Biological effect of varying peptide binding affinity to the BoLA-DRB3*2703 allele
Biological effect of varying peptide binding affinity to the BoLA-DRB3*2703 allele
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DOI：
10.1051/gse:2003016
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发表时间：
2003-01-01
影响因子：
4.1
通讯作者：
Mallard, BA
中科院分区：
文献类型：
--
作者：
Alizadeh, Z;Karrow, N;Mallard, BA
MHC I类和II类分子是免疫调节细胞表面糖蛋白，其选择性结合T淋巴细胞并将抗原肽呈递给T淋巴细胞。鼠和人的研究表明，可变肽结合亲和力的MHC 11分子的影响Th 1/Th 2的反应，诱导独特的细胞因子的表达。为了检测肽与牛MHC（BoLA）结合的生物学效应，（BoLA-DQ和纤维蛋白原片段）和来自卵清蛋白（OVA）的非自身肽，以及来自口蹄疫病毒（FMD-V）的VP 2和VP 4肽用于（1）测定与BoLA-DRB 3 *2703等位基因的结合亲和力，先前与乳腺炎易感性相关，和（2）确定肽结合亲和力是否影响T淋巴细胞功能。肽结合亲和力通过竞争性测定法测定，所述测定法使用高亲和力生物素化的自身肽，在各种浓度的竞争性肽的存在下与纯化的BoLA-DRB 3 *2703孵育。抑制自身肽结合50%所需的非自身肽的浓度（IC 50）是可变的，范围为26.92至> 320 μ M。通过测量来自BoLA-DRB 3 *2703纯合奶牛的单核细胞培养物中的DNA合成、细胞分裂和IFN-γ产生来确定肽特异性T淋巴细胞功能。当与未刺激的对照培养物相比时，观察到所有评估参数的淋巴细胞功能差异;然而，肽结合亲和力并不总是解释观察到的淋巴细胞功能差异。
MHC class I and II molecules are immunoregulatory cell surface glycoproteins, which selectively bind to and present antigenic peptides to T-lymphocytes. Murine and human studies show that variable peptide binding affinity to MHC 11 molecules influences Th1/Th2 responses by inducing distinctive cytokine expression. To examine the biological effects of peptide binding affinity to bovine MHC (BoLA), various self peptides (BoLA-DQ and fibrinogen fragments) and non-self peptides from ovalbumin (OVA), as well as VP2 and VP4 peptides from foot and mouth disease virus (FMD-V) were used to (1) determine binding affinities to the BoLA-DRB3*2703 allele, previously associated with mastitis susceptibility and (2) determine whether peptide binding affinity influences T-lymphocyte function. Peptide binding affinity was determined by a competitive assay using high affinity biotinylated self-peptide incubated with purified BoLA-DRB3*2703 in the presence of various concentrations of competing peptides. The concentrations of non-self peptide required to inhibit self-peptide binding by 50% (IC50) were variable, ranging from 26.92 to > 320 muM. Peptide-specific T-lymphocyte function was determined by measuring DNA synthesis, cell division, and IFN-gamma production in cultures of mononuclear cells from a BoLA-DRB3*2703 homozygous cow. When compared to non-stimulated control cultures, differences in lymphocyte function were observed for all of the assessed parameters; however, peptide-binding affinity did not always account for the observed differences in lymphocyte function.