Method of detecting heart failure, device for detecting heart failure, sandwich immunoassay method, and combination of antibodies

Inventors

UDA, Tomohiko • KITAYAMA, Saeko • Ishii, Kenyo

Assignees

Kyoritsu Seiyaku Corp

Abstract

[Problem]To provide means for detecting heart failure more simply and highly accurately.[Solution Means]A method of detecting heart failure from a sample collected from an organism, the method comprising the step of: performing sandwich immunoassay of NT-proANP or a fragment thereof contained in the sample using a first antibody for capturing for which an epitope lies on any site among positions 31 to 67 of an amino acid sequence of NT-proANP and a second antibody for labeling for which an epitope lies on any site among positions 31 to 67 of the amino acid sequence of NT-proANP, and the like.The epitopes of the two types of antibodies: one for capturing and the other for labeling, both of which lie among positions 31 to 67 of the amino acid sequence of NT-proANP. This, therefore, enables detention of a fragment having the same amount of substance as NT-proANP and simple and highly accurate detection of heart failure, even if NT-proANP is further cleaved and decomposed into 3 pieces during circulation in blood.

Core Innovation

The invention relates to a sandwich immunoassay for detecting heart failure from a sample collected from an organism by capturing NT-proANP or a fragment thereof and detecting a level of NT-proANP or a fragment thereof to detect heart failure. The capturing is performed using a first antibody in which a first epitope lies within positions 31 to 67 of the amino acid sequence of NT-proANP, and a second antibody for labeling is added, where a second epitope lies within positions 31 to 67 of the same amino acid sequence.

The method detects heart failure based on the measured level of NT-proANP or a fragment thereof in the sample. The document states that circulating NT-proANP is fragmented into pieces that include a stable 31 to 67 region, enabling accurate measurement of equivalent NT-proANP substance despite cleavage or decomposition.

The document further describes embodiments implemented as an immunoassay and includes immunochromatography-based structures for measurement. An immunochromatography test strip includes a sample application, a labeled-antibody retention portion, and a measurement portion including a fixed capture antibody, with a flow path that develops upstream to downstream to carry the sample through the regions.

Claims Coverage

The independent claim covers detecting heart failure by a sandwich format that uses two non-overlapping antibodies recognizing epitopes located within NT-proANP positions 31 to 67, followed by measuring NT-proANP or a fragment and detecting heart failure based on the measured level. The claim also includes VH/VL and CDR-based structural limitations for antibodies A, B, and C, and requires the first and second antibodies to be different selections from antibody A, antibody B, and antibody C.

Overall, the claim coverage is centered on a sandwich immunoassay for heart failure detection using a first antibody and a second labeled antibody that recognize epitopes within NT-proANP positions 31 to 67, together with VH/VL and CDR-based structural limitations specifying antibodies A, B, and C and requiring the first and second antibodies to be different.

Stated Advantages

Documented Applications