Diversity of escape variant mutations in Simian virus 40 large tumor antigen (SV40 Tag) epitopes selected by cytotoxic T lymphocyte (CTL) clones. Journal   Molecular phylogenetics and evolution. Journal of advanced nursing. Journal of cellular biochemistry. American journal of physiology. Heart and circulatory physiology. Virology. Citation   Virology. 364(1):155-68 Publication date   2007 Jul 20 Authors   Mylin LM Schell TD Epler M Kusuma C Assis D Matsko C Smith A Allebach A Tevethia SS Investigators   Todd Schell Satvir S. Tevethia Grant agencies   National Center for Research Resources National Heart, Lung, and Blood Institute National Cancer Institute Grants   NCI CA25000 MeSH headings   Antigens, Polyomavirus Transforming Simian virus 40 MeSH qualifiers   genetics immunology Abstract   To better understand the relationship between epitope variation and tumor escape from immune surveillance, SV40 T antigen-transformed B6/K-0 cells were subjected to selection with individual CTL clones specific for the SV40 T antigen H-2D(b)-restricted epitopes I or V. CTL-resistant populations were isolated from a majority of the selection cultures and substituted epitope sequences were identified within most of the resistant populations. Tag sequences deleted of all or portions of the selection-targeted epitope were identified, but in lower numbers compared to epitope sequences bearing single residue substitutions. Relatively few flanking residue substitutions were identified, and only in epitope I-targeted selections. The diversity (numbers and epitope residue locations) of substituted epitope residue positions varied between selections. These findings suggest that the scope of spontaneously occurring mutations that could allow for escape from individual CD8+ T cell clones is large.