A researcher newly discovered a mutant mouse with an interesting T cell phenotype. He called this new mutation: HD, bred the mouse and then used these founders to produce a strain homozygous for HD. Some of his finding is summarized in the table shown below:
Q1. What did he find?
Q2. He next made bone marrow chimeras, injecting bone marrow from HD mice to lethally irradiated wild type mice. They found that the thymocytes in such chimeras exhibited a staining pattern similar to that of HD mice. In contrast when they did the inverse, they found that the thymocytes exhibited a normalCD4/CD8 phenotype. What do such results tell you?
Q3. Based on such results, advance a hypothesis regarding the cause of the phenotype.
Q4. Based on your hypothesis, what do you forecast would happen to developing T cell in an HD mouse which has been made transgenic for a TCR restricted to I- Ab. Describe your reasoning.