N-ACETYL-D-GLUCOSAMINE FOR ENHANCED SPECIFICITY OF STREP A IMMUNOASSAY
Methods, compositions and kits for detecting Group A streptococcus in a biological sample are described. More particularly, the present disclosure provides an immunoassay in which the specificity of detection of Group A streptococcus is enhanced by addition of N-acetyl-D-glucosamine. These methods, compositions and kits are useful in convenient, reliable and early diagnosis of streptococcal infection in a human subject.
1 . A device, comprising:
a matrix comprising (i) a sample receiving zone, (ii) a labeling zone comprising a labeled antibody with specific binding to Group A streptococcus antigen, to form a labeled antibody-bound antigen, and (iii) a capture zone comprising a capture antibody that binds the labeled antibody-bound antigen, wherein the sample receiving zone, the labeling zone and the capture zone are arranged on the matrix in a liquid flow path, and
wherein at least one of the sample receiving zone and the labeling zone comprise N-acetyl-D-glucosamine (NAG) monomer to reduce the rate of false positives associated with detection of Group A streptococcus infection.
2 . The device of claim 1 , wherein the labeled antibody with specific binding to Group A streptococcus antigen is a polyclonal antibody.
3 . The device of claim 2 , wherein the polyclonal antibody is fluorescently labeled.
4 . The device of claim 1 , wherein the labeled antibody with specific binding to Group A streptococcus antigen is a monoclonal antibody.
5 . The device of claim 4 , wherein the monoclonal antibody is fluorescently labeled.
6 . The device of claim 1 , wherein the capture antibody is a polyclonal antibody.
7 . The device of claim 1 , wherein the capture antibody is a monoclonal antibody.
8 . A device, comprising:
a matrix comprising (i) a sample receiving zone, (ii) a labeling zone comprising a labeled antibody with specific binding to Group A streptococcus antigen, to form a labeled antibody-bound antigen, and (iii) a capture zone comprising a capture antibody that binds the labeled antibody-bound antigen, wherein the sample receiving zone, the labeling zone and the capture zone are arranged on the matrix in a liquid flow path, and
wherein at least one of the sample receiving zone and the labeling zone comprise a reagent that blocks binding of the labeled antibody with specific binding to Group A streptococcus antigen with human epithelial cell wall glycoproteins, to reduce the rate of false positives associated with detection of Group A streptococcus infection.
9 . The device of claim 8 , wherein the labeled antibody with specific binding to Group A streptococcus antigen is a polyclonal antibody.
10 . The device of claim 9 , wherein the polyclonal antibody is fluorescently labeled.
11 . The device of claim 8 , wherein the labeled antibody with specific binding to Group A streptococcus antigen is a monoclonal antibody.
12 . The device of claim 11 , wherein the monoclonal antibody is fluorescently labeled.
13 . The device of claim 8 , wherein the capture antibody is a polyclonal antibody.
14 . The device of claim 8 , wherein the capture antibody is a monoclonal antibody.
15 . The device of claim 8 , wherein the reagent is selected from the group consisting of N-acetyl glucosamine (NAG), glucosamine, acetyl-galactosamine, galactosamine, mannosamine, acetyl-muramic acid, chitin, chitosan and hyaluronic acid.
16 . A method for detecting the presence or absence of Group A streptococcus in a biological sample, comprising:
providing a device according to claim 8 ;
placing a biological sample on the device; and
determining the presence or absence of Group A streptococcus.
17 . The method of claim 16 , further comprising:
providing an instrument for collecting the biological sample; and
collecting a biological sample on the instrument.
18 . The method of claim 16 , further comprising:
providing instructions for use, wherein the instructions do not caution to not touch the tongue, sides or top of mouth with the instrument when collecting the sample.
19 . A kit, comprising:
a device according to claim 1 ;
a container comprising an extraction reagent;
an instrument for collecting a biological sample; and
instructions for use.
20 . The kit of claim 19 , wherein the instrument is a swab.