Haemolytic complement activity and C3c serum concentration in pigs

Because of the importance of the complement system in disease resistance th rough direct lysis of target cells and support of other mechanisms of the i mmune system, individual variation in haemolytic complement activity and C3 concentration in pigs prior and after vaccination were evaluated. Possible effects on the variation of these parameters were investigated. Total comp lement activity was determined based on complement-mediated haemolysis of a ntibody-sensitised erythrocytes and C3c levels were measured by immunonephe lometry in German Landrace pigs and an experimental pig population. Both me thods revealed remarkable individual differences. The arithmetic means of t otal haemolytic complement activity including all pigs were 42.3 +/- 28.2 U /ml before vaccination and 59.1 +/- 50.6 U/ml after three immunisations. Me an plasma concentrations pf C3c were between .102 +/- .035 g/l before immun isation and .126 +/- .038 g/l on day 4 after Aujeszky vaccination. Existing phenotypic variation may be in part influenced by pig genetic factors. Bot h haemolytic Complement activity as well. as C3c serum levels are potential ly useful measures of complement capacity on the way to improve defence pow er against many pathogens by breeding.