Alhafiz Gader Abdulaziz, Alghatam Fatema Hassan, Almohammed Hams, Hussen Jamal
Department of Microbiology, College of Veterinary Medicine, King Faisal University, Al-Ahsa, Saudi Arabia.
Front Vet Sci. 2022 Apr 14;9:885523. doi: 10.3389/fvets.2022.885523. eCollection 2022.
Mastitis represents one of the most important infectious diseases in camels with heavy economic losses due to reduced milk quantity and quality. Balanced immune cell composition and function in the mammary gland are essential for effective immune response to mastitis pathogens. The objective of the present study was to characterize the cellular immune response to subclinical mastitis in the mammary gland of dromedary camels. Therefore, immunostaining and flow cytometry were used to compare the cellular composition, leukocyte phenotype, and cell viability in camel milk from healthy she-camels ( = 8) and she-camels with subclinical mastitis (SCM; = 6). In addition, the phagocytic activity of milk phagocytes was compared between healthy and affected animals. The health status of the mammary gland was evaluated based on the California Mastitis Test (CMT) score. SCM (CMT score of ≥3 in the absence of clinical signs of mastitis) was found in six of the 56 sampled quarters (10.7 %) with only one affected quarter per animal. In comparison to milk from healthy camels, milk from SCM animals showed higher somatic cell count (SCC), higher numbers of CD45+ leukocytes with an expanded fraction of CD172a+ myeloid cells. Within the myeloid cell population, there was an increase in the percentage of granulocytes (CD172aCD14) with a decreased percentage of macrophages (CD172aCD14) in milk from affected animals compared to healthy animals. The decrease in lymphoid cells in SCM milk was mainly due to the decreased fraction of CD4+ helper T cells. Camel SCM was also associated with a stimulated phenotype, increased cell viability, and enhanced phagocytic activity of the milk phagocytes, macrophages and granulocytes. Collectively, the present study identified significant changes in SCC, leukocyte count, phenotype, viability, and function in association with subclinical mastitis in camels. The results of the present study support a better understanding of host-pathogen interaction mechanisms in the camel mammary gland.
乳腺炎是骆驼最重要的传染病之一，由于产奶量和质量下降而造成巨大经济损失。乳腺中平衡的免疫细胞组成和功能对于有效抵抗乳腺炎病原体的免疫反应至关重要。本研究的目的是表征单峰骆驼乳腺对亚临床乳腺炎的细胞免疫反应。因此，采用免疫染色和流式细胞术比较了健康母骆驼（n = 8）和患有亚临床乳腺炎（SCM；n = 6）的母骆驼的骆驼奶中的细胞组成、白细胞表型和细胞活力。此外，还比较了健康动物和患病动物乳汁吞噬细胞的吞噬活性。根据加利福尼亚乳腺炎检测（CMT）评分评估乳腺的健康状况。在56个采样乳腺中，有6个（10.7%）发现患有SCM（在无乳腺炎临床症状的情况下CMT评分为≥3），每只动物只有一个受影响的乳腺。与健康骆驼的奶相比，SCM动物的奶显示出更高的体细胞计数（SCC）、更多的CD45 +白细胞以及CD172a +髓样细胞比例增加。在髓样细胞群体中，与健康动物相比，患病动物奶中粒细胞（CD172aCD14）百分比增加，巨噬细胞（CD172aCD14）百分比降低。SCM奶中淋巴细胞的减少主要是由于CD4 +辅助性T细胞比例降低。骆驼SCM还与刺激的表型、增加的细胞活力以及乳汁吞噬细胞、巨噬细胞和粒细胞增强的吞噬活性有关。总体而言，本研究确定了与骆驼亚临床乳腺炎相关的SCC、白细胞计数、表型、活力和功能的显著变化。本研究结果有助于更好地理解骆驼乳腺中宿主 - 病原体相互作用机制。
