Effect of host genotypes on the number of mast cells that developed in the skin tissues grafted from WBB6F₁-W/W^v mice. The skin of WBB6F₁-W/W^v mice was grafted to WBB6F₁-+/+ mice or WBB6F₁-tg/tg mice. The number of mast cells in the skin graft and the surrounding host skin was counted various days after transplantation. The bars represent the mean ± standard error (SE) of 5 mice. In some cases, the SE was too small to be shown by bars. ^*P < .01 by t test when compared with the values of host skin.