The Immunology Podcast

Ep. 123: “Immunological Memory” Featuring Dr. Rafi Ahmed

Jan 27, 2026
Guest
Rafi Ahmed
Dr. Rafi Ahmed, Emory vaccine center director known for foundational work on T-cell memory and PD-1 biology. He discusses how memory T and B cells persist, long-lived plasma cell niches, T-cell exhaustion in chronic infection, and how PD-1 blockade can reinvigorate immunity. Short stories about classic experiments and why vaccines protect against severe disease round out the conversation.
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INSIGHT

EBV-Infected B Cells Present Novel MS Epitopes

  • EBV infection may trigger MS by driving B cells to present distinct, truncated myelin peptides on MS-associated HLA-DR15 alleles.
  • These B cell-presented peptides escape thymic negative selection and activate autoreactive T cells in patients.
INSIGHT

Molecular Mimicry Connects EBV To MS Autoimmunity

  • Molecular mimicry links EBNA1 (an EBV antigen) to the brain autoantigen ANO2, with cross-reactive CD4 T cells and antibodies enriched in MS.
  • Cross-reactivity exacerbates EAE in mice and aligns TCR clonotypes between EBV and ANO2 responses in patients.
INSIGHT

Microbiota Drives T-Cell Plasticity Against Tumors

  • Gut-colonizing microbes can prime antigen-specific CD4 T cells that migrate and convert phenotype to support anti-tumor responses.
  • Microbiota-induced Th17-to-Th1 plasticity can enhance PD-1 checkpoint efficacy in early tumors.
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