Problem
You are performing experiments that require you to transplant cells from one mouse (the donor) to another (the recipient). To ensure the transplanted cells engraft and survive within the recipient mouse you need to limit the likelihood of transplant rejection.
You know that the adaptive immune system is crucial for triggering and maintaining transplant rejection responses. Therefore, you decide to use recipient mice with genetic mutations that cause adaptive immune deficiencies*.
As these are just preliminary experiments you want to use mice strains your lab already has access to. You have the following knockout mice (note, knockouts do not express the gene in question):
a) TdT knockouts (no TDT)
b) Artemis knockouts (no Artemis)
c) Ig Heavy chain knockouts (no Ig Heavy chain; Ig = immunoglobulin)
Which mouse strain would have the most severe adaptive immune deficiency, and therefore be the best recipient mouse for your experiments?