iF647 Anti-Human CD33 Antibody

Cat # Size Price Quantity
11670125 tests$120
116702100 tests$250

Product Details


CloneGemtuzumab
ApplicationFlow Cytometry
ReactivityHuman
FormatiF647
Target NameCD33, Siglec-3, gp67, p67, Siglec3
IsotypeHuman IgG4
Antibody TypeMonoclonal
Regulatory StatusRUO
FormulationPhosphate-buffered solution, pH 7.2, containing 0.09% sodium azide and 0.2% (w/v) BSA
Protein ConcentrationSupplied at a lot-specific concentration.
Storage&HandlingThe antibody solution should be stored undiluted between 2°C and 8°C, and protected from prolonged exposure to light. Do not freeze.
Recommended UsageFor flow cytometric staining, it is recommended to use 5 µL of this reagent per 0.5-1.0 million cells in a 100 µL volume. Optimal reagent performance should be determined by titration for each specific application. iF647 has an excitation max at 656 nm and an emission max at 670 nm.
Excitation LaserRed Laser (633 nm)
Research AreasMonocytes, Macrophages, Dendritic cells, Innate Immunity, Cancer Marker
See All FormatsClone Gemtuzumab

Background Information


Human CD33 is a sialic acid–binding immunoglobulin-like lectin (Siglec) expressed predominantly on myeloid lineage cells, including hematopoietic progenitors, monocytes, and myeloid blasts in acute myeloid leukemia (AML). Structurally, CD33 is a type I transmembrane glycoprotein composed of an N-terminal V-set Ig-like domain that mediates ligand recognition, a C2-set Ig-like domain, a single transmembrane region, and a cytoplasmic tail containing immunoreceptor tyrosine-based inhibitory motifs (ITIMs). These ITIMs recruit phosphatases such as SHP-1 and SHP-2 to transmit inhibitory signaling that dampens cellular activation.

CD33 recognizes sialylated glycans on host cell surfaces as its endogenous ligands, enabling it to function as a “self-recognition” receptor that helps regulate myeloid cell activation, cytokine release, and phagocytosis. Through these interactions, CD33 contributes to the maintenance of immune homeostasis and prevention of excessive inflammation. However, this inhibitory signaling axis can be co-opted in disease states.

In acute myeloid leukemia, CD33 is highly expressed on leukemic blasts, making it a clinically important biomarker and therapeutic target. Its expression is generally absent or low on non-hematopoietic tissues, which improves its suitability for targeted therapy. Overexpression of CD33 in AML is associated with disease burden and progression, and it is frequently used for diagnosis and stratification.

Gemtuzumab is a humanized monoclonal antibody directed against CD33, and it is conjugated to the cytotoxic agent calicheamicin. Upon binding CD33 on AML cells, the antibody–drug conjugate is internalized, releasing calicheamicin intracellularly to induce DNA double-strand breaks and apoptosis. Clinically, gemtuzumab ozogamicin has been used in AML therapy, either as monotherapy or in combination regimens, improving outcomes in selected patient populations by selectively targeting CD33-positive leukemic cells while sparing most normal tissues.

Isotype Control


iF647 Human IgG4 Isotype Control Antibody

Data Sheets


iF647 Anti-Human CD33 Antibody TDS

Related Protocols


Flow Cytometry Protocol

Frequently Asked Questions


How do I determine the optimal antibody concentration/titer for my experiment?
We recommend titrating each new antibody lot on your own cell type and instrument, since optimal concentration depends on cell density, target expression level, and cytometer sensitivity. Suggested starting dilutions or test sizes (e.g., µg or µl per 10^6 cells) are provided on the product page as a starting reference point, not a fixed requirement.

Can these antibodies be used for intracellular or intranuclear staining, or only surface staining?
Intended use (surface, intracellular, or both) is specified per product, indicated under Application. The appropriate Related Protocol is linked for each product. If you need to detect both surface and intracellular markers in the same panel, confirm each antibody's compatibility with your fixation/permeabilization protocol before combining them.

What controls should I use alongside these antibodies?
Matched isotype controls (same host species, isotype, and conjugate) are available for most clones to help distinguish specific binding from background/non-specific staining and are linked on each product page. Unstained, single-color compensation, and fluorescence-minus-one (FMO) controls are also recommended, especially for multicolor panel design.

Can I combine InnoCyto Flow Cytometry antibodies into a multicolor panel?
Yes — antibodies across our catalog are designed to be panel-compatible, and conjugate options are offered specifically to support multiplexing. When building a panel, pair bright fluorophores with low-expression targets, avoid excessive spectral overlap, and confirm compensation is set up correctly for your specific fluorochrome combination. Use our Panel Builder to simplify the process.

Have a product or application question? Consult our FAQs or contact us.