T-B Coculture Assay
Overview
T-B coculture assays measure the functional capacity of T cell subsets to provide B cell help by co-incubating sorted T cells with autologous B cells and quantifying B cell differentiation outputs (plasmablast generation, antibody secretion, class switching). These assays can be combined with blocking antibodies to identify the cytokine mediators of T-B cooperation.
Key Points from Literature
- Tph-driven memory B cell → plasmablast differentiation in dengue: Sorted CXCR5⁻PD-1⁺ (Tph) cells cocultured with autologous B cells drive memory B cell differentiation into plasmablasts. Naive B cells are poor responders to Tph-provided help — in contrast to the TLR7-driven EF pathway in SLE, where naive cells are the dominant ASC precursors (see Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue).
- IL-21 blocking identifies dominant effector cytokine: Anti-IL-21 blocking antibody in the coculture system reduces plasmablast output by ~60%, establishing IL-21 as the primary but not exclusive mediator. The residual ~40% output likely reflects CD40L-mediated costimulation and/or other cytokines (see Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue).
- Complements the Jenks2018 in vitro differentiation system: The Jenks2018 EF differentiation protocol (rNAV + TLR7 + IFN-γ + IL-21 → aNAV → DN2 → PB) uses purified cytokines without T cells. The Ansari2025 T-B coculture demonstrates that T cells (specifically Tph) can provide these signals physiologically, adding the T cell arm to the EF pathway model (see In Vitro B Cell Stimulation for the Jenks2018 approach).
Contradictions & Debates
None documented in current wiki sources.
Related Pages
Peripheral Helper T Cell, IL-21, Plasmablast, Memory B Cell, In Vitro B Cell Stimulation, ELISpot