Mapping of T-helper epitopes of rinderpest virus hemagglutinin protein

Rinderpest virus (RPV) is a highly contagious and often fatal disease of do mestic and wild ruminants, caused by rinderpest virus of the genus Morbilli virus under the family Paramyxoviridae. Hemagglutinin (H) and fusion (F) pr oteins of this enveloped virus confer protective immunity against experimen tal challenge with virulent rinderpest virus. We have earlier demonstrated that immunization with a single dose of recombinant extracellular baculovir us expressing H protein elicits II-specific humoral and lymphoproliferative responses in cattle. The lymphoproliferative responses are predominantly B oLA class II restricted. In this work, we have analyzed lymphoproliferative responses of peripheral lymphocytes from immunized cattle to truncated H p rotein fragments expressed in E. coli for locating domains harboring T-h ep itopes. One region (aa 113-182) recognized by immune T cells is conserved i n the H protein of measles virus, which was earlier shown to contain a domi nant Th epitope in mouse. Synthetic peptides within this region of measles virus H protein were used to identify a Th epitope conserved in the H prote in of RPV virus (aa 123-137) in cattle. A second Th epitope located at the C-terminus of RPV-H was mapped to the region corresponding to aa 512-609 us ing truncated protein fragments expressed in E. coli, The C-terminal epitop e (aa 575-583) was mapped using synthetic peptides corresponding to measles virus H as well as RPV-H protein.