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Updated: May 17, 2026
Flow Cytometric Characterization of Murine B Cell Development
Published on: January 22, 2021
Morphologic, flow cytometric, functional, and molecular analyses of S100B positive lymphocytes, unique cytotoxic
Yukari Miki1, Yuka Gion, Yuriko Mukae
1Department of Medical Technology, Graduate School of Health Sciences, Okayama University, Okayama, Japan.
Insights
Unique S100B⁺ lymphocytes, found in human blood, were characterized. These cells, including T and NK cell subtypes, release S100B and may play a role in antitumor immunity.
Area of Science:
- Immunology
- Cell Biology
- Human Physiology
Background:
- S100B protein is released by various cells and exhibits cytokine-like activities.
- S100B⁺ lymphocytes are unique peripheral blood lymphocytes (PBL) containing S100B protein, but their characteristics are largely unknown.
- Understanding S100B⁺ lymphocytes is crucial for insights into immune responses and potential therapeutic targets.
Purpose of the Study:
- To precisely characterize S100B⁺ lymphocytes in healthy adults.
- To determine their proportion in PBL, immunophenotypes, function, and S100B mRNA expression.
- To evaluate their S100B-releasing activity upon stimulation.
Main Methods:
- Flow cytometry for immunophenotyping of S100B⁺ lymphocytes.
- Analysis of S100B mRNA expression using molecular techniques.
- Functional assays including proliferation and cytotoxic activity assessments upon stimulation.
Main Results:
- S100B⁺ lymphocytes were detected in all individuals, ranging from 0.42% to 16.15% of PBL.
- Two subtypes were identified: a CTL subtype (CD3⁺ CD8⁺ CD16⁻) and an NK subtype (CD3⁻ CD3⁻ CD16⁺).
- Both subtypes expressed S100B mRNA, with higher levels in S100B⁺ lymphocytes compared to S100B⁻ lymphocytes. CTL subtypes proliferated and released S100B upon stimulation, while NK subtypes showed NK activity.
Conclusions:
- S100B⁺ lymphocytes represent a distinct subtype of cytotoxic lymphocytes.
- The CTL and NK subtypes exhibit characteristics of T cells and NK cells, respectively.
- These findings suggest a unique role for S100B⁺ lymphocytes in antitumor immunity.
Abstract:
Little is known about the S100B⁺ lymphocytes, which are unique human peripheral blood lymphocytes (PBL) containing the S100B protein. It has recently been shown that S100B is released from various types of S100B⁺ cells and exhibits varied cytokine-like activities. In this study, we precisely characterized the S100B⁺ lymphocytes of healthy adults with respect to the proportion in the whole PBL, immunophenotypes, function, and their S100B mRNA expression and also evaluated their S100B-releasing activity upon stimulation. S100B⁺ lymphocytes were detected in all individuals examined, and the proportion of S100B⁺ lymphocytes in the whole PBL ranged from 0.42% to 16.15% (mean, 4.21%). In addition, two subtypes of S100B ⁺ lymphocytes, a CTL subtype (CD3⁺ CD8⁺ CD16⁻) and a NK subtype (CD3⁻ CD3⁻ CD16⁺), were detected. The majority of the CTL subtype of S100B⁺ lymphocytes expressed the αβ-T-cell receptor. Surprisingly, S100B mRNA was detected not only in S100B⁺ lymphocytes, but also in every S100B⁺ lymphocytes, although the expression levels of S100B mRNA in S100B⁻ lymphocytes were much lower than those of S100B⁺ lymphocytes. The CTL subtype of S100B⁺ lymphocytes exhibited blastic morphological changes, proliferated and released S100B upon stimulation with phytohemagglutinin. The NK subtype of S100B⁺ lymphocytes exhibited morphological NK activity when cocultivated with NK-sensitive target, K-562 cells. Thus, the CTL subtype of S100B⁺ lymphocytes exhibit the biological characteristics of T cells, while the NK subtype of S100B⁺ lymphocytes exhibit the characteristics of NK cells. These results suggest that S100B⁺ lymphocytes are a particular subtype of cytotoxic lymphocytes that play a unique role in antitumor immunity.
