[A cytoplasmic antigen related to the cell cycle identified by a human autoimmune serum]

A human serum from a patient with an autoimmune disorder, previously characterized for its ability to specifically recognize a chromatin-associated PSL or p55 antigen, was found also to detect a 30-32 K polypeptide in the cytoplasm of human HeLa cells. This molecule is strictly cytoplasmic, does not cross react with nuclear PSL and is synthesized only during the S phase of the cell cycle.