CEACAM1 Activation by CbpF-Expressing E. coli

Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed its presence and involvement in colorectal, esophageal and breast cancer. We previously demonstrated that F. nucleatum binds and activates the human inhibitory receptors TIGIT and CEACAM1 leading to inhibition of T and NK cell anti-tumor immunity. CEACAM1 was found to be bound and activated by the fusobacterial trimeric autotransporter adhesin CbpF. Here we report the generation of a recombinant E. coli expressing full-length CbpF that efficiently binds and activates CEACAM1.

A sticky bacterium versus antiadhesive surfaces: The adhesion preference of bacteria expressing trimeric autotransporter adhesin

<p>The COVID-19 pandemic caused by a virus has been posing a global threat to humanity and human society. It reminded us of the horror of infectious diseases. Pathogenic bacteria also cause infectious disease, but bacteria are not as much of a threat as viruses because antibiotics are effective against them. This is changing, however, with the emergence of antibiotic-resistant bacteria. The global expansion of multidrug-resistant bacteria has become a clinical problem, and the threat of bacterial infection would come back in the near future. The overuse of antibiotics amplifies the opportunity for resistant bacteria to emerge and spread. The increased antibiotic use during this COVID-19 pandemic could also increase the threat of resistant bacteria. As an alternative to antibiotics, antibiofouling surfaces have drawn intensive research interest and have been developed. <i>Acinetobacter</i> sp. Tol 5 exhibits high adhesiveness to various surfaces through AtaA, a member of the trimeric autotransporter adhesin (TAA) family. We examined the adhesion of Tol 5 and other bacteria expressing different TAAs to antiadhesive surfaces. The results highlighted Tol 5’s stickiness through AtaA, which enables cells to adhere even to antiadhesive materials including polytetrafluoroethylene with a low surface free energy, a hydrophilic polymer brush exerting steric hindrance, and mica with an ultrasmooth surface. Tol 5 cells also adhered to a zwitterionic 2-methacryloyloxyethyl-phosphorylcholine-polymer-coated surface but were exfoliated by a weak shear stress, suggesting that exchangeable bound water molecules contribute to AtaA’s interaction with materials.</p>

A sticky bacterium versus antiadhesive surfaces: The adhesion preference of bacteria expressing trimeric autotransporter adhesin

<p>The COVID-19 pandemic caused by a virus has been posing a global threat to humanity and human society. It reminded us of the horror of infectious diseases. Pathogenic bacteria also cause infectious disease, but bacteria are not as much of a threat as viruses because antibiotics are effective against them. This is changing, however, with the emergence of antibiotic-resistant bacteria. The global expansion of multidrug-resistant bacteria has become a clinical problem, and the threat of bacterial infection would come back in the near future. The overuse of antibiotics amplifies the opportunity for resistant bacteria to emerge and spread. The increased antibiotic use during this COVID-19 pandemic could also increase the threat of resistant bacteria. As an alternative to antibiotics, antibiofouling surfaces have drawn intensive research interest and have been developed. <i>Acinetobacter</i> sp. Tol 5 exhibits high adhesiveness to various surfaces through AtaA, a member of the trimeric autotransporter adhesin (TAA) family. We examined the adhesion of Tol 5 and other bacteria expressing different TAAs to antiadhesive surfaces. The results highlighted Tol 5’s stickiness through AtaA, which enables cells to adhere even to antiadhesive materials including polytetrafluoroethylene with a low surface free energy, a hydrophilic polymer brush exerting steric hindrance, and mica with an ultrasmooth surface. Tol 5 cells also adhered to a zwitterionic 2-methacryloyloxyethyl-phosphorylcholine-polymer-coated surface but were exfoliated by a weak shear stress, suggesting that exchangeable bound water molecules contribute to AtaA’s interaction with materials.</p>

