Optimization of Salmonella enterica serovar typhi DeltaaroC DeltassaV derivatives as vehicles for delivering heterologous antigens by chromosomal integration and in vivo inducible promoters.

Novel candidate live oral vaccines based on a Salmonella enterica serovar Typhi ZH9 (Ty2 DeltaaroC DeltassaV) derivative that directed the expression of either the B subunit of Escherichia coli heat-labile toxin or hepatitis B virus core antigen from the bacterial chromosome using the in vivo inducible ssaG promoter were constructed. The levels of attenuation of the two S. enterica serovar Typhi ZH9 derivatives were similar to that of the parent as assessed by measuring the replication of bacteria within human macrophage-like U937 cells.

Expression of heterologous antigens in Salmonella Typhimurium vaccine vectors using the in vivo-inducible, SPI-2 promoter, ssaG.

DNA derived from regions upstream of the Salmonella enterica serovar Typhimurium ssaG gene were used to drive expression of different reporter genes in putative Salmonella vaccine strains. Expression from ssaG was shown to be significantly upregulated once Salmonella had entered murine or human macrophages, and levels of expression were dependent on the length of the ssaG 5' sequence incorporated. S.

Salmonella typhi and S typhimurium derivatives harbouring deletions in aromatic biosynthesis and Salmonella Pathogenicity Island-2 (SPI-2) genes as vaccines and vectors.

The S. typhimurium strain (TML deltaaroC deltassaV) WT05, harbouring defined deletions in genes involved in both the aromatic biosynthesis pathway (aroC) and the Salmonella Pathogenicity Island-2 (SPI-2) (ssaV) was shown to be significantly attenuated in C57 BL/6 interferon gamma knockout mice following oral inoculation. Similarly, the S.

Immunogenicity of peptides derived from a fibronectin-binding protein of S. aureus expressed on two different plant viruses.

The D2 peptide derived from an S. aureus fibronectin-binding protein (FnBP) was expressed on the surface of the icosahedral cowpea mosaic virus (amino acids 1-30 of D2) or on the rod-shaped potato virus X (amino acids 1-38 of D2), termed CPMV-MAST1 and PVX-MAST8, respectively. Mice and rats were immunized subcutaneously with CPMV-MAST1 and mice with PVX-MAST8 in adjuvant and high titres of FnBP-specific antibody were obtained.

Pseudomonas aeruginosa outer-membrane protein F epitopes are highly immunogenic in mice when expressed on a plant virus.

A synthetic peptide (peptide 10) representing a surface-exposed, linear B cell epitope from outer-membrane (OM) protein F of Pseudomonas aeruginosa was shown previously to afford protection in mice from P. aeruginosa infection. This peptide was expressed in tandem with the protein F peptide 18 on each of the two coat proteins of cowpea mosaic virus (CPMV).

Chimeric plant virus particles administered nasally or orally induce systemic and mucosal immune responses in mice.

The humoral immune responses to the D2 peptide of fibronectin-binding protein B (FnBP) of Staphylococcus aureus, expressed on the plant virus cowpea mosaic virus (CPMV), were evaluated after mucosal delivery to mice. Intranasal immunization of these chimeric virus particles (CVPs), either alone or in the presence of ISCOM matrix, primed CPMV-specific T cells and generated high titers of CPMV- and FnBP-specific immunoglobulin G (IgG) in sera. Furthermore, CPMV- and FnBP-specific IgA and IgG could also be detected in the bronchial, intestinal, and vaginal lavage fluids, highlighting the ability of CVPs to generate antibody at distant mucosal sites.

Intranasal immunization with a plant virus expressing a peptide from HIV-1 gp41 stimulates better mucosal and systemic HIV-1-specific IgA and IgG than oral immunization.

Control of pandemic human immunodeficiency virus type 1 (HIV-1) infection ideally requires specific mucosal immunity to protect the genital regions through which transmission more often occurs. Thus a vaccine that stimulates a disseminated mucosal and systemic protective immune response would be extremely useful. Here we have investigated the ability of a chimeric plant virus, cowpea mosaic virus (CPMV), expressing a 22 amino acid peptide (residues 731-752) of the transmembrane gp41 protein of HIV-1 IIIB (CPMV-HIV/1), to stimulate HIV-1-specific and CPMV-specific mucosal and serum antibody following intranasal or oral immunization together with the widely used mucosal adjuvant, cholera toxin.

Induction of differential T-helper-cell responses in mice infected with variants of the parasitic nematode Trichuris muris.

