ANALYSIS OF ANTIBODY-RESPONSE TO THE MEASLES-VIRUS USING SYNTHETIC PEPTIDES OF THE FUSION PROTEIN - EVIDENCE OF NONRANDOM PAIRING OF T-CELLAND B-CELL EPITOPES

The measles virus induces a life-long immune response associated with antibodies specific for the fusion protein. To map the linear immunodo minant recognition sites of the fusion (F) protein of the measles viru s, we have reacted a complete set of 108 overlapping pentadecapeptides with purified IgG obtained from donor sera with elevated anti-measles titers. The antibodies recognized about 20% of the peptides and gener ated a characteristic binding pattern, defining about 6 or 7 distincti ve regions (31-75; 111-145; 151-165; 191-215; 271-320; 421-440; 481-53 0) which include the major hydrophobic segment (111-145) of the inters ubunit region and the C-terminal Cys-cluster region. The binding sites were located in close proximity of the few experimentally defined T c ell epitopes. This pairing of T and B cell epitopes was corroborated b y computer-assisted T cell prediction. The significance of a non-rando m association of T and B cell epitopes for processing and presentation is discussed. It is speculated that in long-term immunity against mea sles (F protein), B cells of the same sIg specificity play an importan t role both as antigen presenting cells and as antibody producing cell s. In contrast to human sera from late convalescent donors, mouse and rabbit MV antisera with high neutralizing titers as well as neutralizi ng MV-F specific monoclonal antibodies did not react with the peptides .