Decreased production of mast cells in S1/S1d anemic mice.

Production of tissue mast cells was evaluated in genetically anemic mice of Si ISid genotype. In the skin of adult Si ISid mice the numbers of mast cells per centimeter were less than 1 % of the numbers observed in congenic + I + mice. as reported for adult WI WV mice. Any mast cells were scarcely detected in other tissues in both SiIS1d and WIWV mice. Since bone marrow cell transplantation from 51151d mice increases the numbers of mast cells in the skin. stomach. and mesentery of WI WV mice. the bone marrow of S1IS1d mice would seem to contain precursors of mast cells. These precursor cells may arrive at peripheral tissues. as is suggested by the observation that the numbers of mast cells increase in the skin of W/WV mice grafted to recipients. The lack of mast cells in the 51151d mice seems to be due to a tissue defect that locally induces the differentiation of mast cells. as isindicated by the observation that bone marrow transplantation from + I + donors does not increase the numbers of mast cells in the skin. stomach. and mesentery of 51151d mice and the observation that mast cells do not develop in skin of Si ,51d mice grafted to + I + recipients.