A total of 39 Vibrio cholerae non O1 non O139 strains were isolated from surface waters of different parts of Dhaka City, Bangladesh. All these strains showed lack of ctx or zot gene, as demonstrated by the PCR analys...A total of 39 Vibrio cholerae non O1 non O139 strains were isolated from surface waters of different parts of Dhaka City, Bangladesh. All these strains showed lack of ctx or zot gene, as demonstrated by the PCR analysis. Eighteen representative strains were tested for enterotoxin production using a rabbit ileal loop model, of which live cells of 8 strains and culture filtrates of 6 strains produced fluid accumulation in ileal loops. However, none of them produced heat stable toxin （ST）, as detected by suckling mouse assay. On the other hand, 15% of isolates produced cytotoxin as detected by the Chinese Hamster Ovary （CHO） cell assay. Fifty times concentrated culture filtrates of the representative strains did not give any precipitin band against the anti-cholera toxin, suggesting the strains produced an enterotoxin, which is antigenically different from known cholera toxin （CT）. Eighty percent of the total isolates were found to be positive for heat labile haemolysin detected by tube method, whereas, 39% were found positive by the Christie-Atkins-Munch-Petersen （CAMP） method. However, 87% of the isolates were positive for haemagglutinin/protease and all of the strains were positive for mannose-sensitive-haemagglutinin assay.展开更多
The hemolysin oligomer promotes the proliferation of B-1a cells and the expression of CD25, which is indicative of cell activation, on B-1a cells. The upregulation of CD86 induced by the oligomer showed its selective ...The hemolysin oligomer promotes the proliferation of B-1a cells and the expression of CD25, which is indicative of cell activation, on B-1a cells. The upregulation of CD86 induced by the oligomer showed its selective bias for the B7-2 member of B7 family while the monomer failed to induce these effects. The oligomer induced the expression of CXCR3, associated with B cell activation, while the monomer induced the expression of CXCL4, a powerful angiostatic chemokine. In conclusion, we found that B-1a cells responded to the apoptogenic monomer by expressing CXCL4, whereas oligomerization of the immunogen induced CXCR3 to shift the response towards activation.展开更多
Cholera continues to be one of the most common causes of morbidity and mortality among children and adults in developing countries. Vaccine against cholera is an approach in the control of this epidemic and pandemic d...Cholera continues to be one of the most common causes of morbidity and mortality among children and adults in developing countries. Vaccine against cholera is an approach in the control of this epidemic and pandemic disease. From the development of very early oral cholera vaccine, advances in vaccine development documented due to a good illustration of the epidemiology, outbreak strategy, and pathophysiology of the disease causing pathogen. The newer-generation oral cholera vaccines are safe and guarantee a high level of protection during outbreak settings for several years. Yet infants and young children in developing countries are hyporesponsive to vaccines and show poor protection against cholera. In this review, we survey and analyse our current knowledge on the etiology of cholera, its clinical manifestation, global epidemiology and elaborate the vaccine candidates, which are effective against the pathogen and the corresponding immune responses to the available vaccines. These reviews comprehensively cover the salient features of recent discoveries related to Vibrio cholerae virulence, past and present vaccine candidates and their advantages and disadvantages with their development strategies. We believe that the advances that have been included in this review will give a comprehensive insight to the prevention and control of cholera outbreaks and development of effective cholera vaccines.展开更多
文摘A total of 39 Vibrio cholerae non O1 non O139 strains were isolated from surface waters of different parts of Dhaka City, Bangladesh. All these strains showed lack of ctx or zot gene, as demonstrated by the PCR analysis. Eighteen representative strains were tested for enterotoxin production using a rabbit ileal loop model, of which live cells of 8 strains and culture filtrates of 6 strains produced fluid accumulation in ileal loops. However, none of them produced heat stable toxin （ST）, as detected by suckling mouse assay. On the other hand, 15% of isolates produced cytotoxin as detected by the Chinese Hamster Ovary （CHO） cell assay. Fifty times concentrated culture filtrates of the representative strains did not give any precipitin band against the anti-cholera toxin, suggesting the strains produced an enterotoxin, which is antigenically different from known cholera toxin （CT）. Eighty percent of the total isolates were found to be positive for heat labile haemolysin detected by tube method, whereas, 39% were found positive by the Christie-Atkins-Munch-Petersen （CAMP） method. However, 87% of the isolates were positive for haemagglutinin/protease and all of the strains were positive for mannose-sensitive-haemagglutinin assay.
文摘The hemolysin oligomer promotes the proliferation of B-1a cells and the expression of CD25, which is indicative of cell activation, on B-1a cells. The upregulation of CD86 induced by the oligomer showed its selective bias for the B7-2 member of B7 family while the monomer failed to induce these effects. The oligomer induced the expression of CXCR3, associated with B cell activation, while the monomer induced the expression of CXCL4, a powerful angiostatic chemokine. In conclusion, we found that B-1a cells responded to the apoptogenic monomer by expressing CXCL4, whereas oligomerization of the immunogen induced CXCR3 to shift the response towards activation.
文摘Cholera continues to be one of the most common causes of morbidity and mortality among children and adults in developing countries. Vaccine against cholera is an approach in the control of this epidemic and pandemic disease. From the development of very early oral cholera vaccine, advances in vaccine development documented due to a good illustration of the epidemiology, outbreak strategy, and pathophysiology of the disease causing pathogen. The newer-generation oral cholera vaccines are safe and guarantee a high level of protection during outbreak settings for several years. Yet infants and young children in developing countries are hyporesponsive to vaccines and show poor protection against cholera. In this review, we survey and analyse our current knowledge on the etiology of cholera, its clinical manifestation, global epidemiology and elaborate the vaccine candidates, which are effective against the pathogen and the corresponding immune responses to the available vaccines. These reviews comprehensively cover the salient features of recent discoveries related to Vibrio cholerae virulence, past and present vaccine candidates and their advantages and disadvantages with their development strategies. We believe that the advances that have been included in this review will give a comprehensive insight to the prevention and control of cholera outbreaks and development of effective cholera vaccines.
