During the last 10 years of our long-term field studies of water pythons, we have become confronted with the profound impact of pathogens on water python life-history traits such as growth, nutritional status, reproductive success, survival, and adaptive immune response and function. Our research has revealed a dramatic impact of water python MHC genotype on ability to combat pathogens, and, for the first time, in a natural population, the significant effects of MHC-genes on vertebrate fitness.

Natural antibodies (NAbs), which in spite of their important immunological functions have often been dismissed from immunological analyses as “non-specific background” signals, and therefore largely been ignored in immunological research. Our research on water python immune function suggests that NAbs play a crucial role in maintaining immunocompetence during the aging process.