PDCD1 and lymphoma: The splenocytes from mice treated with (MS@OVAinMOF)@(polyICinMOF) plus a low dose of i.p. anti-PD-1 (group f) show significantly higher cytotoxicity against E.G7-OVA lymphoma cells expressing OVA than those from mice treated with groups free OVA plus a high dose of i.p. anti-PD-1 (group a), only free OVA (group b), free OVA plus a low dose of i.p. anti-PD-1 (group c), OVAonMS plus a low dose of i.p. anti-PD-1 (group d), and OVA/polyIConMS plus a low dose of i.p. anti-PD-1 (group e).