Inoue S, Takeuchi Y, Horiuchi Y, Murakami T, Odaka A. CD69 on Tumor-Infiltrating Cells Correlates With Neuroblastoma Suppression by Simultaneous PD-1 and PD-L1 Blockade.
J Surg Res 2023;
289:190-201. [PMID:
37141702 DOI:
10.1016/j.jss.2023.03.042]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/15/2023] [Accepted: 03/26/2023] [Indexed: 05/06/2023]
Abstract
INTRODUCTION
Tumor-infiltrating cells play an important role in tumor immunology, and tumor-infiltrating lymphocytes (TILs) are critical in antitumor reaction related to immune checkpoint inhibition targeting programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1).
METHODS
In nude mice, which are immune deficient because they lack T cells, and inbred A/J mice, which are syngeneic to neuroblastoma cells (Neuro-2a) and have normal T cell function, we investigated the importance of T lymphocytes in immune checkpoint inhibition in mouse neuroblastoma and analyzed the immune cells in the tumor microenvironment. Then, we subcutaneously injected mouse Neuro-2ainto nude mice and A/J mice, administered anti-PD-1 and anti-PD-L1 antibodies by intraperitoneal injection, and evaluated tumor growth. At 16 d after Neuro-2a cells injection, mice were euthanized, tumors and spleens were harvested, and immune cells were analyzed by flow cytometry.
RESULTS
The antibodies suppressed tumor growth in A/J but not in nude mice. The co-administration of antibodies did not affect regulatory T cells (culster of differentiation [CD]4+CD25+FoxP3+ cells) or activated CD4+ lymphocytes (expressing CD69). No changes in activated CD8+ lymphocytes (expressing CD69) were observed in spleen tissue. However, increased infiltration of activated CD8+ TILs was seen in tumors weighing less than 300 mg, and the amount of activated CD8+ TILs was negatively correlated with tumor weight.
CONCLUSIONS
Our study confirms that lymphocytes are essential for the antitumor immune reaction induced by blocking PD-1/PD-L1 and raises the possibility that promoting the infiltration of activated CD8+ TIL into tumors may be an effective treatment for neuroblastoma.
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