To evaluate the downstream effects of anti-Ly6a crosslinking, we examined the effect of anti-Ly6a antibodies on CD8+ T cell activity in the presence and absence of target tumor cells by high-resolution mass spectrometry proteomic analyses. Spleen cells were isolated from gp10025–33 TCR transgenic mice and incubated for 3 days with IL-2, IFNα, and gp10025–33 peptide. Next, CD8+ T-cells were isolated and incubated overnight with anti-Ly6a antibody (or IgG with or without B16F10 melanoma cells. CD8+ T-cells were then sorted and subjected to proteomic analysis using high-resolution mass spectrometry