ABSTRACT
Protection against Trichinella infections has been achieved using various parasite antigens and adjuvants. Recently, we reported that immunization of mice with an attenuated Salmonella strain displaying a 30-mer peptide (residues 210-239) from the Trichinella spiralis gp43 antigen using the ShdA autotransporter induced partial protection against T. spiralis infection. To improve the efficacy of vaccination, we used the MisL autotransporter system to display the Ts30mer peptide on the surface of Salmonella enterica ser. Typhimurium in combination with a prime-boost vaccination strategy. This vector and immunization regimen induced superior protection against T. spiralis when compared to our previously reported approach. Data presented herein showed a significant reduction in adult worm and muscle larvae burdens, high IgG titers, and increased production of intestinal mucus with entrapped adult worms. This prime-boost vaccination scheme is a suitable strategy to elicit enhanced protective immunity against T. spiralis.
Subject(s)
Antibodies, Helminth/biosynthesis , Antigens, Helminth/immunology , Antigens, Neoplasm/immunology , Salmonella/genetics , Trichinella spiralis/immunology , Trichinellosis/prevention & control , Animals , Antibodies, Helminth/genetics , Antibodies, Helminth/immunology , Antigens, Helminth/genetics , Antigens, Neoplasm/genetics , Female , Gene Expression , Intestines/parasitology , Larva , Mice , Mice, Inbred BALB C , Muscles/parasitology , Recombinant Fusion Proteins/metabolism , Salmonella/immunology , Salmonella/metabolism , Trichinella spiralis/genetics , VaccinationABSTRACT
The Bam complex is a highly conserved multiprotein machine essential for the assembly of ß-barrel outer membrane proteins. It is composed of the essential outer membrane protein BamA and four outer membrane associated lipoproteins BamB-E. The Yersinia enterocolitica Adhesin A (YadA) is the prototype of trimeric auotransporter adhesins (TAAs), consisting of a head, stalk and a ß-barrel membrane anchor. To investigate the role of BamA in biogenesis of TAAs, we expressed YadA in a BamA-depleted strain of Escherichia coli, which resulted in degradation of YadA. Yeast-two-hybrid experiments and immunofluorescence studies revealed that BamA and YadA interact directly and colocalize. As BamA recognizes the C-terminus of OMPs, we exchanged the nine most C-terminal amino acids of YadA. Substitution of the amino acids in position 1, 3 or 5 from the C-terminus with glycine resulted in DegP-dependent degradation of YadA. Despite degradation all YadA proteins assembled in the outer membrane. In summary we demonstrate that (i) BamA is essential for biogenesis of the TAA YadA, (ii) BamA interacts directly with YadA, (iii) the C-terminal amino acid motif of YadA is important for the BamA-dependent assembly and differs slightly compared with other OMPs, and (iv) BamA and YadA colocalize.
