Product Overview and Origin

Immunoglobulin M, mu Chain from Normal Human Plasma (catalog number np001053, Athens reference 16-16-090713-MU) is the isolated heavy chain subunit of human IgM, prepared from pooled normal human plasma. IgM is the largest of the classical human immunoglobulin isotypes, existing predominantly as a pentameric structure with five immunoglobulin units joined by disulfide bonds and a J chain. The mu (μ) heavy chain, with a molecular weight of approximately 65–70 kDa per monomer, defines the IgM isotype and carries the constant-region domains (Cμ1–Cμ4) responsible for complement activation and early immune responses.

The source plasma is collected exclusively at blood collection centers certified by the United States Food and Drug Administration (FDA). The supplier conducts donor screening and viral testing in full compliance with current FDA regulations, ensuring the traceability and safety profile expected for human-derived research reagents. This product is intended for in vitro research use only and is not suitable for therapeutic or diagnostic use in humans.

Recommended Handling and Storage Guidelines

Proper handling of this human plasma-derived protein is essential to preserve structural integrity and biological activity throughout its shelf life. The following guidelines are recommended:

• Aliquoting: Upon first thaw, prepare single-use aliquots to avoid repeated freeze-thaw cycles, which can cause protein aggregation and loss of immunoreactivity.
• Storage temperature: Store at –20 °C or –80 °C for long-term stability. Short-term working stocks may be held at 2–8 °C for up to 5–7 days. Specific storage conditions stated on the product datasheet take precedence.
• Thawing: Thaw gently on ice or at 2–8 °C; avoid rapid warming at 37 °C, which may promote aggregation of the pentameric IgM structure.
• Centrifugation: If precipitate is visible after thawing, briefly centrifuge at low speed (e.g., 300–500 × g for 5 minutes) and use the supernatant.
• Protein concentration: Verify working concentration by UV absorbance (A280) or BCA/Bradford assay before use in quantitative experiments.

Note: Refer to the Certificate of Analysis (CoA) and product datasheet supplied with each lot for confirmed concentration, purity, and specific storage instructions.

Research Applications

The mu chain of IgM serves as a critical reference material and research tool across multiple immunological disciplines. Established applications include:

• ELISA and immunoassay development: Used as a standard or calibrator for quantifying IgM in human serum samples; serves as an antigen for evaluating anti-IgM antibody performance.
• Western blotting: Provides a positive-control band for anti-μ chain or anti-human IgM secondary antibodies, assisting in optimization of detection conditions.
• Flow cytometry controls: Useful as a reference for anti-human IgM reagent titration and fluorochrome-conjugated antibody validation.
• Immunodiffusion and immunoelectrophoresis: Applied in Ouchterlony double-diffusion and related techniques for isotype characterization.
• Complement pathway studies: The μ heavy chain constant regions are involved in classical complement pathway activation; isolated mu chain preparations can serve as structural controls.
• Antibody engineering and validation: Reference material for confirming isotype-specific binding in hybridoma screening and recombinant antibody development workflows.

Quality, Safety and Regulatory Considerations

Human-derived material precautions: Although source plasma is collected at FDA-licensed centers with mandatory donor screening and viral testing per current FDA requirements, no testing method can completely eliminate the theoretical risk of transmitting infectious agents. All personnel handling this product must treat it as potentially biohazardous and apply appropriate biosafety measures, including the use of personal protective equipment (gloves, lab coat, eye protection) and work within a suitable containment environment consistent with institutional biosafety guidelines.

Disposal: Dispose of all materials that have come into contact with this product in accordance with local, national, and institutional regulations governing human-derived biological waste.

Lot-to-lot variability: As a plasma-derived protein, minor lot-to-lot variation in glycosylation pattern and electrophoretic mobility is expected and is characteristic of biological materials. Researchers performing highly sensitive quantitative assays should verify performance with each new lot prior to use in critical experiments.

Not for human use: This product is strictly for in vitro research purposes only. It is not intended for administration to humans or animals.