A genetically attenuated Bordetella pertussis strain includes a mutated pertussis toxin (ptx) gene, and a heterologous ampG gene, and a hybrid protein including the N-terminal fragment of filamentous haemagglutinin (FHA) and a heterologous epitope or antigenic protein or protein fragment, different from FHA. The strain can be used in an attenuated vaccine for the treatment or prophylaxis of an infectious disease.
1. A live attenuated Bordetella pertussis strain comprising a mutated pertussis toxin (ptx) gene, a deleted dermonecrotic toxin (dnt) gene, a heterologous ampG gene, an inactivated filamentous haemagglutinin (FHA) gene, and a gene encoding a hybrid protein comprising an N-terminal fragment of filamentous haemagglutinin (FHA) and a heterologous antigen, wherein the gene encoding the hybrid protein is inserted into the locus of the deleted dnt gene and the Bordetella pertussis strain lacks a native FHA protein.
2. The Bordetella pertussis strain of claim 1 , wherein the mutated ptx gene comprises at least one mutation leading to an enzymatically inactive protein that retains immunogenic properties.
3. The Bordetella pertussis strain of claim 1 , wherein the ampG gene is replaced with a heterologous ampG gene leading to a residual tracheal cytotoxin (TCT) activity of less than 5%.
4. The Bordetella pertussis strain of claim 3 , wherein the heterologous ampG gene is from E. coli.
5. The Bordetella pertussis strain of claim 1 , wherein the heterologous antigen comprises at least one epitope of a protein expressed by a pathogen responsible for an infection of the respiratory tract.
6. The Bordetella pertussis strain of claim 1 , wherein the hybrid protein comprises the N-terminal fragment of FHA fused to the extracellular domain of the matrix protein (Me2) of the influenza A virus.
7. The Bordetella pertussis strain of claim 1 , wherein the hybrid protein comprises the N-terminal fragment of the FHA protein fused to three copies of the extracellular domain of the matrix protein (Me2) of the influenza A virus.
8. The Bordetella pertussis strain of claim 1 , wherein the hybrid protein comprises the N-terminal fragment of the FHA protein fused to at least an antigenic fragment of the G protein of the Respiratory Syncytial Virus (SRV).
9. The Bordetella pertussis strain of claim 1 , wherein the hybrid protein comprises the N-terminal fragment of the FHA protein fused to an antigenic fragment of the PcsB protein of S. pneumoniae.
10. A method for enhancing the immune response toward a microbial pathogen in a subject, the method comprising administering to a subject the live attenuated Bordetella pertussis strain comprising a mutated pertussis toxin (ptx)gene, a deleted dermonecrotic toxin (dm) gene, a heterologous ampG gene, an inactivated filamentous haemagglutinin (FHA) gene, and a gene encoding a hybrid protein comprising an N-terminal fragment of filamentous haemagglutinin (FHA) and a heterologous antigen, wherein the gene encoding the hybrid protein is inserted into the locus of the deleted dnt gene and the Bordetella pertussis strain lacks a native FHA protein, and wherein the heterologous antigen comprises an antigen from the microbial pathogen.
11. The Bordetella pertussis strain of claim 10 , wherein the microbial pathogen is an influenza virus.
12. The Bordetella pertussis strain of claim 10 , wherein the microbial pathogen is a Respiratory Syncytial Virus (SRV).
13. The Bordetella pertussis strain of claim 10 , wherein the microbial pathogen is Streptococcus pneumoniae.