A single parameter histogram for Flow Cytometric analysis of HCV E2 expression on surface of Huh7.5 cells using caprine anti p412 Ab. Huh7.5 cells were infected with pooled HCV positive sera. After one week cells were harvested and incubated with caprine anti p412 Ab, washed and stained with FITC labeled anti goat Ab. Labeled cells were analyzed with flow cytometry (FACS Calibure, Becton Dickinson). Results showed that the mean fluorescence intensity of the infected Huh7.5 cells (B &D) was markedly higher (30%) than the uninfected Huh7.5 cells (A & C) demonstrating the specificity of anti p412 Ab to recognize the E2 protein on surface of HCV infected cells.