Antibody conjugates

Abstract

Antibody / signal-generating moiety conjugates are disclosed that include an antibody covalently linked to a signal-generating moiety through a heterobifunctional polyalkyleneglycol linker. The disclosed conjugates show exceptional signal-generation in immunohistochemical and in situ hybridization assays on tissue sections and cytology samples. In one embodiment, enzyme-metallographic detection of nucleic acid sequences with hapten-labeled probes can be accomplished using the disclosed conjugates as a primary antibody without amplification.

Description

RELATED APPLICATION DATA [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60 / 675,759, filed Apr. 28, 2005, which application is incorporated by reference herein.BACKGROUND OF THE INVENTION [0002] 1. Field [0003] The present invention relates to reagents and methods for detecting a molecule of interest in a biological sample. More particularly, the present invention relates to antibody conjugates and methods for using such conjugates to detect a molecule of interest in a biological sample such as a tissue section. [0004] 2. Background [0005] Covalent conjugates of antibodies and signal-generating moieties can be used in immunoassays for detecting specific target molecules in biological samples. The antibody portion of such conjugates specifically binds to a target in the sample and the signal-generating moiety is utilized to provide a detectable signal that indicates the presence / and or location of the target. One type of conjugate that has become...

AI Technical Summary

Benefits of technology

[0014] Antibody conjugates with signal generating moieties are disclosed, as are methods for making and using the conjugates. The disclosed antibody conjugates exhibit superior performance for detection of molecules of interest in biological samples, especially for detection of such molecules in tissue sections and cytology samples. In particular, disclosed antibody-enzyme conjugates retain high amounts of antibody specificity and enzymatic activity, and thereby provide more intense staining with less background than conjugates currently used for detection of antigens in biological samples.

Problems solved by technology

However, coupling can lead to inactivation of either or both of the antibody and the enzyme due to steric effects or because the coupling reagents react with functional groups located on portions of the enzyme or antibody that are critical for their function or specificity.

Although site specific conjugation can be used to help minimize loss of antibody specificity and enzyme activity due to loss of critical functional groups, such methods do not address loss of antibody specificity and enzyme activity that arise from steric effects such as those steric effects due to aggregation of multiple conjugates and from interactions between the antibody and the enzyme(s) in a conjugate.

Detrimental steric effects also can arise due to unintended cross-linking between multiple enzymes, antibodies and / or conjugates, which occurs during preparation of a conjugate composition.

Although such linkers contain more atoms and should provide greater separation between an antibody and an enzyme(s), it is believed that the hydrophobic nature of such linkers increases detrimental aggregation of conjugates in aqueous solution due to hydrophobic effects.

However, use of such homo-bifunctional linkers can lead to cross-linking of antibodies, enzymes and / or conjugates during preparation of the conjugates.

Furthermore, cross-linking leads to lower monodispersity in a conjugate composition, which can have detrimental effects on consistency of results, especially in tissue and cell samples where detection of a target with a conjugate may be limited by diffusion through cell membranes.

Some heterobifunctional polyethylene glycol linkers are known, but there are no known attempts to use them as coupling reagents for forming antibody-enzyme conjugates.

However, as the number of enzymes linked to a single antibody increases, the likelihood increases that conjugate function will be impaired for steric reasons due to crowding of multiple enzymes around the single antibody.

While the approach described in these patents does increase the average number of signal-generating moieties per specific-binding component, the use of a polymeric scaffold (typically of low mono-dispersity) increases background and decreases reproducibility.

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