Mucosal binding compositions for generating mucosal immune response; Chlamydia, HIV virus, hepatitis B virus or enterotoxigenic Escherichia coli antigen and cholera toxin binding subunit fusion protein expression, for use as a recombinant vaccine

Enterotoxigenic Escherichia coli (ETEC) K88 is a zoonotic pathogen. Previous studies have shown that lactic acid bacteria (LAB) have great potential in promoting health and resisting pathogenic infections; however, relatively little research has been done on the Pediococcus genus of LAB. This study is aimed at exploring the mechanisms imparted by Pediococcus acidilactici P25 against ETEC K88 in Caenorhabditis elegans. The probiotic performance of P25 was investigated in vitro. Colonization of K88 in the intestinal tract of C. elegans and abundance of enterotoxin genes were measured. In addition, the transcriptome of C. elegans infected by K88 was analyzed. The result showed that P25 possessed the ability to produce acid, as well as high tolerances to acidic and high bile salt concentrations. Coculture revealed that the growth of ETEC K88 was significantly inhibited by the presence of P25. The median survival of C. elegans fed P25 was 2 days longer than the group infected with K88 alone (P<0.01). At the same time, the number of colonizing K88 and the abundances of estB and elt were reduced by up to 71.70% and 2.17 times, respectively, by P25. Transcriptome data indicated that P25 affected expression of genes relative to innate immune response and upregulated the abundance of genes in multiple pathways of C. elegans, including peroxisome, longevity, and mitogen-activated protein kinase (MAPK) pathways. These results demonstrated that in the presence of P25, K88 colonization and their expression of enterotoxin genes were reduced. This was accomplished through the alteration of environmental parameters (pH and bile salt) as well as through the promotion of the innate immune response processes, increased longevity, and increased antipathogenic bacteria-related pathways. This work highlights the potential application of P. acidilactici P25 as a probiotic resistant to ETEC K88.

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Salmonella landau as a live vaccine against Escherichia coli O157:H7 investigated in a mouse model of intestinal colonization

Canadian Journal of Microbiology ◽

10.1139/w99-059 ◽

1999 ◽

Vol 45 (9) ◽

pp. 723-731 ◽

Cited By ~ 16

Author(s):

J Wayne Conlan ◽

Rhonda KuoLee ◽

Ann Webb ◽

Malcolm B Perry

Keyword(s):

Escherichia Coli ◽

Immune Response ◽

Mouse Model ◽

Mucosal Immunity ◽

Host Resistance ◽

Mucosal Immune Response ◽

Escherichia Coli O157 ◽

Local Immune Response ◽

Intestinal Colonization ◽

E Coli

The present study was performed to assess the potential of a humoral mucosal immune response directed against the O157 antigen of Escherichia coli O157:H7 to prevent intestinal colonization by the pathogen. To this end, mice were gavaged with inocula of Salmonella landau, a Salmonella strain that naturally expresses the O157 antigen. Salmonella landau was avirulent for mice. Despite this, mice exposed to S. landau developed high titres of serum and coproantibodies against the O157 antigen. These mice, compared with controls, demonstrated some ability to resist transient intestinal colonization by an oral inoculum of an isolate of E. coli O157:H7. These findings suggest that a local immune response directed against the O157 antigen might increase host resistance to this pathogen.Key words: Salmonella landau, Escherichia coli O157:H7, mucosal immunity, mice.

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