The heterogeneity of lymphocytes and their interaction.
D000917:Antibody Formation; D006087:Graft vs Host Reaction; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular; D008214:Lymphocytes / Q000276:immunology*; D008938:Mitosis; D012882:Skin Tests; D013950:Thymus Gland / Q000276:immunology