CD1d-restricted invariant NK T (iNKT) cells and dendritic cells (DCs) have been shown to play crucial roles in various types of immune responses, including TLR9-dependent antiviral responses initiated by plasmacytoid DCs (pDCs). However, the mechanism by which this occurs is enigmatic because TLRs are absent in iNKT cells and human pDCs do not express CD1d. To explore this process, pDCs were activated with CpG oligodeoxyribonucleotides, which stimulated the secretion of several cytokines such as type I and TNF-α. These cytokines and other soluble factors potently induced the expression of activation markers on iNKT cells, selectively enhanced double-negative iNKT cell survival, but did not induce their expansion or production of cytokines. Notably, pDC-derived factors licensed iNKT cells to respond to myeloid DCs: an important downstream cellular target of iNKT cell effector function and a critical contributor to the initiation of adaptive immune responses. This interaction supports the notion that iNKT cells can mediate cross-talk between DC subsets known to express mutually exclusive TLR and cytokine profiles.
Pig immunoreceptor DAP10 cDNA was cloned from a peripheral blood lymphocyte (PBL) cDNA library using human DAP10 cDNA as a probe. The length of the pig DAP10 cDNA is 465 bp and it contains an open reading frame of 237 bp. The predicted polypeptide sequence is 79 amino acids, consisting of an 18-amino acid leader, a 16-amino acid extracellular domain, a 24-amino acid transmembrane segment, and a 21-amino acid cytoplasmic domain. The amino acid sequence of pig DAP10 has 68% and 78% sequence identity with human DAP10 and mouse DAP10, respectively. Pig DAP10 has a conserved aspartic acid in the transmembrane domain, two cysteines in the extracellular domain, and a phophatidylinositol-3 kinase-binding site (YxxM) in the cytoplasmic region. Genomic organization reveals that pig DAP10 comprises four exons and three introns. Pig DAP10 and DAP12 are genetically linked on Chromosome (Chr) 6 at 6q21 in opposite transcriptional orientation, separated by 152 bp. In Northern blot analysis, DAP10 transcripts were detected predominantly in lymphohematopoietic tissues. Pig NKG2D cDNA has an open reading frame of 642 bp. Its expected polypeptide sequence is 214 amino acids. Pig NKG2D has 66% sequence identity with human NKG2D and 56% identity with mouse NKG2D. The NKG2D gene maps to pig Chr 5q25. RT-PCR analysis reveals that pig NKG2D transcripts are expressed in PBLs, NK cells, macrophages, and monocytes. When transiently transfected into COS-7 cells, pig NKG2D requires DAP10 for cell surface expression.
CD69 is a type II membrane protein belonging to C-type lectin family receptor, and expressed on activated leukocytes. Pig CD69 was cloned by RT-PCR using degenerate primers. Pig CD69 cDNA contains a 600 bp open reading frame with its predicted polypeptide sequence of 200 amino acids. Pig CD69 has 75%, 67%, and 57% sequence identity with cow, human, and mouse CD69, respectively. A splicing isoform, which lacks exon 2 encoding the transmembrane domain, was detected. Pig CD69 gene is located on Chromosome (Chr) 5q25 where the NKG2D gene was mapped. In RT-PCR analysis, pig CD69 mRNA was detected in activated PBL, NK cells, macrophages, monocytes, and granulocytes, but not in resting cells. The inducers for CD69 gene expression were PMA, PHA, LPS, G7 mAb, PNK-E mAb, PM16-6 mAb and the K562 cell line. Moreover, CD69 mRNA is expressed in bone marrow, spleen, thymus and lymph nodes but not in muscle, mammary gland, or the pig kidney cell line (LLC-PK(1)). These results indicate that pig Chr 5q25 contains the NK gene complex and CD69 can be used as an activation marker in pig cells of innate as well as acquired immune systems.
Natural killer (NK) cells express receptors for MHC class I that contain immunoreceptor tyrosine-based inhibitory motif (ITIM) sequences in their cytoplasmic domain. Whereas these receptors inhibit NK cell cytotoxicity, certain isoforms of these NK receptors (e.g., KIR2DS, CD94/NKG2C, and Ly49D) do not have ITIMs, but associate with DAP12 and activate NK cell function. We cloned pig DAP12 cDNA from a pig peripheral blood lymphocyte (PBL) cDNA library using human DAP12 cDNA as a probe. The length of the pig DAP12 cDNA is 526 bp and contains an open reading frame of 324 bp. It has 79% identity with the human DAP12 cDNA sequence in the coding region and 73% identity with mouse DAP12 cDNA. The predicted polypeptide sequence of pig DAP12 is 108 amino acids, being composed of a 23-amino acid leader, a 14-amino acid extracellular domain, a 24-amino acid transmembrane segment, and a 47-amino acid cytoplasmic region. The amino acid sequence of pig DAP12 has 74% and 71% sequence identity with human DAP12 and mouse DAP12, respectively. Pig DAP12 has a conserved aspartic acid in the transmembrane region, and two conserved cysteine residues in the extracellular domain. It also contains an immunoreceptor tyrosine-based activation motif sequence in the cytoplasmic region. Genomic organization reveals that pig DAP12 consists of five exons and four introns. Southern blot analysis of pig genomic DNA revealed that DAP12 is a single-copy gene. In Northern blot analysis, DAP12 transcripts were detected in spleen, liver, thymus, and lymph node. DAP12 transcripts are expressed not only in PBLs, but also in granulocytes, macrophages, and monocytes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.