However, the number of affected glomeruli was slightly lower in immunized mice ( Figure?8E ). and STEC O91:H21 strains and were protected against weight loss during experimental contamination. Additionally, contamination with the STEC O91:H21 strain resulted in kidney damage in control unimmunized mice; however, the extent of damage was slightly lower in immunized mice. Our findings suggest that IgG antibodies induced by this vaccine candidate may have a role in inhibiting bacterial adhesion and complement-mediated killing. Conclusion This study provides evidence that IgG responses are involved in the host defense against STEC. However, our results do not rule out that other classes of antibodies also participate in the protection against this pathogen. Additional work is needed to improve the protection conferred by our vaccine candidate and to elucidate the relevant immune responses that lead to complete AG-1478 (Tyrphostin AG-1478) protection against this pathogen. Keywords: Shiga toxin-producing (STEC) are a group of foodborne pathogens that cause diarrhea and dysentery. In some cases, these infections can lead to more severe and potentially deadly complications, such as Hemolytic Uremic Syndrome (HUS), mainly in children under AG-1478 (Tyrphostin AG-1478) 5 years old and the elderly (1). STEC is commonly found in the intestines of ruminant animals, such as cattle and sheep, and can contaminate food products derived from these animals (2). Through the fecal excretion of these animals, STEC can contaminate other food products such as vegetables, fruits, and water sources. As a result, STEC outbreaks are associated with contaminated food, affecting public health and the food industry (3). Globally, O157:H7 is the most common serotype of STEC associated with cases of HUS. The main virulence factor of STEC is the Shiga toxin (Stx). During contamination, this toxin can spread systemically and cause damage to the kidneys and central nervous system, leading to HUS (4). Adhesion and colonization of the intestine are key actions in STEC contamination. A group of STEC strains, formerly called enterohemorrhagic (EHEC), harbor the pathogenicity island (PAI) called Locus of Enterocyte Effacement (LEE) (5). These strains are currently called LEE-positive STEC to differentiate them from other STEC strains that lack LEE (LEE-negative) (6). One of the genes located in the LEE PAI is the gene, which encodes Intimin, a non-fimbrial adhesin considered the main factor mediating the adherence of these bacteria (7). Additionally, the LEE PAI encodes the type three secretion system (T3SS), which facilitates the translocation of multiple proteins into the enterocytes. These proteins include the translocated intimin receptor (Tir) and other virulence factors that induce architectural and physiological changes in the intestinal epithelial cells through signal transduction mechanisms (1, 8). Adhesion mediated by the LEE PAI results in the attaching and effacement (A/E) lesion, characterized by a rearrangement of the cytoskeleton and the production of a pedestal-like structure at the site of bacterial attachment. This leads to the loss of intestinal microvilli, AG-1478 (Tyrphostin AG-1478) inflammation, and diarrhea (9C11). The LEE PAI is also carried by enteropathogenic (EPEC) and the murine pathogen modeling of chimeric proteins involved the prediction of B-cell epitopes using several tools available at the Immune Epitope Database (IEDB) server (41). These tools included BepiPred 2.0 (42) with a threshold value set at 0.5, and the Kolaskar and Tongaonker antigenicity method (43) with a threshold value of 1 1.0 and a window size of 7. Additionally, prediction of peptides binding to MHC-II molecules was performed AG-1478 (Tyrphostin AG-1478) using the NetMHCIIpan 4.1 method (44). For this, a set of seven human HLA-DR alleles were analyzed: HLA-DRB1*03:01, HLA-DRB1*07:01, HLA-DRB1*15:01, HLA-DRB3*01:01, HLA-DRB3*02:02, HLA-DRB4*01:01, HLA-DRB5*01:01. The default parameter of an epitope length of 15 amino acids was AG-1478 (Tyrphostin AG-1478) defined. The predicted three-dimensional structure of Chimera 3 (Chi3) and Chimera 4 (Chi4) was constructed using RaptorX (45) and Phyre2 (using intensive modelling mode) SPTAN1 (46). The quality evaluation and validation of the models were performed using RAMPAGE (47) and PROSA-web (48). The chemical and physical properties of the chimeric proteins were predicted using Protein-Sol (49) and ProtParam.