Methods for detecting symmetrical dimethylarginine
Method of detecting Symmetrical dimethyl arginine (SDMA) in biological samples. SDMA analogs for generating anti-SDMA antibodies having little or no cross-reactivity with asymmetrical dimethyl arginine, arginine, and monomethylarginine. The analogs have a protected or free thiol (—SH) group or hydroxyl (—OH) group that allow them to be linked to a suitable conjugation target which can be, for example, a protein containing molecule of a label. The anti-SDMA antibodies can be used in diagnostic immunoassay for the diagnosis of SDMA associated disorders and/or diseases.
1. An antibody specific for free Symmetrical Dimethylarginine (SDMA), wherein the antibody has reactivity for asymmetrical dimethylarginine (ADMA) of less than 25% of its reactivity for SDMA.
2. The antibody of claim 1 wherein the antibody is raised in an animal injected with the compound of the following formula:
or a salt thereof, wherein R 1 is X—R 2 , wherein X is O or S, and R 2 is a protein functionalized with a thiol or hydroxyl reactive group.
3. The antibody of claim 1 , wherein the antibody has reactivity for asymmetrical dimethylarginine (ADMA) of less than 10% of its reactivity for SDMA.
4. The antibody of claim 1 , wherein the antibody has reactivity for asymmetrical dimethylarginine (ADMA) of less than 5% of its reactivity for SDMA.
5. The antibody of claim 1 , wherein the antibody has reactivity for asymmetrical dimethylarginine (ADMA) of less than 1% of its reactivity for SDMA.
6. The antibody of claim 1 , having free SDMA specifically bound thereto.
7. The antibody of claim 1 , having specifically bound thereto a compound of the formula:
or a salt thereof, wherein R 1 is X—R 2 and X is O or S and R 2 is a label having a thiol or hydroxyl reactive group.
8. The antibody of claim 7 , wherein the label is a protein.
9. The antibody of claim 7 , wherein the protein is an enzyme.
10. The antibody of claim 7 , wherein the label is an enzymatic label.
11. The antibody of claim 2 , having specifically bound thereto a compound of the formula:
or a salt thereof, wherein R 1 is X—R 2 and X is O or S and R 2 is a label having a thiol or hydroxyl reactive group.
12. The antibody of claim 11 , wherein the label is a protein.
13. The antibody of claim 11 , wherein the protein is an enzyme.
14. The antibody of claim 11 , wherein the label is an enzymatic label.
15. A device for determining the presence of SDMA in a sample comprising a solid phase having bound thereto the antibody of claim 1 .
16. A device for determining the presence of SDMA in a sample comprising a solid phase having bound thereto the antibody of claim 2 .
17. A method for detecting the presence or amount of free SDMA in a biological sample, the method comprising:
(a) contacting the sample with the antibody of claim 1 and an SDMA analog conjugated to a label, and
(b) detecting the presence or amount of the label associated with the antibody, thereby determining the presence or amount of free SDMA in the sample.
18. The method of claim 17 , wherein the SDMA analog comprises the compound of the following formula:
or a salt thereof, wherein R 1 is selected from the group consisting of thiol, protected thiol, hydroxyl, protected hydroxyl, amino, protected amino, carboxylate, and protected carboxylate.
19. The method of claim 17 wherein the antibody does not substantially bind to L-arginine, and N-methylarginine.
20. A method for detecting the presence or amount of free SDMA in a biological sample, the method comprising:
(a) contacting the sample with the antibody of claim 2 and an SDMA analog conjugated to a label, and
(b) detecting the presence or amount of the label associated with the antibody, thereby determining the presence or amount of free SDMA in the sample.
21. The method of claim 20 wherein the antibody does not substantially bind to L-arginine, and N-methylarginine.
22. A method for determining renal function in an animal subject comprising:
(a) obtaining a biological sample from a subject; and
(b) conducting the method of claim 17 to determine the amount of free SDMA in the sample,
(c) determining the renal function by comparing the amount of SDMA in the sample to one or more SDMA standards that correlate to renal function in an animal.
23. The method of claim 22 wherein the antibody does not substantially bind to L-arginine, and N-methylarginine.
24. A method for diagnosing renal disease in a subject comprising:
(a) determining the amount of free SDMA in a biological sample from the subject according to claim 17 ;
(b) comparing the amount of SDMA in the sample to the amount of SDMA in the sample of a healthy subject;
(c) diagnosing that the subject has renal disease when the amount of SDMA in the sample from the subject is higher than the SDMA in the sample from the healthy subject.
25. The method of claim 24 wherein the antibody does not substantially bind to L-arginine, and N-methylarginine.
26. A method for determining renal function in an animal subject comprising:
(a) obtaining a biological sample from a subject; and
(b) conducting the method of claim 20 to determine the amount of free SDMA in the sample,
(c) determining the renal function by comparing the amount of SDMA in the sample to one or more SDMA standards that correlate to renal function in an animal.
27. The method of claim 26 wherein the antibody does not substantially bind to L-arginine, and N-methylarginine.
28. A method for diagnosing renal disease in a subject comprising:
(a) determining the amount of free SDMA in a biological sample from the subject according to claim 20 ;
(b) comparing the amount of SDMA in the sample to the amount of SDMA in the sample of a healthy subject;
(c) diagnosing that the subject has renal disease when the amount of SDMA in the sample from the subject is higher than the SDMA in the sample from the healthy subject.
29. The method of claim 28 wherein the antibody does not substantially bind to L-arginine, and N-methylarginine.