P-MAPA is a complex compound, derived from Aspergillus oryzae cultures, that has shown immunomodulatory properties in infection and cancer animal models. Despite promising results in these models, the mechanisms of cellular activation by P-MAPA, suggested to be Toll-like receptor- (TLR-) dependent, and its effect on human immune cells, remain unclear. Using an ex vivo model of human whole blood, the effects of P-MAPA on complement system activation, production of cytokines, and the expression of complement receptors (CD11b, C5aR, and C3aR), TLR2, TLR4, and the coreceptor CD14 were analyzed in neutrophils and monocytes. P-MAPA induced complement activation in human blood, detected by increased levels of C3a, C5a, and SC5b-9 in plasma. As a consequence, CD11b expression increased and C5aR decreased upon activation, while C3aR expression remained unchanged in leukocytes. TLR2 and TLR4 expressions were not modulated by P-MAPA treatment on neutrophils, but TLR4 expression was reduced in monocytes, while CD14 expression increased in both cell types. P-MAPA also induced the production of TNF-α, IL-8, and IL-12 and oxidative burst, measured by peroxynitrite levels, in human leukocytes. Complement inhibition with compstatin showed that P-MAPA-induced complement activation drives modulation of C5aR, but not of CD11b, suggesting that P-MAPA acts through both complement-dependent and complement-independent mechanisms. Compstatin also significantly reduced the peroxynitrite generation. Altogether, our results show that P-MAPA induced proinflammatory response in human leukocytes, which is partially mediated by complement activation. Our data contribute to elucidate the complement-dependent and complement-independent mechanisms of P-MAPA, which ultimately result in immune cell activation and in its immunomodulatory properties in infection and cancer animal models.

中文翻译：

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P-MAPA，一种真菌衍生的免疫调节化合物，在人类全血模型中诱导促炎反应

P-MAPA 是一种复杂的化合物，源自米曲霉培养物，已在感染和癌症动物模型中显示出免疫调节特性。尽管在这些模型中取得了有希望的结果，但 P-MAPA 的细胞激活机制（表明是 Toll 样受体（TLR-）依赖性）及其对人类免疫细胞的影响仍不清楚。使用离体在人全血模型中，分析了 P-MAPA 对补体系统激活、细胞因子产生以及补体受体（CD11b、C5aR 和 C3aR）、TLR2、TLR4 和辅助受体 CD14 在中性粒细胞和单核细胞中的表达的影响. P-MAPA 诱导人血液中的补体激活，通过血浆中 C3a、C5a 和 SC5b-9 的水平升高来检测。因此，CD11b 表达增加，C5aR 在激活后减少，而 C3aR 表达在白细胞中保持不变。TLR2 和 TLR4 表达不受 P-MAPA 对中性粒细胞的调节，但单核细胞中的 TLR4 表达降低，而两种细胞类型中的 CD14 表达均增加。P-MAPA 还诱导 TNF- α 的产生、IL-8 和 IL-12 以及氧化爆发，通过过氧亚硝酸盐水平测量，在人类白细胞中。用坎普他汀进行补体抑制显示 P-MAPA 诱导的补体激活驱动 C5aR 的调节，但不驱动 CD11b 的调节，表明 P-MAPA 通过补体依赖性和补体非依赖性机制起作用。Compstatin 还显着减少了过氧亚硝酸盐的产生。总之，我们的结果表明 P-MAPA 在人类白细胞中诱导促炎反应，这部分是由补体激活介导的。我们的数据有助于阐明 P-MAPA 的补体依赖性和补体非依赖性机制，最终导致免疫细胞激活及其在感染和癌症动物模型中的免疫调节特性。