Fig. 5.

CD4 help enhances proliferation of memory-like Clone 4 CD8⁺ T cells in the pLNs of InsHA mice. (A) Irradiated InsHA mice were either injected with 5 × 10⁶ CFSE-labeled naive HNT Thy1.1⁺ CD4⁺ T cells or PBS. On day 10, both groups of mice were refilled with 100 × 10⁶ spleen and LN cells from unmanipulated InsHA mice. Three days later, the refilled InsHA mice received enriched CFSE-labeled memory-like Clone 4 Thy1.1⁺ CD8⁺ T cells, generated by injection of naive cells into irradiated BALB/c mice 13 days earlier. Five days after secondary transfer, InsHA mice were killed, and donor CD8⁺ Thy1.1⁺ lymphocytes from pLN, LN, and spleen were analyzed by FACS. Histograms represent CFSE fluorescence on gated CD8⁺ Thy1.1⁺ lymphocytes. (B) The presence of CD8⁺ Thy1.1⁺ and CD8⁻ Thy1.1⁺ donor T cells in the pancreas was evaluated by FACS. FACS event counts in the depicted gates are indicated. (C) Plots represent expression of CD44, CD62L, and CD25 as a function of CFSE fluorescence on gated CD8⁺ Thy1.1⁺ lymphocytes in the pLN. Data from 1 representative experiment of 3 are presented.