WT mice were injected s.c. with B16-SIY melanoma cells and treated with control IgG, anti-CD73, anti-4-1BB, or both anti-CD73 and anti-4-1BB. (a) Tumor size (5 mice/group). (b) Survival curves. Percentage of CD4+ (c) or CD8+ (d) among tumor-infiltrating CD45+ T cells, and percentage of Foxp3+ (e) among total tumor-infiltrating CD4+ T cells. Ratios of CD4+Foxp3- (effectors) to CD4+Foxp3+ (Tregs) cells (f), and CD8+ to Gr1+CD11b+ MDSCs (g). Representative flow dot plots for percentage of IFN-γ+ in tumor-infiltrating CD8+ T cells (h), and the ratio of CD8+IFN-γ+ to CD4+Foxp3+ Tregs (i). (j)(k) Detection of infiltrating SIY-specific CD8+ T cells. 

Strain specific CD73 expression analysis in wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice by flow cytometry.  Splenocytes were collected from wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice, stimulated with anti-CD3ε in vivo (7.5 μg/mice for 24 hours, i.p.). Mouse CD73 was only detectable in wild-type mice. Human CD73 was only detectable in homozygous B-hCD73/h4-1BB mice.

Strain specific CD73 expression analysis in wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice by flow cytometry.  Splenocytes were collected from wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice, stimulated with anti-CD3ε in vivo (7.5 μg/mice for 24 hours, i.p.). Mouse CD73 was only detectable in wild-type mice. Human CD73 was only detectable in homozygous B-hCD73/h4-1BB mice.

Strain specific CD73 expression analysis in wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice by flow cytometry.  Splenocytes were collected from wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice, stimulated with anti-CD3ε in vivo (7.5 μg/mice for 24 hours, i.p.). Mouse CD73 was only detectable in wild-type mice. Human CD73 was only detectable in homozygous B-hCD73/h4-1BB mice.

Strain specific 4-1BB expression analysis in wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice by flow cytometry.  Splenocytes were collected from wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice, stimulated with anti-CD3ε in vivo (7.5 μg/mice for 24 hours, i.p.). Mouse 4-1BB was only detectable in wild-type mice. Human 4-1BB was only detectable in homozygous B-hCD73/h4-1BB mice.

Strain specific 4-1BB expression analysis in wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice by flow cytometry.  Splenocytes were collected from wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice, stimulated with anti-CD3ε in vivo (7.5 μg/mice for 24 hours, i.p.). Mouse 4-1BB was only detectable in wild-type mice. Human 4-1BB was only detectable in homozygous B-hCD73/h4-1BB mice.

Strain specific 4-1BB expression analysis in wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice by flow cytometry.  Splenocytes were collected from wild-type C57BL/6 mice and homozygous B-hCD73/h4-1BB mice, stimulated with anti-CD3ε in vivo (7.5 μg/mice for 24 hours, i.p.). Mouse 4-1BB was only detectable in wild-type mice. Human 4-1BB was only detectable in homozygous B-hCD73/h4-1BB mice.