Catalog No.	PA007393.m1
Product Name	Anti-human CD64 Antibody (Clone: M22) | PA007393.m1
Supplier Name	Syd Labs, Inc.
Brand Name	Syd Labs
Clone	M22.
Isotype	Mouse IgG1 kappa.
Source/Host	The anti-human CD64 monoclonal antibody (clone:M22) was produced in mammalian cells.
Specificity/Sensitivity	The in vivo grade recombinant mouse monoclonal antibody (clone: M22) specifically binds to human CD64.
Applications	ELISA, flow cytometry, neutralization, functional assays such as bioanalytical PK and ADA assays, and those assays for studying biological pathways affected by the human CD64 protein. Human Fc receptor blocking solution, human Fc receptor blocking reagent, and human Fc receptor blocking antibody.
Form Of Antibody	0.2 uM filtered solution, pH 7.4, no stabilizers or preservatives.
Endotoxin	< 1 EU per 1 mg of the protein by the LAL method.
Purity	>95% by SDS-PAGE under reducing conditions and HPLC.
Shipping	Anti-Human CD64 Monoclonal Antibodies is shipped with ice pack. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage	Use a manual defrost freezer and avoid repeated freeze-thaw cycles. 12 months from date of receipt, -20 to -70°C as supplied. 1 month from date of receipt, 2 to 8°C as supplied.
Note	The human CD64 Fc blocking antibody (M22 or H22 Fc blocking antibody) is an anti-human Fc receptor antibody for human FcR blocking reagent. Various isotypes are available for certain applications. Condition of sample preparation and optimal sample dilution should be determined experimentally by the investigator.
Order Offline	Phone: 1-617-401-8149 Fax: 1-617-606-5019 Email: message@sydlabs.com Or leave a message with a formal purchase order (PO) Or credit card.

Description

PA007393.m1: Recombinant Anti-human CD64 Monoclonal Antibody (Clone: M22), Mouse IgG1 Kappa, In vivo Grade

Background

The recombinant M22 or H22 antibody binds to human and non-human primate CD64 or FcγRI, a cluster of differentiation molecule found on monocytes, macrophages, and neutrophils. CD64 plays a central role in macrophage antibody-dependent cellular cytotoxicity and clearance of immune complexes, and is a candidate biomarker for bacterial infection and sepsis.

The most popular human Fc blocking reagents include:
Anti-human CD16 (clone 3G8), and CD32 (Clone IV.3): for flow cytometry, immunohistochemistry (IHC), and immunoprecipitation (IP). It is highly specific for FcγRII (CD32) and FcγRIII (CD16), and reduces background staining; it may not block all Fc receptors. Clones 10.1, and M22 or H22 are the most widely used anti-human FcγRI (CD64) clone for Fc blocking in flow cytometry and functional assays. It prevents non-specific Fc receptor binding on monocytes, macrophages, and dendritic cells, improving antibody specificity.
Purified human IgGs or mixes of human isotype controls: for general Fc blocking in IHC and immunofluorescence (IF). It is cheap and easy to use but it is less specific, and may even introduce unwanted immunoglobulins. Syd Labs supply various human IgG isotype controls.
Normal mouse serum, purified mouse IgG or isotype controls: for flow cytometry. It can serve as a control to block Fc receptors but it is non-specific for Fc receptors. It is cheap and easy to use but it is less specific, and may even introduce unwanted immunoglobulins. Our recombinant mouse IgG antibody mixes are affordable; the ratio of various IgGs is optimized and adjustable without any unwanted immunoglobulins.
Bovine Serum Albumin (BSA) or FBS: for general blocking in Western Blot (WB) and IHC. They are readily available to reduce non-specific binding but less effective at Fc receptor blocking.
Commercial Fc blocking solutions: for flow cytometry, IHC, and functional assays. They are normally pre-optimized and highly effective but more expensive than DIY solutions.

