Production and characterisation of two monoclonal antibodies recognising equine IgG Fc receptors

Despite the importance of IgG Fc receptors in the regulation of various immunological mechanisms, these receptors have not been well characterised in the domesticated animals including equines. This paper describes the production of two monoclonal antibodies (CVS 59 and CVS 61) that recognise equine IgG Fc receptors. Fusions were conducted using BALB/c mice hyperimmunised with equine peripheral blood mononuclear cells. Hybridoma supernatants were screened on the basis of their ability to inhibit the rosetting of equine antibody coated sheep erythrocytes with equine peripheral blood mononuclear cells. The mAbs were then characterised for cellular distribution of the antigen by flow cytometry. Using immunoprecipitation, it was shown that both under reducing and non-reducing conditions, CVS 59 and CVS 61 precipitated a 80 and 40 kD protein, respectively. From the functional study coupled with cellular distribution and molecular weight of the antigen recognised by these mAbs, it would appear that CVS 59 and CVS 61 recognise an epitope on equine equivalent of human and murine FcγRIII and FcγRII, respectively.