Anti-human CD64 Antibody (H22) | PA007393.m1

Catalog No.	PA007393.m1
Product Name	Anti-human CD64 Antibody (H22) | PA007393.m1
Supplier Name	Syd Labs, Inc.
Brand Name	Syd Labs
Clone	H22.
Isotype	Mouse IgG1 kappa.
Source/Host	The anti-human CD64 monoclonal antibody (clone: H22) was produced in mammalian cells.
Specificity/Sensitivity	The in vivo grade recombinant mouse monoclonal antibody (clone: H22) 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 (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: H22), Mouse IgG1 Kappa, In vivo Grade

The recombinant 22 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 22 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 22 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 for Anti-human CD64 Monoclonal Antibody (Clone:H22):

1、CD64 as novel molecular imaging marker for the characterization of synovitis in rheumatoid arthritis
Wessel F Theeuwes,et al.Arthritis Res Ther. 2023.PMCID: PMC10468866
“Background
Rheumatoid arthritis (RA) is one of the most prevalent and debilitating joint diseases worldwide. RA is characterized by synovial inflammation (synovitis), which is linked to the development of joint destruction. Magnetic resonance imaging and ultrasonography are widely being used to detect the presence and extent of synovitis. However, these techniques do not reveal the activation status of inflammatory cells such as macrophages that play a crucial role in synovitis and express CD64 (Fc gamma receptor (FcγR)I) which is considered as macrophage activation marker.
Objectives
We aimed to investigate anti-human CD64 antibody expression and its correlation with pro-inflammatory cytokines and pro-damaging factors in human-derived RA synovium. Furthermore, we aimed to set up a molecular imaging modality using a radiolabeled CD64-specific antibody as a novel imaging tracer that could be used to determine the extent and phenotype of synovitis using optical and nuclear imaging.
Methods
First, we investigated anti-human CD64 antibody expression in synovium of early- and late-stage RA patients and studied its correlation with the expression of pro-inflammatory and tissue-damaging factors. Next, we conjugated an anti-CD64 antibody with IRDye 800CW and diethylenetriamine penta-acetic acid (DTPA; used for 111In labeling) and tested its binding on cultured THP1 cells, ex vivo RA synovium explants and its imaging potential in SCID mice implanted with human RA synovium explants obtained from RA patients who underwent total joint replacement.
Results
We showed that CD64 is expressed in synovium of early and late-stage RA patients and that FCGR1A/CD64 expression is strongly correlated with factors known to be involved in RA progression. Combined, this makes anti-human CD64 antibody a useful marker for imaging the extent and phenotype of synovitis. We reported higher binding of the [111In]In-DTPA-IRDye 800CW anti-CD64 antibody to in vitro cultured THP1 monocytes and ex vivo RA synovium compared to isotype control. In human RA synovial explants implanted in SCID mice, the ratio of uptake of the antibody in synovium over blood was significantly higher when injected with anti-CD64 compared to isotype and injecting an excess of unlabeled antibody significantly reduced the antibody-binding associated signal, both indicating specific receptor binding.
Conclusion
Taken together, we successfully developed an optical and nuclear imaging modality to detect CD64 in human RA synovium in vivo.”

