126. Glycosylation of a monoclonal antibody DOES NOT affect:
(1) in vivo stability of antibody
(2) mediation of phagocytosis and cytotoxicity of antibody
(3) efficacy of monoclonal antibody
(4) fluorescence spectrum of antibody

Detailed Explanation:

Question:
Glycosylation of a monoclonal antibody DOES NOT affect:

✅ Correct Answer: (4) fluorescence spectrum of antibody

What Is Glycosylation in Monoclonal Antibodies?

Glycosylation is the enzymatic addition of sugar moieties (glycans) to proteins. In monoclonal antibodies (mAbs), glycosylation typically occurs in the Fc region (fragment crystallizable region) and can have profound biological and therapeutic implications.

Functions of Glycosylation in Monoclonal Antibodies:

✅ (1) In Vivo Stability

• Glycosylation improves protein folding and solubility.

• Increases circulating half-life by reducing degradation and clearance.

✅ (2) Phagocytosis and Cytotoxicity

• The Fc region’s glycan profile influences interaction with Fc gamma receptors (FcγRs).

• Crucial for antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis, both major mechanisms for therapeutic action.

✅ (3) Efficacy of Monoclonal Antibodies

• Glycosylation directly affects binding affinity, immune response modulation, and therapeutic outcomes.

• Altered glycosylation can enhance or reduce mAb potency.

❌ (4) Fluorescence Spectrum of Antibody

• Fluorescence is related to the intrinsic amino acid composition (e.g., tryptophan, tyrosine).

• Glycans are non-chromophoric and do not emit or absorb light in the range typically analyzed by fluorescence spectroscopy.

• Thus, glycosylation has no effect on the fluorescence spectrum of the antibody.

Conclusion:

While glycosylation is essential for the stability, immune interaction, and efficacy of monoclonal antibodies, it does not influence their fluorescence spectrum. This distinction is vital in designing, analyzing, and utilizing mAbs in both diagnostics and therapeutics.

✅ Correct Answer: (4) fluorescence spectrum of antibody