Biology subjects

Long, A. H.

Publications and source records attributed to Long, A. H..

2 recordsLinked to original sources

bioRxiv2026

Aging restricts maturation of CXCL13+ T follicular helper cells in human immunity

A decline in specific antibody responses is a hallmark of human aging, yet the differential contributions of B and T lymphocytes and their interactions remain unclear. CXCL13 is a critical chemokine that shapes germinal center organization, but the regulation of human-specific CXCL13+ Tfh cells during aging is not known. Using human tonsil organoids, single-cell RNA sequencing, and CRISPR perturbations, we mapped age-associated changes in T follicular helper (Tfh) cells, the cell type that provides T cell "help" to B cells in germinal centers (GCs). Tonsil organoids from older donors generated weaker influenza-specific antibody responses, which we traced to Tfh cell defects rather than B cells. Single-cell profiling revealed a selective loss of mature CXCL13 GC-Tfh cells accompanied by accumulation of Tfh precursor states. Trajectory analysis showed that aging arrests Tfh cell maturation at the early activated precursor transition, and CRISPR perturbations identified BACH2 and SOX4 as transcriptional regulators of differentiation reduced with age. These findings reveal a human-specific mechanism of immune aging with implications for strategies to restore humoral immunity.

immunology↗

bioRxiv2026

Fetal Thymic Expression Defines the Immunogenicity of Tumor Associated Antigens

Tumor associated antigens (TAAs) are promising targets for cancer immunotherapy, yet their immunogenicity varies widely and remains poorly understood. Here, we show that the immunogenic potential of TAAs is largely shaped by their expression in the thymus, likely established during fetal development. By integrating single-cell transcriptomic data across fetal and postnatal thymic epithelial cells (TECs), we find that TAA expression in fetal TECs predicts both in vitro CD8 T cell immunogenicity and the immune pressure against TAAs that occurs clinically in patients treated with immune checkpoint inhibitors. Notably, CD8 T cells recognizing TAAs highly expressed in the fetal thymus exhibit attenuated transcriptional, signaling, and metabolic responses even in the naive state, consistent with a tolerogenic imprinting imparted during thymic development and selection. Further, fetal thymic expression of TAAs can be leveraged to prioritize candidate targets for therapeutic use. These findings provide a biologic basis for the extreme variability seen in TAA immunogenicity and define guiding principles for rational antigen selection to drive the next generation of effective TAA-targeted immunotherapies.

immunology↗