Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
BMC Vet Res. 2014 Apr 2;10:79. doi: 10.1186/1746-6148-10-79.
Endogamy increases the risk of manifestation of deleterious recessive genes. Mitochondrial DNA allows the separation of American Zebu (Bos indicus and Bos taurus) and evaluate the effect of mitochondrial DNA on productive traits of cattle. However, the effect of endogamy and mitochondrial DNA (mtDNA) on the immune system remains unclear. The aim of this study was to evaluate the association between endogamy, mtDNA and immune parameters.
A total of 86 cattle (43 cows and 43 calves) were used in this study. Age, endogamy, milk yield, and origin of mtDNA were measured and their influence on immunological parameters was evaluated. Older cows had increased CD4+ T cells, decreased CD21+ and γδhigh T cells as well as increased CD4+/CD8+ and T/B ratio. Multiple regression analysis indicated that endogamy in calves was associated with increased CD8+ T and CD21+ B lymphocytes, and decreased γδhigh T cells in peripheral blood. Cows with medium and lower endogamy had a lower percentage of B lymphocytes and γδlow T cells and cows with lower endogamy had higher levels of γδ T cells and γδhigh T cells, as well as the CD4+/CD48+ cell ratio. Calves with higher endogamy had higher levels of CD8+ T lymphocytes, whereas calves with lower endogamy had lower levels of γδlow T cells.
These results demonstrated for the first time that endogamy influences the immune system of cattle.
同系交配会增加有害隐性基因表现的风险。线粒体 DNA 可用于分离美亚牛（Bos indicus 和 Bos taurus），并评估线粒体 DNA 对牛生产性状的影响。然而，同系交配和线粒体 DNA（mtDNA）对免疫系统的影响尚不清楚。本研究旨在评估同系交配、mtDNA 与免疫参数之间的关系。
本研究共使用了 86 头牛（43 头母牛和 43 头小牛）。测量了年龄、同系交配、产奶量和 mtDNA 的来源，并评估了它们对免疫参数的影响。年龄较大的奶牛 CD4+T 细胞增加，CD21+和 γδhigh T 细胞减少，CD4+/CD8+和 T/B 比值增加。多元回归分析表明，小牛的同系交配与外周血中 CD8+T 和 CD21+B 淋巴细胞增加以及 γδhigh T 细胞减少有关。中低同系交配的奶牛 B 淋巴细胞和 γδlow T 细胞比例较低，而低同系交配的奶牛 γδ T 细胞和 γδhigh T 细胞以及 CD4+/CD48+细胞比例较高。同系交配较高的小牛 CD8+T 淋巴细胞水平较高，而同系交配较低的小牛 γδlow T 细胞水平较低。
这些结果首次表明，同系交配会影响牛的免疫系统。
