Live
The present invention provides compositions and methods of inducing an immune response in a subject in need thereof, comprising administering to the subject an immunologically-effective amount of a live Salmonella Typhi vector comprising a heterologous antigen from a pathogen, wherein the heterologous antigen comprises an outer membrane protein, an antigenic fragment thereof or a variant thereof, wherein the antigen is delivered to a mucosal tissue of the subject by an outer membrane vesicle.
1. An immunogenic live Salmonella Typhi vector that has been engineered to express one or more heterologous antigens from a pathogen, wherein the heterologous antigen comprises outer membrane protein OmpW or an antigenic fragment or variant thereof and comprises outer membrane protein OmpA or an antigenic fragment or variant thereof, wherein the live Salmonella Typhi vector is capable of delivering immunogenic, recombinant outer membrane vesicles (rOMVs) to a mucosal tissue when administered to a subject, wherein the vesicles comprise the heterologous antigens, wherein the Salmonella Typhi vector has been engineered to overexpress a lipid A deacylase PagL.
2. The Salmonella Typhi vector of claim 1 , wherein the pathogen is selected from Acinetobacter baumannii and Klebsiella pneumoniae.
3. The Salmonella Typhi vector of claim 1 , wherein the outer membrane proteins are each encoded by a nucleic acid sequence that is chromosomally integrated in S. Typhi.
4. The Salmonella Typhi vector of claim 1 , wherein a homologous S. Typhi outer membrane protein has been deleted or inactivated.
5. The Salmonella Typhi vector of claim 1 , wherein the outer membrane proteins each encoded by a nucleic acid sequence are each inserted into an S. Typhi locus selected from the group consisting of guaBA, rpoS, htrA, ssb, and combinations thereof.
6. The Salmonella Typhi vector of claim 1 , wherein at least one outer membrane protein encoded by a nucleic acid sequence is inserted into the rpoS locus of S. Typhi.
7. The Salmonella Typhi vector of claim 1 , wherein the outer membrane protein OmpW encoded by a nucleic acid sequence is chromosomally integrated into the guaBA locus.
8. The Salmonella Typhi vector of claim 1 , wherein the outer membrane protein OmpA encoded by a nucleic acid sequence is chromosomally integrated into the rpoS locus.
9. The Salmonella Typhi vector of claim 1 , wherein the OmpA comprises one or more mutations.
10. The Salmonella Typhi vector of claim 9 , wherein the mutation comprises one or more substitution mutations selected from D271A and R286A.
11. The Salmonella Typhi vector of claim 9 , wherein OmpA comprises both D271A and R286A mutations.
12. The Salmonella Typhi vector of claim 1 , wherein the S. Typhi overexpresses a cytolysin A (ClyA) protein to facilitate outer membrane vesicle formation.
13. The Salmonella Typhi vector of claim 12 , wherein the ClyA is mutated to reduce hemolytic activity of ClyA.
14. The Salmonella Typhi vector of claim 13 , wherein the ClyA mutant is selected from the group consisting of ClyA I198N, ClyA A199D, ClyA E204K, ClyA C285W and combinations thereof.
15. The Salmonella Typhi vector of claim 12 , wherein the ClyA is a fusion protein.
16. The Salmonella Typhi vector of claim 15 , wherein the ClyA comprises I198N, A199D, and E204K substitution mutations.
17. The Salmonella Typhi vector of claim 1 , wherein the PagL amino acid sequence is selected from SEQ ID NO:2 and SEQ ID NO:4.
18. An immunogenic composition comprising a combination of the live Salmonella Typhi vectors according claim 1 , wherein a first Salmonella Typhi vector expresses i) OmpA, an antigenic fragment thereof or a variant thereof from Acinetobacter baumannii ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from Acinetobacter baumannii and a second Salmonella Typhi vector expresses i) OmpA, an antigenic fragment thereof or a variant thereof from Klebsiella pneumoniae ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from Klebsiella pneumoniae.
19. An immunogenic composition comprising isolated recombinant outer membrane vesicles from the Salmonella Typhi of claim 1 , comprising one or more heterologous antigens from a pathogen, wherein the heterologous antigen comprises an outer membrane protein, an antigenic fragment thereof or a variant thereof, wherein the Salmonella Typhi has been engineered to express the heterologous antigen.
20. An immunogenic composition comprising a combination of the isolated recombinant outer membrane vesicles of claim 19 , wherein a first isolated recombinant outer membrane vesicle comprises i) OmpA, an antigenic fragment thereof or a variant thereof from Acinetobacter baumannii ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from Acinetobacter baumannii and a second isolated recombinant outer membrane vesicle comprises i) OmpA, an antigenic fragment thereof or a variant thereof from Klebsiella pneumoniae ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from Klebsiella pneumoniae.