CML (cell-mediated lysis) is an assay that can be used to qu…
CML (cell-mediated lysis) is an assay that can be used to quantify T cell reactivity. In a CML assay, killer T cells are mixed with potential target cells that have been loaded with radioactive chromium (Cr51). If the targets are killed by the CTLs, then they release their Cr51into the supernatant. The level of killing is then quantified by the total amount of Cr51released. The Major Histocompatibility Complex (MHC) is a set of proteins on the surface of cells and the collection of MHC alleles expressed by an individual is called the ‘haplotype’. MHC mismatch between donor and recipient is the major reason for graft rejection, and the rejection process is mediated by a CTL response against the foreign tissues. You have four different strains of mice, shown in the table below. You do not know the MHC haplotypes of any of these mice, and you have been asked to determine the tissue compatibility between these strains using the CML assay. Your data is shown below: KILLERS LYSIS OF 51Cr LOADED TARGETS FROM: (cpm 51Cr released) BALB/c CBA SJL C3H BALB/c 300 60,000 63,000 66,000 CBA 345 300 66,000 SJL 320 65,000 C3H 300 How many different MHC haplotypes are there among these four strains? Which strains share MHC haplotype? Explain your reasoning using the data above and why these results led you to this conclusion.