2、The CD64/CD28/CD3ζ chimeric receptor reprograms T-cell metabolism and promotes T-cell persistence and immune functions while triggering antibody-independent and antibody-dependent cytotoxicity
Sara Caratelli,et al.Exp Hematol Oncol. 2025.PMCID: PMC11834217
“Background
Recent studies have shown that CD32/CD8a/CD28/CD3ζ chimeric receptor cells directly kill breast cancer cells, suggesting the existence of cell surface myeloid FcγR alternative ligands (ALs). Here, we investigated the metabolism, ALs, cytotoxicity, and immunoregulatory functions of anti-human CD64 antibody/CD28/CD3ζ in colorectal cancer (CRC) and squamous cell carcinoma of the head and neck.
Methods
The anti-human CD64 antibody/CD28/CD3ζ -SFG retroviral vector was used to produce viruses for T-cell transduction. T-cell expansion and differentiation were monitored via flow cytometry. Gene expression was assessed by RNA-seq. Bioenergetics were documented on a Seahorse extracellular flux analyzer. CD64/CD28/CD3ζ polarization was identified via confocal microscopy. Cytotoxicity was determined by MTT assay and bioluminescent imaging, and flow cytometry. Tridimensional antitumor activity of CD64/CD28/CD3ζ T cells was achieved by utilizing HCT116-GFP 3D spheroids via the IncuCyte S3 Live-Cell Analysis system. The intraperitoneal distribution and antitumor activity of NIR-CD64/CD28/CD3ζ and NIR-nontransduced T cells were investigated in CB17-SCID mice bearing subcutaneous FaDu Luc + cells by bioluminescent and fluorescent imaging. IFNγ was assessed by ELISA.
Results
Compared to CD16/CD8a/CD28/CD3ζ T cells, CD32/CD8a/CD28/CD3ζ T cells, and non-transduced T cells, CD64/CD28/CD3ζ T cells exhibited the highest levels of cell expansion and persistence capacity. A total of 235 genes linked to cell division and 52 genes related to glycolysis were overexpressed. The glycolytic phenotype was confirmed by functional in vitro studies accompanied by preferential T-cell effector memory differentiation. Interestingly, oxamic acid was found to inhibit CD64-CR T cell proliferation, indicating the involvement of lactate. Upon CD64/CD28/CD3ζ T-cell conjugation with CRC cells, CD64/CD28/CD3ζ cells polarize at immunological synapses, leading to CRC cell death. CD64/CD28/CD3ζ T cells kill SCCHN cells, and in combination with the anti-B7-H3 mAb (376.96) or anti-EGFR mAb, these cells trigger antibody-dependent cellular cytotoxicity (ADCC) in vitro under 2D and 3D conditions. The 376.96 mAb combined with CD64/CD28/CD3ζ T cells had anti-SCCHN activity in vivo. In addition, they induce the upregulation of PD-L1 and HLA-DR expression in cancer cells via IFNγ. PD-L1 positive SCCHN cells in combination with anti-PD-L1 mAb and CD64-CR T cells were killed by ADCC, which enhanced direct cytotoxicity. These findings indicate that the glycolytic phenotype is involved in CD64-CR T cell proliferation/expansion. These cells mediate long-lasting HLA-independent cytotoxicity and ADCC in CRC and SCCHN cells.
Conclusions
CD64/CD28/CD3ζ T cells could significantly impact the rational design of personalized studies to treat CRC and SCCHN and the identification of novel FcγR ALs in cancer and healthy cells.”

3、Immunoglobulins stimulate cultured Schwann cell maturation and promote their potential to induce axonal outgrowth
Nevena Tzekova,et al.J Neuroinflammation. 2015.PMCID: PMC4450464
“Background
Schwann cells are the myelinating glial cells of the peripheral nervous system and exert important regenerative functions revealing them as central repair components of many peripheral nerve pathologies. Intravenous immunoglobulins (IVIG) are widely used to treat autoimmune and inflammatory diseases including immune-mediated neuropathies. Nevertheless, promotion of peripheral nerve regeneration is currently an unmet therapeutical goal. We therefore examined whether immunoglobulins affect glial cell homeostasis, differentiation, and Schwann cell dependent nerve regenerative processes.
Methods
The responses of different primary Schwann cell culture models to IVIG were investigated: immature or differentiation competent Schwann cells, myelinating neuron/glial cocultures, and dorsal root ganglion explants. Immature or differentiating Schwann cells were used to study cellular proliferation, morphology, and gene/protein expression. Myelination rates were determined using myelinating neuron/glia cocultures, whereas axonal outgrowth was assessed using non-myelinating dorsal root ganglion explants.
Results
We found that IVIG specifically bind to Schwann cells and detected CD64 Fc receptor expression on their surface. In response to IVIG binding, Schwann cells reduced proliferation rates and accelerated growth of cellular protrusions. Furthermore, we observed that IVIG treatment transiently boosts myelin gene expression and myelination-related signaling pathways of immature cells, whereas in differentiating Schwann cells, myelin expression is enhanced on a long-term scale. Importantly, myelin gene upregulation was not detected upon application of IgG1 control antibodies. In addition, we demonstrate for the first time that Schwann cells secrete interleukin-18 upon IVIG stimulation and that this cytokine instructs these cells to promote axonal growth.
Conclusions
We conclude that IVIG can positively influence the Schwann cell differentiation process and that it enhances their regenerative potential.”

