRIC agent could be isolated in the cell culture system from endemic trachoma in Iran, but the number of specimens tested was too small to give an assessment of the sensitivities of the two methods of isolation in relation to the finding of inclusions in conjunctival scrapings. Isolates of TRIC agent from endemic trachoma in the Middle East and the Far East have shown biological differences from TRIC isolates of genital origin in London, USA, and Taiwan (Alexander, Wang, and Grayston, I967; McComb and Bell, I967; Wang and Grayston, I970, 197!). It was, therefore, not clear whether the irradiated McCoy cell system could provide a satisfactory alternative to the yolk sac of embryonated hen's eggs for isolation of TRIC agent from endemic trachoma. This paper compares the results of isolation of TRIC agent in cell culture with those of isolation in the yolk sac of embryonated eggs from scrapings collected during a field study of trachoma in certain villages in Iran. It also relates these isolations to the findings of inclusions in conjunctival scrapings stained by iodine or Giemsa stain, and the results of microimmunofluorescence typing of the isolates.