Fig. 4. Cytochalasin D differentially inhibits CEACAM3-mediated internalization. Following a 30 min pre-incubation period with either cytochalasin D or carrier, HeLa cell lines were infected with N313 (Opa₅₇). After 30 min, total cell-associated bacteria and gentamycin-protected bacteria were quantitated by dilution plating. Black bars show efficient inhibition of gonococcal internalization by HeLa-CEACAM3 (A; black bars) but not by HeLa-CEACAM1 (B), whereas gonococcal adherence (grey bars) to either cell line was not affected by the inhibitor.