<prompt> Which of the following is characteristic of the mucosal immune system?A vigorous response is made to all nonself antigens encounteredChronic inflammation makes an inhospitable environment for microbesIL-2 and IFN-g contribute to a Th-1 like environmentTolerance to foreign antigens is the norm rather than the exception  <response>: Ans. dBecause the mucosal immune system is constantly exposed to so many nonself epitopes that are essentially harmless, it is tolerant of most of them. Although it can respond to microbes that pose a pathogenic threat, the mucosal system generally avoids the development of chronic inflammation because of the damage that could be inflicted on the delicate mucosal linings. The immunologic environment is generally described as more Th - 2 like than Th - 1 like. IgG is present at far lower levels than is IgA. 