FIG. 1.

Parallel assessments of infectivity of C. trachomatis serovar L2 (CT-L2), serovar D (CT-D), and C. pneumoniae (CPn) for each CHO cell mutant. The infectivity of each chlamydial strain for monolayers of each cell line was tested in triplicate. Approximately 48 h postinfection, chlamydial inclusions were detected by immunofluorescence and enumerated by counting inclusions. Similar data were obtained in at least three independent experiments. Qualitative estimates of attachment are indicated as follows: no binding (NB) or cellular-associated binding on a progressive numerical scale of 1+ to 4+, where 1+ represents approximately 10 EBs apparently associated with cell surfaces and 4+ represents many EBs bound with entire staining of the cells.