Alpha-3 chain type IV collagen polypeptides

An isolated and substantially pure polynucleotide encoding 238 amino acids of the carboxy terminal end of the triple helical domain and all 233 amino acids of the carboxy terminal noncollageneous domain of the bovine .alpha.3 chain of type IV collagen. An isolated and substantially pure polynucleotide encoding 218 amino acids of the carboxy terminal noncollagenous domain of the human .alpha.3 chain of type IV collagen. Such polynucleotides are useful to express large amounts of proteins in vectors and such expressed proteins are useful to detect Goodpasture antibodies in blood and to remove Goodpasture antibodies from the bloodstream of patients suffering from Goodpasture syndrome.