[Possibilities of selection for high disease resistance in swine based on immunological indicators]

Disease resistance results from different processes which partly are immunological in nature. Immunological processes can be subdivided into innate (non-specific) resistance (phagocytosis) and acquired resistance. The latter can be subdivided in cellular and humoral immunity. These three compartments of the immune system do not act independently but are complementary. Parameters for each of the compartments have a genetic basis, and expression is affected by many genes, some of which are known. Experimental results suggest that especially aspects of innate disease resistance (the killing capacity of phagocytes) are negatively correlated with humoral immune response. Comparison of pig breeds supports this idea. On the other hand selection experiments show that simultaneous improvement of various aspects of the immune system is possible. Consequently, selection programmes should utilize index selection including parameters of all three compartments. Research in mice and various farm animal species studied genetic aspects of immune parameters. Little attention has been paid to the relationships between immune responsiveness and resistance to specific infections. To support the implementation of selection programmes for disease resistance in pigs, further experiments using e.g. mice as a model and the design of simulation models are useful.