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Updated: Mar 18, 2026

Author Spotlight: Elucidating the Pathways of TFH Cell Differentiation in Acute LCMV Challenges
Published on: April 26, 2024
Activin A programs the differentiation of human TFH cells
Michela Locci1, Jennifer E Wu1, Fortuna Arumemi1
1Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA.
Follicular helper T cells (TFH cells) are CD4(+) T cells specialized in helping B cells and are associated both with protective antibody responses and autoimmune diseases. The promise of targeting TFH cells therapeutically has been limited by fragmentary understanding of extrinsic signals that regulate the differentiation of human TFH cells. A screen of a human protein library identified activin A as a potent regulator of TFH cell differentiation. Activin A orchestrated the expression of multiple genes associated with the TFH program, independently or in concert with additional signals. TFH cell programming by activin A was antagonized by the cytokine IL-2. Activin A's ability to drive TFH cell differentiation in vitro was conserved in non-human primates but not in mice. Finally, activin-A-induced TFH programming was dependent on signaling via SMAD2 and SMAD3 and was blocked by pharmacological inhibitors.
Follicular helper T cells (TFH cells) are CD4(+) T cells specialized in helping B cells and are associated both with protective antibody responses and autoimmune diseases. The promise of targeting TFH cells therapeutically has been limited by fragmentary understanding of extrinsic signals that regulate the differentiation of human TFH cells. A screen of a human protein library identified activin A as a potent regulator of TFH cell differentiation. Activin A orchestrated the expression of multiple genes associated with the TFH program, independently or in concert with additional signals. TFH cell programming by activin A was antagonized by the cytokine IL-2. Activin A's ability to drive TFH cell differentiation in vitro was conserved in non-human primates but not in mice. Finally, activin-A-induced TFH programming was dependent on signaling via SMAD2 and SMAD3 and was blocked by pharmacological inhibitors.
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