Amino acid sequence of thymopoietin isolated from skin.

The isolation of thymopoietin-reactive material in fetal bovine skin was monitored by means of a radioimmunoassay to thymopoietin. The amino acid sequence of this material was determined to be identical with that of thymopoietin isolated from the thymus. Experimental evidence suggests that thymopoietin in the circulation derives from the thymus and not from the skin, suggesting that the thymopoietin in keratinocytes has a local function, either apocrine and/or immunoregulatory.