Bacterial delivery vehicles comprising tracer nucleic acid sequences

Abstract

The present disclosure relates generally to genetically tagged bacterial delivery vehicles comprising unique tracer nucleic acid sequences (herein referred to as “tracers”) for use in detecting and/or quantitating the presence of two or more different said bacterial delivery vehicles within a mixture of vehicles. The present disclosure relates to methods wherein the bacterial delivery vehicles are detected through, for example, performance of multiple cycles of amplification using primers that bind to sequences within the unique tracer. Such methods can be advantageously used in quality control to detect and quantitate mixtures of bacterial delivery vehicles within a pharmaceutical composition.

What is claimed: 
     
         1 . A method for detecting and/or quantitating bacterial delivery vehicles, in a multivalent bacterial delivery vehicle mixture wherein each bacterial delivery vehicle comprises a nucleic acid payload with a unique tracer, the method comprising detecting and/or quantitating (i) each bacterial delivery vehicle and/or (ii) in total the bacterial delivery vehicles, through amplification of the tracer using primers that bind to the unique tracer sequence. 
     
     
         2 . The method of  claim 1 , wherein the unique tracer has a constant region to which primers can bind for initiation of an amplification reaction, and the method comprises detecting and quantitating each bacterial delivery vehicle through amplification of the tracer using primers that bind within the constant region of the tracer sequence. 
     
     
         3 . The method of  claim 2 , wherein the unique tracer further comprises variable sequences to which primers can bind for amplification and wherein said method further comprises a distinct amplification reaction or a second amplification reaction which uses primer binding to the variable sequences for an amplification method. 
     
     
         4 . The method of  claim 1 , wherein the unique tracer comprises a variable region to which primers can bind for amplification, and the method comprises detecting and/or quantitating each bacterial delivery vehicle through amplification of the tracer using primers that bind within the variable region of the tracer sequence. 
     
     
         5 . The method of  claim 1 , wherein each bacterial delivery vehicle comprises a nucleic acid payload with different sequence and a different tracer associated with each different payload. 
     
     
         6 . The method of  claim 1 , wherein the tracer comprises no more than 20 nucleotides homology stretch with the DNA of the bacterial production strain and/or the DNA of the target bacterial cell. 
     
     
         7 . The method of  claim 1 , wherein the tracer is selected from one or more of the groups consisting of:
 (i) a tracer comprising a barcode;   (ii) a tracer comprising a constant region and a barcode:   (iii) tracer comprising a barcode flanked on each side by a constant region   (iv) a tracer containing a barcode wherein the barcode is between 25 and 50 nucleic acids long;   (v) a tracer containing a constant region wherein the constant region is between 25 and 50 nucleic acids long;   (vi) a tracer embedded in a non-coding region;   (vii) a tracer embedded in a coding region; and   (viii) a tracer embedded in a coding region wherein the tracer comprises altered codon usage while encoding a protein with an unaltered amino acid sequence.   
     
     
         8 . The method of  claim 1 , wherein detection and/or quantitation of each bacterial delivery vehicle are attained through performance of multiple cycles of amplification using primers that bind to the unique tracer nucleic acid sequence. 
     
     
         9 . The method of  claim 1 , wherein the bacterial delivery vehicles are bacteriophage derived scaffolds. 
     
     
         10 . The method of  claim 9 , wherein the bacterial delivery vehicles are bacteriophage derived particles composed of a DNA nucleic acid payload of interest packaged in a bacteriophage-derived capsid. 
     
     
         11 . A method for detecting and/or quantitating bacterial delivery vehicles in a sample derived from a subject after administration to a subject of a multivalent bacterial delivery vehicle mixture wherein each bacterial delivery vehicle comprises a nucleic acid payload with a unique tracer nucleic acid sequence, the method comprising detecting and/or quantitating (i) each bacterial delivery vehicle and/or (ii) in total the bacterial delivery vehicles, in said sample, through performance of multiple cycles of amplification using primers that bind to the unique tracer sequence. 
     
     
         12 . The method of  claim 11 , wherein the unique tracer has a constant region to which primers can bind for initiation of an amplification reaction, and the method comprises detecting and/or quantitating each bacterial delivery vehicle through amplification of the tracer using primers that bind within the constant region of the tracer sequence. 
     
     
         13 . The method of  claim 12 , wherein the unique tracer further comprises variable sequences to which primers can bind for amplification and wherein said method further comprises a distinct amplification reaction or a second amplification reaction which uses primer binding to the variable sequences for an amplification method. 
     
     
         14 . The method of  claim 11 , wherein the unique tracer comprises a variable region to which primers can bind for amplification, and the method comprises detecting and/or quantitating each bacterial delivery vehicle through amplification of the tracer using primers that bind within the variable region of the tracer sequence. 
     
     
         15 . The method of  claim 11 , wherein each bacterial delivery vehicle comprises a nucleic acid payload with different sequence and a different tracer associated with each different payload. 
     
     
         16 . The method of  claim 11 , wherein the tracer comprises no more than 20 nucleotides homology stretch with the DNA of the bacterial production strain and/or the DNA of the target bacterial cell. 
     
     
         17 . The method of  claim 11 , wherein the tracer is selected from one or more of the groups consisting of:
 (i) a tracer comprising a barcode;   (ii) a tracer comprising a constant region and a barcode:   (iii) tracer comprising a barcode flanked on each side by a constant region   (iv) a tracer containing a barcode wherein the barcode is between 25 and 50 nucleic acids long;   (v) a tracer containing a constant region wherein the constant region is between 25 and 50 nucleic acids long;   (vi) a tracer embedded in a non-coding region;   (vii) a tracer embedded in a coding region; and   (viii) a tracer embedded in a coding region wherein the tracer comprises altered codon usage while encoding a protein with an unaltered amino acid sequence.   
     
     
         18 . The method of  claim 11 , wherein detection and/or quantitation of each bacterial delivery vehicle are attained through performance of multiple cycles of amplification using primers that bind to the unique tracer nucleic acid sequence. 
     
     
         19 . The method of  claim 11 , wherein the bacterial delivery vehicles are bacteriophage derived scaffolds. 
     
     
         20 . The method of  claim 11 , wherein the bacterial delivery vehicles are bacteriophage derived particles composed of a DNA nucleic acid payload of interest packaged in a bacteriophage-derived capsid.