Grandoni Francesco, Napolitano Francesco, Scatà Maria Carmela, De Matteis Giovanna
Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (CREA) - Centro di ricerca Zootecnia e Acquacoltura, Monterotondo, RM, 00015, Italy.
Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (CREA) - Centro di ricerca Zootecnia e Acquacoltura, Monterotondo, RM, 00015, Italy.
Vet Immunol Immunopathol. 2020 Jan;219:109957. doi: 10.1016/j.vetimm.2019.109957. Epub 2019 Oct 17.
Cluster of differentiation 4 (CD4) is the accessory protein non-covalently bounded to T cell receptor (TCR) that recognize an invariant region of MHC class II on antigen presenting cell (APC). Its cytoplasmic tail, physically associated with a protein tyrosine kinase, is important in the activation of helper/inducer T (T) lymphocytes. The anti-bovine CD4 monoclonal antibody (mAb) CC8 is a clone usefully used in flow cytometry assay in the last 20 years and no anomalous labelling has been described in previous reports. The aim of this study was to investigate the lack and reduced binding of clone CC8 to T lymphocytes in three different breeds of dairy cattle: Italian Friesian (FRI), Pezzata Rossa Friulana (PRI) and their crossbreed (MET). Two unexpected flow cytometric phenotypes were found: CC8 (reduced labelling) in 25%, 35% and 15% of the animals in the three breeds respectively, and CC8 (complete lack of labelling) in 15% of PRI cows. The complete sequencing of CD4 coding region (CDS) has allowed to identify two new missense mutations in the exon 5: Q306H and K310 N associated with the two phenotypes. A further new synonymous mutation (g.103634725 G > A) was found in exon 6. Further studies are needed to understand the effects of the news mutations, but these results demonstrate that flow cytometry is a powerful tool to discover polymorphic determinants of antigens involved in the immune responses.
分化簇4（CD4）是一种与T细胞受体（TCR）非共价结合的辅助蛋白，TCR可识别抗原呈递细胞（APC）上MHC II类分子的恒定区。其胞质尾部与一种蛋白酪氨酸激酶物理相连，在辅助/诱导性T淋巴细胞的激活中起重要作用。抗牛CD4单克隆抗体（mAb）CC8是一个在过去20年中在流式细胞术检测中有用的克隆，之前的报告中未描述过异常标记。本研究的目的是调查克隆CC8在三种不同品种的奶牛：意大利弗里生牛（FRI）、弗留利红斑点牛（PRI）及其杂交品种（MET）中与T淋巴细胞结合不足和结合减少的情况。发现了两种意外的流式细胞术表型：在三个品种中分别有25%、35%和15%的动物出现CC8（标记减少），在15%的PRI奶牛中出现CC8（完全无标记）。CD4编码区（CDS）的全序列分析已确定外显子5中有两个新的错义突变：Q306H和K310N，与这两种表型相关。在外显子6中发现了另一个新的同义突变（g.103634725 G>A）。需要进一步研究以了解新突变的影响，但这些结果表明流式细胞术是发现参与免疫反应的抗原多态性决定因素的有力工具。
