Current immuno-oncology primarily focuses on adaptive cellular immunity mediated by T lymphocytes. The other important lymphocytes, B cells, are largely ignored in cancer immunotherapy. B cells are generally considered to be responsible for humoral immune response to viral and bacterial infections. The role of B cells in cancer immunity has long been under debate. Recently, increasing evidence from both preclinical and clinical research has shown that B cells can also induce potent anti-cancer immunity, via humoral and cellular immune responses. Yet it is unclear how to efficiently integrate B cell immunity in cancer immunotherapy. In the current perspective, anti-tumor immunity of B cells is discussed regarding antibody production, antigen presentation, cytokine release and contribution to intratumoral tertiary lymphoid structures. Afterwards, immunosuppressive regulatory phenotypes of B cells are summarized. Furthermore, strategies to activate and modulate B cells using nanomedicines and biomaterials are discussed. This article provides a unique perspective on “PLAN B" (promoting and leveraging anti-tumor B cell immunity) using nanomedicines and biomaterials for cancer immunotherapy. This is envisaged to form a new research direction with the potential to reach the next breakthrough in immunotherapy.

当前的免疫肿瘤学主要关注由 T 淋巴细胞介导的适应性细胞免疫。其他重要的淋巴细胞 B 细胞在癌症免疫治疗中基本上被忽略了。B细胞通常被认为负责对病毒和细菌感染的体液免疫反应。B细胞在癌症免疫中的作用长期以来一直存在争议。最近，越来越多的临床前和临床研究证据表明，B 细胞还可以通过体液和细胞免疫反应诱导有效的抗癌免疫。然而，目前尚不清楚如何在癌症免疫治疗中有效地整合 B 细胞免疫。从目前的角度来看，B 细胞的抗肿瘤免疫的讨论涉及抗体产生、抗原呈递、细胞因子释放和对肿瘤内三级淋巴结构的贡献。然后，总结了 B 细胞的免疫抑制调节表型。此外，还讨论了使用纳米药物和生物材料激活和调节 B 细胞的策略。本文对利用纳米药物和生物材料进行癌症免疫治疗的“PLAN B”（促进和利用抗肿瘤B细胞免疫）提供了独特的视角，有望形成新的研究方向，有望实现免疫治疗的下一个突破。