Transfer of the immunologically competent T-lymphocytes from a donor into host expression different MHC antigens can have severe consequences, causing a fatal syndrome known as graft versus host disease (GVH). The following table explores a ran model of GVH, it displays the minimum number of parental strain t- cells which cause fatal GVH in sevearl treatment groups of F1 hybrid off spring derived from mating of two MHC different strain, a and b.
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Minimum number of A or B strain t- cells which cause lethal GVH in the AxB F1 106
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Group
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(A X B) F1 hosts age and treatment
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Strain A T cells
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Strain B t cells
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1
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Intreated new born F1
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5
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5
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2
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Untreated adult f1
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1000
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1000
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3
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Adult F1 given 300 rad irradiation or an anti - proliferative drug
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5
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5
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4
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Adult F1 immunized with 10 of the strain parental t - cells and then irradiated as in group 3
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1000
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5
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5
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Adult F1 immunized with 107 a strain t- cells taken from donors that had previously been made tolerant to MHC of B, and then irradiated as in group 3.
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5
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5
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Give a mechanistic explanation for finding which is consistent with all the data. Describe your answer with reasoning.