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Characterization of bovine gammadelta T cell WC1 coreceptors: Sequence, expression, and function

Chuang Chen, University of Massachusetts Amherst

Abstract

To better characterize the WC1 coreceptor family, by adapting Q-PCR for quantification, thirteen functional genes were found associated with ten different breeds of animals and the domain 1 sequence for an individual gene is highly conserved among breeds, with zero to three amino acids differences found per gene. Despite these differences, phylograms confirmed that the evolutionary divergence between individual WC1 genes was still greater than the divergence among animals for a particular gene. Analysis of the WC1 cDNA sequences indicated that the thirteen WC1 genes code for three distinct WC1 forms. ^ We mapped the epitopes to particular SRCR domains and evaluated their distribution among WC1 molecules. We found that mAb CC15 is a pan-reactive anti-WC1 mAb recognizing an epitope in the closely related SRCR domains 2 and 7. Five other broadly-reactive anti-WC1 mAbs recognize epitopes in the related SRCR domains 4 and 9. Finally, the subpopulation-specific anti-WC1 mAbs were found to react with epitopes in the most variable WC1 domain, i.e. domain 1. ^ By applying real-time QPCR and quantification analysis of the serologically defined subpopulations of bovine γδ T cells, three subpopulations of WC1+ γδ T cells can be characterized by different expression patterns of thirteen WC1 genes. We for the first time determined the sites of tyrosine phosphorylation in both Type II (WC1-9) and Type III (WC1-11) cytoplasmic tail sequences in vivo. We found that tyrosine phosphorylation sites were different among WC1 cytoplasmic tails and observed that optimal levels of tyrosine phosphorylation and the time to reach the optimal level varied among them. WC1 cytoplasmic domain phosphorylation was also associated to its function in that three types of WC1 cytoplasmic tails resulted in WC1-mediated potentiation of the TCR-induced stimulation of Jurkat T cells at different levels. Co-crosslinking of TCR and the Type III (WC1-11) WC1 cytoplasmic tail induced the highest amount of Jurkat T cells IL-2 production, followed by co-crosslinking of TCR and the Type II (WC1-9) WC1 cytoplasmic tail. Similar findings were obtained in ex vivo primary bovine γδ T cells by using various anti-WC1 mAbs that reacted with WC1 molecules with different types of WC1 cytoplasmic tails.^

Subject Area

Immunology

Recommended Citation

Chen, Chuang, "Characterization of bovine gammadelta T cell WC1 coreceptors: Sequence, expression, and function" (2012). Doctoral Dissertations Available from Proquest. AAI3545909.
http://scholarworks.umass.edu/dissertations/AAI3545909

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