title: Reciprocity in lymphocyte interactions.
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology; D001402:B-Lymphocytes / Q000502:physiology; D006801:Humans; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008214:Lymphocytes / Q000502:physiology*; D008222:Lymphokines / Q000502:physiology; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology
chemical_list: D008222:Lymphokines