Figure 2.

TCL1 antisera staining of formalin-fixed tissues. An intense positive signal was confined to the large immunoblastic/plasmacytic tumor cells in AIDS IBLP 1 (A, ×400X; B, ×1,000 magnification), whereas non-AIDS IBLP 1 (C, ×400; D, ×1,000 magnification) was negative. Non-tumor cell elements were negative for TCL1 protein expression in both samples. TCL1 staining appeared mainly within the cytoplasm. Germinal center B cells also stained with TCL1 antisera (E, ×100; F, ×200 magnification). Both uninfected and HIV-infected (data not shown) HYP contained activated germinal centers that reacted with TCL1 antisera. In these samples, TCL1 staining was most intense in naive, nonproliferating mantle-zone B cells and in rare interfollicular zone cells of unknown phenotype. A reduced staining intensity was seen in follicle-center cells (centroblasts and centrocytes). Overall, the level of staining in the different tissues analyzed correlated with the TCL1 transcript levels detected by virtual Northern analysis.