We chose C57BL/6 wild-type (WT) and six well-characterized immunodeficient mouse strains, namely nude [2], scid [3], NOD-scid [5], B6.129S4-IL2Rg−/− (IL2Rg−/−) [24], Rag2−/− [4], and NOD-scid-IL2Rg−/− [5, 7] mice, to assess immunodeficiency. The gene discussed is IL2RG; the disease is Immunodeficiency.