APC Anti-Human CD33 Antibody

Product Details


Clone033AM1
ApplicationFlow Cytometry
ReactivityHuman
FormatAPC
Target NameCD33, Siglec-3,p67, gp67
IsotypeMouse IgG1
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. APC has an excitation max at 650 nm and an emission max at 660 nm.
Excitation LaserRed Laser (633 nm)
See All FormatsClone 033AM1

Background Information


CD33, also known as Siglec-3 (sialic acid-binding immunoglobulin-like lectin 3), is a transmembrane glycoprotein primarily expressed on cells of the myeloid lineage, including monocytes, macrophages, granulocytes, and myeloid progenitor cells. It functions as an inhibitory immune receptor that helps regulate innate immune responses and maintain immune homeostasis. CD33 contains an extracellular V-set immunoglobulin-like domain responsible for ligand recognition, a C2-set immunoglobulin-like domain, a single transmembrane region, and a cytoplasmic tail containing immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Upon activation, these ITIMs recruit phosphatases such as SHP-1 and SHP-2, dampening cellular activation and inflammatory signaling.

The primary ligands for CD33 are sialylated glycans expressed on the surface of mammalian cells. By recognizing these self-associated carbohydrate structures, CD33 contributes to self-tolerance by suppressing unnecessary immune activation. Alterations in glycan expression can influence CD33 signaling and immune regulation.

CD33 is best known for its role in hematologic malignancies, particularly acute myeloid leukemia (AML), where it is expressed on leukemic blasts in the majority of patients while being absent from normal hematopoietic stem cells. This expression pattern has made CD33 an important therapeutic target. The antibody-drug conjugate gemtuzumab ozogamicin delivers a cytotoxic payload specifically to CD33-positive leukemic cells and has been approved for the treatment of certain patients with AML. Additional therapeutic strategies under investigation include bispecific antibodies, chimeric antigen receptor (CAR) T cells, CAR-natural killer (NK) cells, and other antibody-drug conjugates targeting CD33.

Beyond oncology, CD33 has been implicated in neurodegenerative disease. Genetic variants of CD33 are associated with altered risk of Alzheimer's disease, likely through effects on microglial function and amyloid-β clearance. Consequently, CD33 is also being explored as a therapeutic target for modulating neuroinflammation and enhancing microglial-mediated clearance of pathological proteins.

Isotype Control


APC Mouse IgG1 Isotype Control Antibody

Data Sheets


APC 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.