Non-specific reaction inhibitor, method for inhibiting non-specific reaction, and kit
Provided is a non-specific reaction inhibitor for achieving the accurate detection and quantitation of a trace component (a target substance) contained in a sample, in an immunoassay, by simply and effectively inhibiting a non-specific reaction associated with the measurement. The non-specific reaction inhibitor comprises a substance of the formula I: wherein R 1 and R 2 together form a double bond between carbons, to which they are respectively bonded directly, or R 1 is a hydrogen atom and R 2 is a group formed by removing H from an SH-group-containing compound, B is a support, and L is a spacer arm portion.
1. An immunological measurement method, said method comprising:
providing (1) a sample containing a target substance and a non-specific reaction substance capable of binding directly to a maleimide group, (2) a non-specific reaction inhibitor of the formula I:
wherein R 1 and R 2 together form a double bond between carbons to which they are respectively bonded directly, B is a support that is inactive in an assay system, and L is a spacer arm portion having a length of 4 to 20 Å, and (3) a reagent prepared by immobilizing an antibody or an antigen specific for the target substance on a support, or labeling an antibody or an antigen specific for the target substance, by a maleimide method using a cross-linking agent containing a maleimide group;
treating the sample (1) with the non-specific reaction inhibitor (2), to absorb a non-specific reaction activity of the non-specific reaction substance by the non-specific reaction inhibitor (2), said non-specific reaction substance being contained in the sample (1);
reacting the treated sample with the reagent (3) to form an immunological complex; and
analyzing the immunological complex in the immunological measurement method by accounting for the non-specific reaction substance.
2. The immunological measurement method according to claim 1 , wherein the immunological measurement method is a latex agglutination optical measurement method, an enzyme immunoassay, a nephelometric immunoassay, an enzyme-linked immunosorbent assay, a fluorescence immunoassay, or a radioimmunoassay.
3. An immunological measurement method, said method comprising:
providing (1) a sample containing a target substance and a non-specific reaction substance capable of binding directly to a maleimide group, (2) a non-specific reaction inhibitor of the formula I:
wherein R 1 and R 2 together form a double bond between carbons to which they are respectively bonded directly, B is a support that is inactive in an assay system, and L is a spacer arm portion having a length of 4 to 20 Å, and (3) a reagent prepared by immobilizing an antibody or an antigen specific for the target substance on a support, or labeling an antibody or an antigen specific for the target substance, by a maleimide method using a cross-linking agent containing a maleimide group;
reacting the sample (1) with the reagent (3) in the presence of the non-specific reaction inhibitor (2) to form an immunological complex, while absorbing a non-specific reaction activity of the non-specific reaction substance by the non-specific reaction inhibitor (2), said non-specific reaction substance being contained in the sample (1); and
analyzing the immunological complex in the immunological measurement method by accounting for the non-specific reaction substance.
4. The immunological measurement method according to claim 1 , wherein the immunological measurement method is a measurement by a sandwich method, and one or more steps of immunological reactions specific for the target substance contained in the sample is carried out in the presence of the non-specific reaction inhibitor (2).
5. The immunological measurement method according to claim 3 , wherein the immunological measurement method is a latex agglutination optical measurement method, an enzyme immunoassay, a nephelometric immunoassay, an enzyme-linked immunosorbent assay, a fluorescence immunoassay, or a radioimmunoassay.