Natural killer cells in host defense against veterinary pathogens

Abstract

Natural Killer (NK) cells constitute a major subset of innate lymphoid cells that do not express the T- and B-cell receptors and play an important role in antimicrobial defense. NK cells not only induce early and rapid innate immune responses, but also communicate with dendritic cells to shape the adaptive immunity, thus bridging innate and adaptive immunity. Although the functional biology of NK cells is well-documented in a variety of infections in humans and mice, their role in protecting domestic animals from infectious agents is only beginning to be understood. In this article, we summarize the current state of knowledge about the contribution of NK cells in pathogen defense in domestic animals, especially cattle and pigs. Understanding the immunobiology of NK cells will translate into strategies to manipulate these cells for preventive and therapeutic purposes.

Mechanisms of Adaptive Immunity to Porcine Reproductive and Respiratory Syndrome Virus

“…NK cells produce cytokines, such as IFNγ, show cytotoxic activity against infected cells not expressing MHCI, can induce dendritic cell maturation, and effect the destruction of infected cells in ADCC [161]. However, NK cells may deploy even more extensive and important functions in porcine immunity than are currently realized.…”

Mucosal Immune System of Cattle

“…22,23 Alpha-and beta-interferon, the last component of this innate response, sets up an immediate wall against virus infections and also provides anti-inflammatory response. The second wave occurs a day or two later, when natural killer cells enhance AMP production, 1,5 kill parasites 18,19 and virally infected cells, 24 but also produce cytokines to help the adaptive immune response. 24 The adaptive phase occurs in the organized mucosa-associated lymphoid tissues (MALT) (discussed later).…”

“…The second wave occurs a day or two later, when natural killer cells enhance AMP production, 1,5 kill parasites 18,19 and virally infected cells, 24 but also produce cytokines to help the adaptive immune response. 24 The adaptive phase occurs in the organized mucosa-associated lymphoid tissues (MALT) (discussed later). 25 MALT is the initial induction site for mucosal immunity for antigens that are sampled from mucosal surfaces.…”

Enteric Immunity

“…5) that enhance defensin production, 25,26 kill parasites, 35,36 and virally infect cells 45 but also produce cytokines to help the adaptive immune response. 45 The adaptive phase occurs in the organized gut-associated lymphoid tissues (GALT) described above. 8 GALT is the initial induction site for mucosal immunity for antigens that are sampled from mucosal surfaces.…”