报告人：Junling Ma 教授 加拿大维多利亚大学

报告题目：Original Antigenic Sin in CD4+ T Cells

时间：2025年5月30日 10:00-11:30

地点：数学楼423

报告摘要：

  Original antigenic sin (OAS) is the phenomenon where prior exposure to an antigen results in a decreased adaptive antibody response to a heterologous infection. This phenomenon may negatively impact the effectiveness of immunity acquired from vaccination or previous infections. We demonstrate that this phenomenon arises because the proliferation and regulation signals of CD4+ T cells are antigen-nonspecific. Fast-responding memory CD4+ T cells trigger a regulatory T cell (Treg) response, which prematurely suppresses the naïve CD4+ T cell response, leading to a similar OAS effect in CD4+ T cells. We illustrate this mechanism using a mathematical model that incorporates the proliferation of naïve and memory CD4+ T cells, interleukin-2 (IL-2), and Tregs. Our model is calibrated with experimental data and uses numerical simulations to study how the CD4+ T cell response varies with the level of cross-reactivity between memory CD4+ T cells and the antigen causing the secondary infection. Our results indicate that the immune response is weakest at an intermediate level of cross-reactivity, a key feature of OAS. This mechanism can also explain OAS in antibody responses.

报告人简介：

   Dr. Junling Ma，加拿大维多利亚大学数学与统计学院教授。于1997年在西安交通大学获得硕士学位，2003年在美国普林斯顿大学获得博士学位。主要从事生物数学方面研究，主要研究方向有传染病动力学，公共卫生政策，免疫系统动力学，生态系统等。文章发表在Nature Communications, Proceedings of National Academy of Sciences, PLoS Computational Biology, Frontiers of Computational Neurosciences, Immunology, Infectious Disease Modeling, Mathematical Biosciences, Journal of Mathematical Biology, Journal of Theoretical Biology等期刊。

邀请人：肖燕妮教授