ABSTRACT
Host defense in the female reproductive tract (FRT) and at other mucosal surfaces of the body, including the gastrointestinal tract and lungs, is provided by a variety of measures that can be grouped into two broad categories: innate and adaptive immunity. Innate immunity comprises antigen non-specific mechanisms that are inherent or act within the first few hours of encountering antigen. Examples include the physical barriers of the skin and mucous membranes that line the inner surfaces of the body (i.e. lungs, intestine, reproductive tract), the chemical barrier of pH, the proteins and lipids elaborated upon initial infection by infected or injured cells, and the leukocytes other than T and B cells that ingest and destroy pathogens.
