Bacillus subtilis A temperature resistant and needle free delivery system of immunogens

摘要

Although most vaccines are currently administered systemically, they are less effective against mucosal infections. Ideally, an efficient mucosal vaccine should provide protection not only at the mucosal delivery site but also systemically.1 Mucosal vaccination can induce immune responses both at the mucosal surface usually by producing secretory IgA antibodies and at distant organs through systemic IgG production. The major antibody isotype found at mucosal sites and in external secretions is secretory IgA, predominantly in dimeric form, whereas the principle isotype found in the peripheral blood and in tissue spaces is IgG. A robust mucosal response is manifested by significantly higher fecal IgG and Secretory IgA (slgA) responses and a mixed Thl/Th2 response as reflected by increased levels of interferon gamma and IL-2 cytokines and a balanced IgGl:IgG2a ratio. SlgA antibodies are considered major effectors in the adaptive immune defense of the mucosal system. More recently, the focus has shifted to mucosal vaccines capable of successfully generating both mucosal and systemic immune responses.