The cotton-top tamarin revisited: Mhc class I polymorphism of wild tamarins, and polymorphism and allelic diversity of the class II DQA1, DQB1, and DRB loci

1994 ◽  
Vol 40 (3) ◽  
pp. 167-176 ◽  
Author(s):  
Ulf Gyllensten ◽  
Tomas Bergstr�m ◽  
Agnetha Josefsson ◽  
Mats Sundvall ◽  
Anne Savage ◽  
...  
Keyword(s):  
Mhc Class I ◽  
Allelic Diversity ◽  
Class Ii ◽  
Class I

scholarly journals Allelic diversity and patterns of selection at the major histocompatibility complex class I and II loci in a threatened shorebird, the Snowy Plover (Charadrius nivosus)

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Medardo Cruz-López ◽  
Guillermo Fernández ◽  
Helen Hipperson ◽  
Eduardo Palacios ◽  
John Cavitt ◽  
...  
Keyword(s):  
Mhc Class I ◽  
Mhc Class Ii ◽  
Balancing Selection ◽  
Allelic Diversity ◽  
Class Ii ◽  
Class I ◽  
Mhc Genes ◽  
Snowy Plover ◽  
Snowy Plovers ◽  
Private Alleles

Abstract Background Understanding the structure and variability of adaptive loci such as the major histocompatibility complex (MHC) genes is a primary research goal for evolutionary and conservation genetics. Typically, classical MHC genes show high polymorphism and are under strong balancing selection, as their products trigger the adaptive immune response in vertebrates. Here, we assess the allelic diversity and patterns of selection for MHC class I and class II loci in a threatened shorebird with highly flexible mating and parental care behaviour, the Snowy Plover (Charadrius nivosus) across its broad geographic range. Results We determined the allelic and nucleotide diversity for MHC class I and class II genes using samples of 250 individuals from eight breeding population of Snowy Plovers. We found 40 alleles at MHC class I and six alleles at MHC class II, with individuals carrying two to seven different alleles (mean 3.70) at MHC class I and up to two alleles (mean 1.45) at MHC class II. Diversity was higher in the peptide-binding region, which suggests balancing selection. The MHC class I locus showed stronger signatures of both positive and negative selection than the MHC class II locus. Most alleles were present in more than one population. If present, private alleles generally occurred at very low frequencies in each population, except for the private alleles of MHC class I in one island population (Puerto Rico, lineage tenuirostris). Conclusion Snowy Plovers exhibited an intermediate level of diversity at the MHC, similar to that reported in other Charadriiformes. The differences found in the patterns of selection between the class I and II loci are consistent with the hypothesis that different mechanisms shape the sequence evolution of MHC class I and class II genes. The rarity of private alleles across populations is consistent with high natal and breeding dispersal and the low genetic structure previously observed at neutral genetic markers in this species.

MHC Sınıf I ve MHC Sınıf II Gen Düzenlenmesi

2020 ◽  
Vol 8 (3) ◽  
pp. 144-156
Author(s):  
Şule KARATAŞ ◽  
Fatma SAVRAN OĞUZ
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Gene Regulation ◽  
Mhc Class I ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Class I ◽  
Mhc Molecules ◽  
Class Ii Mhc ◽  
Regulation Mechanisms

Introduction: Peptides obtained by processing intracellular and extracellular antigens are presented to T cells to stimulate the immune response. This presentation is made by peptide receptors called major histocompatibility complex (MHC) molecules. The regulation mechanisms of MHC molecules, which have similar roles in the immune response, especially at the gene level, have significant differences according to their class. Objective: Class I and class II MHC molecules encoded by MHC genes on the short arm of the sixth chromosome are peptide receptors that stimulate T cell response. These peptides, which will enable the recognition of the antigen from which they originate, are loaded into MHC molecules and presented to T cells. Although the principles of loading and delivering peptides are similar for both molecules, the peptide sources and peptide loading mechanisms are different. In addition, class I molecules are expressed in all nucleated cells while class II molecules are expressed only in Antigen Presentation Cells (APC). These differences; It shows that MHC class I is not expressed by exactly the same transcriptional mechanisms as MHC class II. In our article, we aimed to compare the gene expressions of both classes and reveal their similarities and differences. Discussion and Conclusion: A better understanding of the transcriptional mechanisms of MHC molecules will reveal the role of these molecules in diseases more clearly. In our review, we discussed MHC gene regulation mechanisms with presence of existing informations, which is specific to the MHC class, for contribute to future research. Keywords: MHC class I, MHC class II, MHC gene regulation, promoter, SXY module, transcription