Best choice of human Fc blocking reagents based on your application are:
For flow cytometry: anti-human CD16 (Clone 3G8), CD32 (Clone IV.3), and CD64 (Clone 10.1, and M22 or H22).
For Immunohistochemistry (IHC) and Immunofluorescence (IF): Normal mouse serum, purified mouse or human IgGs or isotype controls or commercial Fc blocking kits. Our recombinant mouse IgG antibody mixes and recombinant human IgG isotype controls are affordable; the ratio of various IgGs is optimized and adjustable without any unwanted immunoglobulins.
For Western Blot and ELISA: BSA or FBS.
For functional assays (e.g., blocking Fc-mediated effects): Commercial Fc blocking reagents.

References of Anti-Human CD64 Monoclonal Antibodies:

1、Effects of linsitinib on M22 and IGF:1-treated 3D spheroids of human orbital fibroblasts.
Hikage F, et al. Sci Rep. 2025 Jan 2;15(1):384. doi: 10.1038/s41598-024-83193-x. PMID: 39747159.
“In the present study, to elucidate the pharmacological effects of Lins on GO pathogenesis, HOFs and GHOFs were treated with a recombinant human TSHR antibody, M22, IGF-1 and Lins and then subjected to cellular metabolic analysis by a seahorse bioanalyzer, physical property analysis of 3D spheroids and qPCR for various ECM proteins, their modulators, and inflammatory cytokines. …Metabolic indices were calculated using the OCR and ECAR values obtained by the Seahorse XFe96 Bioanalyzer as follows. …The 3D spheroid configuration was observed by using a phase contrast microscope (PC, Nikon ECLIPSE TS2; Tokyo, Japan) as described previously. …As shown in Fig. 1, simultaneous stimulation of both IGF-1R and TSHR by IGF-1 and M22, respectively, caused significant increases in both mitochondrial and glycolytic functions in HOFs, but such effects were substantially less in GHOFs. …Collectively, the results indicated that IGF1 and/or M22 synergistically induced fibrogenetic changes in 3D HOF spheroids, suggesting that IGF1 and M22-treated 3D HOF spheroids may become an in vitro GO model.”

2、Unexpected Crosslinking Effects of a Human Thyroid Stimulating Monoclonal Autoantibody, M22, with IGF1 on Adipogenesis in 3T3L-1 Cells.
Umetsu A, et al. Int J Mol Sci. 2023 Jan 6;24(2):1110. doi: 10.3390/ijms24021110. PMID: 36674625.
“The three-dimensional structure of M22 complexed with the A unit of TSHR has been characterized by X-ray crystallography. …Therefore, these results suggest that the human-specific TSmAb M22 may also have some effects on the mouse TSHR in addition to the human TSHR. In fact, and interestingly, Neumann et al. reported that serum free T4 levels were significantly increased in mice that were given M22. …Therefore, based upon these collective findings, examining the effects of M22 and/or IGF1 on mouse-derived adipocytes would be of considerable interest because such simpler experimental conditions may facilitate a better understanding of the currently unknown mechanisms responsible for causing the M22-induced stimulation of TSHR. …Therefore, in this study, we report on an evaluation of the effects of M22 and/or IGF1 on several biological aspects of 2D- and 3D-cultured 3T3-L1 preadipocytes during their adipogenesis. …However, the additive effects of IGF1 and/or M22 on DIF+ were different between the 2D and 3D cultures.”

3、A New Method of Myostatin Inhibition in Mice via Oral Administration of Lactobacillus casei Expressing Modified Myostatin Protein, BLS-M22.
Sung DK, et al. Int J Mol Sci. 2022 Aug 13;23(16):9059. doi: 10.3390/ijms23169059. PMID: 36012334.
“To test this hypothesis, we developed a Lactobacillus casei expressing modified human myostatin protein (BLS-M22) using the same antigen-presenting platform. …This study aimed to address whether an oral administration of BLS-M22 could elicit sufficient levels of myostatin-specific antibodies and whether the generation of the antibodies could improve the dystrophic features of an animal model of DMD (mdx model). …To assess the immunogenicity of BLS-M22, the mdx mice were administered BLS-M22 via a mixed-with-feed method with 3% of the total feed weight. …These results indicated that BLS-M22 administrated four times was the best way to achieve the highest production of anti-myostatin antibodies. …This study showed that L. casei expressing modified myostatin protein on its surface (BLS-M22) inhibited myostatin and improved the dystrophic features of mdx mice.”

