Conjugated Primary Antibodies
Conjugated primary antibodies carry a reporter label bound directly to the antibody, eliminating the need for a secondary antibody step. Our range includes DyLight fluorescent conjugates, HRP conjugated and biotin conjugated primary antibodies across over 2,000 research targets.
Browse All Conjugated Primary AntibodiesWhat is a Conjugated Primary Antibody?
A conjugated primary antibody is a primary antibody that has been directly labelled with a reporter molecule during manufacture. The reporter can be a fluorescent dye (fluorophore), an enzyme such as horseradish peroxidase (HRP), or a small molecule such as biotin. Because the label is attached directly to the antibody that recognises the target, no secondary antibody is required for detection.
This is sometimes called a directly conjugated antibody or directly labelled antibody, in contrast to the indirect method where an unlabelled primary is detected by a labelled secondary. Both approaches have distinct advantages depending on whether you need signal amplification, multiplexing capability, or reduced background from secondary reagents.
All products are for research use only and are not intended for diagnostic or therapeutic applications.
Key Advantages of Direct Conjugation
- No secondary antibody required, reducing protocol steps and incubation time
- Eliminates secondary antibody cross-reactivity and non-specific background
- Enables true multiplexing: multiple targets detected simultaneously with unique labels
- Essential when primary antibodies from the same host species need to be used together
- Shorter protocols benefit limited or precious sample material
- Avoids signal from endogenous immunoglobulins in same-species tissue
- Compatible with IF, WB, ELISA, flow cytometry and IHC workflows
Conjugated vs Unconjugated Antibody: Which to Use?
The choice between a conjugated primary antibody and an unconjugated primary with a secondary depends on multiplexing needs, signal sensitivity, background control and sample availability.
| Consideration | Conjugated Primary Antibody | Unconjugated Primary + Secondary |
|---|---|---|
| Protocol steps | Fewer (direct detection) | More (two incubation and wash cycles) |
| Multiplexing same-species primaries | Yes, straightforward | Difficult without species-matched secondaries |
| Signal amplification | No amplification step | Yes (multiple secondary molecules per primary) |
| Background / cross-reactivity | Lower (no secondary) | Higher risk with complex tissue or serum |
| Low-abundance target detection | May need higher primary concentration | Better sensitivity through amplification |
| Protocol reproducibility | High (one fewer variable) | Secondary lot variation can affect signal |
| Same-species tissue (IHC) | No endogenous immunoglobulin binding | Requires Fc blocking or absorbed secondary |
| Direct ELISA | Fewer steps, less cross-reactivity | More steps but greater sensitivity |
DyLight Conjugated Antibodies for Fluorescent Protein Tag Detection
Directly conjugated DyLight antibodies targeting GFP and RFP enable secondary-free detection of fluorescent protein-tagged constructs. Each target is available across four DyLight wavelengths, so the detection channel can be freely chosen to fit the imaging system and other fluorophores in the panel. This eliminates the need to match secondary antibody species and avoids cross-channel interference from secondary reagents in multiplex experiments.
Anti-GFP Antibody · DyLight Conjugates
Anti-RFP Antibody · DyLight Conjugates
DyLight Conjugated Loading Control Antibodies
GAPDH is available as a DyLight-conjugated primary antibody across four wavelengths, enabling secondary-free western blot normalisation and IF detection. Using a directly conjugated GAPDH antibody eliminates the secondary incubation step and avoids any risk of the secondary antibody cross-reacting with other antibodies in a multiplex blot. The choice of wavelength allows the GAPDH channel to be freely assigned within the panel.
Anti-GAPDH Antibody · DyLight Conjugates
DyLight Conjugated Immune Cell Marker Antibodies
DyLight-conjugated primary antibodies against immune cell markers enable direct detection in flow cytometry and immunofluorescence without secondary antibody steps. Directly conjugated CD45 is widely used as a pan-leukocyte marker in flow panels where same-species primary antibodies would otherwise require separate species-matched secondaries, and Calnexin {DyLight 633} provides secondary-free ER marker detection in multiplexed IF experiments.
Biotin Conjugated Primary Antibodies
Biotin conjugated primary antibodies carry a biotin label bound directly to the antibody, enabling detection via streptavidin or avidin-conjugated reporters without a conventional secondary antibody step. The biotin-streptavidin interaction provides signal amplification and format flexibility: the same biotinylated primary can be detected with fluorescent, HRP, alkaline phosphatase or gold-labelled streptavidin, making it adaptable across IF, WB, ELISA, flow cytometry and IHC workflows. Our biotin conjugated primary antibody range covers over 1,600 targets including CD markers, loading controls, proliferation markers and fluorescent protein tags.
Applications for Conjugated Primary Antibodies
Directly conjugated primary antibodies are used across a broad range of research applications where eliminating the secondary antibody step provides advantages in protocol efficiency, signal specificity or multiplexing capability.
Immunofluorescence (IF)
Directly conjugated primary antibodies simplify IF protocols and enable same-species multiplexing. DyLight-conjugated primaries provide photostable signal without secondary incubation and reduce linkage error in super-resolution microscopy by removing the 10-15 nm distance introduced by a primary plus secondary combination.
Flow Cytometry (FC)
Multi-colour flow cytometry panels routinely use conjugated primary antibodies to simultaneously phenotype cell populations. Direct conjugation eliminates the secondary step and avoids cross-reactivity between channels in complex multi-parameter panels where multiple primaries from the same species are needed.
Western Blot (WB)
HRP or DyLight conjugated primary antibodies allow direct blot detection without secondary incubation. Particularly useful when working with samples from the same species as the primary host, where secondary antibodies can produce non-specific bands from endogenous immunoglobulins.
ELISA
In direct ELISA formats, a conjugated primary antibody detects the captured antigen without a secondary step. This is preferred in competitive ELISA designs and in assays using complex sample matrices where secondary amplification steps would compromise signal linearity.
Same-Species Tissue (IHC)
When studying mouse tissue with a mouse-derived primary, secondary antibodies produce high background from endogenous tissue immunoglobulins. A directly conjugated primary antibody bypasses this without the need for species-absorbed secondary reagents or extensive blocking protocols.
Multiplexing
Using multiple conjugated primary antibodies, each carrying a spectrally distinct fluorophore, allows simultaneous detection of several targets in a single sample. This is the standard approach for multi-colour flow cytometry and multiplex immunofluorescence where same-species primaries would be incompatible with conventional secondary detection.
Our Commitment to You
DyLight fluorescent, HRP and biotin conjugate formats
No secondary antibody required for detection
Compatible with IF, WB, ELISA, FC and IHC applications
Free shipping on all orders
1-year product guarantee on all antibodies
Browse Conjugated Primary Antibodies
Explore our full range of over 2,000 directly conjugated primary antibodies including DyLight fluorescent conjugates, HRP conjugated and biotin conjugated formats across a wide range of research targets.
Browse All Conjugated Primary Antibodies