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Raymond Johnson, MD, PhD

Associate Professor of Medicine (Infectious Diseases) and of Microbial Pathogenesis; Director ID/Rheum Research Conference, Internal Medicine

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Raymond Johnson, MD, PhD
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Yale Medicine

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Research Summary

My laboratory studies Chlamydia pathogenesis for the purpose of facilitating vaccine development. Chlamydia trachomatis is the most common sexually transmitted bacterial infection in the world. It also causes a blinding eye infection known as trachoma. Understanding the adaptive immune response to this pathogen is essential for rational vaccine development.

Extensive Research Description

The primary goal of our laboratory is to understand protective immunity against chlamydia infections of the reproductive tract to facilitate vaccine development. That effort includes a focus on T cell interactions with infected epithelial cells because chlamydia replicates primarily in reproductive tract epithelium. We utilize T cell cloning as a research tool because unlike strategies based on flow cytometry-RNAseq, this approach provides representative T cell clones that can be used as experimental tools to understand mucosal T cell immunobiology, and do cause-and-effect pathogenesis rather than associative-biology. The payout has been the discovery of novel T cell subsets involved in the adaptive immune response to chlamydia genital tract infections and a wealth of data enabled by subset-representative T cell clones, including transcriptomic identification of differentiation and activation pathway biomarkers, and investigations of their contributions to host defense and immunopathology. We have found that IL-13 is a central player in chlamydia immunobiology, but not in the conventional Th1/Th2 narrative sense. We are currently focused chlamydia-specific CD4 and CD8 T cells polarized to coproduce IFN-γ and IL-13 that prevent immunopathology during primary C. muridarum genital tract infections, and a highly conserved biomarker that is likely the signaling scaffold for IL-13 production in this novel T cell phenotype. We also apply the mucosal immunology learned to other human diseases.

Coauthors

Research Interests

Chlamydia trachomatis; Trachoma; Infectious Disease Medicine

Research Image

Two CD8 T cells attacking an infected epithelial cell

EM photo of a Chlamydia-specific CD8 T cell clone attacking an infected epithelial cell. The Chlamydia inclusion is visible in the epithelial cell opposite the nucleus. Arrow identifies a T cell granule.

Selected Publications

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