Haemolytic complement activity and C3c serum concentration in pigs

Abstract. Because of the importance of the complement system in disease resistance through direct lysis of target cells and support of other mechanisms of the immune 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 complement activity was determined based on complement-mediated haemolysis of antibody-sensitised erythrocytes and C3c levels were measured by immunonephelometry in Gemian Landrace pigs and an experimental pig population. Both methods revealed remarkable individual differences. The arithmetic means of total 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. Mean plasma concentrations of C3c were between .102 ± .035 g/1 before immunisation and .126 ± .038 g/1 on day 4 after Aujeszky vaccination. Existing phenotypic variation may be in part influenced by pig genetic factors. Both haemolytic complement activity as well as C3c semm levels are potentially useful measures of complement capacity on the way to improve defence power against many pathogens by breeding.