Isotype Controls
An isotype control shares the host species, immunoglobulin class and subclass, and conjugation format of a primary antibody, but carries no specificity for the target antigen. Run in parallel at a matched concentration, it isolates non-specific binding from the primary antibody's true signal, giving a defined baseline for flow cytometry gating, IHC/IF background staining and ELISA assay development.
Matched isotype control panels
Two panels cover the matching requirements most assay development teams run into first: a VHH-format control for nanobody-based workflows, and a full human immunoglobulin subclass set for antibody engineering and Fc-dependent assay work.
Alpaca VHH Isotype Control [cAb-Lys2]
A single-domain VHH control raised against hen egg lysozyme, sharing no epitope with the antigens under study. Available unconjugated and pre-conjugated to FITC, PE, APC and PerCP, giving a matched baseline for any nanobody-based flow cytometry panel without a secondary labelling step.
View product →Human Immunoglobulin Subclass Controls
A polyclonal panel spanning IgG1, IgG2, IgG3, IgG4, IgA, IgE and IgM, each available unconjugated or conjugated to Alexa Fluor 488, 546 or 647. Matches the subclass and conjugate of a human or humanised primary antibody for FC, IF and IHC background controls.
View product →Flow cytometry gating controls
Conjugated isotype controls are run alongside a stained panel to set the boundary of the negative population before positive gates are drawn. Matching the host species, isotype and fluorophore or tandem dye of each primary in the panel means the negative population reflects non-specific antibody binding rather than an unrelated conjugate signal. Our range covers mouse IgG1, IgG2a, IgG2b and IgM, rat IgG1, IgG2a and IgG2b, and rabbit IgG, across unconjugated and directly conjugated formats.
IHC and IF background controls
On a parallel tissue section or coverslip, an isotype control applied at the same concentration and detection format as the primary antibody shows whether staining reflects Fc receptor binding or other non-specific interactions rather than antigen recognition. This matters most when interpreting weak or heterogeneous staining, where separating true low-level expression from background is otherwise difficult. Our polyclonal isotype panel spans mouse, rat and human hosts across the IgG subclasses, IgA, IgE and IgM, each validated for FC, IF and IHC.
Nanobody (VHH) and single-domain assay controls
Nanobodies, or VHH single-domain antibodies, are heavy-chain-only binding fragments derived from camelid antibodies and lack the light chain and Fc region of a conventional IgG. A conventional isotype control cannot match this format, so a VHH-format control is needed to isolate non-specific binding in nanobody-based flow cytometry, imaging or pull-down assays. Our alpaca VHH isotype control is built on the same cAb-Lys2 scaffold used across our nanobody range and is available in the same conjugate formats as our labelled VHH reagents.
ELISA and antibody panel assay development
In a plate-based immunoassay, an isotype control run as a coated-well or reagent control confirms that plate signal reflects binding to the coated antigen rather than non-specific adsorption of the antibody itself. The same matching logic extends to new antibody panel validation, where an isotype control alongside a defined reference standard establishes both the background floor and a known positive signal before a panel is taken into routine use. Our human IgG1 subclass panel also includes a recombinant reference antibody against hen egg lysozyme (HEL) for use as a positive control during method development.
Looking for a specific isotype match?
Our isotype control range spans monoclonal and polyclonal formats across dozens of host species and conjugation options.
Browse isotype controls