Figure 6.

CK47 neutralization of Asian-genotype CHIKV envelope-pseudotyped lentiviral infection. Asian-genotype CHIKV (CK12–686 strain) -pseudotyped lentiviruses harboring a luciferase-encoding reporter gene were generated by plasmid transfection. Two different types of viruses were produced: wild type (encoding aspartic acid at position 350; 350D) and mutant (mutated to encode glutamic acid at position 350; D350E). Prior to infection of cells, pseudotyped lentiviruses were pre-incubated for two hours with four-fold serial dilutions of CK47 (ranging from 1:200 to 1:204800). Infectivity was evaluated at 72 hours post-infection by measuring luciferase activity. (a) Dose-dependent inhibition curve of CHIKV-pseudotyped lentivirus by CK47; CHIKV Asian genotype wild type (CK12–686 350D) is shown as a black line and mutant (CK12–686 D350E) is shown as a red line. Data represents mean of infection normalized to pseudotyped lentivirus-infected cells without antibody; error bars indicate standard error of the mean (SEM) of three independent experiments. (b) Probit analysis was performed to determine value of the mAb dilution that showed inhibition of half of the maximum infection (EC₅₀) by Asian-genotype virus. Bars represent mean EC₅₀ of CK47 on CHIKV Asian genotype wild type CK12–686 350D (black), and mutant CK12–686 D350E (red); error bars indicate SEM. P-values indicate statistical significance of mean EC₅₀ analyzed by unpaired, two-tailed Student t-test.