CORD-BLOOD CONTAINS HIGH NUMBERS OF AUTOIMMUNE T-CELLS RECOGNIZING MULTIPLE MYELIN PROTEINS AND ACETYLCHOLINE-RECEPTOR

To analyze Ag-specific T cell autoimmunity in the newborn, umbilical c ord blood cells of newborns were investigated by an immunospot assay f or occurrence and numbers of cells secreting IFN-gamma after short-ter m culture in presence of myelin basic protein (MBP), proteolipid prote in, myelin associated glycoprotein, nicotinic acetyl choline receptor and the synthetic MBP amino acid sequences 1-20, 63-88, and 110-128. T hese Ag were chosen because they represent putative targets for autoim mune 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 compa red to peripheral blood of patients with neurologic diseases. No immun odominant 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 enumeratio n of autoimmune T cells in cord blood and peripheral blood obtained fr om corresponding mothers at delivery, revealed that the high cell numb ers in newborns were not a result of contamination from the mothers bl ood. The high numbers of T cells recognizing nervous system myelin pro teins and acetylcholine receptor in cord blood could have importance f or the mechanism and timing of tolerance induction, and also reflect e xcessive myelination and receptor maturation at birth.