FIG. 6.

Comparative defensin activity. (A) Various HD5 peptides were tested at a 3.3 μM concentration against E. coli cells under the same conditions as shown above for N. gonorrhoeae. (B) Activities of HNP1, HBD1, and HBD2 at a 3.3 μM concentration against N. gonorrhoeae. In panels A and B, the data depicted are the means minus standard deviations for three experiments; see Fig. 5 for details. (C) Dose-response curve for HNP1, HBD1 and HBD2, and HD5 (aa 56 to 94) for comparison against C. trachomatis. HBD1-40 and HBD1-44 are predominant native forms of HBD1 40 and 44 aminoacids in length, respectively. The assay was conducted as described in the legend for Fig. 5 with the exception that chlamydia were preincubated for 2 h with and without defensins prior to infection of Ishikawa cells. Depicted are the means of duplicates.