**5. General overview of immune response in mammals**

The natural and initial response of mammals to invading pathogens, including mycobacteria is the innate immune response [65, 66]. This involves recruitment of inflammatory cells (granulocytes) to the site of infection and subsequent ingestion and disruption of the harmful agent, which then is engulfed by macrophages [67, 68]. These are necessitated by innate immune cells, hence the name cell-mediated immunity [66]. Cell-mediate response is transient (acute) and last 1 day to 2 weeks [66]. However, humoral (antibodies) response or immunity which forms after initial expose to a pathogen is long lasting [66]. In adaptive immunity, two cells play key role [66]. These are the T (T-cell) and B (B-cell) lymphocytes [66]. T-cells develop in the bone marrow and matures in the thymus, they recognises and fights viral particulates. B-cells on the other hand matures in the bone marrow and work to eliminate bacteria and viruses from the body [66].
