Anti-Human CD21/CR2 Polyclonal Antibody

What it means: Target is the antigen (protein) this antibody is designed to recognize. The target on this page is CR2.

How to interpret here: Use CR2 to confirm you’re buying an antibody against the correct biomarker/antigen—especially when targets have close family members, isoforms, or similar subunits that can cross-react. Species fit: Reactivity is listed as Human. Choose a reactivity that matches your sample species; cross-species use should be treated as unvalidated unless specifically supported. Application fit: Listed applications include ELISA, IHC, WB. Use this as a short-list filter—an antibody that works well in one application may not perform the same in another. Clonality: Polyclonal indicates recognition of multiple epitopes, which can improve sensitivity but may increase background or band complexity depending on the sample. Host: Raised in Rabbit. This matters for choosing the correct secondary antibody (anti-Rabbit), and for avoiding background when your sample contains endogenous immunoglobulins from the same host species. Isotype: IgG can affect Fc-specific secondaries, Protein A/G binding, and multiplex design when pairing antibodies from different hosts/isotypes. Conjugate: Not listed here, which typically means the antibody is unlabeled and requires a compatible secondary reagent for detection (depending on your application). Immunogen/epitope context: E. coli - derived recombinant Human CD21/CR2 (Lys729-Asp958). can help you judge domain coverage and anticipate cross-reactivity (e.g., conserved regions vs unique segments). Purification: Purified by antigen affinity column. often reduces background compared with crude preparations; it can matter most for low-abundance targets and sensitive imaging/quantitation.

Why it matters for buying:

• Correct biology: The target defines what you are measuring/staining—mistargeting wastes samples and time, and can produce misleading conclusions.
• Specificity risk management: Targets in the same family (or processed/isoform forms) can look similar; using target + immunogen/construct context helps reduce cross-reactivity surprises.
• Workflow success: Reactivity, applications, and clonality determine whether the antibody is likely to work in your exact sample type and readout.
• Reproducibility: Clone number (for monoclonals), isotype, and purification details help you maintain consistency across lots and over long projects.

Practical guidance:

• Confirm the exact target identity: If your study distinguishes subunits/isoforms, validate that this target name matches the specific protein form you intend to detect.
• Plan specificity controls: Use orthogonal controls (e.g., positive/negative samples, knockdown/knockout where feasible, or peptide competition when appropriate) to confirm target-specific signal.
• Match detection reagents: Choose secondaries that match the host/isotype and avoid cross-reactivity in multiplex panels.
• Start with application-backed use: Prioritize antibodies with explicit support for your intended application(s) and sample species to reduce optimization burden.

What to watch out for:

• Family-member cross-reactivity: Closely related proteins can produce off-target bands or staining; interpret signals cautiously if multiple family members are expressed in your sample.
• Isoforms and processing: Alternative splicing, cleavage, and PTMs can shift apparent size or localization—multiple bands or unexpected patterns may still be target-related.
• Species mismatch: A target from one species may not be recognized in another; treat cross-species use as a separate validation task.
• Matrix effects: Fixation, lysis conditions, and epitope accessibility can change performance across WB/IHC/IF/ELISA—even for the same antibody.