Methods for reducing complexity of a sample using small epitope antibodies

1 . A method for reducing the complexity of a sample that comprises a mixture of proteins, said method comprising separating a small epitope antibody-protein complex, wherein proteins comprising an epitope bound by the small epitope antibody are enriched.

2 - 24 . (canceled)

25 . A method for reducing the complexity of a sample that comprises a mixture of proteins, said method comprising:

(a) contacting the sample with at least one small epitope antibody to form an antibody-protein complex; and

(b) separating said antibody-protein complex from unbound protein in the sample.

26 . A method according to claim 25 , wherein steps (a) and (b) are performed sequentially.

27 . A method according to claim 25 , wherein steps (a) and (b) are performed simultaneously.

28 . A method according to claim 25 , wherein the small epitope antibody binds an epitope consisting of about 3 to about 5 amino acids.

29 . A method according to claim 25 , wherein the at least one small epitope antibody comprises at least about 100 small epitope antibodies.

30 . A method according to claim 25 , further comprising separating protein from the antibody-protein complex.

31 . A method for determining presence or absence of a protein of interest in a sample, said method comprising detecting the protein of interest, if any, in an enriched protein fraction, wherein the enriched protein fraction is prepared by the method of claim 1 , and wherein detection of the protein of interest indicates presence of the protein in the sample.

32 . A method according to claim 31 , wherein said detection comprises mass spectrometry.

33 . A method for determining the amount of a protein of interest in a sample, said method comprising quantifying the amount of the protein of interest in an enriched protein fraction, wherein the enriched protein fraction is prepared by the method of claim 1 .

34 . A method according to claim 33 , wherein said quantifying comprises mass spectrometry.

35 . A method for identifying a protein in a small epitope antibody-protein complex, wherein the small epitope antibody-protein complex is prepared according to claim 1 .

36 . A method according to claim 35 , wherein said identifying comprises mass spectrometry.

37 . A method for identification of a biomarker, said method comprising comparing the proteins in the two or more enriched protein fractions, wherein each of the enriched protein fractions is prepared from a sample according to the method of claim 1 .

38 . A method according to claim 37 , wherein the two or more samples comprise samples from at least one individual who has a disease condition and at least one individual who does not have the disease condition, and wherein presence or absence of the biomarker is indicative of the disease condition.

39 . A method for determining presence or absence of a disease condition in an individual, the method comprising determining the level of a biomarker in a sample from the individual, wherein the biomarker is identified according to the method of claim 38 , and wherein the level of the biomarker is indicative of the presence or absence of the disease condition.

40 . A method according to claim 37 , wherein the two or more samples comprise samples from at least one individual who has received treatment for a disease condition and at least one individual who has not received treatment for the disease condition, and wherein presence or absence of the biomarker is indicative of efficacy of the treatment.

41 . A method for determining efficacy of treatment for a disease condition in an individual, the method comprising determining the level of a biomarker in a sample from the individual, wherein the biomarker is identified according to the method of claim 40 , and wherein the level of the biomarker is indicative of the efficacy of treatment.

42 . A method according to claim 37 , wherein the two or more samples comprise samples from at least one individual who has been exposed to a toxin or pathogen and at least one individual who has not been exposed to the toxin or pathogen, and wherein presence or absence of the biomarker is indicative of exposure of an individual to the toxin or pathogen.

43 . A method for determining exposure of an individual to a toxin or pathogen, the method comprising determining the level of a biomarker in a sample from the individual, wherein the biomarker is identified according to the method of claim 42 , and wherein the level of the biomarker is indicative of exposure to the toxin or pathogen.

44 - 51 . (canceled)