Department of Poultry Sciences, The University of Georgia, Athens, Georgia, United States of America.
USDA-ARS, Poultry Microbiological Safety and Processing Research Unit, Athens, Georgia, United States of America.
PLoS One. 2021 Mar 15;16(3):e0247080. doi: 10.1371/journal.pone.0247080. eCollection 2021.
Campylobacter is one of the major foodborne pathogens causing bacterial gastroenteritis worldwide. The immune response of broiler chickens to C. jejuni is under-researched. This study aimed to characterize the immune response of chickens to Campylobacter jejuni colonization. Birds were challenged orally with 0.5 mL of 2.4 x 108 CFU/mL of Campylobacter jejuni or with 0.5 mL of 0.85% saline. Campylobacter jejuni persisted in the ceca of challenged birds with cecal colonization reaching 4.9 log10 CFU/g on 21 dpi. Campylobacter was disseminated to the spleen and liver on 7 dpi and was cleared on 21 dpi from both internal organs. Challenged birds had a significant increase in anti-Campylobacter serum IgY (14&21 dpi) and bile IgA (14 dpi). At 3 dpi, there was a significant suppression in T-lymphocytes derived from the cecal tonsils of birds in the challenge treatment when compared to the control treatment after 72 h of ex vivo stimulation with Con A or C. jejuni. The T-cell suppression on 3 dpi was accompanied by a significant decrease in LITAF, K60, CLAU-2, IL-1β, iNOS, and IL-6 mRNA levels in the ceca and an increase in nitric oxide production from adherent splenocytes of challenged birds. In addition, on 3 dpi, there was a significant increase in CD4+ and CD8+ T lymphocytes in the challenge treatment. On 14 dpi, both pro and anti-inflammatory cytokines were upregulated in the spleen, and a significant increase in CD8+ T lymphocytes in Campylobacter-challenged birds' ceca was observed. The persistence of C. jejuni in the ceca of challenged birds on 21 dpi was accompanied by an increase in IL-10 and LITAF mRNA levels, an increase in MNC proliferation when stimulated ex-vivo with the diluted C. jejuni, an increase in serum specific IgY antibodies, an increase in both CD4+ and CD8+ cells, and a decrease in CD4+:CD8+ cell ratio. The balanced Th1 and Th2 immune responses against C. jejuni might explain the ceca's bacterial colonization and the absence of pathology in Campylobacter-challenged birds. Future studies on T lymphocyte subpopulations should elucidate a pivotal role in the persistence of Campylobacter in the ceca.
空肠弯曲菌是引起全球细菌性肠胃炎的主要食源性病原体之一。家禽对空肠弯曲菌的免疫反应研究较少。本研究旨在描述鸡对空肠弯曲菌定植的免疫反应。鸡经口攻毒 0.5 mL 浓度为 2.4 x 108 CFU/mL 的空肠弯曲菌或 0.5 mL 0.85%生理盐水。攻毒后 21 天，空肠弯曲菌持续定植于盲肠，盲肠中细菌载量达到 4.9 log10 CFU/g。攻毒后 7 天，空肠弯曲菌传播至脾脏和肝脏，并于 21 天从这两个内脏器官中清除。攻毒鸡血清抗空肠弯曲菌 IgY（14 天和 21 天）和胆汁 IgA（14 天）显著增加。攻毒后 3 天，与对照组相比，攻毒组鸡的回肠扁桃体 T 淋巴细胞在 ConA 或 C. jejuni 体外刺激 72 小时后显著减少。3 天时，T 细胞的抑制伴随着盲肠组织中 LITAF、K60、CLAU-2、IL-1β、iNOS 和 IL-6 mRNA 水平的显著下降，以及攻毒鸡粘附性脾细胞中一氧化氮的产生增加。此外，攻毒后 3 天，攻毒组 CD4+和 CD8+T 淋巴细胞数量显著增加。14 天时，脾脏中促炎和抗炎细胞因子均上调，同时观察到攻毒组鸡盲肠中 CD8+T 淋巴细胞数量显著增加。21 天时，攻毒组鸡盲肠中 C. jejuni 的持续存在伴随着 IL-10 和 LITAF mRNA 水平的增加，当用稀释的 C. jejuni 体外刺激时，MNC 增殖增加，血清特异性 IgY 抗体增加，CD4+和 CD8+细胞增加，CD4+:CD8+细胞比值降低。针对 C. jejuni 的平衡 Th1 和 Th2 免疫反应可能解释了盲肠的细菌定植和空肠弯曲菌攻毒鸡无病变的原因。未来对 T 淋巴细胞亚群的研究应阐明其在空肠弯曲菌盲肠定植中的关键作用。
