central memory T cells (TCM)   Memory lymphocytes that express CCR7 and recirculate between blood and secondary lymphoid tissues similarly to naive T cells. They require restimulation in secondary lymphoid tissues to become fully mature effector T cells.
central tolerance Immunological tolerance to self antigens that is established while lymphocytes are developing in central lymphoid organs. Cf. peripheral tolerance.
centroblasts   Large, rapidly dividing activated B cells present in the dark zone of germinal centers in follicles of peripheral lymphoid organs.
centrocytes Small B cells that derive from centroblasts in the germinal centers of follicles in peripheral lymphoid organs; they populate the light zone of the germinal center.
cGAS (cyclic GAMP synthase) A cytosolic enzyme that is activated by double-stranded DNA to form cyclic guanosine monophosphate-adenosine monophoshate. See cyclic dinucleotides (CDNs).
checkpoint blockade Approach to tumor therapy that attempts to interfere with the normal inhibitory signals that regulate lymphocytes.
Chediak–Higashi syndrome A defect in phagocytic cell function caused by a defect in a protein involved in intracellular vesicle fusion. Lysosomes fail to fuse properly with phagosomes, and killing of ingested bacteria is impaired.
chemokines Small chemoattractant protein that stimulates the migration and activation of cells, especially phagocytic cells and lymphocytes. Chemokines have a central role in inﬂammatory responses. Properties of individual chemokines are listed in Appendix IV.
chemotaxis Cellular movement occurring in response to chemical signals in the environment.
chimeric antigen receptor (CAR) Engineered fusion proteins composed of extracellular antigen-specific receptors (e.g., single-chain antibody) and intracellular signaling domains that activate and co-stimulate, expressed in T cells for use in cancer immunotherapy.
chronic allograft vasculopathy Chronic damage that can lead to late failure of transplanted organs. Arteriosclerosis of graft blood vessels leads to hypoperfusion of the graft and its eventual fibrosis and atrophy.
chronic granulomatous disease (CGD) An immunodeficiency in which multiple granulomas form as a result of defective elimination of bacteria by phagocytic cells. It is caused by defects in the NADPH oxidase system of enzymes that generate the superoxide radical involved in bacterial killing.
An autoinﬂammatory disease due to defects in the gene NLRP3, one of the components of the inﬂammasome.
chronic rejection   Late failure of a transplanted organ, which can be due to immunological or nonimmunological causes.
CIIV An early endocytic compartment containing MHC class II molecules in dendritic cells.
class I cytokine receptors A group of receptors for the hematopoietin superfamily of cytokines. These include receptors using the common γ chain for IL-2, IL-4, IL-7, IL-15, and IL-21, and a common β chain for GM-CSF, IL-3, and IL-5.
class II-associated invariant chain peptide (CLIP) A peptide of variable length cleaved from the invariant chain (Ii) by proteases. It remains associated with the MHC class II molecule in an unstable form until it is removed by the HLA-DM protein.
class II cytokine receptors A group of heterodimeric receptors for a family of cytokines that includes interferon (IFN)-α, IFN-β, IFN-γ, and IL-10.