Abstract: Provided are labeling reagents and methods for labeling primary antibodies and for detecting a target in a sample using an immuno-labeled complex that comprises a target-binding antibody and one or more labeling reagents. The labeling reagents comprise monovalent antibody fragments or non-antibody monomeric proteins whereby the labeling proteins have affinity for a specific region of the target-binding antibody and are covalently attached to a label. Discrete subsets of labeling reagent and immune-labeled complexes are provided that facilitate the simultaneous detection of multiple targets in a sample-complexes are distinguished by i) a ratio of label to labeling reagent, or ii) a physical property of said label, or iii) a ratio of labeling reagent to said target-binding antibody, or iv) by said target-binding antibody. This is particularly useful for fluorophore labels that can be attached to labeling reagents and subsequently immuno-labeled complexes in ratios for the detection of multiple targets.

Abstract: The present invention provides novel immunolabeling complexes and certain components of such complexes, as well as methods of preparing and using such complexes, and kits for use in preparing labeling proteins and for immunolabeling. The pre-formed immunolabeling complexes of the invention comprise both a target-binding antibody and a labeling protein that contains covalently attached labels, where the labeling protein binds selectively and with high affinity to a selected region of the target-binding antibody. Novel labeling proteins of the invention include non-antibody peptides and proteins, such as a complex of protein G and a labeled albumin, and monovalent antibody fragments, such as labeled Fab fragments of an anti-Fc antibody. In methods of the invention, the preformed immunolabeling complexes are added to the sample alone or in combination, for purposes of labeling and optionally detecting the target of interest.

Abstract: The present invention provides methods and non-fluorescent carbocyanine quencher compounds having the general formula: Wherein the A moiety is a substituted pyridinium, unsubstituted pyridinium, substituted quinolinium, unsubstituted quinolinium, substituted benzazolium, unsubstituted benzazolium, substituted indolinium, or substituted indolinium. The invention further provides luminescent donor molecule-quencher pairs and luminescent donor molecule-quencher-luminescent acceptor molecule conjugates wherein the quencher is a cyanine compound of the present invention. The energy transfer pairs are used to detect an analyte of interest in a sample.

Abstract: The present invention provides labeling reagents and methods for labeling primary antibodies and for detecting a target in a sample using an immuno-labeled complex that comprises a target-binding antibody and one or more labeling reagents. The labeling reagents comprise monovalent antibody fragments or non-antibody monomeric proteins whereby the labeling proteins have affinity for a specific region of the target-binding antibody and are covalently attached to a label. Typically, the labeling reagent is an anti-Fc Fab or Fab? fragment that was generated by immunizing a goat or rabbit with the Fc fragment of an antibody.

Abstract: The invention is a novel fluorescently labeled microparticle, where the microparticle internally incorporates at least one dipyrrometheneboron difluoride dye. Appropriate selection of substituents results in dipyrrometheneboron difluoride derivatives that, when incorporated into polymer microparticles, give the desired excitation and emission wavelengths. The spectral characteristics of the labeling dyes in liquid are not greatly changed when the dye is incorporated into the particles, and the spectral excitation and emission wavelengths are compatible with commonly used filter sets. Other embodiments of the fluorescent microparticles include additional dyes and/or bioreactive substances.

Abstract: The subject invention provides a method for analyzing the metabolic activity in cells by improving the retention of a detectable reporter molecule only in intact cells where a particular enzyme is present. In particular, improved retention results from a two part process involving conjugation of haloalkyl-substituted derivatives of a reporter molecule with intracellular cysteine-containing peptides while unblocking the reporter molecule. The method for analyzing metabolic activity of cells involves the use of a substrate having the formXR-REPORTER-BLOCKwherein -BLOCK is a group selected to be removable by action of a specific analyte, to give REPORTER spectral properties different from those of the substrate,-REPORTER- is a molecule that, when no longer bound to BLOCK by a BLOCK-REPORTER bond, has spectral properities different from those of the substrate, andXR-- is a haloalkyl moiety that can covalently react with an intracellular thiol (Z--S--H) to form a thioether conjugate (Z--S--R--).