FIG. 6.

IHC analyses of tissue sections from TR339-infected IFN-α/βR^−/− mice. Magnification, ×400. (A) Distribution of Sindbis virus antigen in the DLN at 24 h p.i. (detected by using CY2-conjugated secondary antibody and visualized by using an FITC filter). (B) Spleen at 24 h p.i. costained for Sindbis virus antigen (CY2) and B-cell marker, B220 (Texas red). Micrographs were taken with FITC and Texas red filters superimposed to demonstrate localization of Sindbis virus antigen in the splenic marginal zone surrounding B-cell follicle. Panels C and D represent TR339-infected spleen, at 24 h p.i., costained for Sindbis virus antigen (CY2) and macrophage marker, Mac-1 (Texas red), respectively. Cells on which virus antigen and Mac-1 colocalize are indicated with paired arrows. Panels E and F show anti-Sindbis (CY2) and Mac-1 (Texas red) costaining, respectively, in the spleen at 72 h p.i. Extensive colocalization of signal is evident, as indicated by paired arrows, and the tissue appears to be severely damaged in keeping with ISH and H&E data. Panels G and H show colocalization of Sindbis virus antigen (CY2) and the Küpffer cell marker, F4/80 (Texas red), in virus-infected liver at 72 h p.i.