INDIVIDUAL-DIFFERENCES IN CELL-MEDIATED AND HUMORAL IMMUNITY IN PIGS

Previous experiments displayed consistent individual behavioural diffe rences in pigs. Some showed a more active behavioural response (aggres sive and resistant; so-called A/R pigs), others a more passive behavio ural response (non-aggressive and non-resistant; so-called NA/NR pigs) . Moreover, these behavioural coping strategies were associated with d ifferent behavioural, physiological and endocrine responses under stre ss conditions. In the present study we selected 32 A/R and 32 NA/NR in dividuals and tested their immune reactivity in reaction to stress usi ng several cell-mediated (CMI) and humoral immunological tests. Active A/R pigs had a higher in vivo and in vitro CMI to nonspecific and spe cific antigens, while after stress CMI reduced more in A/R than in NA/ NR pigs. In contrast, humoral immunity was highest in NA/NR pigs. Furt hermore, some serologically typed swine lymphocyte antigen (SLA) class I haplotypes were not equally distributed between A/R and NA/NR pigs. In general, these findings show that measurement of immune reactivity is an important tool to define how animals cope with environmental de mands.