A new tuberculosis vaccine boosts the effectiveness of a childhood vaccine and protects against the growing worldwide problem of drug-resistant tuberculosis bacteria, reports a new study in Science Translational Medicine.
The vaccine is now being developed for clinical testing in humans, and if successful will help protect against the growing army of drug-resistant tuberculosis bacteria and disease that many consider a global public health emergency.
The effectiveness of childhood vaccine BCG wanes over time; within several decades, it is no longer able to fight off tuberculosis bacteria and thus cannot be relied on to prevent the disease in adults.
Now, Sylvie Bertholet of Novartis Vaccines and Diagnostics Italy and colleagues present a vaccine made with a combination of proteins from Mycobacterium tuberculosis and show that the new vaccine significantly boosts the protection of the childhood vaccine, plus offers bonus protection against drug-resistant tuberculosis.
The vaccine consists of four proteins fused into a single molecule. Each protein was chosen for its ability to protect against tuberculosis in experimental models. Combining proteins is important in a vaccine because there are many different types of tuberculosis bacteria, and no single protein will be effective against all strains.
Moreover, no two humans are alike; each person responds differently to individual proteins. A combination of proteins similar to those that exist in natural tuberculosis bacteria increases the likelihood that the vaccine will be effective. The researchers tested the new vaccine in mice, guinea pigs, and monkeys, and found that the four-protein vaccine triggered key immune cell responses in the animals.
For example, in mice that inhaled air contaminated with tuberculosis bacteria, the vaccine protected against subsequent infection, even against a strain with known resistance to several common drugs.
To mimic the weak protection often seen in people, the authors also injected guinea pigs with the short-term BCG vaccine. A few months after treatment, the four-protein vaccine protected the guinea pigs against infection, effectively boosting immunity from the BCG vaccine.
Read the abstract for “Super Vaccine for Tuberculosis on the Horizon.”