Coeliac- and enteropathy-associated autoantibodies in Spanish insulin-dependent diabetes mellitus patients and their relation to HLA antigens.

The frequency of reticulin (ARA), endomysium (EmA), and gut epithelial cell (GECA) autoantibodies, and gliadin antibodies (AGA), was investigated in 86 Spanish diabetic patients by indirect immunofluorescence (IFI) and ELISA, along with their HLA phenotype. Four patients (5%) showed ARA-IgG (R1 pattern), eight (9%) showed AGA-IgG, and eight (9%) showed AGA-IgA. No EmA or GECA-positive patients were found. In diabetic patients, HLA-DR7 is increased in ARA-IgG+ vs. ARA-IgG- (though not significantly), and HLA-DR6 and HLA-DQ1 are significantly increased in the AGA-IgG+ group vs. the AGA-IgG- group. Comparison with a non-diabetic coeliac group showed that HLA-DR4 and HLA-DQ3 are significantly increased in the AGA-IgA+ group, whereas HLA-DQ2 shows a significant decrease in the AGA-IgG+ and AGA-IgA+ patients. Finally, when compared to the healthy group, HLA-DR7 frequency is decreased in the ARA-IgG- group, while HLA-DQ3 is significantly increased and HLA-DR6 and HLA-DQ1 significantly decreased in the AGA-IgG- group.Altogether, these data suggest that the genetic background leading to the appearance of coeliac-specific autoantibodies in Spanish diabetic patients differ depending on the autoantibody produced and is also different to the genetic background leading to diabetes in Spain.

Lens culinaris, Phaseolus vulgaris and vicia faba lectins specifically trigger IL-8 production by the human colon carcinoma cell line CACO-2.

Cultured Caco-2 cells were stimulated with Lens culinaris, Phaseolus vulgarisandVicia fabalectins. The production of IL-1, IL-6, IL-8 and MCP-1 was measured by ELISA and RT-PCR. IL-8 production appeared to be specifically triggered upon stimulation with all three lectins used, since none of the other cytokines tested were produced. The IL-8 secreted may induce the extravasation of activated neutrophils and generate tissue damage. A similar mechanism may be implicated in the lesions observed after infection by some enteric pathogens, with lectin-like domains on their membrane. Finally, this model may be suitable one to study the regulation of IL-8 production.

Successful in vitro immortalization of human intestinal mucosal lymphocytes with Herpesvirus saimiri.

Mucosal intestinal lymphocytes form the first immune-cell line of defense in the intestine. Several methodologies, most of them cumbersome and time consuming, have been used to obtain T-cell clones to unveil their physiological role. In the present work we take advantage of the recently described technique of transformation of T lymphocytes using Herpesvirus saimiri to show that it is possible to immortalize intestinal T-cell lines derived from healthy and diseased colonic samples and thence easily obtain in vitro intestinal T-cell lines as a model for physiopathological studies. Intestinal samples were obtained by colonoscopy and digested with dispase and collagenase. Mucosal lymphocytes (assessed by the expression of the CD3 and CD103 markers) were isolated using a Percoll gradient centrifugation and transformed with Herpesvirus saimiri. Sustained growth was observed 3 months later, showing that the cells were successfully transformed, a finding further confirmed by PCR. All cell lines were CD8+TcRalphabeta+ and HLA-DR+. CD25 was expressed on 1% of Crohn's disease-derived cells and on 25% of cells derived from patients with ulcerative colitis. CD80 expression was found on 80-90% of the cells. These immortal cell lines of intestinal origin may be useful in future experiments aimed at elucidating the role of mucosal lymphocytes in health and disease.

Cell surface phenotype and ultramicroscopic analysis of purified human enterocytes: a possible antigen-presenting cell in the intestine.

Epithelial cells of the intestine seem to act as antigen-presenting cells to surrounding lymphoid tissue and may be crucial to maintain the pool of peripheral T lymphocytes. The scope of this study was to carry out an immunophenotypic and ultramicroscopic analysis of purified human enterocytes to elucidate their role as antigen-presenting cells, in the immune responses in the gut-associated lymphoid tissue. A method has been developed to obtain purified and viable human enterocyte populations, later labeled with relevant monoclonal antibodies directed to leukocyte antigens and subjected to cytofluorometric analysis. Phenotypic analysis revealed the presence of markers common to "classical" antigen-presenting cells (CD14, CD35, CD39, CD43, CD63 and CD64), reinforcing the idea that enterocytes may act as such. Moreover, several integrins (CD11b, CD11c, CD18, CD41a, CD61 and CD29) were also found. CD25 (IL-2 receptor alpha chain) and CD28, characteristic of T cells, were detected on the surface of these cells; this latter finding rises the possibility that enterocytes could be activated by IL-2 and/or via CD28 through binding to its ligands CD80 or CD86. Finally, the presence of CD21, CD32, CD35 and CD64 that may bind immune complexes via Fc or C3, suggests their participation in the metabolism of immune complexes. Furthermore, the finding of a Birbeck's-like granule in the cytoplasm of the cells, shows that enterocytes contain an ultramicroscopic feature previously thought to be characteristic of Langerhans' cells, an antigen-presenting cell. The phenotype detected on the surface of enterocytes, along with their ultramicroscopic characteristics, suggests that they may play an important role in the immune responses elicited in the gut, presenting antigens to surrounding lymphoid cells, and establishing cognate interactions with them.