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A Simple Flow Cytometry Based Assay to Determine In Vitro Antibody Dependent Enhancement of Dengue Virus Using Zika Virus Convalescent Serum
Published on: April 10, 2018
Dengue virus-induced helper cytokine has two polypeptide chains which bear different determinants
P Chaturvedi1, R Mukherjee, U C Chaturvedi
1Postgraduate Department of Microbiology, K.G. Medical College, Lucknow, India.
International Journal of Experimental Pathology
|December 1, 1991
Summary
Dengue virus type 2 induces a T cell helper factor (HF) crucial for antibody production. This HF is a double-chain protein linked by disulfide bonds, requiring both chains for its immune-enhancing activity.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- Dengue virus type 2 (DV) infection stimulates T helper cell responses.
- A T cell helper factor (HF) generated in mouse spleen enhances antigen-specific antibody production.
Purpose of the Study:
- To elucidate the molecular structure of the DV-induced T cell helper factor (HF).
Main Methods:
- Treatment of HF with reducing agents (glutathione, ouabain, dithiothreitol) to cleave disulfide bonds.
- Purification of polypeptide chains using high-performance liquid chromatography (HPLC).
- Assay of helper activity of individual chains and their re-mixtures.
- Antigen-binding and antibody-binding assays using coupled immunosorbent columns.
Main Results:
- Reducing agents abrogated HF activity by cleaving disulfide bonds, separating two polypeptide chains.
- Individual chains lacked helper activity; activity was restored upon mixing.
- One chain bound to DV-antigen, the other to anti-I-Ak antibody.
Conclusions:
- DV-induced HF is a disulfide-bonded heterodimer.
- Each chain possesses specific binding capabilities: one for DV antigen, the other for I-A determinants.
- Both chains are essential for the helper activity of HF.
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