4、Avian IgY antibodies and their recombinant equivalents in research, diagnostics and therapy
Edzard Spillner,et al.Biologicals. 2012.PMCID: PMC7106491
“The generation and use of avian antibodies is of increasing interest in a wide variety of applications within the life sciences. Due to their phylogenetic distance, mechanisms of immune diversification and the way in which they deposit IgY immunoglobulin in the egg yolk, chickens provide a number of advantages compared to mammals as hosts for immunization. These advantages include: the one-step purification of antibodies from egg yolk in large amounts facilitates having a virtually continuous supply; the epitope spectrum of avian antibodies potentially grants access to novel specificities; the broad absence of cross-reactivity with mammalian epitopes avoids assay interference and improves the performance of immunological techniques. The polyclonal nature of IgY antibodies has limited their use since avian hybridoma techniques are not well established. Recombinant IgY, however, can be generated from mammalian monoclonal antibodies which makes it possible to further exploit the advantageous properties of the IgY scaffold. Moreover, cloning and selecting the immune repertoire from avian organisms is highly efficient, yielding antigen-specific antibody fragments. The recombinant approach is well suited to circumvent any limitations of polyclonal antibodies. This review presents comprehensive information on the generation, purification, modification and applications of polyclonal and monoclonal IgY antibodies.”

5、Guselkumab binding to CD64+ IL-23–producing myeloid cells enhances potency for neutralizing IL-23 signaling
Kacey L Sachen,et al.Front Immunol. 2025.PMCID: PMC11937023
“IL-23 is implicated in the pathogenesis of immune-mediated inflammatory diseases, and myeloid cells that express Fc gamma receptor 1 (FcγRI or anti-human CD64 antibody) on their surface have been recently identified as a primary source of IL-23 in inflamed tissue. Our complementary analyses of transcriptomic datasets from psoriasis and IBD showed increased expression of anti-human CD64 antibody and IL-23 transcripts in inflamed tissue, and greater abundance of cell types with co-expression of CD64 and IL-23. These findings led us to explore potential implications of CD64 binding on the function of IL-23–targeting monoclonal antibodies (mAbs). Guselkumab and risankizumab are mAbs that target the IL-23p19 subunit. Guselkumab has a native Fc domain while risankizumab contains mutations that diminish binding to FcγRs. In flow cytometry assays, guselkumab, but not risankizumab, showed Fc-mediated binding to CD64 on IFNγ-primed monocytes. Guselkumab bound anti-human CD64 antibody on IL-23–producing inflammatory monocytes and simultaneously captured IL-23 secreted from these cells. Guselkumab binding to CD64 did not induce cytokine production. In live-cell confocal imaging of CD64+ macrophages, guselkumab, but not risankizumab, mediated IL-23 internalization to low-pH intracellular compartments. Guselkumab and risankizumab demonstrated similar potency for inhibition of IL-23 signaling in cellular assays with exogenous addition of IL-23. However, in a co-culture of IL-23–producing CD64+ THP-1 cells with an IL-23–responsive reporter cell line, guselkumab demonstrated Fc-dependent enhanced potency compared to risankizumab for inhibiting IL-23 signaling. These in vitro data highlight the potential for guselkumab binding to CD64 in inflamed tissue to contribute to the potent neutralization of IL-23 at its cellular source.”

