Quality control for cytochemical assays

Abstract

A method and device is described for a quality control device for immunohistochemical testing of surgical biopsies. Immunohistochemistry testing involves the use of antibodies to detect the presence of proteins that have diagnostic or prognostic importance. In this invention, peptides are covalently attached to glass microscope slides. The peptides represent antibody contact sites to the native protein. Namely, the peptide contains the same amino acid sequence as the epitope in the native protein to where the antibody binds. Alternatively, peptides may not necessarily share the exact sequence as found in the native protein but they still bind to the antibody. To use this invention, tissue sections derived from surgical biopsies may be mounted on glass slides bearing the peptides. As the immunohistochemical stain is performed on the tissue section, a similar reaction sequence occurs at the site of the glass slide where the peptide is located. At the conclusion of the immunohistochemical stain, a colored reaction product deposits at the site of the peptide. Since the immunohistochemical reaction at the peptide is largely the same as that which occurs in the tissue section, the peptide serves a quality control function.

1 . A method for verifying the proper performance of an assay of a tissue section or cell containing an analyte that is detected in the assay comprising: 
 covalently attaching a soluble analyte mimic to a microscope slide to form a covalent bond between the analyte mimic and the slide, said analyte mimic being a smaller molecule than the analyte and capable of producing a reaction in the assay;    performing the assay on both the tissue section or cell and on the analyte mimic; and    assessing assay performance by examining the result of the assay on the tissue section or cell and the analyte mimic.    
     
     
         2 . The method of  claim 1  wherein the tissue section or cells are mounted on the same slide as the analyte mimic.  
     
     
         3 . The method of  claim 1  wherein the assay is an immunohistochemical stain.  
     
     
         4 . The method of  claim 1  wherein the analyte mimic is covalently attached to the microscope slide by first attaching chemically reactive moieties to the slide and then reacting the chemically reactive moieties with the analyte mimic.  
     
     
         5 . The method of  claim 4  wherein the microscope slide includes a glass surface.  
     
     
         6 . The method of  claim 5  wherein the chemically reactive moieties are attached to the slide through a silane linker.  
     
     
         7 . The method of  claim 4  wherein the chemically reactive moiety comprises an isocyanate.  
     
     
         8 . The method of  claim 1  wherein the analyte mimic is a peptide.  
     
     
         9 . The method of  claim 1  wherein the assay further comprises an antibody that binds to the analyte in tissue sections or cells.  
     
     
         10 . The method of  claim 9  wherein the antibody also binds to the analyte mimic.  
     
     
         11 . The method of  claim 10  wherein the antibody binds to the analyte mimic at an amino acid sequence that is similar to an amino acid sequence in the analyte.  
     
     
         12 . The method of  claim 1  wherein the assay performance is assessed by comparing the result of the assay with a previously determined range for the assay result on the analyte mimic, the range representing a proper performance of the assay.  
     
     
         13 . The method of  claim 1  further comprising a plurality of analyte mimics on the slide.  
     
     
         14 . A microscope slide on which an assay is performed, said assay being capable of detecting an analyte in a tissue section or cell and further comprising an antibody that binds to the analyte, wherein the slide comprises a soluble analyte mimic covalently attached to the slide such that the bonds between the analyte mimic and the slide are covalent, said analyte mimic being a smaller molecule than the analyte and wherein the antibody is capable of binding to the analyte mimic.