New vaccine for TB which can even protect in late stage of infection and in TB infection relapsed form latent Mycobacterium tuberculosis (TB) infection.
About 90% of the worlds population has got contracted with tuberculosis bacteria one or the other time in their life, and in some population infection do not produce any disease rather they just harbor tuberculosis bacteria in them hence they are called as carrier of infection they do not develop disease because of their stronger immunity and timely vaccinations.
In some individuals they get disease and get cured too after a successful treatment with antitubercular drugs and antibiotics, such individuals do carry infection in even after getting cured, such infection is called as latent infection and it is asymptomatic, in such individuals there are chances of relapse or reoccurrence of infection due to poor immunological conditions, may be because of certain immunosuppressant drugs and therapies such infection may become life threatening in these patients.
There is a vaccine available for TB which is known as Bacilli Calmette Guerin, or BCG, even this vaccine it is not completely effective in infection or TB caused by relapse or reactivation of latent Mycobacterium tuberculosis in to virulent one.
Dr. Claus Aagaard and Dr. Peter Andersen from the Staten Serum Institute in Denmark visualized the possibility of a new vaccine which will be effective against TB caused by early infection as well as TB caused by reactivation of latent infection.
They developed protein called as H56 which is a triple fusion protein. This protein consisted of two types of proteins. One which is produced by Mycobacterium tuberculosis in early stage of infection and the other which is produced by Mycobacterium tuberculosis in latent stage of infection.
After developing the H56 they vaccinated mice with H56 and BCG vaccine and infected the mice with Mycobacterium tuberculosis, and after 6 months observed the count of Mycobacterium tuberculosis in lungs of infected mice and found that both the vaccines were effective against Mycobacterium tuberculosis, but H56 proteins treated mice showed lower count than those treated with only BCG.
Further study was conducted in mice to find out the effectiveness of H56 containing latent stage protein of Mycobacterium tuberculosis as a vaccine, it was compared with early stage proteins H1 of Mycobacterium tuberculosis and BCG, and was found that H56 was more effective than H1 only early stage vaccine and BCG, as booster dose, which is typically given in humans too in later stages for boosting the immunity against the infection.
To asses the effectiveness of H56 vaccine in treating Mycobacterium tuberculosis infection raised from reactivation of latent Mycobacterium tuberculosis infection, they infected mice with Mycobacterium tuberculosis and treated them with antibiotics and after ten weeks mice were treated with new vaccine H56 and it was found that these mice developed much stronger immunity compared to the mice which were not treated with H56. And the mice treated with H56 showed lower level of Mycobacterium tuberculosis in their lungs.
Dr. Christine Sizemore from NIADS stated in the press release published by NIH that so far no one came up with such a combination to treat latent stage of infection which might help in humans to prevent progression to active disease.
This new vaccine which combines early stage and latent stage proteins is going to enter in clinical trial, where researchers will be finding whether it will provide protection against TB in humans.
New vaccine against TB will be able to save lives of peoples from TB, as every year about 200000 peoples loose their lives because of TB. Press release about this research was published in NIH research matters.