Immune System - Specific Immune Defenses

The specific immune response is activated when microorganisms evade the non-specific defenses. Two types of specific defenses destroy microorganisms in the human body: the cell-mediated response and the antibody response. The cell-mediated response attacks cells which have been infected by viruses. The antibody response attacks both "free" viruses that haven't yet penetrated cells, and bacteria, most of which do not infect cells. However, some bacteria, such as the Mycobacteria that cause tuberculosis, do infect cells.