Department of Dermatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 West Yanjiang Rd., Guangzhou, 510120, China.
Mycopathologia. 2013 Aug;176(1-2):11-22. doi: 10.1007/s11046-013-9650-3. Epub 2013 May 4.
Penicillium marneffei is a pathogenic fungus that can cause a life-threatening systemic mycosis in the immunocompromised hosts. We established the model for the phagocytosis of P. marneffei conidia by RAW264.7 murine macrophages and designated the fate of P. marneffei in RAW264.7 cells with respect to persistence, phagosome-lysosome-fusion. And we impaired the immune status of mouse and compared the fate and phagosome-lysosome-fusion of P. marneffei in immunocompetent and immunosuppressed mouse peritoneal macrophages cells. We found that conidia could germinate and survive in macrophages. Within 30 min and up to 2 h of heat-killed conidia internalization, the majority of all phagosome types were labeled for the EEA1 (endosomal markers) and LAMP-1 (lysosomal markers), respectively. But both the percentages of LAMP-1 and EEA1 that associated with live conidia were significantly lower than that with heat-killed conidia. Administration of cyclophosphamide resulted in a significant suppression of macrophages function (phagocytic and fungicidal) against P. marneffei that were not apparently seen. Our data provide the evidence that (i) intracellular conversion of P. marneffei conidia into yeast cells still could be observed in macrophages. (ii) Phagosomes containing live Penicillium marneffei conidia might inhibit the phagosome-lysosome-fusion and result to no acidification surrounding the organisms. (iii) Immunity impaired by cyclophosphamide could not influence the function, including phagocytosis, fungicidal activity and phagosome-lysosome-fusion, of macrophages against P. marneffei.
马尔尼菲青霉是一种致病性真菌，可在免疫功能低下的宿主中引起危及生命的系统性真菌感染。我们建立了 RAW264.7 鼠巨噬细胞吞噬马尔尼菲青霉分生孢子的模型，并确定了马尔尼菲青霉在 RAW264.7 细胞中的生存、吞噬体-溶酶体融合情况。我们削弱了小鼠的免疫状态，并比较了免疫功能正常和免疫抑制小鼠腹腔巨噬细胞中马尔尼菲青霉的命运和吞噬体-溶酶体融合情况。我们发现分生孢子可以在巨噬细胞中发芽和存活。在热灭活分生孢子内化后的 30 分钟内，所有吞噬体类型的大部分均标记为 EEA1（内体标记物）和 LAMP-1（溶酶体标记物）。但是与热灭活分生孢子相比，与活分生孢子相关的 LAMP-1 和 EEA1 的百分比均明显较低。环磷酰胺的给药导致巨噬细胞对马尔尼菲青霉的吞噬和杀菌功能受到显著抑制，但这种抑制并不明显。我们的数据提供了以下证据：（i）在巨噬细胞中仍可以观察到马尔尼菲青霉分生孢子向酵母细胞的体内转化。（ii）含有活的青霉菌分生孢子的吞噬体可能抑制吞噬体-溶酶体融合，导致周围的生物体无法酸化。（iii）环磷酰胺引起的免疫功能受损不能影响巨噬细胞对马尔尼菲青霉的功能，包括吞噬、杀菌活性和吞噬体-溶酶体融合。
