FIG. 5.

Immunohistochemistry of lymphoid organs (the tissues in each column from top to bottom represent bursa, thymus, and spleen) of 15 × 7 MDV maternal antibody-negative chickens 6 days after inoculation with control (A, B, and C), rMd5 (D, E, and F), rMd5/ΔvIL-8 (G, H, and I), rMd5/vIL-8-ELR (J, K, and L), or rMd5/ΔvIL-8-RV (M, N, and O). MAb against pp38 (H19) was used for the staining. Antigen expression in lymphoid organs is severely impaired only in rMd5/ΔvIL-8, showing that vIL-8 is involved in early cytolytic infection in lymphocytes.