Recombinant bacterium and methods of antigen and nucleic acid delivery

Abstract

The present invention provides a recombinant bacterium and methods of using the recombinant bacterium to induce an immune response.

1 .- 20 . (canceled) 
     
     
         21 . A recombinant  Salmonella  bacterium, wherein the bacterium:
 (a) comprises regulated expression of at least one nucleic acid encoding an antigen;   (b) comprises at least one mutation allowing endosomal escape, such that the antigen is capable of being delivered to the cytosol and inducing host cellular immunity;   (c) is capable of regulated delayed attenuation; and   (d) is capable of regulated delayed lysis.   
     
     
         22 . The bacterium of  claim 21 , wherein the bacterium is further capable of hyper-invasion. 
     
     
         23 . The bacterium of  claim 21 , wherein the bacterium is further capable of reduced bacterium-induced host programmed cell death. 
     
     
         24 . The bacterium of  claim 23 , wherein the programmed cell death is pyroptosis or apoptosis. 
     
     
         25 . The bacterium of  claim 21 , wherein the antigen is a bacterial antigen, a viral antigen, a protozoan antigen, or a fungal antigen. 
     
     
         26 . The bacterium of  claim 25 , wherein the antigen is an influenza antigen or a  Mycobacterium tuberculosis  antigen. 
     
     
         27 . The bacterium of  claim 26 , wherein the influenza antigen is a nucleoprotein (NP) of influenza virus or a hemagglutinin (HA) of influenza virus. 
     
     
         28 . The bacterium of  claim 27 , wherein the influenza antigen is an HA-SopE C-terminal fusion. 
     
     
         29 . The bacterium of  claim 21 , wherein the bacterium further comprises a single vector for the production of influenza virus. 
     
     
         30 . The bacterium of  claim 21 , wherein the bacterium is capable of escaping from a host endosomal compartment before undergoing regulated delayed lysis. 
     
     
         31 . The bacterium of  claim 21 , wherein the nucleic acid further comprises a repeated DNA nuclear targeting sequence and a nuclease resistant polyadenylation encoding sequence. 
     
     
         32 . The bacterium of  claim 31 , wherein the nucleic acid comprises an artificial NF-kB recognition sequence and/or an artificial AP-2 recognition sequence. 
     
     
         33 . The bacterium of  claim 21 , wherein the bacterium comprises the vector pYA4545. 
     
     
         34 . The bacterium of  claim 21 , wherein the bacterium comprises the vector pYA3681. 
     
     
         35 . A vaccine composition comprising the recombinant  Salmonella  bacterium of  claim 21 . 
     
     
         36 . A method for eliciting a cellular immune response in a host, the method comprising administering to the host an effective amount of the vaccine composition of  claim 35 .