The balance of myeloid populations and lymphoid populations must be well controlled. Here we found that osteopontin (OPN) skewed this balance during pathogenic conditions such as infection and autoimmunity. Notably, two isoforms of OPN exerted distinct effects in shifting this balance through cell-type-specific regulation of apoptosis. Intracellular OPN (iOPN) diminished the population size of myeloid progenitor cells and myeloid cells, and secreted OPN (sOPN) increase the population size of lymphoid cells. The total effect of OPN on skewing the leukocyte population balance was observed as host sensitivity to early systemic infection with Candida albicans and T cell-mediated colitis. Our study suggests previously unknown detrimental roles for two OPN isoforms in causing the imbalance of leukocyte populations.

中文翻译：

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分泌的和细胞内的骨桥蛋白使淋巴样细胞和髓样细胞的群体平衡发生倾斜。

骨髓和淋巴样群体的平衡必须得到良好控制。在这里，我们发现骨桥蛋白（OPN）在诸如感染和自身免疫之类的致病性条件下会扭曲这种平衡。值得注意的是，OPN的两种同工型通过细胞凋亡的细胞类型特异性调节，在改变这种平衡方面发挥了独特的作用。细胞内OPN（iOPN）减少了髓样祖细胞和髓样细胞的种群大小，而分泌的OPN（sOPN）增加了淋巴样细胞的种群大小。观察到OPN扭曲白细胞种群平衡的总体效果是宿主对白色念珠菌和T细胞介导的结肠炎的早期全身感染的敏感性。我们的研究表明，先前未知的两种OPN亚型在导致白细胞种群失衡方面的有害作用。