4、2′-O-Galloylhyperin Prevents Tissue Remodeling in Thyroid Eye Disease: Prospects as a Thyrotropin Receptor Antagonist.
Guo Y, et al. J Clin Endocrinol Metab. 2025 Jul 15;110(8):e2711-e2722. doi: 10.1210/clinem/dgae732. PMID: 39673421.
“Pretreated by keracyanin (No. GC43998, GlpBio) and 2′-O-GH (No. YZ-111629, Solarbio) at the indicated concentrations for 60 minutes, M22 (1 μg/mL) was then added to the OFs for another 60 minutes. …Since cAMP is a primary second messenger of TSHR signaling, TSHR activation was determined by cAMP production on M22 (a TSHR-stimulating monoclonal autoantibody) treatment. …As shown in Fig. 2A and 2B, 2′-O-GH decreased cAMP production stimulated by M22 in Nthy-ori-3-1 at a dosage-dependent way, as assessed by IF. …Herein, the FDA-approved drug 2′-O-GH dose-dependently decreased cAMP production and the subsequent cAMP-response element binding protein (CREB) phosphorylation stimulated by a TSHR-stimulating monoclonal autoantibody M22, which was reversed by a consistently activated mutation of TSHR (L629F). …The wounds were then created by scratching the cell monolayer with a micropipette tip.”

5、Thyrotropin Receptor Antagonism by a Novel Small Molecule: Preclinical In Vitro Observations.
Kahaly GJ, et al. Thyroid. 2023 Jun;33(6):732-742. doi: 10.1089/thy.2022.0694. PMID: 37016815.
“SYD5115 blocked M22- and TSAb-induced TSH-R activity with a nanomolar potency in TSH-R-overexpressed CHO cells as well as primary GOF, which demonstrates the ability of this small molecule to block TSH-R overactivity. …The concentration range of M22 was tested in the agonistic format. …The concentrations of M22 in the antagonist assays amounted to 80% (48.4 ng/mL) of those used to achieve the maximum effect on the agonist response. …The concentrations of bTSH in the antagonist assay amounted to 80% (400 nM bTSH for HEK-293-hTSH-R) of those used to achieve the maximum effect on the agonist response. …In detail, this new TSH-R antagonist showed a concentration-dependent inhibition in the TSH-R-Ab blocking bioassay when being stimulated with the M22 mAb as well as being stimulated with TSAb-positive sera from several patients with GH.”

For more references about Anti-Human CD64 Monoclonal Antibodies please contact our scientific support team with message@sydlabs.com.

Syd Labs provides the following in vivo grade recombinant anti-human CD16, CD32, and CD64 monoclonal antibodies:
Recombinant Anti-human CD16 monoclonal antibody (Clone: 3G8)
Recombinant Anti-human CD32 monoclonal antibody (Clone: IV.3)
Recombinant Anti-human CD64 monoclonal antibody (Clone: M22)

Syd Labs provides the following in vivo grade recombinant anti-mouse CD16, CD32, and CD64 monoclonal antibodies:
Recombinant Anti-mouse CD16/CD32 monoclonal antibody (Clone: 2.4G2)

Syd Labs provides the following recombinant anti-human CD16, CD32, and CD64 monoclonal antibodies for flow cytometry:
Recombinant Anti-human CD16 monoclonal antibody (Clone: 3G8) for flow cytometry
Recombinant Anti-human CD32 monoclonal antibody (Clone: IV.3) for flow cytometry
Recombinant Anti-human CD64 monoclonal antibody (Clone: M22) for flow cytometry

Anti-human CD64 (H22) from: Recombinant Anti-human CD64 Monoclonal Antibody, Mouse IgG1 Kappa (Clone: M22): PA007393.m1 Syd Labs

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