Immune status of BALB/c scid mice. A. ELISA measurement of serum IgG levels in BALB/c and BALB/c scid mice (n = 5 per group; dashed line denotes lower limit of detection). B. Flow cytometric measurement of the abundance of CD4+ T cells, CD8+ T cells, and CD3- CD49b+ NK cells in the spleens of BALB/c versus scid mice (n = 10 per group). "Other WBCs" refers to the fraction of spleen cells not labeled by antibodies against CD3, CD4, CD8, and CD49b. C and D. Effect of adoptively transferred naïve lymphocytes on scid mouse resistance to HSV-1. C. Viral titers per eye (dashed line denotes lower limit of detection) and D. duration of survival of scid mice inoculated with 2 × 105 pfu/eye HSV-1 strain KOS. On day 7 p.i., scid mice (n = 8 per group) received an i.v. injection of medium (vehicle) or medium containing 5 × 106 B cells, T cells, or unfractionated WBCs (total WBCs) obtained from naïve BALB/c donors.