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HLA-DR Marks Recently Divided Antigen-Specific Effector CD4 T Cells in Active Tuberculosis Patients
Rashmi Tippalagama1, Akul Singhania1, Paige Dubelko1
1Vaccine Discovery Division, La Jolla Institute for Immunology, La Jolla, CA.
Journal of Immunology (Baltimore, Md. : 1950)
|July 1, 2021
Summary
Human leukocyte antigen-DR (HLA-DR) marks recently divided CD4 T cells. Increased HLA-DR+ cells in active tuberculosis patients indicate a heightened immune response to Mycobacterium tuberculosis.
Area of Science:
- Immunology
- Cellular Biology
- Infectious Diseases
Background:
- T cells are crucial for fighting infections by forming effector populations after antigen encounter.
- Identifying molecular markers for these effector T cells in humans, especially during active tuberculosis (ATB), is essential but poorly understood.
Purpose of the Study:
- To investigate the molecular profile of T cells in individuals with active tuberculosis (ATB).
- To identify markers distinguishing recently divided, antigen-specific effector T cells in ATB patients compared to healthy individuals.
Main Methods:
- Analysis of T cell populations in individuals with active tuberculosis (ATB) and healthy, Mycobacterium tuberculosis-sensitized individuals.
- Investigation of human leukocyte antigen-DR (HLA-DR) expression on CD4 T cells.
- In vitro modeling of T cell responses to Mycobacterium tuberculosis antigens in healthy individuals.
Main Results:
- The frequency of HLA-DR-expressing cells was elevated in circulating CD4 T cells of ATB patients.
- HLA-DR was predominantly expressed on Mycobacterium tuberculosis antigen-specific CD4 T cells.
- In vitro studies confirmed HLA-DR as a marker for recently divided CD4 T cells upon antigen exposure.
Conclusions:
- HLA-DR identifies a CD4 T cell population of recently divided, antigen-specific effector T cells detectable ex vivo.
- The increased frequency of these HLA-DR+ cells in ATB patients suggests their role in the disease.
- These findings aid in monitoring T cell responses in ATB and other infections.
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