Jackson Immuno Research Inc.
specializing in secondary antibodies and conjugates

Product Filter

Find By Code Number

Whole IgG Affinity-Purified Secondary Antibodies

"We only use secondary antibodies from Jackson ImmunoResearch whenever possible! Customer service is also excellent and the price point for their products is very competitive."

Elizabeth Soberg, University of Washington

Leave a Review

Spotlight on...

Multiple Labeling

With BV421™ & BV480™

  • Combine with AF488, RR-X, and AF647 for 5-color imaging
  • Compatible with commonly used filter sets
  • Switch nuclear stain from DAPI to DRAQ5 for additional labeling options

Learn More

Secondary Antibodies for Enzyme Linked Immunosorbent Assay - ELISA

Introduction to ELISA

An enzyme linked immunosorbent assay (ELISA) is a robust and sensitive technique used to detect and quantify specific proteins in samples which may contain  complex mixtures of proteins. Antibodies are used to detect the specific proteins immobilized on the surface of microplate wells. The technique facilitates high volume and fast throughput analysis, ideal for analyzing large numbers of samples.

Browse Secondary Antibodies

ELISA formats and methods

ELISAs are performed a number of ways, the most common is the sandwich or capture assay or with labeled streptavidin to amplify analyte signal from a biotinylated antibody.

ELISA Methods Common ELISA formats. A. Direct. B. Indirect, C. “Sandwich” capture assay ELISA and D. Streptavidin/ biotin signal amplification using a biotinylated primary antibody.

Comparison of ELISA methods by step





Signal amp



Capture antibody


We recommend using 5% normal serum of the species of the detection antibody.


To remove unbound reagents


Conjugated primary antibody

Unconjugated primary




To remove unbound reagents



AP/HRP or fluorophore conjugated secondary antibody

Biotinylated secondary



To remove unbound reagents






To remove unbound reagents

Signal detection

Colorimetric, chemiluminescent or fluorescent.

Blocking for ELISA

Blocking reagents are especially important in ELISA, ideally use serum of the species of the labeled antibody to block all unsaturated binding sites on the microplate to avoid background from nonspecific binding, however BSA may be appropriate. See Normal Serums pages x to y and Bovine serum albumin (BSA) pages x. The addition of a mild detergent such as Tween ® 20 can help to reduce background from hydrophobic interactions.

Secondary antibody conjugates for ELISA

Jackson ImmunoResearch alkaline phosphatase (AP) and horseradish peroxidase (HRP) conjugates can be used for both colorimetric assays, using a chromogenic substrate. For chemiluminescent detection, a luminol based substrate is commonly used with peroxidase conjugates for highly sensitive detection. For more information on reporter enzyme conjugates see pages x. ELISAs can be performed using fluorescent conjugates to allow simultaneous detection of multiple antigens using primary antibodies derived from different species. Using labeled secondary antibodies each antigen can be distinguished specifically by the individual fluorescent signal. The detection limit for fluorescent ELISA is however typically lower than colorimetric or chemiluminescent detection using a reporter enzyme.

Labeled streptavidin with biotinylated primary antibodies for enhanced sensitivity

Signal enhancement can be achieved using a labeled streptavidin to detect a biotinylated antibody (primary or secondary antibody for enhanced amplification). Each antibody can itself present multiple biotin molecules, which are then, in turn, able to bind with multiple streptavidin molecules. These combined factors mean that multiple probe molecules are available to either catalyze the detection substrate to its end product or generate fluorescent emission - achieving a brighter signal and greater sensitivity.

Read more about Signal Enhancement

ELISA with JIR Secondary Antibodies

Recommended dilution ranges for ELISA are shown in the table below.

Product ELISA
Horseradish Peroxidase Conjugates [IgG, F(ab') 2] 1:5,000 - 1:100,000
Alkaline Phosphatase Conjugates [IgG, F(ab') 2] 1:5,000 - 1:50,000
Biotin-SP Conjugates [IgG, F(ab') 2] (using enzyme-Conjugated Streptavidin) 1:20,000 - 1:400,000
Horseradish Peroxidase-Conjugated Streptavidin 1-2 µg / ml
Alkaline Phosphatase-Conjugated Streptavidin 1-2 µg / ml