A new polymorphic epitope of bovine CD4 antigen evidenced by flow cytometry

Publication date: Available online 17 October 2019Source: Veterinary Immunology and ImmunopathologyAuthor(s): Francesco Grandoni, Francesco Napolitano, Maria Carmela Scatà, Giovanna De MatteisAbstractCluster 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 (TH) 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 TH 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 resu...
Source: Veterinary Immunology and Immunopathology - Category: Veterinary Research Source Type: research