Anti-Human CD3 Antibody (Clone: OKT3) | Recombinant, In Vivo Grade

Catalog No.	Product Name	Size	List Price (US$)
PA007202.m2a	In vivo Grade Recombinant Anti-human CD3e Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa	1 mg	150.00
PA007202.m2a	In vivo Grade Recombinant Anti-human CD3e Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa	5 mg	350.00
PA007202.m2a	In vivo Grade Recombinant Anti-human CD3e Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa	25 mg	900.00

Catalog No.

Product Name

Size

List Price (US$)

Quantity

PA007202.m2a

In vivo Grade Recombinant Anti-human CD3e Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa

1 mg

150.00

PA007202.m2a

In vivo Grade Recombinant Anti-human CD3e Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa

5 mg

350.00

PA007202.m2a

In vivo Grade Recombinant Anti-human CD3e Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa

25 mg

900.00

Description

Background & Mechanism of Action: Recombinant Anti-Human CD3 (Clone: OKT3)

The recombinant OKT3 antibody engineered by Syd Labs binds with high affinity and specificity to the CD3 epsilon (CD3ε) chain of the T-cell receptor (TCR)-CD3 complex, a structure exclusively expressed on mature T cells and medullary thymocytes. When cross-linked in the presence of accessory cells (such as monocytes) or via plate-bound formats, this potent anti-human cd3 okt3 interaction triggers a profound cascade leading to T-cell activation (mitogenesis) in vitro. This unique biological property establishes the OKT3 clone as the gold-standard reagent for okt3 for t cell stimulation and robust okt3 t cell expansion protocols, particularly within CAR-T manufacturing and ex vivo adoptive cell therapy workflows.

In addition to ex vivo applications, this functional grade okt3 is highly critical for studying in vivo immune modulation and receptor dynamics. The OKT3 antibody fundamentally blocks the functional association between the antigen receptor and the CD3 complex, thereby halting both the generation and effector functions of cytotoxic T cells. Following an initial dose of this in vivo grade okt3, mature T cells rapidly disappear from the peripheral circulation within minutes to hours. During continuous treatment, T cells exhibiting typical lineage markers (CD2, CD4, and CD8) will eventually reappear in the bloodstream, but notably, these cells remain entirely devoid of surface CD3.

After a 48-hour cessation of OKT3 exposure, the normal array of surface molecules, including CD3, is re-expressed on all circulating T cells. This selective removal of CD3 via rapid internalization—known as comodulation of the antigen receptor—is considered the primary mechanism of action explaining the profound immunoblocking effects of the OKT3 clone in vivo. Because of this targeted modulation, the Syd Labs OKT3 antibody is exceptionally effective for modeling the induction of immunosuppression, tracking cellular depletion, and evaluating treatments for initial and steroid-resistant transplant rejections in humanized mouse models.

PA007202.m2a: In vivo Grade Recombinant Anti-human CD3 Monoclonal Antibody (Clone: OKT3), Mouse IgG2a Kappa

Recombinant mouse IgG2a Monoclonal Antibody.
Clone: OKT3 or OKT-3.
Isotype: Mouse IgG2a kappa.
Source: The anti-human CD3 monoclonal antibody (clone: OKT3) was produced in mammalian cells.
Specificity/Sensitivity: The in vivo grade recombinant mouse monoclonal antibody (clone: OKT3) specifically binds to the human T cell receptor CD3.
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 CD3 protein.
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: The anti-human CD3 monoclonal antibody (clone number: OKT3) 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.

References of Anti-Human CD3 Monoclonal Antibody (Clone: OKT3)

Humanization of a strategic CD3 epitope enables evaluation of clinical T-cell engagers in a fully immunocompetent in vivo model

Julie A Zorn, et al. Sci Rep. 2022 Mar 3;12(1):3530. doi: 10.1038/s41598-022-06953-7. PMID: 35241687; PMCID: PMC8894342

“T-cell engagers (TCEs) are a growing class of biotherapeutics being investigated in the clinic for treatment of a variety of hematological and solid tumor indications. However, preclinical evaluation of TCEs in vivo has been mostly limited to xenograft tumor models in human T-cell reconstituted immunodeficient mice, which have a number of limitations. To explore the efficacy of human TCEs in fully immunocompetent hosts, we developed a knock-in mouse model (hCD3E-epi) in which a 5-residue N-terminal fragment of murine CD3-epsilon was replaced with an 11-residue stretch from the human sequence that encodes for a common epitope recognized by anti-human CD3E antibodies in the clinic.”

