Recombinant bacille Calmette-Guérin priming against measles

Area of Science:

• Immunology
• Vaccinology
• Virology

Background:

• Live attenuated measles virus (MV) vaccines are often ineffective in young infants due to maternal antibody interference.
• There is a critical need for effective immunization strategies for infants to establish early protection against measles.

Purpose of the Study:

• To evaluate the efficacy of a novel immunization strategy using recombinant bacille Calmette-Guérin expressing the MV nucleocapsid (N) protein (rBCG::N) for priming T cell memory in infants.
• To assess the protective immune responses and clinical outcomes following MV challenge in mice immunized with rBCG::N.

Main Methods:

• C3H/He mice were immunized with rBCG::N.
• Mice were subsequently infected intracranially with MV strain CAM/R40.
• T cell responses, ELISA antibodies to N protein, neutralizing antibodies, viral titers, histologic encephalitis, and mortality were assessed.

Main Results:

• rBCG::N immunization induced T cell responses and ELISA antibodies to the N protein, along with low levels of neutralizing antibodies.
• Significant reduction in virus titer in brain homogenates was observed in rBCG::N-immunized mice compared to controls.
• A decrease in the incidence and severity of histologic encephalitis and reduced mortality were noted in the rBCG::N group.

Conclusions:

• Recombinant BCG expressing the MV nucleocapsid protein (rBCG::N) can prime for T cell memory and provide protection against measles virus infection.
• These findings support the potential of rBCG::N as a promising vaccine candidate for early infant immunization against measles.
• Further investigation in primate models is warranted to advance the development of rBCG::N vaccines.