Figure 1.
CD8 expression is down-regulated on responding T cells during viral and bacterial infections. Ly5.2 mice adoptively transferred with naive OT-I.PL T cells were inoculated with 5 × 106 PFU VV-OVAp per mouse, or 104 LM-OVA i.p. At the indicated time points, spleens were harvested, and OT-I and endogenous CD8 T cells were identified using CD8 and Thy 1.1 staining. Representative staining of CD8 levels on OT-I cells after VV-OVAp (A) infection or LM-OVA (B) infection are shown. Dashed lines indicate CD8 expression levels of uninfected controls and OT-I cells at day 7 of infection. (C) Kinetics of CD8 down-regulation in infections. Each of the values represents the mean of three or more mice, and error bars represent the SD. Data are representative of more than four experiments. (D) OT-I.PL cells were adoptively transferred and primed with VV-OVAp, as described. At days 3, 5, and 7 after infection, OT-I cells were sorted from the spleen and RNA isolated. Naive OT-I CD8 T cells were sorted as a control. Equivalent amounts of total RNA were used for generation of cDNA, and real-time PCR was used to quantify expression of CD8α, CD8β, and GAPDH. Each column represents the fold change compared with naive samples, and the experiment was repeated with similar results.