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Updated: Aug 10, 2026
Evaluation of Tumor-infiltrating Leukocyte Subsets in a Subcutaneous Tumor Model
Published on: April 13, 2015
[Analysis of infiltrating lymphocytes in choroidal melanoma]
1Department of Ophthalmology, Shinshu University School of Medicine, Nagano-ken, Japan.
Insights
Tumor infiltrating lymphocytes (TILs) in choroidal melanoma show more CD8+ T cells and activated memory cells. This suggests a localized immune response within the tumor microenvironment.
Area of Science:
- Immunology
- Oncology
- Ophthalmology
Background:
- Choroidal malignant melanoma is a rare eye cancer.
- Understanding the tumor immune microenvironment is crucial for treatment strategies.
Observation:
- Immunohistochemistry revealed sparse lymphocytes around the tumor.
- Flow cytometry analyzed tumor infiltrating lymphocytes (TILs) and peripheral blood lymphocytes (PBLs).
Findings:
- TILs showed a higher ratio of CD8+ to CD4+ T cells compared to PBLs.
- A significant increase in CD29+ (memory) T cells and a decrease in CD45RA+ (naive) T cells were observed in TILs.
- Most TILs expressed HLA-DR, indicating activation.
Implications:
- The findings suggest a localized, antigen-specific immune response in choroidal melanoma.
- This immune profile may inform the development of immunotherapies for ocular cancers.
Abstract:
We performed immunohistochemistry on tumor infiltrating lymphocytes (TILs) in a 78-year-old man with choroidal malignant melanoma. Cell suspensions of TILs from fresh specimens and peripheral blood lymphocytes (PBLs) were stained with anti-CD3, anti-CD4, anti-CD8, anti-CD29, anti-CD45RA, and anti-human leukocyte antigen (HLA)-DR monoclonal antibodies and analyzed using three-color flow cytometry. In light microscopy, the number of infiltrating lymphocytes around the tumor was very small. Immunohistochemically, T lymphocytes were more numerous than B lymphocytes. Flow cytometric analysis showed that CD8+ cells were more numerous than CD4+ cells in CD3+ cells in TILs, and most of these cells also expressed HLA-DR antigen. CD29+ (memory) cells were increased and CD45RA+ (naive) cells were decreased in CD4+ cells in TILs as compared with PBLs. We concluded that the increase in the percentage of activated memory T lymphocytes and the decrease of naive T lymphocytes may reflect a localized antigen-specific immunological response in choroidal malignant melanoma.
