Figure Q24–1 Viral nuclear protein recognition by cytotoxic T cells (problem 24–7). (A) Sequences of a segment of the nuclear protein from the 1968 and 1934 strains of influenza virus. peptides used in the experiments in (B) are highlighted by pink bars. The amino acid differences between the viral proteins are highlighted in blue.
(B) cytotoxic T-cell-mediated lysis of target cells. The target cells were untreated (none), infected with virus (1968 or 1934 strain), or preincubated with high concentrations of the indicated viral peptide.
Why do not all viral peptides sensitize the target cells for lysis by the cytotoxic T cells?
b. It is thought the MHC molecules come to the cell surface with peptides already bound. If that is so, how do you imagine that these experiments worked?
24–8 Working out the rules by which T cells interact with their target cells was complicated. Some of the key observations came from studying the way cytotoxic T cells killed cells infected with choriomeningitis virus (LCMV).
(A) Figure Q24–3 Scanning of the T cell repertoire by dendritic cells (problem 24–9).
(A) contacts between different T cells and one dendritic cell. T cells are green and dendritic cells are red. The dendritic cell labeled with of images. Times are shown
At first glance, it would seem a dangerous strategy ing the same k-type MHC protein, but they did not lyse as hours: minutes. (B) plot of T cell contacts for individual dendritic cells over time.
(A, from p Bousso and proteins (Figure Q24–2). Similarly, cytotoxic T cells from e. robey, Nat. Immunol.
4:579–581, 2003. With permission from Macmillan d-type mice lysed infected d-type cells, but not infected minutes publishers Ltd.) k-type cells. LCMV can kill both k-type and d-type mice.
cytotoxic fbroblasts T cells added to
Figure Q24–2 pattern of killing of LcMV-infected fibroblasts by cytotoxic T cells from an LcMV-infected k-type mouse (problem 24–8).
A. If homozygous d-type mice were bred to homozygous k-type mice to generate d-type/k-type heterozygous progeny, would you expect that cytotoxic T cells from these heterozygotes, when infected with LCMV, to be able to lyse infected d-type cells? How about infected k-type cells? Explain your answers.
b. Oddly enough, LCMV infection does not kill mice that lack a thymus—such as “nude” mice, so called because they also lack hair. If a thymus is transplanted back into a nude mouse, it will die when infected with LCMV. Suppose that a d-type/k-type heterozygous nude mouse was given a thymus from an d-type donor. Would you expect its cytotoxic T cells to be able to lyse infected d-type cells? How about infected k-type cells? Explain your answers.