Minimal molecular and cellular requirements for elicitation of secondary anti-vesicular stomatitis virus cytotoxic T lymphocytes.

Abstract The minimum cellular and molecular requirements for elicitation of secondary anti-vesicular stomatitis virus (VSV) cytotoxic T lymphocytes (CTL) have been examined in vitro using virus and cell-derived antigens incorporated into liposomes as an eliciting agent. The major surface glycoprotein (G protein) of VSV and partially purified H-2d, H-2b, or H-2k antigens were incorporated into liposomes and tested for their ability to elicit anti-VSV CTL specific for VSV-infected target cells of the homologous H-2 haplotype. In order to elicit anti-VSV CTL in culture with G-H-2 liposomes, it was necessary for the G protein and the H-2 antigens to be contained within the same liposome. The ability of effector cells generated in this manner to lyse a target cell depended upon the presence on the target cell surface of both viral antigens and an H-2 haplotype syngeneic to the partially purified antigens within the G-H-2 liposome. Non-H-2-related differences between mouse strains did not appear to be important. Through the use of temperature-sensitive mutants of VSV, it was shown that anti-VSV CTL elicited with G-H-2 liposomes require the expression of G protein for effective interaction with, and lysis of, the target cell. Elicitation of anti-VSV CTL with liposomes containing G protein from Indiana or New Jersey serotypes of VSV was successful only when the G protein was serologically homologous to the VSV serotype used to prime the mice. In addition, it was determined that CTL elicited with liposomes containing G protein from the Indiana or New Jersey serotypes of VSV had preference for lysis of target cells infected with the homologous virus strain. The effector cells in this study were shown to be T cells of the Ly-2+ phenotype. Effective elicitation of secondary anti-VSV CTL with G-H-2 liposomes required the presence of both Ly-1+ and Ly-2+ cells. Removal of adherent cells did not drastically affect the ability of G-H-2 liposomes to elicit anti-VSV effector cells from the remaining nonadherent population, but removal of 2-mercaptoethanol from the culture medium resulted in a complete loss of the ability to elicit CTL in this system.