Immunoassay for the detection of procalcitonin

Abstract

The present invention relates to an in vitro method for the detection of Procalcitonin or a fragment thereof of at least 20 amino acid residues in length in a biological sample derived from a bodily fluid obtained from a subject, comprising the steps of: (i) contacting said sample with at least two antibodies or functional fragments thereof directed against different epitopes within Procalcitonin, and (ii) qualitatively or quantitatively detecting binding of said at least two antibodies to Procalcitonin or said fragment thereof, wherein binding indicates the presence or concentration of Procalcitonin or said fragment in said sample, wherein at least one antibody or functional fragment thereof is directed against an epitope comprised in the sequence spanning amino acid residues 2 to 52 of Procalcitonin. The invention also pertains to antibodies directed against an N-terminal epitope of Procalcitonin and kits comprising antibodies directed against PCT.

1 . In vitro method for the detection of Procalcitonin or a fragment thereof of at least 20 amino acid residues in length in a biological sample derived from a bodily fluid obtained from a subject, comprising the steps of:
 a. contacting said sample with at least two antibodies or functional fragments hereof directed against different epitopes within Procalcitonin, and   b. qualitatively or quantitatively detecting binding of said at least two antibodies to Procalcitonin or said fragment thereof, wherein binding indicates the presence or concentration of Procalcitonin or said fragment in said sample,
 wherein at least one antibody or functional fragment thereof is directed against an epitope comprised in the sequence spanning amino acid residues 2 to 52 of Procalcitonin. 
   
     
     
         2 . Method according to  claim 1 , wherein the antibody or functional fragment thereof, which is directed against an epitope comprised in the sequence spanning amino acid residues 2 to 52 of Procalcitonin, is a monoclonal antibody. 
     
     
         3 . The method according to  claim 1 , wherein one other antibody or functional fragment thereof is directed against an epitope comprised in the sequence spanning amino acid residues 53 to 116 of Procalcitonin. 
     
     
         4 . The method according to  claim 1 , wherein the epitope comprised in the sequence spanning amino acid residues 2 to 52 of Procalcitonin is an epitope comprised in the sequence spanning amino acid residues 16 to 40 of Procalcitonin. 
     
     
         5 . The method according to  claim 4 , wherein the epitope comprised in the sequence spanning amino acid residues 16 to 40 of Procalcitonin is selected from a group consisting of an epitope comprised in the sequence spanning amino acid residues 21 to 40 of Procalcitonin, an epitope comprised in the sequence spanning amino acid residues 16 to 35 of Procalcitonin and an epitope comprised in the sequence spanning amino acid residues 25 to 37 of Procalcitonin. 
     
     
         6 . The method according to  claim 3 , wherein the epitope comprised in the sequence spanning amino acid residues 53 to 116 of Procalcitonin is an epitope comprised in the sequence spanning amino acid residues 96 to 116 of Procalcitonin or an epitope comprised in the sequence spanning amino acid residues 60 to 91 of Procalcitonin. 
     
     
         7 . The method according to  claim 1 , wherein the antibody or functional fragment thereof, which is directed against an epitope comprised in the sequence spanning amino acid residues 53 to 116 of Procalcitonin, is a monoclonal antibody. 
     
     
         8 . Antibody or a functional fragment thereof directed against an epitope comprised in the sequence spanning amino acid residues 16 to 40 of Procalcitonin. 
     
     
         9 . Antibody or a functional fragment thereof according to  claim 8 , wherein the antibody or functional fragment thereof is directed against an epitope is selected from a group consisting of an epitope comprised in the sequence spanning amino acid residues 21 to 40 of Procalcitonin, an epitope comprised in the sequence spanning amino acid residues 16 to 35 of Procalcitonin and an epitope comprised in the sequence spanning amino acid residues 25 to 37 of Procalcitonin. 
     
     
         10 . Antibody according to  claim 8 , wherein the antibody is monoclonal. 
     
     
         11 . Antibody according to  claim 10 , wherein the antibody is produced by a hybridoma cell line that is deposited at the DSMZ under accession number DSM ACC2993, DSM ACC2996 or DSM ACC2997. 
     
     
         12 . Kit comprising at least
 a. a first antibody or a functional fragment thereof directed against an epitope comprised in the sequence spanning amino acid residues 2 to 52 of Procalcitonin, and   b. a second antibody or a functional fragment thereof directed against an epitope comprised in the sequence spanning amino acid residues 53 to 116 of Procalcitonin.   
     
     
         13 . Kit according to  claim 12 , wherein the first antibody is directed against an epitope comprised in the sequence spanning amino acid residues 16 to 40 of Procalcitonin, preferably against an epitope that is selected from a group consisting of an epitope comprised in the sequence spanning amino acid residues 21 to 40 of Procalcitonin, an epitope comprised in the sequence spanning amino acid residues 16 to 35 of Procalcitonin and an epitope comprised in the sequence spanning amino acid residues 25 to 37 of Procalcitonin. 
     
     
         14 . Kit according to  claim 12 , wherein the second antibody is directed against an epitope comprised in the sequence spanning amino acid residues 60 to 91 of Procalcitonin or directed against an epitope comprised in the sequence spanning amino acid residues 96 to 116 of Procalcitonin. 
     
     
         15 . A method of performing a sandwich immunoassay for the detection and or quantification of Procalcitonin in a biological sample from a bodily fluid comprising employing a kit of  claim 12 . 
     
     
         16 . The method according to  claim 1  for the determination of the presence or absence of Procalcitonin or a fragment thereof or for the quantification of Procalcitonin or a fragment thereof in a biological sample from a bodily fluid. 
     
     
         17 . The method according to  claim 16  for the diagnosis, prognosis, risk stratification, therapy monitoring, therapy guidance, or stratification for application of therapeutic measures of a disease or condition associated with elevated Procalcitonin levels. 
     
     
         18 . The method according to  claim 17 , wherein the disease or condition is selected from the group of local bacterial infections, sepsis, severe sepsis, septic shock, non-infectious disease including cardiovascular diseases (acute coronary syndrome, heart failure, coronary artery disease, atherosclerosis, stroke), cancer, diabetes, chronic gastrointestinal diseases, chronic renal diseases, hypertension, orthopaedic diseases including osteoporosis, and neurodegenerative diseases including Alzheimer's disease. 
     
     
         19 . The hybridoma cell line deposited at the DSMZ under accession number DSM ACC2993, DSM ACC2996 or DSM ACC2997.