Submitted to: Asociacion Nacional De Especialistas En Ciencas
Publication Type: Proceedings
Publication Acceptance Date: 2/24/2005
Publication Date: 4/27/2005
Citation: Kogut, M.H. 2005. The impact of innate immunity on disease resistance and susceptibility in poultry. XXX Convencion Anual de ANECA, April 27-30, 2005, Puerto Vallarta, Mexico. 2005 CDROM.
Technical Abstract: The immune system of vertebrates is made up of two functional branches, the innate and acquired. Acquired immunity, the clonal expansion of T and B cells by specific antigens, has been intensively studied over the years. Innate immunity (the non-clonal, primarily non-specific response to pathogens) has been regarded for years as simply the 'first line of defense' that serves to limit infections during the first few hours after exposure, but does little else until the clonal expansion of the more sophisticated acquired immune response. However, this canon has changed dramatically over the last 10 years. It has become readily apparent that the host response to microbial pathogens in the earliest stages of infections is one of the most critical determinants in disease resistance and susceptibility. Thus, the innate response is more vital to the overall responsiveness of the host than originally conceived. The most up-to-date research shows that innate host defenses plays three main roles in the overall response to infections: 1) recognition of an organism as 'infectious or non-infectious', 2) control of the initial infections to reduce and/or prevent the pathogenesis of the disease, and 3) initiation of the correct specific acquired response. It is this third functional role of the innate response that demonstrates it as the central coordinator of the host systemic defenses. Current research in our lab is focused on characterizing the role of the heterophil (avian equivalent to the mammalian neutrophil) in the innate host defenses against bacterial infections. We have investigated three phenomena: 1) the ability of heterophils to be primed by cytokines; 2) the ability of heterophils to recognize opsonized and non-opsonized Salmonella enteritidis via PRRs and to respond by producing cytokines that influence the local immune responses; and 3) that differences in resistance to Salmonella infection in different lines of chickens may, at least in part, be explained by differences in the ability of their heterophils to produce cytokines.