Cord blood contains high numbers of autoimmune T cells recognizing multiple myelin proteins and acetylcholine receptor.

Abstract

To analyze Ag-specific T cell autoimmunity in the newborn, umbilical cord blood cells of newborns were investigated by an immunospot assay for occurrence and numbers of cells secreting IFN-gamma after short-term culture in presence of myelin basic protein (MBP), proteolipid protein, myelin associated glycoprotein, nicotinic acetylcholine receptor and the synthetic MBP amino acid sequences 1-20, 63-88, and 110-128. These Ag were chosen because they represent putative targets for autoimmune attack in multiple sclerosis and myasthenia gravis. Surprisingly, numbers of T cells recognizing MBP, proteolipid protein, MBP peptides, and acetylcholine receptor were high in cord blood of newborns compared to peripheral blood of patients with neurologic diseases. No immunodominant T cell epitope could be discerned among the Ag included. The responses to purified protein derivate and PHA were lower among cord blood cells than peripheral blood cells of adults. Parallel enumeration of autoimmune T cells in cord blood and peripheral blood obtained from corresponding mothers at delivery, revealed that the high cell numbers in newborns were not a result of contamination from the mothers blood. The high numbers of T cells recognizing nervous system myelin proteins and acetylcholine receptor in cord blood could have importance for the mechanism and timing of tolerance induction, and also reflect excessive myelination and receptor maturation at birth.