6、Protection of cell therapeutics from antibody-mediated killing by CD64 overexpression
Alessia Gravina,et al.Nat Biotechnol. 2023.PMCID: PMC10188358
“Allogeneic cell therapeutics for cancer therapy or regenerative medicine are susceptible to antibody-mediated killing, which diminishes their efficacy. Here we report a strategy to protect cells from antibody-mediated killing that relies on engineered overexpression of the IgG receptor anti-human CD64 antibody. We show that human and mouse iPSC-derived endothelial cells (iECs) overexpressing CD64 escape antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity from IgG antibodies in vitro and in ADCC-enabled mice. When CD64 expression was combined with hypoimmune genetic modifications known to protect against cellular immunity, B2M−/−CIITA−/− CD47/CD64-transgenic iECs were resistant to both IgG antibody-mediated and cellular immune killing in vitro and in humanized mice. Mechanistic studies demonstrated that CD64 or its intracellularly truncated analog CD64t effectively capture monomeric IgG and occupy their Fc, and the IgG bind and occupy their target antigens. In three applications of the approach, human CD64t-engineered thyroid epithelial cells, pancreatic beta cells and CAR T cells withstood clinically relevant levels of graft-directed antibodies and fully evaded antibody-mediated killing.”

7、Mouse and human antibodies bind HLA-E-leader peptide complexes and enhance NK cell cytotoxicity
Dapeng Li,et al.Commun Biol. 2022.PMCID: PMC8960791
“The non-classical class Ib molecule human leukocyte antigen E (HLA-E) has limited polymorphism and can bind HLA class Ia leader peptides (VL9). HLA-E-VL9 complexes interact with the natural killer (NK) cell receptors NKG2A-C/CD94 and regulate NK cell-mediated cytotoxicity. Here we report the isolation of 3H4, a murine HLA-E-VL9-specific IgM antibody that enhances killing of HLA-E-VL9-expressing cells by an NKG2A+ NK cell line. Structural analysis reveal that 3H4 acts by preventing CD94/NKG2A docking on HLA-E-VL9. Upon in vitro maturation, an affinity-optimized IgG form of 3H4 showes enhanced NK killing of HLA-E-VL9-expressing cells. HLA-E-VL9-specific IgM antibodies similar in function to 3H4 are also isolated from naïve B cells of cytomegalovirus (CMV)-negative, healthy humans. Thus, HLA-E-VL9-targeting mouse and human antibodies isolated from the naïve B cell antibody pool have the capacity to enhance NK cell cytotoxicity.”

8、Design, optimization, production and activity testing of recombinant immunotoxins expressed in plants and plant cells for the treatment of monocytic leukemia
Matthias Knödler,et al.Bioengineered. 2023.PMCID: PMC10444015
“Antibody–drug conjugates (ADCs) can improve therapeutic indices compared to plain monoclonal antibodies (mAbs). However, ADC synthesis is complex because the components are produced separately in CHO cells (mAb) and often by chemical synthesis (drug). They are individually purified, coupled, and then the ADC is purified, increasing production costs compared to regular mAbs. In contrast, it is easier to produce recombinant fusion proteins consisting of an antibody derivative, linker and proteinaceous toxin, i.e. a recombinant immunotoxin (RIT). Plants are capable of the post-translational modifications needed for functional antibodies and can also express active protein toxins such as the recombinant mistletoe lectin viscumin, which is not possible in prokaryotes and mammalian cells respectively. Here, we used Nicotiana benthamiana and N. tabacum plants as well as tobacco BY-2 cell-based plant cell packs (PCPs) to produce effective RITs targeting CD64 as required for the treatment of myelomonocytic leukemia. We compared RITs with different subcellular targeting signals, linkers, and proteinaceous toxins. The accumulation of selected candidates was improved to ~ 40 mg kg−1 wet biomass using a design of experiments approach, and corresponding proteins were isolated with a purity of ~ 80% using an optimized affinity chromatography method with an overall yield of ~ 84%. One anti-CD64 targeted viscumin-based drug candidate was characterized in terms of storage stability and cytotoxicity test in vitro using human myelomonocytic leukemia cell lines. We identified bottlenecks in the plant-based expression platform that require further improvement and assessed critical process parameters that should be considered during process development for plant-made RITs.”

