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Microanatomical localization of PD-1 in human tonsils
Yoshiko Iwai1, Taku Okazaki, Hiroyuki Nishimura
1Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
Immunology Letters
|July 4, 2002
Summary
Programmed cell death protein 1 (PD-1) is expressed on T cells and centrocytes within human tonsils. This suggests PD-1 plays a crucial role in germinal center reactions and immune tolerance.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Programmed cell death protein 1 (PD-1) is an immunoinhibitory receptor structurally belonging to the CD28 family.
- PD-1 deficiency in mice leads to a breakdown of peripheral tolerance and autoimmune symptoms.
- Previous studies identified PD-1 expression on activated lymphocytes and myeloid cells, but its distribution in lymphoid organs was largely unknown.
Purpose of the Study:
- To investigate the microanatomical distribution of PD-1 in human lymphoid organs.
- To elucidate the potential role of PD-1 in germinal center (GC) reactions.
Main Methods:
- Immunohistochemistry was performed on human tonsil tissues.
- Monoclonal antibodies against human PD-1 were utilized for staining.
Main Results:
- PD-1 expression was observed on the majority of T cells in human tonsils.
- A small subset of centrocytes in the light zone of germinal centers also expressed PD-1.
- The localization of PD-1 on centrocytes suggests a role in clonal selection within GCs.
Conclusions:
- PD-1 is expressed in specific cellular subsets within human tonsils, including T cells and germinal center centrocytes.
- The findings indicate that PD-1 may play a significant role in regulating germinal center reactions and immune responses.