Factor H polymorphisms in the diagnosis and therapy of inflammatory diseases such as age-related macular degeneration
The invention relates to antibodies, including monoclonal and polyclonal, or fragments thereof, which discriminate between the histidine and tyrosine isoforms of Complement Factor H and to their use in diagnostic methods and therapeutic treatments relating to Complement Factor H mediated diseases.
1. A method for determining a risk factor for a complement mediated disease in an individual comprising:
a) obtaining a plasma sample from an individual to be tested;
b) exposing said sample to at least one antibody, or antigen-binding fragment thereof, produced by a deposited hybridoma having an ECACC accession number A 07042601 (His402 variant) and specific for a histidine 402 variant (His402 variant) of Complement Factor H, and/or at least one antibody, or antigen-binding fragment thereof, produced by a deposited hybridoma having an ECACC accession number A 08011002 (Tyr402 variant) and specific for a tyrosine 402 variant (Tyr402 variant) of Complement Factor H;
c) determining specific binding of said antibody to plasma Complement Factor H and where binding of the histidine specific antibody produced by the deposited hybridoma having the ECACC accession number A 07042601 takes place concluding that the histidine 402 variant is present, or where binding of the tyrosine specific antibody produced by the deposited hybridoma having the ECACC accession number A 08011002 takes place concluding that the tyrosine 402 variant is present; and
d) where the histidine 402 variant is present, concluding that the individual either has, or is at increased risk of developing a complement mediated disease, or where the binding of only the tyrosine specific antibody indicates a homozygous state for the tyrosine 402 variant, i.e. that there is no histidine 402 variant present, concluding that the individual is at reduced risk of developing a complement mediated disease.
2. The method according to claim 1 wherein said antibody or antigen-binding fragment thereof is specific for the histidine 402 variant of Complement Factor H.
3. The method according to claim 1 wherein said antibody or antigen-binding fragment thereof is specific for the tyrosine 402 variant of Complement Factor H.
4. The method according to claim 1 wherein step b) includes exposing said sample to only the antibody or antigen-binding fragment thereof specific for the tyrosine 402 variant of Complement Factor H and step c) includes quantitatively determining whether the individual is homozygous for the tyrosine variant.
5. The method according to claim 1 wherein the disease is Age-Related Macular Degeneration.
6. The method according to claim 1 wherein following step b) unbound antibodies are removed so that a subsequent determination of binding can be undertaken without, or with a minimum amount of, background interference from unbound antibodies.
7. The method according to claim 1 wherein step a) is followed by a step of exposing plasma to antibody or antigen-binding fragment thereof that recognises both variants of Complement Factor H and washing away any unbound plasma proteins.
8. The method according to claim 7 , further including adding a secondary antibody linked directly or indirectly to a labeling system, said secondary antibody binding an isoform-specific antibody or antigen-binding fragment thereof specific for one of the His402 variant or Tyr 402 variant.
9. The method according to claim 8 wherein said labelling system includes any one or more of the following: enzyme-linked immunosorbent assay (ELISA) systems, bioluminescent systems, chemiluminescent systems or pigmented indicator systems.
10. An isolated antibody or antigen-binding fragment thereof that is specific for a histidine 402 variant of Complement Factor H, said antibody being produced by a deposited hybridoma having an ECACC accession number A 07042601.
11. An isolated non-human clone that secretes the antibody according to claim 10 .
12. An isolated antibody or antigen-binding fragment thereof that is specific for a tyrosine 402 variant of Complement Factor H, said antibody being produced by a deposited hybridoma having an ECACC accession number A 08011002.
13. An isolated non-human clone that secretes the antibody according to claim 12 .
14. A therapeutic composition for inhibiting binding of Complement Factor H to either ligands or tissues, comprising a monoclonal antibody or antigen-binding fragment thereof, specific for either a histidine 402 variant or a tyrosine 402 variant of Complement Factor H, said monoclonal antibody being produced by a deposited hybridoma having an ECACC accession number A 07042601 (histidine 402 variant) or a deposited hybridoma having an ECACC accession number A 08011002 (tyrosine 402 variant).
15. A kit for determining a risk factor for a complement mediated disease in an individual according to the method set forth in claim 1 , wherein said kit comprises an isolated antibody or antigen-binding fragment thereof, specific for the histidine 402 variant of Complement Factor H and/or an isolated antibody or antigen-binding fragment thereof, specific for the tyrosine 402 variant of Complement Factor H, said antibody being produced by the deposited hybridoma having an ECACC accession number A 07042601 (histidine 402 variant) or the deposited hybridoma having an ECACC accession number A 08011002 (tyrosine 402 variant); and
an indicator or label for determining binding of said isolated antibody or antigen-binding fragment thereof to Complement Factor H.
16. The kit according to claim 15 wherein said kit further includes an isolated antibody, or antigen-binding fragment thereof, that recognises any isoform of Complement Factor H.
17. The kit according to claim 16 wherein said antibody or antigen-binding fragment thereof that recognizes any isoform of Complement Factor H is monoclonal or polyclonal.
18. The kit according to claim 15 wherein said kit further includes labelling means that enables binding of said one or more antibodies, or antigen-binding fragments thereof, to Complement Factor H to be determined.
19. The kit according to claim 18 wherein said kit includes a secondary antibody which is coupled to an enzyme-linked immunosorbent assay (ELISA) system or a light activated assay system or a pigmented assay system.
20. The kit according to claim 19 wherein said secondary antibody has an antigen-binding specificity for the antibody produced by the deposited hybridoma having an ECACC accession number A 07042601 (His 402 variant) or the deposited hybridoma having an ECACC accession number A 08011002 (Tyr402 variant).