Bioprocess separation: In practical biochemical workflows, immunoaffinity chromatography is primarily used to do which of the following?

Introduction / Context:
Immunoaffinity chromatography exploits the exquisite specificity of antigen–antibody binding to isolate target molecules from complex biological mixtures. It is widely used to purify low-abundance proteins for downstream analytics and therapeutics manufacturing.

Given Data / Assumptions:

• A solid support carries covalently immobilized antibodies against the target antigen.
• Binding is reversible; elution occurs by pH, ionic strength, or chaotropes under conditions that preserve activity when possible.
• Goal is selective purification, not degradation.

Concept / Approach:
The core idea is selective capture: only molecules bearing the epitope are retained strongly on the column while non-specific proteins flow through. After washing, the antigen is eluted in concentrated form with high purity, often surpassing that achieved by conventional ion exchange or size exclusion alone.

Step-by-Step Solution:

Verification / Alternative check:
Standard protocols for tag-free protein purification frequently employ monoclonal antibody columns (e.g., for hormones, cytokines), confirming purification as the purpose.

Why Other Options Are Wrong:

• Break down antibody structure: that is done by chemical reduction/enzymatic digestion, not immunoaffinity chromatography.
• Quantitative degradation of antigen: antithetical to purification; chromatography does not intentionally degrade targets.
• None of the above / nucleic acid concentration: unrelated to immunoaffinity.

Common Pitfalls:
Confusing affinity capture with immunodetection (e.g., Western blot). Chromatography is preparative and aims at isolation, not just detection.

Final Answer:
Purify a protein antigen from a complex mixture using a bound antibody