Abatacept is a recombinant fusion protein engineered to specifically interfere with T-cell activation pathways. Structurally, it consists of the extracellular domain of cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4, also known as CD152) fused to the modified Fc region of human immunoglobulin G1 (IgG1). This fusion creates a single, stable glycoprotein molecule with both binding and effector-modulating properties. The molecular weight of Abatacept is approximately 92 kilodaltons (kDa).
The CTLA-4 domain of Abatacept retains high affinity for CD80 (B7-1) and CD86 (B7-2) on antigen-presenting cells (APCs). This binding is competitive with the natural T-cell surface receptor CD28, which normally interacts with CD80/CD86 to deliver a critical costimulatory signal required for full T-lymphocyte activation. By occupying these ligands, the CTLA-4 component effectively blocks T-cell costimulation, thereby inhibiting the cascade of downstream immune responses. The immunoglobulin Fc fragment in Abatacept contributes to molecular stability, prolongs serum half-life through neonatal Fc receptor (FcRn) recycling, and facilitates purification through Protein A affinity, but it is engineered to minimize unwanted immune effector functions such as complement activation or antibody-dependent cytotoxicity.
InnoCyto biosimilars are research-grade recombinant antibodies or proteins engineered to closely replicate the sequence, structure, and target-binding activity of approved or well-characterized therapeutic antibodies (e.g., checkpoint inhibitors, anti-cytokine biologics). They are intended for research use to study the mechanism of action, efficacy, and combination potential of these therapeutic classes without the cost or access restrictions of clinical-grade material.
How similar are these biosimilars to the original therapeutic antibody?
Each biosimilar is produced using the published or inferred variable region sequence of the reference therapeutic and is expressed recombinantly to match the parent antibody's target specificity, isotype, and general binding profile. While designed for high functional similarity, InnoCyto biosimilars are for research use only and are not clinically validated equivalents of the approved drug product.
Are these antibodies suitable for in vivo studies?
Yes. InnoCyto biosimilars are manufactured with the same low-endotoxin, azide-free, carrier-free standards used across our in vivo product lines, making them suitable for animal efficacy, combination, and mechanism-of-action studies. Product pages indicate whether a given biosimilar is validated for in vivo use, in vitro use, or both.
What is the difference between a biosimilar and a recombinant "research antibody" targeting the same protein?
A biosimilar is specifically designed to mimic a known, named therapeutic antibody (matching its clinical target epitope and mechanism), whereas a general recombinant research antibody may target the same protein but bind a different epitope or lack the same functional properties. Biosimilars are the right choice when your study is benchmarking against, or modeling the action of, an approved or clinically studied biologic.
What quality and purity standards do biosimilar antibodies meet?
All biosimilars undergo the same rigorous QC pipeline as our other antibody lines: ≥95% purity by SDS-PAGE/SEC-HPLC, low-endotoxin testing via LAL assay, and binding/functional validation against the intended target. Certificates of Analysis (CoA) are provided per lot with full specifications.
Which therapeutic targets and mechanisms are covered in the Biosimilar line?
The line spans major immuno-oncology and immunology targets, including immune checkpoint pathways (e.g., PD-1/PD-L1, CTLA-4), cytokine and cytokine-receptor blockers, and other clinically relevant mechanisms. See each product page for the specific reference therapeutic and mechanism of action represented.
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