Figure 4.

Identification of mouse endogenous retrovirus envelop gp70 as an immunotherapeutic target in K7M2 but not F420

(A) From the RNAseq data set, mouse retroviral transcripts were filtered to remove non-expressed transcripts in either sample. Remaining transcripts were log2-transformed and plotted. K7M2 showed 3 transcripts expressed above any in F420, and those top three highest expressed retroviral transcripts in K7M2 are labeled in both samples. Boxes represent mean and standard deviation of expression of all expressed retroviral transcripts.

(B) RNA was quantified for murine retrovirus envelope gp70 in both cell lines using real-time quantitative PCR. Error bar is standard error of the mean.

(C) Tetramer staining of intratumoral T cells following immunotherapy. Little or no staining was seen in F420, whereas all samples from K7M2 had detectable anti-gp70 T cells in K7M2. Lines are mean with standard error of the mean. The combination group was statistically higher than the anti-PD1 group (p = 0.028).

RNA: ribonucleic acid; gp70: glycoprotein 70.