背景:金黄色葡萄球菌可通过在“携带者”或“致病性”状态下分泌许多超抗原外毒素而引起严重感染。HLADQ和HLADR人源化小鼠已被用作小动物模型来研究两种分子在金黄色葡萄球菌感染期间的作用。然而,HLA-DP对金黄色葡萄球菌感染的影响尚不清楚.
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。
Staphylococcus aureus can cause serious infections by secreting many superantigen exotoxins in \"carrier\" or \"pathogenic\" states. HLA DQ and HLA DR humanized mice have been used as a small animal model to study the role of two molecules during S. aureus infection. However, the contribution of HLA DP to S. aureus infection is unknown yet.
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.
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.
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.