To examine whether B2M mediates CD8+ T cell retention to CRATERs, we inserted a gRNA targeting b2m into a melanoma-specific CRISPR vector24 that was injected into Tg(cd8α: EGFP) embryos along with melanoma-generating vectors (described above), inducing melanoma-specific B2M-depleted tumors (Figure S3A). The gene discussed is CD8A; the disease is melanoma.