Method for diagnosing primary biliary cirrhosis (PBC) using novel autoantigens
Methods and compositions are described for the diagnosis of primary biliary cirrhosis. Novel autoantigens are described for use in assays which employ test samples from individuals.
1. A method of diagnosing primary biliary cirrhosis (PBC) comprising:
a. contacting a test sample from an individual suspected of having PBC with one or more purified recombinant target antigens of hexokinase 1 comprising SEQ ID NO: 1 or a homologous sequence of hexokinase 1, comprising a sequence selected from the group consisting of SEQ ID NOS. 7, 8 and 11;
b. detecting binding of the one or more purified recombinant target antigens to one or more autoantibodies specific for the one or more purified recombinant target antigens in the test sample; and
c. comparing the level of autoantibodies to a control;
wherein an increased level of the one or more autoantibodies bound to the one or more purified recombinant target antigens as compared to a threshold level of hexokinase 1 or a homologous sequence of hexokinase 1 autoantibodies obtained from a healthy individual is indicative of primary biliary cirrhosis.
2. The method of claim 1 , wherein the one or more purified recombinant target antigens are immobilized on a solid support.
3. The method of claim 1 , wherein the test sample is contacted with two or more of the purified recombinant target antigens.
4. The method of claim 1 , wherein the test sample is contacted with three or more of the purified recombinant target antigens.
5. The method of claim 1 , wherein the test sample is contacted with four or more of the purified recombinant target antigens.
6. The method of claim 1 , wherein the test sample is cells, tissues or body fluids.
7. The method of claim 1 , wherein the test sample is blood, plasma or serum.
8. The method of claim 1 , wherein the one or more purified recombinant target antigens are produced using cell-free protein expression.
9. The method of claim 1 , wherein the one or more purified recombinant target antigens further comprises a tag sequence located at the C-terminal or N-terminal, or at both the C-terminal and N-terminal.
10. The method of claim 1 , wherein the detection step further comprises a labeled anti-immunoglobulin (IG) antibody and wherein the one or more purified recombinant target antigen, autoantibody, and anti-IG antibody form a complex.
11. The method of claim 2 , wherein the one or more purified recombinant target antigens further comprises a tag sequence located at the C-terminal, N-terminal, or at both the C-terminal and N-terminal.
12. The method of claim 11 , wherein the one or more purified recombinant target antigens are immobilized on the solid support using the tag sequence.