Immunogenicity and protective efficacy of enterotoxigenic Escherichia coli (ETEC) total RNA against ETEC challenge in a mouse model

Abstract

Enterotoxigenic Escherichia coli (ETEC), an essential cause of post-weaning diarrhea (PWD) in piglets, leads to significant economic losses to the pig industry. The present study aims to identify the role of ETEC total RNA in eliciting immune responses to protect animals against ETEC infection. The results showed that the total RNA isolated from pig-derived ETEC K88ac strain effectively stimulated the IL-1β secretion of porcine intestinal epithelial cells (IPEC-J2). The mouse model immunized with ETEC total RNA via intramuscular injection (IM) or oral route (OR) was used to evaluate the protective efficiency of the ETEC total RNA. The results suggested that 70 μg ETEC total RNA administered by either route significantly promoted the production of the serum IL-1β and K88ac specific immunoglobulins (IgG, IgM, and IgA). Besides, the ETEC RNA administration augmented strong mucosal immunity by elevating K88ac specific IgA level in the intestinal fluid. Intramuscularly administered RNA induced a Th1/Th2 shift toward a Th2 response, while the orally administered RNA did not. The ETEC total RNA efficiently protected the animals against the ETEC challenge either by itself or as an adjuvant. The histology characterization of the small intestines also suggested the ETEC RNA administration protected the small intestinal structure against the ETEC infection. Particularly of note was that the immunity level and protective efficacy caused by ETEC RNA were dose-dependent. These findings will help understand the role of bacterial RNA in eliciting immune responses, and benefit the development of RNA-based vaccines or adjuvants.

Dual-Use Vaccine for Diarrhoeal Diseases: Cross-Protective Immunogenicity of a Cold-Chain-Free, Live-Attenuated, Oral Cholera Vaccine against Enterotoxigenic Escherichia coli (ETEC) Challenge in BALB/c Mice

“…These observations indicate that the immunised mice have elicited the anti-LT and anti-LT-B antibodies that hinder the LT and LT-B subunit of ETEC from binding to the GM1 ganglioside receptors on the epithelial cells of the intestine, preventing the endocytosis of LT into the cell. These observations are similar to those reported [51,52].…”

Whole Genome Sequencing and CRISPR/Cas9 Gene Editing of Enterotoxigenic Escherichia coli BE311 for Fluorescence Labeling and Enterotoxin Analyses

“…In searching for inhibitors against ETEC as antibiotic alternatives, some infection experimental models are often established based on the ETEC infection [ 51 , 52 , 53 ]. The decreased colonization and proliferation of ETEC in the gastrointestinal tract is a key aim in the control of pathogen infection, making in vivo ETEC tracking particularly important.…”

Iturin A Rescued STb-R-Induced Pork Skeletal Muscle Growth Restriction through the Hypothalamic-Pituitary-mTORC1 Growth Axis

“…On the one hand, STb-R invasion leads to inflammation, which modifies the secretion of hormones associated with the growth axis, since the concentration of IGF-1 and its synthesis in the liver decrease shortly after acute infection or endotoxin administration [ 25 , 26 ]. On the other hand, STb-R infection impedes nutrient absorption, thus decreasing the expression of the growth axis, and the destruction of the intestinal structure when challenged by ETEC also supports this view [ 21 , 27 ]. In general, our results demonstrate that Iturin A relieves the inhibitory effect of STb-R on the growth axis.…”