CD4 and neoplasm: Given that MB49 regression does not take place in mice devoid of T and B cells (Fig 1), the pattern of immune infiltrate thus suggest an efficient anti-tumour cytotoxic CD8+ T-cell response against MB49, and an impairment of the immune response by regulatory T cells and possibly some IL17A-expressing CD4+ (Th17) and CD8+ (Tc17) lymphocytes in MB49-I tumours.