Frontiers in reproductive immunology – Forum introduction

It has been 50 years since Sir Peter Medawar kindled scientific interest in the unique problem posed by the existence of the fetal allograft within the uterus [1]. The resultant efforts of immunologists and reproductive physiologists to understand the mechanisms by which the conceptus successfully evades rejection by the maternal immune system has led to a richer understanding of the nature of immune responses in the uterus and of their regulation by maternal and conceptus signals (see Billington, 1993 for a reflection on the progress since Medawar's seminal paper [2]). Increasingly, the fact that the immune system is functional in the reproductive tract of the female is being recognized not only as a potential threat to the conceptus but as an important part of host defense in the female. The female reproductive tract is invaded by microorganisms at mating, parturition, and other times and it is critical to the health of the female that the immune system functions effectively in the uterus. Indeed, one can view the principles of reproductive immunology as at the center of combating one of the major health crises in the world – the spread of venereal diseases, including acquired immune deficiency syndrome.