Figure 2.

Transgenic mice with Cre recombinase under the control of the endogenous OX40 promoter were crossed with GFP reporter mice to generate F₁ mice that show stable expression of GFP in cells that have expressed OX40. OX40Cre⁺ GFP⁺ or littermates were injected subcutaneously with MCA205 tumours and the tumour-infiltrating cells were harvested at day 14. (a) Dot plots show GFP expression in peripheral blood mononuclear cells (PBMC) or tumour-infiltrating cells from tumour-bearing OX40Cre⁺ GFP⁺ F₁ mice or littermates. (b) CD4 and CD8 expression on gated GFP⁺ cells in the peripheral blood of a naive mouse or in a tumour. (c) GFP expression in gated d14 tumour-infiltrating CD4⁺ or CD11b⁺ cells from OX40Cre⁺ GFP⁺ or littermates. (d) Analysis of CD44 expression on gated CD8⁺ cells in the tumour-draining lymph node, non-draining lymph node and tumour of day 17 tumour-bearing OX40Cre⁺ GFP⁺ mice or littermates.