(Tags: T_Cell_Engagers; Immunocompetent_Mouse_Models)

Comparison of CD3e Antibody and CD3e-sZAP Immunotoxin Treatment in Mice Identifies sZAP as the Main Driver of Vascular Leakage

Shihyoung Kim, et al. Toxins (Basel). 2022 Jun 15;14(6):410. doi: 10.3390/toxins14060410. PMID: 35740248; PMCID: PMC9220018

“Anti-CD3-epsilon (CD3e) monoclonal antibodies (mAbs) and CD3e immunotoxins (ITs) are promising targeted therapy options for various T-cell disorders. CD3e-ITs may induce vascular leak syndrome (VLS) via the CD3e binding portion of IT, that may induce an excessive activation of T cells, and the toxin portion that can directly damage vascular endothelial cells and induce extensive cell death and inflammation. To dissect and compare the roles of these two components of ITs in inducing VLS in mice, we created a new murine CD3e-IT by conjugating the sZAP with S-CD3e-mAb.”

(Tags: CD3e_Immunotoxin; Vascular_Leakage)

TCRαβ/CD3 disruption enables CD3-specific antileukemic T cell immunotherapy

Rasmus O. Nielsen, et al. JCI Insight. 2018 Jul 12;3(13):e99442. doi: 10.1172/jci.insight.99442. PMID: 29997304; PMCID: PMC6124532

“T cells engineered to express chimeric antigen receptors (CARs) against B cell antigens are being investigated as cellular immunotherapies. Similar approaches designed to target T cell malignancies have been hampered by the critical issue of T-on-T cytotoxicity, whereby fratricide or self-destruction of healthy T cells prohibits cell product manufacture. T cells were transduced with a lentiviral vector incorporating an anti-CD3ε CAR derived from OKT3, either before or after TALEN-mediated disruption of the endogenous TCRαβ/CD3 complex.”

(Tags: CAR_T_Cell_Fratricide; CD3_Specific_CAR_T)

A humanized CD3ε-knock-in mouse model for pre-clinical testing of anti-human CD3 therapy

Paul S. Moore, et al. PLoS One. 2021 Feb 17;16(2):e0245917. doi: 10.1371/journal.pone.0245917. PMID: 33596227; PMCID: PMC7888618

“Pre-clinical murine models are critical for translating drug candidates from the bench to the bedside. In this study, we report a murine genetic knock-in model which expresses both a murine and a humanized-CD3ε-exon, rendering it sensitive to manipulation with anti-human CD3. Our results show a viable humanized CD3 murine model that develops normally, is functionally engaged by anti-human CD3 and can instruct on pre-clinical tests of anti-human CD3 antibodies.”

(Tags: CD3e_Knock_In; Preclinical_Antibody_Testing)

Differential depletion of total T cells and regulatory T cells and prolonged allotransplant survival in CD3Ɛ humanized mice treated with polyclonal anti human thymocyte globulin

Maja Buszko, et al. PLoS One. 2017 Mar 3;12(3):e0173088. doi: 10.1371/journal.pone.0173088. PMID: 28257450; PMCID: PMC5336254

“Thymoglobulin (ATG) is a polyclonal rabbit antibody against human thymocytes used as a T cell-depleting agent to prevent or treat allotransplant rejection. In the field of allotransplantation, another antibody-based immunosuppressive therapy specifically targets CD3 molecules, where the main effect of anti-CD3 monoclonal antibodies (mAbs) (OKT3) is T cell depletion. We found that a single intravenous (i.v.) injection of ATG into BALB/c huCD3Ɛ transgenic mice resulted in T cell depletion in the circulation and in the secondary lymphoid organs, with concomitant preservation of Tregs.”

(Tags: Thymoglobulin_ATG; T_Cell_Depletion)