Tears, nasal secretions and saliva, which contain bacteria-destroying enzymes. Granulocytes and macrophages are phagocytic white blood cells. This migration of white blood cells causes the redness and inflammation associated with infection. If an invading pathogen escapes the innate defenses, the body can launch an adaptive, or specific response against one type of antigen. Antibodies bind that specific antigen and immobilize it, preventing it from causing infection.
Antibodies are specific for only one antigen.
Specialized white blood cells called B cells produce antibodies. B cells must interact with Helper T cells, other specialized white blood cells, to initiate antibody production. Pathogens that escape antibody detection can enter and infect cells. The surface of infected cells changes, and this change is recognized by T cells. Cytotoxic T cells kill infected cells, preventing these cells from producing more pathogen.