HRP-conjugated anti-mouse primary antibodies are immunoreagents in which horseradish peroxidase is covalently linked to an immunoglobulin that directly binds a specific mouse antigen. 

The first and more common format is HRP-conjugated anti-mouse secondary antibodies — anti-mouse immunoglobulin reagents (e.g., goat anti-mouse IgG-HRP) that bind to mouse primary antibodies and provide the enzymatic signal for detection. These are the reagents most frequently encountered under the "HRP anti-mouse" designation and are used to detect mouse-derived primary antibodies in Western blotting, ELISA, and immunohistochemistry.

The second format is HRP-conjugated anti-mouse primary antibodies — mouse monoclonal antibodies that directly bind a specific antigen (e.g., His tag, β-actin, synaptophysin) and carry a covalently attached HRP molecule. Examples include HRP-conjugated His-Tag mouse monoclonal antibody, HRP-conjugated β-Actin mouse monoclonal antibody, and HRP-conjugated synaptophysin (SYP, clone H-8) mouse monoclonal antibody. These reagents enable direct detection of the target antigen without requiring a secondary antibody.

Applications

Western Blotting

HRP-conjugated primary antibodies are validated primarily for Western blotting, where they enable direct detection of the target antigen. The HRP-conjugated His-Tag mouse monoclonal antibody is used for Western blot analysis of His recombinant proteins at dilutions of 1:3,000–1:10,000. 

Immunohistochemistry and Immunocytochemistry

HRP-conjugated anti-mouse antibodies, particularly the secondary antibody format, are extensively used in immunohistochemistry (IHC) and immunocytochemistry (ICC). The HRP-conjugated goat anti-mouse IgG is recommended for IHC-P at dilutions of 1:500–1:1,000 and for multiplex IHC at 1:500–1:1,000. 

ELISA

HRP-conjugated anti-mouse antibodies are validated for ELISA at dilutions typically ranging from 1:5,000 to 1:20,000 for the secondary antibody format. The rat anti-mouse IgM HRP conjugate is recommended for ELISA at 1:4,000–1:8,000. 

Direct Detection Advantage

The primary advantage of HRP-conjugated primary antibodies is the elimination of the secondary antibody incubation step. This is particularly valuable in applications where a secondary antibody would produce high background, such as when mouse primary antibodies are applied to mouse tissue.