Cytotoxically double deficient CD8⁺populations effect barrier function in host resistance to donor progenitors.

Cytotoxically normal/wild-type B6 (wt) or B6-cdd mice were primed to BALB.B MiHA twice at 3 weeks and 1 week prior to BM transplantation. Following isolation of spleen and LN cells from these animals, unfractionated or fractionated cells (CD8⁺-depleted/enriched fractions prepared by negative and positive selections using MACS; “Materials and methods”) were transferred into naive B6 mice. Unfractionated lymphocyte transfer inoculum (for both wt and cdd) contained 1 × 10⁷CD8⁺ cells. CD8-depleted and -enriched B6-cdd lymphocyte transfer inoculum contained 1.7 × 10⁷ CD8⁺cells and 7.1 × 10⁷ CD8⁺ cells, respectively. Resistance in the adoptively transferred mice was examined by transplanting 2 × 10⁶ BALB.B marrow cells. Untransferred naive B6 recipients were provided as control. B6 recipients transferred with B6-wt or B6-cdd unfractionated cells versus no transfer: P = .0002 (CFU-IL3, left panel),P = .0017 (CFU-GM–CSF, right panel).