Conjugated Primary Antibodies

Conjugated primary antibodies are chemically modified antibodies that allow for the direct attachment of a label, such as a fluorescent dye or enzyme. These conjugated antibodies streamline detection by directly binding to their target, enabling the visualization or detection of specific target molecules in biological samples. There are several benefits to using conjugated primary antibodies including reduced assay time, improved specificity, less background noise, ease of use, high multi-plex labeling, and convenient for use across different samples. Conjugated primary antibodies can be used on multiple platforms and in various applications such as flow cytometry, immunohistochemistry, western blot, and immunocytochemistry. 

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There are two types of detection methods that can be used with primary antibodies—direct and indirect. Direct detection utilizes a primary antibody conjugated to a label (i.e. fluorescent label) for “direct” detection of a target, without the use of a secondary antibody. This method offers speed and simplicity. Direct detection is a quick, one-step process excellent for high-throughput and multiplex assays. Indirect detection utilizes a secondary antibody conjugated to a label that binds to an unlabeled primary antibody, resulting in the “indirect” detection of a target (Figure 1). Learn more about direct versus indirect detection methods in the table below. 

Fluorescence labeling is a highly versatile approach to immunohistochemistry (IHC), offering the ability to detect numerous targets simultaneously with increased sensitivity and specificity. Conjugated primary antibodies for IHC offer innovative multiplex staining techniques with a streamlined workflow and less time-consuming process for tissue labeling. 

Conjugated primary antibodies have helped transform the world of spatial biology by offering researchers the ability to understand the spatial organization, function, and behavior of individual cells within tissues. This analysis of single cells allows for deep insights into:

• Cell types, cell states and cell functions
• Cell-cell interactions
• Cellular communication
• Cellular environment
• Tissue microenvironments and architecture

Thermo Fisher Scientific offers high-quality, easy-to-choose, and easy-to-use conjugated primary antibodies for IHC and spatial biology designed to enable detailed cellular profiling and tissue imaging. Our conjugated primary antibodies have been validated across various tissue types and confirmed against secondary antibody IHC labeling. These conjugated primary antibodies are offered in a variety of fluorophores, including Alexa Fluor and Alexa Fluor PLUS, for a convenient single-step labeling method. Directly conjugated primary antibodies allow researchers to achieve high-plex labeling with 8–10 biological targets on one staining mix (Figure 2). 

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Related spatial biology protocols:

• IHC FFPE Tissue Low pH Antigen Retrieval—Direct Method
• IHC FFPE Tissue High pH Antigen Retrieval—Direct Method
• Download imaging protocol handbook

Spatial biology posters:

• Advancements in multiplexed spatial phenotyping