The Growth Cycle of a Trachoma Agent in FL Cell Cultures

FL cell cultures were infected with a Chinese strain of trachoma, and the development of infectivity during a single growth cycle was studied. A noninfective phase lasting at least 24 hr after infection was demonstrated. Infectivity reappeared at 28 hr and reached a maximum at 48 to 72 hr. These findings agree well with the morphological findings reported before, according to which particles of elementary body size changed their appearance shortly after infection, could again be demonstrated at 28 hr, and then rapidly increased in number.