(a) Polyclonal anti–EBNA1-6 human antisera (CP). Nuclear positive staining on HBL-6 (KSHV⁺, EBV⁺) cells. (630× magnification). (b) Polyclonal anti–EBNA1-6 (CP) shows all EBV⁺ B958 cells have nuclear reactivity. (c) Monoclonal anti–EBNA-2 shows no staining of HBL-6 cells, but B958 cells are positive (d).