Malcolm B. C. Dunlop

Effects of fourH-2K mutations on virus-induced antigens recognized by cytotoxic T cells

Lysis of ectromelia- or LCM virus-infected macrophage target cells by virus-specific cytotoxic T cells from mice immunized with the homologous virus occurred only where donors of T cells and target cells shared eitherH-2K orH-2D genes. With both viruses, use of T cell or target cell donors bearing mutations (B6.C-H-2ba, B6-H-2bh, B6-H-2bg1, and B6-H-2bg2), all of which apparently occurred in the same single genetic element in theH-2Kb region, abolished (H-2ba) or impaired (H-2bh,H-2bg1 andH-2bg2) lysis in T cell-target cell combinations that shared (apart from the mutations) all other genes in theK, I-A, orI-B regions of theH-2 complex. The data suggest that virus-induced antigenic patterns on infected B6.C-H- 2ba (mutant) cells are more different antigenically from those on C57BL/6 (wild type) cells than are those on infected cells from the other mutants -B6-H-2bh, B6-H-2bg1, and B6-H-2bg2. (B6.C-H-2ba× B6 -H-2bh)F1 mice behaved like B6-H-2bh, indicating no complementation, and confirming that theH-2K gene(s) involved in recognition of virus-infected cells by virus-specific T cells behave as a single element. These findings are discussed in relation to the nature of virus-induced antigenic patterns that are recognized by virus-specific cytotoxic T cells.

In vitro primary induction of cytotoxic T cells against virus-infected syngeneic cells.

An in vitro method is described for primary induction of murine cytotoxic T cells against syngeneic cells infected with ectromelia or lymphocytic choriomeningitis (LCM) virus. Cytotoxicity was assayed by 51Cr release from macrophage or L929 target cells. Cytotoxic activity was sensitive to anti-theta and complement and was expressed only against target cells infected with the same virus and sharing H-2K or H-2D genes with the infected stimulator cells. The crucial factors in generating responses were mouse strain, responder: stimulator ratio, nature of infected stimulator cells, and presence of sufficient macrophages. C57BL/6 cells were less demanding than CBA/H and BALB/c cells. Under optimal conditions defined here, the in vitro response had similar kinetics and potency to the primary response in the spleen in vivo.

Induction of a primary cytotoxic t cell response to lymphocytic choriomeningitis virus-infected cells in vitro. I. Kinetics of response and nature of effector cells.

We obtained primary cytotoxic T cell responses by culturing mixtures of unprimed C57BL/6 or CBA/H spleen (7 parts) and lymph node (1 part) cells, with syngeneic, lymphocytic choriomeningitis (LCM) virus-infected peritoneal cells at 37°C for various intervals. Cells from culture were assayed against LCM-infected, 51 Cr-labelled C57BL/6 peritoneal target cells, or L929 cells respectively. In C57BL/6 responses cytolytic activity first appeared on Day 4 and increased to Day 6 of culture. In CBA/H responses activity appeared later (Day 6), but could be maintained to Day 18, if freshly infected peritoneal cells were added at various times. In vitro derived primary effectors seemed to kill targets by a single-hit mechanism, since a straight line log effectors: log targets lysed relation held. Effector cells displayed ϑ -alloantigen. Efficient lysis of targets occurred only where donors of infected stimulator cells and targets shared K or D genes from the H-2 complex.