TESTING OF BOVINE SERA BY ELISA FOR IGG, IGM AND IGA RHEUMATOID FACTORS

Sera from 19 colostrum-deprived calves less than 1 week old, 24 cole s trum-supplemented calves less than 1 week old, 36 3-5-month-old calves and 200 females greater than 9 months of age were tested by ELISA for the presence of IgM, IgG and IgA rheumatoid factors (RF). An increasi ng level of IgM- and IgG-RF with age was found. IgG-RF levels in the c olostrum-supplemented calves were significantly higher than in the non -supplemented calves (p < 0.001). Individual IgG-RF values correlated with serum IgG levels, as determined by zinc sulphate turbidity testin g (r = 0.59, p < 0.01). No IEA-RF was detected. The cross-reactivity o f IgM-RF with heterologous IgG was found to be greatest with rabbit Ig G, followed by mouse and chicken IgG. The significance of rheumatoid f actors in relation to diagnostic testing is discussed. (C) 1998 Elsevi er Science B.V.