Recombinant BCG as a candidate oral vaccine vector

Area of Science:

• * Microbiology and Immunology
• * Vaccine Development
• * Genetic Engineering

Background:

• * Bacille Calmette-Guerin (BCG) is a widely used vaccine with a history of oral administration.
• * BCG's safety profile, low production cost, and adjuvant properties make it suitable for recombinant vaccine development.
• * Genetic manipulation of mycobacteria, including BCG, has been a challenge due to slow growth and limited characterization.

Purpose of the Study:

• * To develop and apply genetic manipulation technologies for Bacille Calmette-Guerin (BCG).
• * To enable the expression of foreign antigens in BCG for potential recombinant vaccine applications.
• * To identify and characterize promoter elements for optimized antigen expression in mycobacteria.

Main Methods:

• * Development of phage and plasmid shuttle systems for DNA manipulation in Escherichia coli and mycobacteria.
• * Utilization of the aminoglycoside phosphotransferase gene as a selectable marker in mycobacteria.
• * Construction of an expression probe shuttle plasmid with a beta-galactosidase reporter gene to screen for promoter activity.

Main Results:

• * Successful genetic manipulation of BCG and other mycobacteria has been achieved.
• * A foreign antigen from Mycobacterium leprae was expressed in BCG.
• * Multiple mycobacteriophage DNA sequences with functional promoter activities were identified.

Conclusions:

• * Genetic engineering technologies have been established for BCG, enabling the expression of foreign antigens.
• * These advancements support the development of recombinant BCG as an effective vaccine vehicle.
• * Further research is needed to optimize recombinant BCG for applications, including potential oral administration.