IMMUNOLOGY2026™ Conference Recordings For Attendees-TyCHE enables time-resolved lineage tracing of B cells in primary and recall germinal center reactions

TyCHE enables time-resolved lineage tracing of B cells in primary and recall germinal center reactions

Video Transcription

Video Summary

Jessie Fielding presented Tyche, a Bayesian software package for inferring time-resolved lineage trees when mutation rates vary widely across cell types. The talk focused on B cells, whose BCR sequences mutate during affinity maturation in germinal centers, producing plasma and memory cells with very different evolutionary rates. Tyche addresses this by assigning different mutation rates to different cell types and reconstructing ancestral states to build accurate time trees. The method was validated on simulated data from Symbol, where Tyche closely matched true lineage ages and tree shapes, outperforming strict-clock models. Applied to real HIV BCR data, Tyche estimated germinal center start dates that agreed with clinically inferred infection dates and dated when memory B-cell subtypes exited germinal centers. It also successfully resolved recall germinal center reactions after flu vaccination, where strict-clock models failed. Jessie noted Tyche can generalize beyond B cells to other rapidly mutating systems such as bacteria and tumors.

Meta Tag

Date April 18, 2026 1:30 PM - 1:45 PM

Room 102

Session Computational Tool Development

Speaker Jessie Fielding

Track Computational and Systems Immunology (COMP)

Year 2026

Keywords

Tyche

Bayesian lineage trees

B cell affinity maturation

variable mutation rates

time-resolved phylogenetics

April 18, 2026 1:30 PM - 1:45 PM

102

Computational Tool Development

Jessie Fielding

Computational and Systems Immunology (COMP)

2026