Date of Award
Doctor of Philosophy (PhD)
B virus (Macacine herpesvirus 1), subfamily Alphaherpesvirinae, causes a fatal, neurovirulent infection in zoonotically infected humans. Macaques (Macaca sp.) serve as the natural host for B virus and they are frequently seropositive for B virus antibodies without showing any overt signs of disease. The global hypothesis of these studies is that B virus, a highly cytopathic virus in macaques, subverts the innate immune responses in the host (macaques) that has co-evolved with it (the virus) differently than it does the foreign host (humans). The foreign host, frequently fails to produce neutralizing antibodies early after infection and this may be due to a dysregulation or inhibition of pathways known to play a role in the innate immune response which directs the adaptive defense responses. Current knowledge is that at least five major signaling pathways can be activated after a pathogen such as B virus enters a host cell (REF). These include the IRF3 pathway, the NFkB pathway, the NFAT pathway, and the MAPK pathway. Early stimulation of one or more of these pathways leads to the induction of the proinflammatory response and subsequent induction of cytokines such as IL6, IL8 and IL10, and apoptosis. Cytokine induction and apoptosis play important roles in host-pathogen interactions, innate defense induction and subsequent adaptive immune responses. Using a primary cell model that is representative of the first target cells of B virus in the natural and foreign host, we investigated one of the key signaling pathways, the MAPK pathway, induced by B virus early after infection (Farah-Abraham and Hilliard, unpublished data). My data suggest that macaque and human cells differ in the induction kinetics of MAPK (JNK and p38) activation. These data reveal differences between foreign and natural host cells in how each controls apoptosis, and demonstrate that inhibition of p38 activation reduced and with high dose inhibition terminated B virus replication in human cells, and played a role in reduction of apoptosis-associated mediators. The importance of each component in the MAPK pathway is investigated with respect to virus replication in macaque and human cells that represent the primary target cells in acute infection. Knowledge of these events provides an understanding of how the innate immune responses can be modulated by B virus to shape the adaptive immune response to limit how the virus replicates and spreads. Further, these data may provide insight into a novel target for the design of new antivirals to inhibit this deadly zoonotic virus. This research will help us understand how the early molecular mechanisms of host-pathogen interactions result in modulation of the innate immune responses and how certain aspects of a normally defensive (protective) host response can be re-directed or modified depending on the nature of the virus:host relationship.
Farah-Abraham, Rachael M., "B Virus Infection Activates p38 And JNK Pathways Differentially In Cells From Macaque Versus Human Hosts: Exploring Inflammation & Apoptosis." Dissertation, Georgia State University, 2011.