CD3⁺CD56⁺NKT-like cells are a rare population of lymphocytes that serve important roles in various types of immune-related diseases, and particularly in cancer. The complement system regulates inflammatory and immune responses by interacting with complement receptors expressed on a range of immune cells. However, whether CD3⁺CD56⁺NKT-like cells are regulated by the complement system has still not been definitively determined. In the present study, the expression of complement receptors and regulators in gated CD3⁺CD56⁺NKT-like cells isolated from human peripheral blood was assessed using PCR and flow cytometry. The results showed that human CD3⁺CD56⁺NKT-like cells expressed a range of complement receptors and regulators, such as CR3, C3aR, C5aR, C5L2, CD46 and CD55. Furthermore, the presence of complement component 3 (C3), a key component in complement activation in culture supernatant, mitigated the activity, IFN-γ production and killing function of CD3⁺CD56⁺NKT-like cells. The present study provides evidences supporting the relationship between complement activation and functional modulation of CD3⁺CD56⁺NKT-like cells, expanding our knowledge of the complement regulatory network, and also highlighting a potential target for treatment of numerous immune-related diseases, particularly NKT cell-based tumor adoptive immunotherapy.

CD3 ⁺ CD56 ⁺ NKT 样细胞是一种罕见的淋巴细胞群，在各种类型的免疫相关疾病中发挥重要作用，尤其是在癌症中。补体系统通过与一系列免疫细胞上表达的补体受体相互作用来调节炎症和免疫反应。然而，CD3 ⁺ CD56 ⁺ NKT 样细胞是否受补体系统调节仍未明确确定。在本研究中，使用 PCR 和流式细胞术评估了从人外周血中分离的门控 CD3 ⁺ CD56 ⁺ NKT 样细胞中补体受体和调节剂的表达。结果表明，人 CD3 ⁺ CD56⁺ NKT 样细胞表达一系列补体受体和调节剂，例如 CR3、C3aR、C5aR、C5L2、CD46 和 CD55。此外，补体成分 3 (C3)（培养上清液中补体激活的关键成分）的存在减轻了 CD3 ⁺ CD56 ⁺ NKT 样细胞的活性、IFN-γ 产生和杀伤功能。本研究提供了支持补体激活与 CD3 ⁺ CD56 ⁺ NKT 样细胞功能调节之间关系的证据，扩展了我们对补体调节网络的认识，并强调了治疗多种免疫相关疾病，特别是 NKT 的潜在靶点基于细胞的肿瘤过继免疫治疗。