MAPPING T-CELL EPITOPES OF RUBELLA-VIRUS STRUCTURAL PROTEIN-E1, PROTEIN-E2, AND PROTEIN-C RECOGNIZED BY T-CELL LINES AND CLONES DERIVED FROM INFECTED AND IMMUNIZED POPULATIONS

To design a safe and effective synthetic peptide vaccine against rubel la virus (RV) infection, it is necessary to identify immunodominant T- cell epitopes of RV structural proteins. To define such epitopes, 49 o verlapping synthetic peptides (17-34 residues in length) corresponding to more than 95% of the amino acid sequence of RV virion proteins El (23 peptides) and C (11 peptides) and all of E2 (15 peptides) were syn thesized and tested for their capacities to induce proliferative respo nses of rubella-specific T-cell lines and T-cell clones derived from 4 study groups (5 women infected with RV in pregnancy, 5 patients with congenital rubella syndrome, 5 seropositive healthy donors, and 5 RV v accine recipients). The most frequently recognized epitopes were El-21 (residues 358-377) with 11/20 responders, E2-4 (residues 54-74) with 6/20 responders, and C11 (residues 255-280) with 11/20 responders, res pectively. El-10 (residues 174-193), El-16 (residues 272-291) and El-1 8 (residues 307-326) were responded to strongly by corresponding T-cel l clones, and were recognized by 4 or 5 T-cell lines. T-cell lines der ived from three congenital rubella syndrome patients did not respond t o any of the synthetic peptides. The results showed that more T-cell e pitopes were present in El (19/23) and C (10/11) than in E2 (8/15). Th e identification of T cell sites recognized frequently by RV-infected or -immunized populations could provide the basis for selecting candid ate T-cell epitopes for the development of an effective synthetic vacc ine against rubella. (C) 1993 Wiley-Liss, Inc.