Chromatographic enzyme immunoassay for T-2 toxin

Area of Science:

• Bioconjugation Chemistry
• Immunochemistry
• Enzyme Immobilization

Background:

• Ribonuclease (RNase) is an enzyme susceptible to modification by cross-linking reagents.
• N-[(gamma-maleimidobutyryl)oxy]succinimide (GMBS) reacts with primary amino groups, potentially affecting enzyme activity.
• Developing specific detection methods for toxins like T-2 is crucial for diagnostics.

Purpose of the Study:

• To develop a method for conjugating RNase to anti-T-2 toxin Fab' fragments.
• To create a sensitive assay for T-2 toxin detection using the developed conjugate.
• To overcome challenges in RNase modification that lead to enzyme inactivation.

Main Methods:

• Selective modification of RNase primary amino groups using citraconylation prior to GMBS cross-linking.
• Preparation of a 1:1.1 M molar ratio conjugate of anti-T-2 toxin Fab' and RNase (Fab'-RNase).
• Development of an immunoassay utilizing a T-2 toxin agarose affinity gel for toxin displacement detection.

Main Results:

• A citraconylation strategy successfully protected RNase activity during conjugation with GMBS.
• A Fab'-RNase conjugate was synthesized with a 76% yield.
• The conjugate enabled the detection of as little as 0.1 microgram of T-2 toxin.

Conclusions:

• Site-specific modification of RNase is achievable and preserves enzyme function for conjugation.
• The Fab'-RNase conjugate offers a sensitive and specific method for T-2 toxin detection.
• This approach demonstrates the utility of enzyme-antibody conjugates in toxin-based immunoassays.