Counter-immunoelectrophoresis (CIE) CIE is a rapid precipitation method used to detect which of the following antigens in clinical specimens or extracts?

Introduction / Context:
Counter-immunoelectrophoresis (CIE) accelerates antigen–antibody precipitation by driving partners toward each other in an electric field, forming visible lines of precipitation. It has been applied in rapid diagnostics for microbial antigens and certain serum markers, especially before widespread ELISA adoption.

Given Data / Assumptions:

• Antigens listed include bacterial capsular antigens and serum proteins.
• CIE requires specific antisera and a gel medium.
• Goal is rapid qualitative detection.

Concept / Approach:

In CIE, antigen and antibody wells are placed opposite each other in agarose; under voltage, they migrate and form a precipitin line at equivalence if the target is present. Historically, CIE has been used to detect meningococcal, pneumococcal, and Haemophilus antigens in CSF. HBsAg and fetal proteins like AFP have also been detected by immunoelectrophoretic methods in certain labs, demonstrating the technique’s breadth.

Step-by-Step Solution:

Verification / Alternative check:

Comparisons with latex agglutination and ELISA show CIE has lower sensitivity but acceptable specificity; positive CIE in CSF for meningococcal antigens was a classic rapid diagnostic adjunct.

Why Other Options Are Wrong:

• Limiting to a single antigen underestimates CIE’s applicability.
• “None” is incompatible with established use cases.

Common Pitfalls:

• Poor sample quality or low antigen levels can cause false negatives; concentration steps may help.

Final Answer:

All of these