A Sticky Bacterium Versus Antiadhesive Surfaces

<p>The COVID-19 pandemic caused by a virus has been posing a global threat to humanity and human society. It reminded us of the horror of infectious diseases. Pathogenic bacteria also cause infectious disease, but bacteria are not as much of a threat as viruses because antibiotics are effective against them. This is changing, however, with the emergence of antibiotic-resistant bacteria. The global expansion of multidrug-resistant bacteria has become a clinical problem, and the threat of bacterial infection would come back in the near future. The overuse of antibiotics amplifies the opportunity for resistant bacteria to emerge and spread. The increased antibiotic use during this COVID-19 pandemic could also increase the threat of resistant bacteria. As an alternative to antibiotics, antibiofouling surfaces have drawn intensive research interest and have been developed. <i>Acinetobacter</i> sp. Tol 5 exhibits high adhesiveness to various surfaces through AtaA, a member of the trimeric autotransporter adhesin (TAA) family. We examined the adhesion of Tol 5 and other bacteria expressing different TAAs to antiadhesive surfaces. The results highlighted Tol 5’s stickiness through AtaA, which enables cells to adhere even to antiadhesive materials including polytetrafluoroethylene with a low surface free energy, a hydrophilic polymer brush exerting steric hindrance, and mica with an ultrasmooth surface. Tol 5 cells also adhered to a zwitterionic 2-methacryloyloxyethyl-phosphorylcholine-polymer-coated surface but were exfoliated by a weak shear stress, suggesting that exchangeable bound water molecules contribute to AtaA’s interaction with materials.</p>

A Sticky Bacterium Versus Antiadhesive Surfaces

<p>The COVID-19 pandemic caused by a virus has been posing a global threat to humanity and human society. It reminded us of the horror of infectious diseases. Pathogenic bacteria also cause infectious disease, but bacteria are not as much of a threat as viruses because antibiotics are effective against them. This is changing, however, with the emergence of antibiotic-resistant bacteria. The global expansion of multidrug-resistant bacteria has become a clinical problem, and the threat of bacterial infection would come back in the near future. The overuse of antibiotics amplifies the opportunity for resistant bacteria to emerge and spread. The increased antibiotic use during this COVID-19 pandemic could also increase the threat of resistant bacteria. As an alternative to antibiotics, antibiofouling surfaces have drawn intensive research interest and have been developed. <i>Acinetobacter</i> sp. Tol 5 exhibits high adhesiveness to various surfaces through AtaA, a member of the trimeric autotransporter adhesin (TAA) family. We examined the adhesion of Tol 5 and other bacteria expressing different TAAs to antiadhesive surfaces. The results highlighted Tol 5’s stickiness through AtaA, which enables cells to adhere even to antiadhesive materials including polytetrafluoroethylene with a low surface free energy, a hydrophilic polymer brush exerting steric hindrance, and mica with an ultrasmooth surface. Tol 5 cells also adhered to a zwitterionic 2-methacryloyloxyethyl-phosphorylcholine-polymer-coated surface but were exfoliated by a weak shear stress, suggesting that exchangeable bound water molecules contribute to AtaA’s interaction with materials.</p>

Recombinant tandem epitope vaccination provides cross protection against Actinobacillus pleuropneumoniae challenge in mice

Actinobacillus pleuropneumoniae (A. pleuropneumoniae/APP) is the pathogen that causes porcine contagious pleuropneumonia. Actinobacillus pleuropneumoniae is divided into 18 serovars, and the cross protection efficacy of epitopes is debatable, which has resulted in the slow development of a vaccine. Consequently, epitope-based vaccines conferring Actinobacillus pleuropneumoniae cross protection have rarely been reported. In this study, B cell epitopes in the head domain of trimeric autotransporter adhesin were predicted, and 6 epitopes were selected. Then, the predicted epitopes (Ba1, Bb5, C1, PH1 and PH2) were connected by linkers to construct a recombinant tandem antigen (rta) gene. The RTA protein encoded by the recombinant rta gene was expressed, and finally the ICR mice were immunized with the RTA protein with or without inactivated Actinobacillus pleuropneumoniae (serovars 1 and 5b) and challenged with Actinobacillus pleuropneumoniae to evaluate the protective effect of the epitope-based vaccine and combined vaccine.The mice in the RTA-immunized group and RTA plus inactivated Actinobacillus pleuropneumoniae vaccine group had a significant improvement in clinical symptoms and a higher level of antibody in the serum than those in the control group. The RTA immune group had a 40% survival rate after Actinobacillus pleuropneumoniae infection, whereas the combination of RTA and inactivated Actinobacillus pleuropneumoniae produced very strong cross immune protection in mice, at least 50% (RTA IB1+ C5) and at most 100% (RTA IB5 + C1), whereas no cross immunoprotection was found in the solo Actinobacillus pleuropneumoniae immune group. Overall, the combination of the RTA protein and inactivated bacteria significantly enhanced the cross protection effects. This implies that RTA protein in combination with a suitable inactivated Actinobacillus pleuropneumoniae strain could be a candidate vaccine for porcine contagious pleuropneumonia.