Polatuzumab, as a therapeutic, is an antibody–drug conjugate (ADC) composed of a humanized monoclonal antibody linked to a potent cytotoxic small molecule. The antibody component is an immunoglobulin G1 kappa (IgG1κ) monoclonal antibody engineered to specifically recognize and bind to human CD79b, a transmembrane component of the B-cell receptor complex. Structurally, the antibody portion comprises two identical heavy chains and two identical light chains connected by disulfide bonds, forming the characteristic Y-shaped configuration typical of IgG molecules. It has an approximate molecular mass of 150 kilodaltons (kDa) and is produced in mammalian expression systems such as Chinese Hamster Ovary (CHO) cells, which ensure appropriate folding and glycosylation.
The antigen-binding regions of Polatuzumab are defined by complementarity-determining regions (CDRs) located in the variable domains of the heavy (VH) and light (VL) chains. These domains provide high-affinity recognition of an epitope in the extracellular portion of CD79b, a signaling subunit involved in B-cell receptor activation. Functionally, Polatuzumab binds to CD79b on the surface of B-lineage cells and is rapidly internalized through receptor-mediated endocytosis. The Fc (fragment crystallizable) region of the IgG1 backbone additionally contributes structural stability and maintains typical Fc–neonatal receptor (FcRn) interactions, which extend the molecule’s half-life.
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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