Zwollo Patty, Ray Jocelyn C, Sestito Michael, Kiernan Elizabeth, Wiens Gregory D, Kaattari Steve, StJacques Brittany, Epp Lidia
Department of Biology, The College of William and Mary, Williamsburg, VA 23185, USA.
Department of Biology, The College of William and Mary, Williamsburg, VA 23185, USA.
Dev Comp Immunol. 2015 Jan;48(1):1-12. doi: 10.1016/j.dci.2014.07.018. Epub 2014 Aug 4.
Bacterial cold water disease (BCWD) is a chronic disease of rainbow trout, and is caused by the Gram-negative bacterium Flavobacterium psychrophilum (Fp), a common aquaculture pathogen. The National Center for Cool and Cold Water Aquaculture has bred two genetic lines of rainbow trout: a line of Fp-resistant trout (ARS-Fp-R or R-line trout) and a line of susceptible trout (ARS-Fp-S, or S-line). Little is known about how phenotypic selection alters immune response parameters or how such changes relate to genetic disease resistance. Herein, we quantify interindividual variation in the distribution and abundance of B cell populations (B cell signatures) and examine differences between genetic lines of naive animals. There are limited trout-specific cell surface markers currently available to resolve B cell subpopulations and thus we developed an alternative approach based on detection of differentially expressed transcription factors and intracellular cytokines. B cell signatures were compared between R-line and S-line trout by flow cytometry using antibodies against transcription factors early B cell factor-1 (EBF1) and paired domain box protein Pax5, the pro-inflammatory cytokine IL-1β, and the immunoglobulin heavy chain mu. R-line trout had higher percentages of EBF(+) B myeloid/ progenitor and pre-B cells in PBL, anterior and posterior kidney tissues compared to S-line trout. The opposite pattern was detected in more mature B cell populations: R-line trout had lower percentages of both IgM(+) mature B cells and IgM-secreting cells in anterior kidney and PBL compared to S-line trout. In vitro LPS-activation studies of PBL and spleen cell cultures revealed no significant induction differences between R-line and S-line trout. Together, our findings suggest that selective resistance to BCWD may be associated with shifts in naive animal developmental lineage commitment that result in decreased B lymphopoiesis and increased myelopoiesis in BCWD resistant trout relative to susceptible trout.
细菌性冷水病（BCWD）是虹鳟鱼的一种慢性疾病，由革兰氏阴性菌嗜冷黄杆菌（Fp）引起，Fp是一种常见的水产养殖病原体。国家冷水与冷水水产养殖中心培育了两个虹鳟鱼遗传品系：一个Fp抗性品系的虹鳟鱼（ARS-Fp-R或R系虹鳟）和一个易感品系的虹鳟鱼（ARS-Fp-S，或S系）。关于表型选择如何改变免疫反应参数，以及这些变化与遗传抗病性有何关系，目前所知甚少。在此，我们量化了B细胞群体分布和丰度的个体间差异（B细胞特征），并研究了未接触病原体动物遗传品系之间的差异。目前可用于区分B细胞亚群的虹鳟鱼特异性细胞表面标志物有限，因此我们基于检测差异表达的转录因子和细胞内细胞因子开发了一种替代方法。通过流式细胞术，使用抗转录因子早期B细胞因子-1（EBF1）和配对结构域盒蛋白Pax5、促炎细胞因子IL-1β以及免疫球蛋白重链μ的抗体，比较了R系和S系虹鳟的B细胞特征。与S系虹鳟相比，R系虹鳟外周血白细胞（PBL）、前肾和后肾组织中EBF(+) B髓样/祖细胞和前B细胞的百分比更高。在更成熟的B细胞群体中检测到相反的模式：与S系虹鳟相比，R系虹鳟前肾和PBL中IgM(+)成熟B细胞和IgM分泌细胞的百分比均较低。PBL和脾细胞培养物的体外脂多糖（LPS）激活研究显示，R系和S系虹鳟之间没有显著的诱导差异。总之，我们的研究结果表明，对BCWD的选择性抗性可能与未接触病原体动物发育谱系定向的转变有关，相对于易感虹鳟，这种转变导致抗性虹鳟的B淋巴细胞生成减少，髓细胞生成增加。
