To understand and potentially to exploit antibody-mediated mechanisms for control of Epstein-Barr virus (EBV) infections, we are describing structures and functions of EBV membrane antigens (MA) which are shown to be humoral immune response targets in patients. Through the development of murine and human monoclonal antibodies (MAb) and with patients' sera, we will approach the immunological roles of these antibodies in basic biochemical and virological studies. Our principal focus is on 1B6 MAb which recognizes a 200,000 dalton, late MA and inhibits release of EBV from infected cells which express that MA. The course of synthesis, processing, transport, and expression of the MA on both the cell surface and virus envelope will be analyzed, in order to develop clues about its function and the mechanism of EBV-release inhibition. Molecular structures of the MA and cross-reactivity of monoclonal and patients' antibodies to individual molecules will be analyzed by two-dimensional (2D) electrophoretic gel analysis of radiolabeled or Western-blotted molecules. The genome for the MA is being cloned by a collaborator (Dr. Hans Wolf) to determine genomic and amino acid sequences, in order that we can synthesize peptides for regions likely to have antigenic epitopes and functional roles. With such peptides, or with rabbit anti-idiotype (Id) antibodies to the murine (or human) MAb, we will test the feasibility of vaccine development and devise functional, epitope-specific radioimmunoassays (RIAs) to assay patients' antibodies in the course of various EBV-related diseases. In this project, we will continue our main focus on the mechanism and consequences of virus-release inhibition and will continue to expand and study our panel of MAbs to various MA. Such additional MAbs will be tested for classifal functions of MA antibodies (virus neutralization, ADCC) and for the two newly defined functions (virus-release inhibition and early antigen (EA) suppression). These studies should not only characterize MA components and mechanisms of the immune response to EBV but could also contribute to diagnosis and development of vaccines (although patient immunizations are not part of this proposal).