Delves, PhD, University College London, London, UK Reviewed / Revised Sep 2021 | Modified Sep 2022 View Patient Education Antigen-Presenting Cells Lymphocytes Mast Cells Natural Killer (NK) Cells Polymorphonuclear Leukocytes Topic Resources Two-signal model for T-cell... Macrophage Subtypes Functions of T Cells The immune system consists of cellular components and molecular components that work together to destroy antigens.