Nfil3 A transcription factor important during the development of several types of immune cells including certain types of NK cells.
NHEJ See nonhomologous end joining.
nitric oxide A reactive molecular gas species produced by cells— particularly macrophages—during infection, that is toxic to bacteria and intracellular microbes.
nivolumab Human anti-PD-1 antibody used for checkpoint blockade in treatment of metastatic melanoma.
NK receptor complex (NKC) A cluster of genes that encode a family of receptors on NK cells.
NKG2 Family of C-type lectins that supply one of the subunits of KLR-family receptors on NK cells.
NKG2D Activating C-type lectin receptor on NK cells, cytotoxic T cells, and γ:δT cells that recognizes the stress-response proteins MIC-A and MIC-B.
NLRC4 An NLR family member that cooperates with NAIP2 and NAIP5.
NLRP family A group of 14 NOD-like receptor (NLR) proteins that contain a pyrin domain and function in the formation of a signaling complex called the inﬂammasome.
NLRP3 A member of the family of intracellular NOD-like receptor proteins that have pyrin domains. It acts as a sensor of cellular damage and is part of the inﬂammasome. Sometimes called NALP3.
N-nucleotides Nontemplated nucleotides inserted by the enzyme terminal deoxynucleotidyl transferase into the junctions between gene segments of T-cell receptor and immunoglobulin heavy-chain V regions during gene segment joining. Translation of these N-regions markedly increases the diversity of these receptor chains.
NOD subfamily A subgroup of NLR proteins that contain a CARD domain which is used for activation of downstream signaling.
NOD1, NOD2 Intracellular proteins of the NOD subfamily that contain a leucine-rich repeat (LRR) domain that binds components of bacterial cell walls to activate the NFκB pathway and initiate inﬂammatory responses.
NOD-like receptors (NLRs) Large family of proteins containing a nucleotide-oligomerization domain (NOD) associated with various other domains, and whose general function is the detection of microbes and of cellular stress.
nonamer   Conserved nine-nucleotide DNA sequence in the recombination signal sequences (RSSs) ﬂanking gene segments in the immunoglobulin and T-cell receptor loci.
non-canonical inflammasome An alternate form of the inﬂammasome that is independent of caspase 1, but instead relies on caspase 11 (mice) or caspases 4 or 5 (human).
non-canonical NFκB pathway A pathway for NFκB activation that is distinct from the one activated by antigen receptor stimulation. This pathway leads to activation of the NFκB-inducing kinase, NIK, which phosphorylates and activates IκB kinase α (IKKα) inducing cleavage of the NFκB precursor protein p100 to form the active p52 subunit.
nonclassical MHC class Ib genes A class of proteins encoded within the MHC that are related to the MHC class I molecules but are not highly polymorphic and present a restricted set of antigens.
non-depleting antibodies Immunosuppressive antibodies that block the function of target proteins on cells without causing the cells to be destroyed.
nonhomologous end joining (NHEJ) DNA repair pathway that directly ligates double-stranded DNA breaks without use of a homologous template.
nonproductive rearrangements   Rearrangements of T-cell receptor or immunoglobulin gene segments that cannot encode a protein because the coding sequences are in the wrong translational reading frame.
nonreceptor kinase Cytoplasmic protein kinases that associate with the intracellular tails of signaling receptors and help generate the signal but are not an intrinsic part of the receptor itself.