Identification of a bluetongue virus serotype 1-specific ovine helper T-cell determinant in outer capsid protein VP2.
Ovine T-cell lines (including one clone [101A]), which are specific for Bluetongue virus serotype 1 (BTV1), have been established and characterized. Although these T-cell lines react with different isolates of BTV1 (including those from South Africa, Australia, Nigeria, and Cameroon), they do not react with heterologous BTV serotypes. Antigen specificity of these T-cells was studied using purified virus particles, infectious subviral particles (ISVP) and cores, or using individual BTV structural proteins that were either isolated by SDS-PAGE or expressed by recombinant strains of vaccinia virus. The results showed that each of the T-cell lines reacted with outer capsid protein VP2 (the BTV protein exhibiting most serotype-specific variation and the major neutralization antigen). However, all of the uncloned T-cell lines also reacted with either the core structural proteins or the outer capsid protein VP5. In contrast, the T-cell clone 101A only reacted with outer capsid protein VP2. Cell surface marker analysis showed that 101A has a helper T-cell phenotype (CD5+, CD4+, CD8-, T-19-). The T-cell lines and clone 101A all produced large amounts of interleukin 2 (IL-2) when stimulated with purified BTV1 virus particles, or with VP2 (up to 120 IU/ml from 2 x 10(5) T-cells). BTV serotype-specific antigenic sites, for B cells and at least one site for ovine helper T-cells, are therefore located within VP2.
Department of Immunology, AFRC Institute for Animal Health, United Kingdom.
H
H
Takamatsu
J N
JN
Burroughs
A M
AM
Wade-Evans
P P
PP
Mertens
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D001820:Bluetongue virus / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification; D002213:Capsid / Q000276:immunology*; D002460:Cell Line; D002999:Clone Cells; D000939:Epitopes / Q000032:analysis*; D005434:Flow Cytometry; D012087:Reoviridae / Q000145:classification*; D012703:Serotyping; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000956:Antigens, Viral; D000939:Epitopes