Nucleotide sequence of a human autoantibody to the alternative pathway C3/C5 convertase (C3NeF).

The production of autoantibodies to the alternative pathway C3/C5 convertase or C3 Nephritic Factor (C3NeF) is one characteristic of membranoproliferative glomerulonephritis. The complete nucleotide sequences of the heavy and light chain variable regions of an IgG C3NeF produced by an EBV transformed B cell line derived from a patient with membranoproliferative glomerulonephritis were determined. The VH and VL gene segments used by this C3NeF are extensively mutated suggesting that antigenic selection and affinity maturation may occur during the generation of these autoantibodies.