Impaired B cell responses to orally administered antigens in lamina propria but not Peyer's patches of Galphai2-deficient mice prior to colitis.

• Despite numerous studies on the intestinal immune system in patients with inflammatory bowel disease (IBD) and animal models of IBD, very little is known about the immune reactivity of mucosal lymphocytes following oral immunizations under these circumstances. The reactivity of Peyer's patch (PP) and lamina propria (LP) T and B lymphocytes in inhibitory G-protein alpha2 subunit-deficient (Galphai2-/-) mice developing an IBD resembling ulcerative colitis was investigated following repeated oral immunizations with keyhole limpet haemocyanin (KLH), together with the adjuvant cholera toxin, prior to colitis. The antigen-specific B-cell response in the LP of both the small and the large intestines was significantly reduced in Galphai2-/- as compared to wild-type mice. In contrast, the frequency of KLH-specific immunoglobulin (Ig)-producing cells in the PP did not differ between Galphai2-/- and wild-type mice, whereas the total frequency of Ig-producing cells as well as the frequency of enteric flora-specific Ig-producing cells in the PP was significantly increased in Galphai2-/- as compared to wild-type mice. Analysis of T cell responses following restimulation ex vivo with KLH revealed a dramatic increase in the production of interferon-gamma in mesenteric lymph node, PP and LP lymphocytes from Galphai2-deficient as compared to wild-type mice, together with decreased production of interleukin-10 in all locations except the PP.

Nyckelord

Administration

Oral

Animals

Antibodies

Bacterial

biosynthesis

B-Lymphocytes

immunology

Colitis

Ulcerative

genetics

immunology

Disease Models

Animal

Epitopes

immunology

GTP-Binding Protein alpha Subunits

deficiency

genetics

Hemocyanin

immunology

Immune Tolerance

immunology

Immunity

Mucosal

Immunization

methods

Immunoglobulin G

biosynthesis

Immunoglobulins

biosynthesis

Intestinal Mucosa

immunology

Male

Mice

Mice

Inbred C57BL

Mice

Mutant Strains

Peyer's Patches

immunology

T-Lymphocytes

Helper-Inducer

immunology

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