Hussen Jamal, Al-Sukruwah Mohammed Ali
Department of Microbiology, College of Veterinary Medicine, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
Animals (Basel). 2022 Jan 28;12(3):317. doi: 10.3390/ani12030317.
The dromedary camel () is an important livestock animal of desert and semi-desert ecosystems. In recent years, several elements of the camel immune system have been characterized. Stress and excitement induced by animal housing represent the most important environmental factors with potential modulatory effects on the immune system. The present study evaluated the impacts of a restricted-housing system on some phenotypic and functional properties of blood leukocytes in dromedary camels.
Immunofluorescence and flow cytometry were used to comparatively analyze samples collected from camels during a free-ranging time and samples collected from the same camels during movement-restricted housing.
In comparison to blood samples collected from the camels during the free-ranging time, samples from movement-restricted camels showed elevated serum myeloperoxidase activity, a significant shape-change in their neutrophils, and higher reactive oxygen species content in their monocytes and neutrophils, indicating increased cellular oxidative stress under movement-restricted housing. The leukogram pattern of the camels under restricted housing was characterized by leukocytosis with increased numbers of neutrophils, eosinophils, lymphocytes, and monocytes, resembling an excitement leukogram pattern. Within the lymphocyte population, only the helper T cells and B cells were expanded in animals under restricted housing. The upregulation of CD163 together with the downregulation of MHC-II on monocytes from excited camels indicate a modulatory potential of animal excitement to polarize monocytes toward an anti-inflammatory phenotype. Functional analysis of bacterial phagocytosis indicates an impaired antibacterial function of phagocytes in excited camels. The downregulation of several cell adhesion molecules on leukocytes from excited camels suggests a role for impaired cell adhesion and tissue migration and leukocyte retention in blood in the observed leukocytosis in animals under excitement.
The present study identified significant changes in blood immune cell composition, phenotype, and function in dromedary camels under restricted-housing conditions. The observed changes in leukocyte composition suggest the development of an excitement leukogram pattern in camels under movement-restricted housing. To evaluate the clinical relevance of the observed changes in immune cell phenotype and function for the immune competence of camels under restricted housing, further studies are required.
单峰骆驼（）是沙漠和半沙漠生态系统中的重要家畜。近年来，骆驼免疫系统的几个要素已得到表征。动物饲养引起的应激和兴奋是对免疫系统具有潜在调节作用的最重要环境因素。本研究评估了限制饲养系统对单峰骆驼血液白细胞某些表型和功能特性的影响。
采用免疫荧光和流式细胞术对骆驼在自由放养期间采集的样本和在行动受限饲养期间从同一骆驼采集的样本进行比较分析。
与在自由放养期间从骆驼采集的血液样本相比，行动受限骆驼的样本显示血清髓过氧化物酶活性升高，中性粒细胞形态发生显著变化，单核细胞和中性粒细胞中的活性氧含量更高，表明在行动受限饲养条件下细胞氧化应激增加。限制饲养条件下骆驼的白细胞计数模式特征为白细胞增多，中性粒细胞、嗜酸性粒细胞、淋巴细胞和单核细胞数量增加，类似于兴奋时的白细胞计数模式。在淋巴细胞群体中，只有辅助性T细胞和B细胞在限制饲养的动物中增多。兴奋骆驼单核细胞上CD163的上调以及MHC-II的下调表明动物兴奋具有将单核细胞极化为抗炎表型的调节潜力。细菌吞噬功能分析表明兴奋骆驼中吞噬细胞的抗菌功能受损。兴奋骆驼白细胞上几种细胞粘附分子的下调表明细胞粘附和组织迁移受损以及血液中白细胞滞留与观察到的兴奋动物白细胞增多有关。
本研究确定了限制饲养条件下单峰骆驼血液免疫细胞组成、表型和功能的显著变化。观察到的白细胞组成变化表明行动受限饲养的骆驼出现了兴奋时的白细胞计数模式。为了评估观察到的免疫细胞表型和功能变化对限制饲养条件下骆驼免疫能力的临床相关性，还需要进一步研究。
