Anitbody and saliva-mediated enhancement of epithelial cell infection by EBV

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Epstein-Barr virus (EBV) is an orally-transmitted human herpesvirus that persists in more than ninety percent of the adult population. A majority of infections are asymptomatic but long term carriage can be associated with development of malignancies of both lymphoid and epithelial origin. The frequency and aggressiveness of these increase in individuals co-infected with the human immunodeficiency virus (HIV). In recent years there has been a reevaluation of the life cycle of persistence of EBV in its human host and a renewed appreciation of the central role that epithelial cells in the oropharynx play in its maintenance. Our long term goals are to understand the parameters involved in targeting this tissue. We and others recently described two ways in which the environment in vivo can influence epithelial infection, in both cases implying that the major envelope glycoprotein gp350/220, which is required to attach virus to its receptor CD21 on a B cell, is not only dispensable for infection of an epithelial cell, but also interferes with the process. Our work indicates that antibodies to gp350/220, which may be found at high levels in HIV-positive individuals, enhance epithelial cell infection. We hypothesize that antibodies to gp350/220 patch the protein in the virus envelope to facilitate access of more relevant virus proteins to the epithelial cell surface. Our immediate goals are to test this hypothesis, to determine what steps in the virus life cycle are impacted and to explore the effect of saliva from HIV infected individuals on virus replication. There are four specific aims. The first aim will evaluate the levels and contribution of antibodies in saliva of HIV infected individuals to epithelial cell infection. The second aim will use BAG technology to make recombinant viruses that lack gp350/220. The third aim will use this virus and antibodies to gp350/220 to determine what steps in epithelial infection are enhanced. The approach will be to use real time PCR analysis of fractionated cells to follow virus entry through into the nucleus. The fourth aim will use microarray technology to determine if intracellular signaling events are impacted and if they influence these early steps in replication. The high prevalence and loads of EBV in HIV infected individuals correlate with elevated incidence of oropharygeal tumors. Our goal is to understand the factors that influence virus replication in order to estimate risk and develop strategies to avoid it.