FIG. 4.

Epitope mapping of anti-GBV-C MAbs. (A) Patterns of competition between GBV-C E2 MAbs for binding to E2 are illustrated. Group I MAbs (M5 and M17) competed extensively with each other but not with group II or IV. Group III competed weakly with groups I and II, and universal M3 competed with all four groups. (B) GBV-C E2 (10 μg/ml) was incubated with either isotype control antibody (IC), M6 (green), or M3 (blue) prior to addition to MOLT-4 cells. Bound E2 was detected by MAb M5 and PE-conjugated isotype-specific species. M3 or IC did not block E2 binding to cells, whereas M6 neutralized E2 binding to cells.