Method for exposing Group A streptococcal antigens and an improved diagnostic test for the identification of Group A streptococci
AssigneeNew Horizons Diagnostics Corporation
InventorsVincent A. Fischetti, David Bernstein
Life of this patent
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Abstract
The present invention relates to the rapid detection of Group A streptococci in clinical specimens, through the enzymatic digestion by a semi-purified Group C streptococcal phage associated lysin enzyme and the identification of the released antigens, through the reaction of a labelled ligand and its respective antigen or receptor. The labelled ligand can be included during the digestion of the bacteria, enabling the total assay time to be less than five minutes. The lysin enzyme is stabilized and can be lyophilized for in situ reconstitution.
Claims23
A method for detecting Group A streptococcal antigens, comprising:
- treating a clinical specimen suspected of containing Group A streptocooci with an extraction reagent comprising Group C streptococcal phage associated lysin enzyme without first culturing said clinical specimen thereby releasing Group A streptococcal antigens into the extraction reagent and detecting said antigens using an immunological ligand receptor assay,
- wherein the contact time between the clinical specimen and said extraction reagent is less than six minutes and wherein all procedures of the assay are performed at room temperature from 21.degree. C. to 29.degree. C., and
- wherein said lysin enzyme lacks proteolytic activity with respect to antibody specific to Group A streptococcal antigen.
A diagnostic kit for detecting Group A streptococcus in clinical specimens, comprising:
- an extraction reagent containing streptococcal Group C phage-associated lysin enzyme for releasing Group A streptococcal antigens, wherein said lysin enzyme lacks proteolytic activity with respect to antibody specific to Group A streptococcal antigen, and
- an immunological ligand which binds with one or more of said Group A streptococcal antigens.
A diagnostic enzymatic extraction assay for Group A streptococcus, in which a clinical specimen suspected of containing Group A streptococcus is treated with an enzymatic extraction reagent to release Group A streptococcal antigen present in said clinical specimen, and in which the presence or absence of said antigen is determined using immunological reagents which bind to said antigen, the improvement comprising:
- treating said clinical specimen with an extraction reagent comprising streptococcal Group C phage associated lysin enzyme to release said Group A streptococcal antigen into said extraction reagent, wherein said lysin enzyme lacks proteolytic activity with respect to antibody specific to Group A streptococcal antigen.
A method for detecting Group A streptococcal antigens, comprising the steps of:
- preparing a single reagent comprising Group C streptococcal phage associated lysin enzyme and an antibody or antibody fragment specific to said Group A streptococcal antigens, wherein said lysin enzyme lacks proteolytic activity with respect to antibody specific to Group A streptococcal antigen,
- treating a clinical specimen suspected of containing Group A streptococci with said single reagent thereby releasing Group A streptococci antigens from said clinical specimen into said reagent, and
- immunologically detecting said released Group A streptococcal antigens.
Dependencies are inferred from the claim text.