Fig. 8. Microinjection of antibodies to the dynein intermediate chain abolishes chlamydial migration and aggregation. Monoclonal antibodies to the dynein intermediate chain were injected into the cytoplasm of Cos-7 cells and subsequently infected with C. trachomatis. The injected antibodies were detected with AlexaFluor-488-conjugated secondary antibodies (green) and chlamydial nascent inclusions were stained with antibodies to L2 EBs and detected with AlexaFluor-594 conjugated secondary antibodies (red). Chlamydial migration and aggregation was abolished in cells injected with a monoclonal antibody to dynein (green cells). Uninjected cells (no green signal in merged image) on the same coverslip show normal chlamydial migration (arrowheads). Injection of an irrelevant antibody, R. rickettsii, or an antibody to the positive directed microtubule motor protein, kinesin, had no effect on chlamydial movement as chlamydiae aggregated normally (arrowheads) at the MTOC of both injected (green cells) and noninjected cells (no green signal in merged image). Bars, 10 µM.