Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK.
Department of Evolutionary Zoology and Human Biology, University of Debrecen, Debrecen, Hungary.
Sci Rep. 2021 Jan 14;11(1):1349. doi: 10.1038/s41598-020-80030-9.
Whilst the immune system often varies seasonally and exhibits differences between males and females, the general patterns in seasonality and sex differences across taxa have remained controversial. Birds are excellent model organisms to assess these patterns, because the immune system of many species is well characterised. We conducted a meta-analysis using 41 wild bird species from 24 avian families to investigate sex differences and seasonal (breeding/non-breeding) variations in immune status, including white blood cell counts, phytohaemagglutinin (PHA) test, bacteria-killing ability (BKA), haemolysis and haemagglutination assays. We found male-biased macrophage concentration, BKA and haemolysis titers, but only during the breeding season. Sex-specific heterophil concentrations, heterophil/lymphocyte ratios and PHA responses differed between breeding and non-breeding, suggesting larger changes in males than in females. Importantly, sex differences in immune status are stronger during the breeding period than during the non-breeding period. Taken together, our study suggests that both seasonal variation and sex differences in immune system are common in birds, although their associations are more complex than previously thought.
虽然免疫系统通常具有季节性变化，并存在性别差异，但在分类群中季节性和性别差异的一般模式仍然存在争议。鸟类是评估这些模式的极好的模式生物，因为许多物种的免疫系统特征明显。我们使用 24 个鸟类科的 41 种野生鸟类进行了荟萃分析，以研究免疫状态的性别差异和季节性（繁殖/非繁殖）变化，包括白细胞计数、植物血凝素（PHA）试验、杀菌能力（BKA）、溶血和血凝试验。我们发现，在繁殖季节，巨噬细胞浓度、BKA 和溶血效价存在雄性偏倚，但仅在繁殖季节存在。在繁殖和非繁殖期间，嗜中性粒细胞浓度、嗜中性粒细胞/淋巴细胞比值和 PHA 反应存在性别特异性差异，表明雄性的变化大于雌性。重要的是，在繁殖期，免疫状态的性别差异比非繁殖期更强。总之，我们的研究表明，鸟类的免疫系统既存在季节性变化，也存在性别差异，尽管它们的关联比以前认为的更为复杂。
