CD4 and neoplasm: Bilateral subcutaneous humanised PD-1 transgenic mouse tumour model with single-sided intra-tumoural OV injection:Survival: prolonged survival compared to parental OV and untreatedDisease control: significantly decreased tumour growth compared to parental OV and untreated, with successful tumour rejection upon rechallengeImmune response: significantly increased systemic CD8+ T cell and effector and central memory T cell proportions; significantly decreased PD-1+ CD4+ and CD8+ T cell proportions