Successful sperm maturation and storage relies on a unique immunological balance that protects the male reproductive organs from invading pathogens, and spermatozoa from a destructive autoimmune response. We previously characterized one subset of mononuclear phagocytes (MPs) in the murine epididymis- CX3CR1⁺ cells, emphasizing their different functional properties. This population partially overlaps with another subset of understudied heterogenous MPs: the CD11c⁺ cells. In the current study, we analyzed the CD11c⁺ MPs for their immune phenotype, morphology, and antigen capturing and presenting abilities. Epididymides from CD11c-EYFP mice, which express EYFP in CD11c⁺ MPs, were divided into initial segment (IS), caput/corpus, and cauda regions. Flow cytometry analysis showed that CD11c⁺ MPs with a macrophage phenotype (CD64⁺ and F4/80⁺) were the most abundant in the IS, while those with a dendritic cell signature (CD64^-MHCII⁺) were more frequent in the cauda. Immunofluorescence revealed morphological and phenotypic differences between CD11c⁺ MPs in the regions examined. To assess the ability of CD11c⁺ cells to take up antigens, CD11c-EYFP mice were injected intravenously with ovalbumin. In the IS, MPs expressing macrophage markers were most active in taking up the antigens. A functional antigen-presenting co-culture study was performed, whereby CD4⁺ T-cells were activated following ovalbumin presentation by CD11c⁺ epididymal MPs. The results demonstrated that CD11c⁺ MPs in all regions were capable of capturing and presenting antigens. Together, this study defines a marked regional variation in epididymal antigen presenting cells that could help to understand fertility and contraception, but also has larger implications in inflammation and disease pathology.

中文翻译：

---

从初始节段到尾部：基于免疫表型和功能的小鼠附睾 CD11c+ 单核吞噬细胞的区域表征

成功的精子成熟和储存依赖于独特的免疫平衡，保护男性生殖器官免受病原体入侵，并保护精子免受破坏性自身免疫反应。我们之前对小鼠附睾-CX3CR1 ⁺细胞中的一个单核吞噬细胞 (MPs) 子集进行了表征，强调了它们不同的功能特性。该群体与另一个未充分研究的异源 MPs 子集部分重叠：CD11c ⁺细胞。在目前的研究中，我们分析了 CD11c ⁺ MP 的免疫表型、形态以及抗原捕获和呈递能力。^{来自 CD11c-EYFP 小鼠的附睾，在 CD11c +}中表达 EYFPMPs 分为初始段 (IS)、头/语料库和马尾区域。流式细胞术分析表明，具有巨噬细胞表型（CD64 ⁺和 F4/80 ^{+ ）的 CD11c +} MP在 IS 中最丰富，而具有树突细胞特征（CD64 ^- MHCII ⁺）的那些在马尾中更常见。^{免疫荧光揭示了所检查区域中 CD11c +} MP之间的形态学和表型差异。评估 CD11c ^+的能力细胞摄取抗原，CD11c-EYFP 小鼠静脉内注射卵白蛋白。在 IS 中，表达巨噬细胞标记的 MP 在吸收抗原方面最为活跃。进行了一项功能性抗原呈递共培养研究，其中 CD4 ^{+ T 细胞在 CD11c +}附睾 MPs呈递卵白蛋白后被激活。结果表明，所有区域的 CD11c ⁺ MPs 都能够捕获和呈递抗原。总之，这项研究确定了附睾抗原呈递细胞的显着区域差异，这可能有助于了解生育力和避孕措施，但对炎症和疾病病理学也有更大的影响。