Evolution of reproductive-immune interactions.

The comparative approach in biological sciences has provided valuable insights into the role of different organ systems in adaptation and evolution, and seeks to establish unifying themes. This approach also plays a key role in identifying model species and systems for the study of specific questions and problems. Further, by applying the concept of homology, information about nonmammalian species may be used either to directly understand mammalian/human regulatory processes, or to formulate hypotheses for direct testing. Individual physiological systems function in a milieu provided by the integrated activities of all of the systems to adapt, adjust and sustain the organism in its environment. The overlapping interfaces between the different physiological systems provide fertile ground for new insights and to enhance our knowledge. These interdisciplinary areas are of great importance if we are to understand the full complexity of organismal function. Of particular interest are the interactions between the reproductive system and the immune system. The reproductive system is unique in that its primary role is to assure the continuity of the species, while the immune system provides internal protection and thus facilitates continued health and survival. The modus operandi of these 2 morphologically diffuse systems involves widely distributed chemical signals in response to environmental input, and both systems must interact for the normal functioning of each. While the major focus of reproductive-immune research has historically been with mammals, and has provided substantial insight into the interactions between these physiological systems, comparative studies offer unique perspectives. Further, dysregulation of normal physiological interactions between the reproductive and immune systems can lead to disorders and diseases effecting one system or the other. Thus, comparative studies of these interactions may shed some light upon the evolutionary mechanisms involved in such cases.