Figure 1. CD27 and CD70 regulate surface expression of their respective binding partner.

A. WT, CD70^−/−, or CD27^−/− T cells were immunized with 50μg polyI:C and 50 μg αCD40 intraperitoneally (polyI:C+αCD40) or not at all (naïve). 24 hours later mice were sacrificed and T cells were isolated from spleens. Shown is the expression of CD27 of B220⁻, CD8⁺ cells from indicated mice. (see supplemental Fig 3 for CD8+ T cell gating strategy) B. Geometric mean fluorescence intensity (gMFI) of CD27 expression on B220⁻, CD8⁺ T cells from mouse groups described in A where gray bars are naïve and white bars are polyI:C+αCD40 activated BMDCs. C. Dendritic cell activation 24 hours post immunization as in A and B. CD70 gMFI from WT (black bars), CD27^−/− (white bars), and CD70−/− (gray bars) was calculated from CD11c⁺, B220⁻, CD11b⁻, CD8⁺ cells using flow cytometery. (see supplemental Fig 3 for DC gating strategy) D. CD70 expression profile of LPS activated bone marrow derived dendritic cells (BMDCs) co-cultured with WT (white histogram), CD27^−/− (gray histogram), WT+ RM27 (CD27 blocking antibody) (dashed line) or without T cells (black histogram). E. Quantitation of CD70 gMFI from D. F. BMDCs activated with LPS and pulsed with either SIINFEKL (OT1 peptide) were co-cultured with CD8 T cells specific for SIINFEKL (OT1) or specific for SSIEFARL (GBT) or without T cells. Shown is the percent of maximum CD70 gMFI calculated from BMDCs at the respective time point without T cells. Each experiment was performed with at least three replicates per group and more than four independent times with similar results. Data shown is from representative experiments. Data shown is the mean +/−SEM. Asterisks represent values that are significantly different using a students t-test with a p-value less than 0.05. Only values that were significant across experiments are shown with an asterisk.