Which T helper subset primarily provides cytokines that support humoral immunity and B cell responses?

Which T helper subset primarily provides cytokines that support humoral immunity and B cell responses?

• A. Th1
• B. Tfh
• C. Th2
• D. Th17

Answer: (C)

T follicular helper cells are the specialized subset that provides the cytokine support and direct B cell help needed for robust humoral immunity. They localize to B cell zones in lymphoid tissues (germinal centers) and interact with B cells through CD40L and ICOS-ICOSL signals, which help B cells proliferate and differentiate. A signature feature is their production of IL-21, a central driver of B cell proliferation, plasma cell differentiation, and formation of memory B cells; IL-4 from these cells also aids isotype switching. The transcription factor Bcl-6 guides their development, and CXCR5 helps them find the B cell follicle area. Because of these specialized interactions, Tfh cells are the main drivers of germinal center reactions that underpin high-affinity antibody responses. In contrast, Th1 cells focus on activating macrophages and cell-mediated responses (IFN-γ), Th2 cells promote broader humoral help but not the focused germinal center B cell work (IL-4, IL-5, IL-13), and Th17 cells drive inflammation and neutrophil recruitment rather than B cell maturation.

T follicular helper cells are the specialized subset that provides the cytokine support and direct B cell help needed for robust humoral immunity. They localize to B cell zones in lymphoid tissues (germinal centers) and interact with B cells through CD40L and ICOS-ICOSL signals, which help B cells proliferate and differentiate. A signature feature is their production of IL-21, a central driver of B cell proliferation, plasma cell differentiation, and formation of memory B cells; IL-4 from these cells also aids isotype switching. The transcription factor Bcl-6 guides their development, and CXCR5 helps them find the B cell follicle area. Because of these specialized interactions, Tfh cells are the main drivers of germinal center reactions that underpin high-affinity antibody responses. In contrast, Th1 cells focus on activating macrophages and cell-mediated responses (IFN-γ), Th2 cells promote broader humoral help but not the focused germinal center B cell work (IL-4, IL-5, IL-13), and Th17 cells drive inflammation and neutrophil recruitment rather than B cell maturation.