Rectal immunization with antigen-containing microspheres induces stronger Th2 responses than oral immunization: a new method for vaccination

The rectum as an effective site for induction of systemic and local immunit y has received little attention. Rectal immunization with microspheres-cont aining ovalbumin (MS-OVA) was tested for its ability to elicit systemic and mucosal immune responses. Rectal immunization with MS-OVA enhanced both Th 2 dominant OVA-specific IgG levels in the serum and OVA-specific IgA levels in fecal extracts more prominently than did oral immunization. Cytokine an alysis of CD4(+) T cells indicated a predominant induction of Th2-type resp onses compared to Th1-type responses following rectal immunization compared to oral immunization. These results demonstrate that rectal immunization w ith microspheres could be an effective new vaccination method. (C) 2001 Els evier Science Ltd. All rights reserved.