scholarly journals Identification of MHC class II restricted T-cell-mediated reactivity against MHC class I binding Mycobacterium tuberculosis peptides

Immunology ◽  
2011 ◽  
Vol 132 (4) ◽  
pp. 482-491 ◽  
Author(s):  
Mingjun Wang ◽  
Sheila T. Tang ◽  
Anette Stryhn ◽  
Sune Justesen ◽  
Mette V. Larsen ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
Mhc Class I ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Class I

Towards a systems understanding of MHC class I and MHC class II antigen presentation

2011 ◽  
Vol 11 (12) ◽  
pp. 823-836 ◽  
Author(s):  
Jacques Neefjes ◽  
Marlieke L. M. Jongsma ◽  
Petra Paul ◽  
Oddmund Bakke
Keyword(s):  
Antigen Presentation ◽  
Mhc Class I ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Class I ◽  
Class Ii Antigen ◽  
Mhc Class Ii Antigen

scholarly journals Th-1 polarization is regulated by dendritic-cell comparison of MHC class I and class II antigens

Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4213-4223 ◽  
Author(s):  
William K. Decker ◽  
Dongxia Xing ◽  
Sufang Li ◽  
Simon N. Robinson ◽  
Hong Yang ◽  
...  
Keyword(s):  
Mhc Class I ◽  
Class Ii ◽  
Class I ◽  
Antigenic Specificity ◽  
Type I ◽  
Peptide Epitopes ◽  
Transcriptional Signature ◽  
Surface Marker Expression ◽  
Conceptual Explanations ◽  
Th 1

Abstract In the control of T-helper type I (Th-1) polarization, dendritic cells (DCs) must interpret a complex array of stimuli, many of which are poorly understood. Here we demonstrate that Th-1 polarization is heavily influenced by DC-autonomous phenomena triggered by the loading of DCs with antigenically matched major histocompatibility complex (MHC) class I and class II determinants, that is, class I and II peptide epitopes exhibiting significant amino acid sequence overlap (such as would be physiologically present during infectious processes requiring Th-1 immunity for clearance). Data were derived from 13 independent antigenic models including whole-cell systems, single-protein systems, and 3 different pairs of overlapping class I and II binding epitopes. Once loaded with matched class I and II antigens, these “Th-1 DCs” exhibited differential cytokine secretion and surface marker expression, a distinct transcriptional signature, and acquired the ability to enhance generation of CD8+ T lymphocytes. Mechanistically, tRNA-synthetases were implicated as components of a putative sensor complex involved in the comparison of class I and II epitopes. These data provide rigorous conceptual explanations for the process of Th-1 polarization and the antigenic specificity of cognate T-cell help, enhance the understanding of Th-1 responses, and should contribute to the formulation of more effective vaccination strategies.

Targeting antigen to MHC Class I and Class II antigen presentation pathways for malaria DNA vaccines

2007 ◽  
Vol 111 (2) ◽  
pp. 92-102 ◽  
Author(s):  
Carlota Dobaño ◽  
William O. Rogers ◽  
Kalpana Gowda ◽  
Denise L. Doolan
Keyword(s):  
Antigen Presentation ◽  
Mhc Class I ◽  
Dna Vaccines ◽  
Class Ii ◽  
Class I ◽  
Class Ii Antigen
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