METHODS: In this study, we have produced HLA DP401 and HLA DRA0101 humanized mice by microinjection of C57BL/6J zygotes. Neo-floxed IAβ+/- mice were crossbred with Ella-Cre and further crossbred with HLA DP401 or HLA-DRA0101 humanized mice. After several rounds of traditional crossbreeding, we finally obtained HLA DP401-IAβ-/- and HLA DRA-IAβ-/- humanized mice, in which human DP401 or DRA0101 molecule was introduced into IAβ-/- mice deficient in endogenous murine MHC class II molecules. A transnasal infection murine model of S. aureus pneumonia was induced in the humanized mice by administering 2 × 108 CFU of S. aureus Newman dropwise into the nasal cavity. The immune responses and histopathology changes were further assessed in lungs in these infected mice.
RESULTS: We evaluated the local and systemic effects of S. aureus delivered intranasally in HLA DP401-IAβ-/- and HLA DRA-IAβ-/- transgenic mice. S. aureus Newman infection significantly increased the mRNA level of IL 12p40 in lungs in humanized mice. An increase in IFN-γ and IL-6 protein was observed in HLA DRA-IAβ-/- mice. We observed a declining trend in the percentage of F4/80+ macrophages in lungs in HLA DP401-IAβ-/- mice and a decreasing ratio of CD4+ to CD8+ T cells in lungs in IAβ-/- mice and HLA DP401-IAβ-/- mice. A decreasing ratio of Vβ3+ to Vβ8+ T cells was also found in the lymph node of IAβ-/- mice and HLA DP401-IAβ-/- mice. S. aureus Newman infection resulted in a weaker pathological injury in lungs in IAβ-/- genetic background mice.
CONCLUSIONS: These humanized mice will be an invaluable mouse model to resolve the pathological mechanism of S. aureus pneumonia and study what role DP molecule plays in S. aureus infection.
方法:在本研究中,我们通过显微注射C57BL/6J受精卵产生了HLADP401和HLADRA0101人源化小鼠。将新漂浮的IAβ+/-小鼠与Ella-Cre杂交,并进一步与HLADP401或HLA-DRA0101人源化小鼠杂交。经过几轮传统杂交,我们最终获得了HLADP401-IAβ-/-和HLADRA-IAβ-/-人源化小鼠,其中将人DP401或DRA0101分子引入缺乏内源性鼠MHCII类分子的IAβ-/-小鼠中。通过将2×108CFU的金黄色葡萄球菌纽曼滴入鼻腔,在人源化小鼠中诱导金黄色葡萄球菌肺炎的经鼻感染鼠模型。在这些感染小鼠的肺中进一步评估免疫应答和组织病理学变化。
结果:我们评估了在HLADP401-IAβ-/-和HLADRA-IAβ-/-转基因小鼠中鼻内递送的金黄色葡萄球菌的局部和全身效应。金黄色葡萄球菌纽曼感染显著增加了人源化小鼠肺中IL12p40的mRNA水平。在HLA-DRA-IAβ-/-小鼠中观察到IFN-γ和IL-6蛋白的增加。我们观察到HLADP401-IAβ-/-小鼠肺中F4/80巨噬细胞的百分比呈下降趋势,而IAβ-/-小鼠和HLADP401-IAβ-/-小鼠肺中CD4与CD8T细胞的比例呈下降趋势。在IAβ-/-小鼠和HLADP401-IAβ-/-小鼠的淋巴结中还发现Vβ3与Vβ8T细胞的比率降低。金黄色葡萄球菌纽曼感染导致IAβ-/-遗传背景小鼠肺部病理损伤较弱。
结论:这些人源化小鼠将是解决金黄色葡萄球菌肺炎的病理机制和研究DP分子在金黄色葡萄球菌感染中的作用的无价小鼠模型。