The resistance or susceptibility of mice to infection with the intestinal nematode parasite Trichuris muris is closely correlated with polarization of T helper (Th) cell responses to the type 2 (Th2) or type 1 (Th1) subset. Comparison of infections with three isolates of T. muris (E/K, E/N, and S) in three inbred strains of mice (CBA, C57BL/10, and B10.

The mycobacterial component of complete Freund's adjuvant induces expulsion of the intestinal nematode Trichinella spiralis in mice.

Expulsion of T. spiralis adult worms was accelerated in high-responder NIH mice vaccinated previously with complete Freund's adjuvant (CFA) emulsified in PBS, whereas the expulsion of this parasite from low-responder C57 BL/10 mice was unaffected. Incomplete Freund's adjuvant (IFA) did not induce protection and it was concluded that the mycobacterial component, present in CFA but absent from IFA, was responsible for inducing these non-specific protective effects.

High levels of protection induced by a 40-mer synthetic peptide vaccine against the intestinal nematode parasite Trichinella spiralis.

Parenteral vaccination, using a 40-mer synthetic peptide from a 43,000 MW immunodominant glycoprotein secreted by the intestinal nematode parasite Trichinella spiralis, induced high levels of protection against a subsequent challenge infection in mice. The expulsion of adult worms from the gut was accelerated following vaccination with peptide 40-80, but peptides 81-120 and 121-160 were not protective. Mesenteric lymph node cells taken from T.

Isolates of Trichuris muris vary in their ability to elicit protective immune responses to infection in mice.

Much of what is currently known of the host-parasite interaction between mice and the parasitic nematode Trichuris muris has come from experiments using a single parasite isolate (E/N). This isolate has been compared with 2 others which, on morphological criteria, belong to the same species. In 3 inbred strains of mouse that show distinct, genetically determined response phenotypes, there was a consistent pattern in terms of parasite survival time regardless of host strain, E/K worms being expelled early, E/N expelled later and S worms very late or not at all.

Oral and parenteral vaccination against Trichinella spiralis infections in high- and low-responder mice.

Vaccination by different routes and with different adjuvants is known to influence profiles of immune responses and may be used to overcome genetically determined low-responsiveness to infection. A mouse model of infection with the intestinal nematode Trichinella spiralis was used to investigate the effect of mode of vaccination upon immune responsiveness and worm expulsion phenotype in high- (NIH) and low- (C57 BL/10) responder strains of mice. Muscle larval homogenate antigen was given subcutaneously in Freund's complete adjuvant (FCA) to induce a systemic immune response or with cholera toxin (CT) orally to stimulate mucosal immunity.

Efficacy of oral vaccination against the murine intestinal parasite Trichuris muris is dependent upon host genetics.

Oral vaccinations with Trichuris muris adult worm homogenate antigen with cholera toxin as the adjuvant were successful in both high-responder BALB/c and low-responder C57BL/10 mice, resulting in high levels of protection against subsequent infection, but were ineffective in the low-responder B10.BR mice. Subcutaneous vaccination with antigen in Freund's complete adjuvant resulted in protection of all of these strains but was most effective in high-responder BALB/c and least effective in B10.

Immunity to Trichinella spiralis transferred by serum from vaccinated mice not protected by immunization.

Serum antibody responses to infection with the intestinal helminth Trichinella spiralis in mice remain at low levels for the first ten to 12 days, slowly increasing to high titres around day 20. It is thought that antibody, therefore, has a limited role in the primary immune response raised against this infection and this is confirmed by the inability of primary infection serum to transfer immunity adoptively. High-responder NIH and low-responder B10 mice were vaccinated with T.

Immune response profiles in vaccinated and non-vaccinated high- and low-responder mice during infection with the intestinal nematode Trichinella spiralis.

NIH and C57 BL/10 (B10) mice show genetically determined differences in their response to Trichinella spiralis infection. This study examines the influence of these on parameters of the immune response to infection after vaccination using muscle-larval excretory-secretory antigen in Freund's complete adjuvant. Serum antibody levels were greatly elevated when mice of both strains were vaccinated prior to infection; however, NIH produced significantly higher-level antibody responses than B10.

Vaccination against the nematode Trichinella spiralis in high- and low-responder mice. Effects of different adjuvants upon protective immunity and immune responsiveness.

Groups of NIH and C57BL/10 (B10) mice were vaccinated subcutaneously with excretory/secretory material from the nematode parasite Trichinella spiralis using a variety of different adjuvants, i.e. complete Freund's adjuvant (CFA), 'TiterMax', alum and ISCOMs.