The MHC is a linked cluster of genes and gene families and is one of the most extensively studied regions of the genome in several species, including humans and mice. Overview of the canine major histocompatibility complexĪn understanding of the general structure and function of the MHC is helpful in order to comprehend its importance in transplantation and disease. These similarities suggest that perhaps these ‘receptors’ of the immune system have descended from a common ancestral gene and are members of one supergene family. The DNA sequences of the MHC class I exon 3, the class II exon 2 and the exon sequences encoding the immunoglobulin constant regions as well as parts of the T cell receptorĪre homologous. During gene expression, RNA splicing usually occurs between the first and second base of the junctional codon. The sizes of the external domains and the placement of disulphide bridges are similar. These genes exhibit a precise correlation between exons and the protein domains they encode. There are several similarities between T cell receptors, immunoglobulin molecules, and MHC class I and class II molecules. Similarly T cells depend on specialized cells such as B cells which process peptide antigens and present these peptides bound to MHC molecules (Klein, 1982). B cells recognize antigens in their native form and depend on T cells to expand clonally to become plasma cells and produce antibodies (immunoglobulins). Another important genetic element in the immune system is the major histocompatibility complex (MHC) which is complex due to a variety of allelic variants at several loci.ĭespite the complexities of the mammalian immune system, different components act in a coordinated manner. The major components of the immune system include the T cells and the B cells which are polymorphic because of gene segment rearrangements, point mutations and gene conversion leading to a variety of T cell receptor (TCR) and B cell receptor (a membrane immunoglobulin) phenotypes.
#1784 PCR 800, PERRYVILLE, MO SERIES#
In dogs, as in other mammals, the immune system has a complex series of functions including distinguishing self from non-self as well as the ability to ‘recall’ previous foreign antigen exposure. The immune system of dogs protects them from a variety of infectious agents. For over 40 years the dog has served as a valuable model for haematopoietic stem cell transplants (reviewed in Thomas and Storb, 1999). Dogs have high rates of spontaneous malignancies and thus have served as models for a variety of cancers including breast cancer (Mol et al., 1999), non-Hodgkin’s lymphoma (Weiden et al., 1979) and prostate cancer (Navone et al., 1998–1999). The dog serves as an important model for drug toxicity trials and for a variety of human diseases such as cyclic neutropenia (Weiden et al., 1974), X-linked severe combined immunodeficiency syndrome (SCID) (reviewed in Felsburg et al., 1999), von Willebrand’s disease (reviewed in Thomas, 1996), severe hereditary haemolytic anaemia (Weiden et al., 1976), haemophilia (reviewed in Fogh et al., 1984), gluten-sensitive enteropathy (Hall and Batt, 1990), rheumatoid arthritis (Halliwell et al., 1972), systemic lupus erythematous (Lewis and Schwartz, 1971) and narcolepsy (Baker et al., 1982). Knowledge of the canine immune system is valuable not only for understanding the pathogenesis of several human diseases, but also for improving canine health. T Cell Receptors and Other T Cell Surface Proteins Molecular analyses – genes and polymorphismĬanine major histocompatibility complex and disease Overview of the canine major histocompatibility N., Seattle, WA 98109, USA 3Division of Immunogenetics, Institute of Animal Breeding, Bremgartenstrasse 109A, 3012-Berne, Switzerland Marti 3ġUniversity of Washington School of Medicine, Department of Medicine 2Transplantation Biology, Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave.
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