Microenvironmental changes on NK cell responses to primary HSV-1

Tarr, Andrew

Abstract

Herpes simplex type 1 (HSV-1) is a common oral pathogen that causes cutaneous ulcers of the gums and oral- labia. At risk populations, such as pediatric and immune compromised dental patients are especially susceptible for the contraction of HSV-1. There are many factors that increase the severity and probability of reoccurrence, stress being one. Stress is thought to have a detrimental effect on the immune system's ability to resist infection, however, studies have shown with certain stressors (i.e., social disruption stress) innate immunity can be enhanced to both viral and bacterial infections. Natural killer (NK) cells are innate- lymphocytes that are known to be potent mediators of anti-HSV-1 immunity. Therefore, mechanisms by which social disruption stress (SDR) enhances NK function, with and without infection with HSV-1, will be examined. Initially, we will determine the effect of an SDR-induced altered microenvironment on NK cell activation receptors (C-type lectin receptors;CD94c/d/e and Ly49d/h), cytokine release (TNF-1, IL-6, IFN-1/2/3, IL-2, IL- 12, IL-18, and IL15), MHC-1-like inhibitory receptor pathway function (SHP-1 expression in the immunoreceptor tyrosine-based inhibitory motif (ITIM), and cytolytic function (CD107a expression after stimulation) without a pathogenic challenge. To examine these possible effects of SDR we will employ qRT- PCR, ELISA, and flow cytometric methodologies. Previous research has shown that SDR increases monocyte/macrophage function and trafficking to the trigeminal (TG) ganglia after primary HSV-1 infection. Therefore experiments were designed to determine the role of innate immune cells (i.e., NK cell) in SDR- treated, HSV-1 infected mice. In order to indentify SDR-induced NK cell responses to HSV-1 infection, a murine model of ocular HSV-1 infection will be used. Differing from the first set of experiments, cytokine profiles (TNF-1, IL-6, IFN-1/2/3, IL-2, IL-12, IL-18, and IL15) important in proliferation, activation, and effector function of NK cells will be determined in the TG and cervical lymph nodes. Additionally, chemokines (CCL3/MIP-11, CCL4/MIP-12, CXCL9/MIG, CXCL10/IP-10, CXCL12/SDF, and CCL5/RANTES) within these tissues will be examined to determine the extent of NK cell trafficking to the site of active viral replication and regional lymph nodes. Furthermore, activation (CD94/NKG2c/d/e and Ly49d/h) and inhibitory (CD94/NKG2a/b and Ly49a/c/g) receptor expression on NK cells will be determined, as well as inhibitory pathway signaling (SHP-1 in the ITIM pathway), and cytolytic function (CD107a, perforin, and granzyme B expression). Lastly, viral glycoproteins (gB, gH and gG) and viral genes indicative of the stage of replication (i.e., ICP0, ICP4, ICP27, and LAT) will be examined as a readout of SDR effects on viral replication. Again, to examine these possible effects of SDR in HSV-1 infected mice, we will employ qRT-PCR, ELISA, and flow cytometric methodologies. These studies were designed to further elucidate the effects of social stress on innate immunity, with and without infection. Mechanisms found in these studies may lead to therapeutic approaches to prevent viral transmission in susceptible patients.

Public Health Relevance

Herpes simplex virus (HSV) is a common oral pathogen that is easily contracted in at risk populations, such as pediatric dental patients, and immune compromised patients. There are many factors that have been shown to complicate onset and progression of HSV;however certain environmental factors, such as social stress, can enhance immunity against viruses. Understanding the mechanisms by which these factors enhance anti-viral immunity is essential to the development of novel strategies to delay onset and progression of HSV in at risk populations.