9、T Cells Expressing a Modified FcγRI Exert Antibody-Dependent Cytotoxicity and Overcome the Limitations of CAR T-cell Therapy against Solid Tumors
Diana Rasoulouniriana,et al.Cancer Immunol Res. 2023.PMCID: PMC10236152
“The pioneering design of chimeric antigen receptor (CAR) T-cell therapy demonstrated the potential of reprogramming the immune system. Nonetheless, T-cell exhaustion, toxicity, and suppressive microenvironments limit their efficacy in solid tumors. We previously characterized a subset of tumor-infiltrating CD4+ T cells expressing the FcγRI receptor. Herein, we detail engineering of a receptor, based on the FcγRI structure, allowing T cells to target tumor cells using antibody intermediates. These T cells showed effective and specific cytotoxicity only when an appropriate antibody was added. Only target-bound antibodies activated these cells, while free antibodies were internalized without activation. Their cytotoxic activity was correlated to target protein density, therefore targeting tumor cells with high antigen density while sparing normal cells with low or no expression. This activation mechanism prevented premature exhaustion. Furthermore, during antibody-dependent cytotoxicity these cells secreted attenuated cytokine levels compared with CAR T cells, thereby enhancing their safety profile. These cells eradicated established melanomas, infiltrated the tumor microenvironment, and facilitated host immune cell recruitment in immunocompetent mice. In NOD/SCID gamma mice the cells infiltrate, persist, and eradicate tumors. As opposed to CAR T-cell therapies, which require changing the receptor across different types of cancer, our engineered T cells remain the same across tumor types, while only the injected antibody changes. Overall, we generated a highly flexible T-cell therapy capable of binding a wide range of tumor cells with high affinity, while preserving the cytotoxic specificity only to cells expressing high density of tumor-associated antigens and using a single manufacturing process.”

10、Examination of IgG Fc Receptor CD16A and CD64 Expression by Canine Leukocytes and Their ADCC Activity in Engineered NK Cells
Robert Hullsiek,et al.Front Immunol. 2022.PMCID: PMC8907477
“Human natural killer (NK) cells can target tumor cells in an antigen-specific manner by the recognition of cell bound antibodies. This process induces antibody-dependent cell-mediated cytotoxicity (ADCC) and is exclusively mediated by the low affinity IgG Fc receptor CD16A (FcγRIIIA). Exploiting ADCC by NK cells is a major area of emphasis for advancing cancer immunotherapies. CD64 (FcγRI) is the only high affinity IgG FcR and it binds to the same IgG isotypes as CD16A, but it is not expressed by human NK cells. We have generated engineered human NK cells expressing recombinant CD64 with the goal of increasing their ADCC potency. Preclinical testing of this approach is essential for establishing efficacy and safety of the engineered NK cells. The dog provides particular advantages as a model, which includes spontaneous development of cancer in the setting of an intact and outbred immune system. To advance this immunotherapy model, we cloned canine CD16A and CD64 and generated specific mAbs. We report here for the first time the expression patterns of these FcγRs on dog peripheral blood leukocytes. anti-human CD64 antibody was expressed by neutrophils and monocytes, but not lymphocytes, while canine CD16A was expressed at high levels by a subset of monocytes and lymphocytes. These expression patterns are similar to that of human leukocytes. Based on phenotypic characteristics, the CD16A+ lymphocytes consisted of T cells (CD3+ CD8+ CD5dim α/β TCR+) and NK cells (CD3− CD5− CD94+), but not B cells. Interestingly, the majority of canine CD16A+ lymphocytes were from the T cell population. Like human CD16A, canine CD16A was downregulated by a disintegrin and metalloproteinase 17 (ADAM17) upon leukocyte activation, revealing a conserved means of regulation. We also directly demonstrate that both canine CD16A and CD64 can induce ADCC when expressed in the NK cell line NK-92. These findings pave the way to engineering canine NK cells or T cells with high affinity recombinant canine CD64 to maximize ADCC and to test their safety and efficacy to benefit both humans and dogs.”

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: H22)

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: H22) for flow cytometry

Anti-human CD64 Monoclonal Antibody(H22): In vivo Grade Recombinant Anti-human CD64 Monoclonal Antibody, Mouse IgG1 Kappa (Clone: 22): PA007393.m1 Syd Labs

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