Rotavirus-specific cytotoxic T lymphocytes recognize overlapping epitopes in the amino-terminal region of the VP7 glycoprotein

Rotavirus-specific cytotoxic T lymphocytes (CTL) play an important role in the resolution of rotavirus infection. The outer capsid glycoprotein, VP7, elicits a class I MHC-restricted CTL response. Vaccinia virus recombinants expressing the VP7 genes from simian rotavirus SA11 (serotype G3) and from the RF strain of bovine rotavirus (serotype G6) were used to analyze the CT L activity to this antigen in BALB/c (H-2(d)) and C57BL/6 (H-2(b)) mice neo natally infected with homologous and heterologous rotaviruses. A vaccinia v irus recombinant expressing the first amino-terminal 88 amino acids of VP7 was constructed and used to search for cross-reactive CTL against this regi on of the protein. By using synthetic K-b, D-b, and K-d motif-fitting pepti des two overlapping CTL epitopes have been identified located in the first hydrophobic domain (H1) of VP7. Splenocytes obtained from rotavirus SA(11)- infected C57BL/6 mice induced the strongest CTL response against target cel ls sensitized with a peptide containing a K-b-restricted CTL epitope (amino acids 8-16). A second K-d-restricted epitope (residues 5-13) was recognize d by splenocytes derived from rotavirus-infected BALB/c mice. These finding s reveal the existence of CTL epitopes in the H1 signal sequence of the VP7 glycoprotein that coexist with a CTL epitope (residues 31-40) previously d escribed within the H2 region. (C) 1999 Academic Press.