*'''Cytokines''' - Protein molecules released by cells when activated by antigen, involved with cell-to-cell comunications, acting as enhancing mediators for immune responses through interaction with specific cell-surface receptors on leukocytes | *'''Cytokines''' - Protein molecules released by cells when activated by antigen, involved with cell-to-cell comunications, acting as enhancing mediators for immune responses through interaction with specific cell-surface receptors on leukocytes |