Potent role of vaccines prepared from macrophages infected with live bacteria in protection against Mycobacterium tuberculosis and Salmonella typhimurium infections

The present study describes a novel and simple vaccination strategy that involves the culturing of live Mycobacterium tuberculosis and Salmonella typhimurium in syngeneic, allogeneic, and xenogeneic macrophages, followed by drug treatment and gamma irradiation, to kill the bacteria. Notable observations were that the lymphocytes obtained from the vaccinated mice proliferated and secreted mainly interferon-gamma and IgG2a, but not interleukin-4 and IgG1. The enumeration of viability of M. tuberculosis indicated a significant level of protection in the vaccinated mice after challenge with live M. tuberculosis. This vaccination strategy worked successfully for tuberculosis but also showed a significant decrease in mortality of mice challenged with live S. typhimurium.