Dominique Kaiserlian

Immortalization of mouse intestinal epithelial cells by the SV40-large T gene. Phenotypic and immune characterization of the MODE-K cell line.

Intestinal epithelial cells from the mouse small intestine were immortalized by SV40 large T gene transfer through a murine ecotropic virus. The resulting cell lines expressed the SV40 large T mRNA and exhibited morphological and phenotypic characteristics of normal enterocytes, including intercellular junctions, and expression of cytokeratin, villin, poly-Ig receptor (i.e., secretory component) and vasoactive intestinal peptide receptors. All expressed cell surface major histocompatibility complex class I molecules, but cell surface class II antigens were undetectable. Functional studies on antigen presentation were carried out using the MODE-K cell line established from the mouse duodenum. Interferon-gamma treatment of MODE-K cells resulted in a high level of class II molecule expression, and the ability to process and present native protein antigens to specific CD4+ T-cell hybridomas, via functional class II molecules. These data suggest that the MODE-K cell line is a suitable model for the analysis of intestinal epithelial cell function in mucosal immunity.

Modulation of antigen trafficking to MHC class II–positive late endosomes of enterocytes

BACKGROUND & AIMS Oral tolerance is recognized as a central immunoregulatory phenomenon. The mechanisms of its induction remain unclear, and the role of the intestinal epithelial cells that are able to present antigens to T lymphocytes is poorly understood. In this report, we analyze under in vivo conditions the intracellular targeting of mucosally administered ovalbumin (OVA) to major histocompatibility complex (MHC) class II antigen containing compartments of enterocytes and compare these pathways between BALB/c and SCID mice, the latter being unable to generate a transferable tolerogenic moiety after a feed of OVA. METHODS OVA, lysosome-associated membrane proteins (LAMP-1), and MHC class II antigens were localized in jejunal biopsy specimens of BALB/c and SCID mice at 0, 5, 10, 20, 40, 60, and 120 minutes after a single feed with OVA by fluorescence and electron microscopy. RESULTS Ten minutes after oral administration, OVA was transported to the proximity of MHC class II antigens within LAMP-1-positive vacuoles and to the basolateral membrane of enterocytes from BALB/c strain mice. However, in SCID mice, OVA reached the paracellular spaces during the same time period through LAMP-1-negative vacuoles of enterocytes, which lacked MHC class II antigens. CONCLUSIONS Orally administered OVA is rapidly targeted to late endosomes containing LAMP-1 and MHC class II antigens in enterocytes of BALB/c mice but not in SCID mice bred on a BALB/c background. We suggest that this targeting process within the enterocytes is one of the requirements for the induction of oral tolerance.

Mucosal and systemic immune responses to measles virus haemagglutinin in mice immunized with a recombinant vaccinia virus

The immune response to a vaccinia virus recombinant expressing the measles virus haemagglutinin (VV-HA) was compared after parenteral or mucosal immunizations in mice. Parenteral immunizations with 10(6) p.f.u. VV-HA induced HA-specific antibody-producing cells (IgG>IgA) and HA-specific class I-restricted cytotoxic T lymphocytes (CTL) in the spleen. In contrast, intranasal administrations of 10(6) p.f.u. of VV-HA induced HA-specific spot-forming cells in the spleen (IgG>IgA) and the lungs (IgA>IgG), and HA-specific CTL in the spleen. Co-immunization by the nasal route with VV-HA and cholera toxin enhanced HA-specific immune responses. Oral immunizations with 10(8) p.f.u. of VV-HA generated low numbers of HA-specific IgA-producing cells in the lamina propria of the gut, and a weak HA-specific CTL activity in the spleen and mesenteric lymph nodes. Oral co-immunization with VV-HA and cholera toxin greatly enhanced the level of HA-specific spot-forming cells in the lamina propria (IgA>IgG). Interestingly, intrajejunal immunizations with 10(8) p.f.u. VV-HA alone induced high levels of anti-HA IgG-producing cells in the spleen and anti-HA IgA-secreting cells in the lamina propria of the gut. These data show that (i) VV-HA by the nasal route is immunogenic and generates a measles-specific mucosal immune response in the lung, which represents the primary site of replication of measles virus and that (ii) VV-HA can also induce measles-specific immunity in the intestine provided that it is protected from degradation in the gastrointestinal tract, or that cholera toxin is used as an adjuvant.

Familial autoimmune enteropathy with circulating anti-bullous pemphigoid antibodies and chronic autoimmune hepatitis

In a family of four children (two boys and two girls), the two brothers had severe, protracted watery diarrhea beginning at 2 and 3 weeks of life, respectively. Duodenal mucosa in both patients showed total villous atrophy and severe inflammatory infiltration of the entire bowel. The first patient also had lymphoid cell infiltration of the pancreas and died at 6 weeks of age. The second boy is alive at 2 years of age and is immunocompetent, but still receives total parenteral nutrition. Indirect immunofluorescence studies revealed circulating antibodies to enterocytes, smooth muscle, thyroid, and islet cells. Bullous pemphigoid antibodies (230 and 180 kd), specific for hemidesmosomal proteins and usually associated with a subepidermal blistering skin disease, were detected by direct and indirect immunofluorescence studies and by Western immunoblot. A diagnosis of autoimmune hepatitis was made, based on evidence of chronic active hepatitis and circulating anti-smooth muscle antibody. Immunosuppressive treatments induced partial clinical remission of the diarrhea but no resolution of the small bowel injury. At 16 months of age, remission of the diarrhea occurred, but persistent autoimmune hepatitis led us to maintain treatment with prednisone and azathioprine, and later with cyclosporine. In this child, as in other patients with autoimmune disease, the link between autoantibodies and organ damage remains uncertain but immunosuppressive treatment is indicated.

Infection of Human Dendritic Cells by Measles Virus Induces Immune Suppression

Measles is characterized by lifelong immunity and a transient immunosuppression which, in developing countries, is responsible for a high morbidity and a high mortality consecutive to secondary infections. Strickingly, the immune suppression is coincident with MV-specific immunity and continues for several weeks after apparent recovery from measles. The immune suppression is characterized by the loss of delayed-type hypersensitivity skin test responses to recall antigens, such as tuberculin, and by the inhibition of antibody production and cellular immune responses to new antigens (1).

Antigen Presentation by a Mouse Duodenal Epithelial Cell Line (Mode-K)

Studies on the immunological aspects of lymphoepithelial interactions in the intestine have been hampered by the difficulty to maintain enterocytes viable in vitro after isolation from the mucosa. We have recently established1 a mouse duodenal epithelial cell line, MODE-K, immortalized by the SV40 large T antigen, which retained phenotypical characteristics of normal enterocytes. We have examined the immunologic function of MODE-K cells in antigen presentation to a specific class II-restricted T cell hybridoma.