Fractionation of fowl immunoglobulins

Serum, Na2SO4-precipitated serum immunoglobulins and bile from 12-week-old fowls, and serum from day-old chicks, were fractionated by Sephadex G-200 gel filtration, DEAE Sephadex A-50 ion exchange chromatography and ultracentrifugation through 10-40 per cent sucrose gradients. Elution of IgM, IgG, IgA and albumin was monitored by examination of fractions in agar gel diffusion against antisera specific to these proteins. Serum and bile from 12-week-old fowls contained IgM and IgA in two molecular sizes and a single molecular size of IgG. Day-old chick serum contained IgM estimated to be 7S, a polymerised form of IgG in addition to the normal 7S component, and a small molecular weight protein antigenically related to IgA. Most of the albumin in bile was of lower molecular weight than serum albumin, while heavy forms of albumin were detected in ultracentrifugation of bile and day-old chick serum.