Transfer of the immunologically competent T-lymphocytes from a donor to host expression different MHC antigens can contain severe consequences, causing a fatal syndrome termed graft versus host disease (GVH). The given table explores a ran model of GVH, it exhibits the minimum number of parental strain t- cells which cause fatal GVH in different treatment groups of F1 hybrid off spring derived from the mating of two MHC different strain, a and b.

Give a mechanistic description for the finding that is constant with all the data. Describe your reasoning.