Evaluation Of Fc Receptor Genes In Bovine Neutrophils

Jamie S. Williams, North Carolina Agricultural and Technical State University


Receptors for the Fc portion of IgG, Fc receptors (FcR) are found on immune cells and contribute to protective functions of the immune system. The FcγRs (I, II and sub isoforms) bind specifically to IgG molecules and are important due to stimulating effector cells to destroy pathogens by phagocytosis and intracellular killing. The SYK kinase is critical for FcγR-mediated phagocytosis and signal transduction in cells. Neutrophils contain a heterogeneous population of FcR. The objectives of this study were to evaluate genetic variation and the impact of IgG binding on transcription of FcγR and secreted levels of phosphorylated Syk between Holstein-Friesian and Jersey X Holstein cows. Blood was collected from Holstein-Friesian and Jersey X Holstein lactating cows at the North Carolina A & T State University dairy farm (n=6). The somatic cell count and packed cell volume were used to evaluate overall health. Genomic DNA was isolated and amplified products were separated on a 1% agarose gel following ethidium bromide staining. Polymorphisms were evaluated by SSCP analysis. Neutrophils treated with whole bovine IgG molecules were used for q-PCR. All genes were transcribed. An increase was observed in the transcription of FcγRII in Jersey X Holstein cows and a significant increase was observed in the Syk protein expression of Jersey X Holstein cows (p<0.05) when compared to Holstein-Friesian cows. Heterogeneity in FcγR gene expression may be related to breed differences in cows and impact downstream cellular function binding of IgG to Fc receptors. These results have implications for control of inflammatory diseases such as mastitis in cattle.