Cy3, Goat Anti-Rabbit IgG

Reactivity: Rabbit

What it means: This secondary antibody is designed to recognize rabbit primary antibodies (e.g., rabbit IgG). It binds to the primary antibody and enables detection through its conjugate (enzyme or fluorophore).

Why it matters: Choose “Rabbit” reactivity when your primary antibody is raised in rabbit. Note that in rabbit-derived samples, endogenous rabbit immunoglobulins may contribute to background in certain applications.

Host: Goat

What it means: “Host” refers to the animal in which the secondary antibody was produced. Host: Goat means the antibody was generated by immunizing a goat, and the resulting goat antibodies were collected and purified to make this secondary antibody.

Why it matters: The host species can affect background and cross-reactivity. For best results, avoid using a goat-host secondary in workflows where goat immunoglobulins are present (e.g., goat serum-based blocking, goat primary antibodies, or goat-rich samples), unless the protocol includes appropriate blocking and controls.

This secondary antibody is conjugated with Cy3, enabling direct fluorescent detection in the orange/red channel.

What it does: Cy3 is a fluorescent dye. After the Cy3-labeled secondary antibody binds to your primary antibody, you can visualize the target using a fluorescence microscope or imaging system with Cy3-compatible filters (typically excitation ~550 nm, emission ~570 nm).

Why it matters: Cy3-conjugated secondary antibodies are commonly used for immunofluorescence (IF) and other fluorescence-based assays, especially for multi-color staining when paired with green- or far-red fluorophores. Cy3 provides bright signal and is a popular choice for orange/red-channel imaging.

Application(s): IF, ICC, FCM

IF (Immunofluorescence): Used as a secondary antibody to bind the primary antibody and provide a fluorescent signal for target visualization under a fluorescence microscope (depending on the conjugate and filter set).

ICC (Immunocytochemistry): Used as a secondary antibody to detect primary antibodies bound to cellular targets in fixed cells, enabling fluorescent imaging of protein localization with the appropriate conjugate.

FCM (Flow Cytometry): Used as a secondary antibody to label primary antibody–bound cells for fluorescence-based detection and analysis by flow cytometry (matched to the instrument’s laser and emission channels).

Isotype: Goat IgG

What it means: This secondary antibody is a goat-derived immunoglobulin G (IgG). In other words, it is an IgG antibody produced in goat and purified for use as a secondary reagent.

Why it matters: “Goat IgG” is mainly useful for understanding the species origin and antibody class of the secondary antibody:

• Species origin (goat): This tells you the secondary itself is made in goat. If your samples contain goat immunoglobulins (e.g., goat serum, goat tissue components, or goat primary antibodies in the same assay), you may need extra blocking or a different secondary to minimize background.
• Antibody class (IgG): IgG is the most common antibody class used for secondaries and is generally high-affinity and stable for routine detection workflows.
• Detection and capture compatibility: Many common reagents (e.g., anti-goat IgG reagents, and in some contexts Protein A/G) are designed around IgG-class antibodies. Knowing it is goat IgG helps ensure compatibility when your workflow involves additional binding/capture steps.
• Controls: If you are using anti-goat detection reagents, “goat IgG” also helps when selecting appropriate negative controls to assess non-specific binding from goat-derived antibodies.