Yellow River carp (Cyprinus carpio) is an economically-important freshwater fish. It is the common host of the epizootic bacterium Flavobacterium columnare, a common fish pathogen that causes columnaris disease resulting in aquacultural losses. However, information on the functions and mechanisms of the immune system of Yellow River carp infected with F. columnare is limited. Therefore, the aim of this study is to evaluate the genetic and histopathological effects of an experimentally-induced F. columnare infection in Yellow River carp. Sixty fish were divided into control (CT group) and challenged groups. The gills were collected for histological and transcriptome analysis to understand the host immune response after challenge with F. columnare. The infected fish of the IF group presented typical columnaris disease symptoms and higher mortality, as well as histological changes. However, some challenged fish showed asymptomatic infection (IC group). Additionally, there were 1776 significant differentially-expressed genes (DEGs) between the IC and CT groups, 1853 DEGs between the IF and CT groups, and 1836 DEGs between the IF and IC groups, All the DEGs were classified into three gene ontology categories, which were allocated to 158 KEGG pathways. Moreover, immune-related genes were confirmed by qRT-PCR. we quantified the level of IL-1, IL-6, TNF-α and IL-8 by ELISA. The results showed the highest expression levels of inflammatory cytokines as well as stress proteins and the adhesion molecules in the lF group, which may contribute to severe infection, and a higher case fatality rate, while the high expression of chemokines, costimulatory molecules and the up regulation of antigen presentation function could help the carp resist F. columnare infection.

黄河鲤鱼（Cyprinus carpio）是一种重要的经济淡水鱼类。它是流行性细菌柱状黄杆菌的常见宿主，柱状黄杆菌是一种常见的鱼类病原体，可引起柱状病，导致水产养殖损失。然而，关于感染F. columnare的黄河鲤的免疫系统的功能和机制的信息是有限的。因此，本研究的目的是评估实验诱导的黄河鲤鱼中F. columnare感染的遗传和组织病理学影响。60 条鱼分为对照组（CT 组）和攻击组。收集鳃进行组织学和转录组分析，以了解用F. 柱状. IF组的感染鱼表现出典型的柱状鱼病症状和较高的死亡率，以及组织学变化。然而，一些受攻击的鱼表现出无症状感染（IC 组）。此外，IC组和CT组之间有1776个显着差异表达基因（DEGs），IF组和CT组之间有1853个DEGs，IF和IC组之间有1836个DEGs，所有DEGs被分为三个基因本体类别，分配给 158 个 KEGG 通路。此外，免疫相关基因通过 qRT-PCR 得到证实。我们通过ELISA量化了IL-1、IL-6、TNF-α和IL-8的水平。结果显示，lF 组中炎症细胞因子以及应激蛋白和粘附分子的表达水平最高，这可能导致严重感染，并且病死率更高，F.柱状感染。