Reappearance of CD1a antigenic sites after endocytosis on human Langerhans cells evidenced by immunogoldrelabeling.

We show evidence of the reappearance of CD1a antigenic sites on the surface of human isolated Langerhans cells after internalization of CD1a antigen/CD1a monoclonal antibody (BL6) complexes. The internalization was visualized by immunogoldlabeling, and the reappearance of CD1a binding sites was shown by immunogoldrelabeling. The relabeling was distinguished from the labeling either by using two sizes of gold granules (15 and 5 nm) or by quantitative estimation with one size of gold granules, before and after the relabeling. This reappearance of sites is cycloheximide insensitive, and is evidenced, even if the transfer of gold particles to lysosomes is blocked by the monensin. These results suggest that the reexpression of CD1a antigens is due to antigens stored in the cytoplasm or to recycling of internalized sites. Some immunolabeled Birbeck granules were observed in continuity with the plasma membrane, which demonstrates their membrane origin and their involvement in the endocytosis process. However, the weak labeling of these organelles makes us believe that they are not specialized CD1a endocytosis structures.

[Use of the immunoblotting technic for the study of antibodies present in the serum of patients with bullous pemphigoid]. / Utilisation de la technique d'immunotransfert pour l'étude des anticorps présents dans le sérum de malades atteints de pemphigoïde bulleuse.

Bullous pemphigoid (BP) is an autoimmune disease characterized, at histology, by subepidermal bullous separations. Antibodies (Ab) and complement are present at the dermal-epidermal junction, and most patient with the disease have serum antibodies directed against a normal constituent of stratified epithelia (10, 25). During the past few years, the immunotransfer technique has been used to study autoimmune bullous diseases of the skin. The antigen (Ag) of bullous pemphigoid has been described by Stanley et al. (16, 17) as the polypeptidic doublet 220-240 KD. However, different results in favour of an heterogeneous antigen have been obtained by Labib et al. (11) who reported the presence of 5 separate polypeptides: 240, 200, 180, 97 and 77 KD. The purpose of the present study was to confirm on infirm these findings. We recorded the antigens recognized at immunotransfer by the circulating antibodies of BP patients, then extended this study to sera from BP patients in whom no antibody had been detected by indirect immunofluorescence (IIF). We report the results of our immunotransfer study in 9 seropositive and 9 seronegative BP patients and in 11 seronegative controls. The antigenic extract we used was prepared from suspensions of epidermal cells and represented the intracellular BP antigen. Epidermal cell suspensions were obtained by trypsinization of human abdominal skin. The cells were homogenized in a Tris-HCl 10 mM pH 7.8 buffer with SDS 2 p. 100 and B-mercaptoethanol 5 p. 100. The soluble proteins were analyzed in a polyacrylamide gel in the presence of SDS.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of epidermal differentiation antigens in cultures of interspecific somatic hybrids (human keratinocytes X mouse fibroblasts 3T3-4E).

Interspecific somatic hybrids have been prepared by fusion of human epidermal cells with mouse fibroblasts 3T3-4E using PEG 4000. Expression of epidermal differentiation antigens (bullous pemphigoid antigens, BP, keratin subsets 55-57 k and 67 k), markers of basal and suprabasal cells, were studied by immunocytochemistry for 10 passages. These markers were detected in the hybrids early after fusion, indicating that cells from both compartments were able to fuse with 3T3-4E cells. However, the hybrids expressing high molecular weight keratins were no longer detected after 7 days in primary cultures and serial passages, whereas those expressing BP antigens and vimentin persisted. Low molecular weight keratins 52 K and 50 K were detected by SDS-PAGE at the second passage in precipitates formed between labeled hybrid lysates and total keratin rabbit antiserum. Karyotype analysis showed mainly murine chromosomes and a submetacentric human chromosome between the 6th and the 10th passage.

Abrogation by subsequent feeding of antibody response including IgE, in parenterally immunized mice.

We have investigated the possibility of oral administration of ovalbumin (OVA) to prevent a secondary antibody response and interrupt reaginic antibody production. Repeated feeding seems necessary for both. Quality of results was dependent on the number of ingestions. Differences in abrogation of antibody response between mice strains were observed. Best results were obtained with AKR mice, good suppression was seen in C3H strain, and inconsistent results were obtained with DBA/2. 10 OVA oral doses were necessary to prevent a secondary antibody response in parenterally immunized mice, but 4 doses interrupted reaginic production in sensitized AKR mice. These results demonstrate that antigen feeding can prevent a secondary antibody response and interrupt reaginic antibody production.

Randomised placebo-controlled double-blind trial of two dosages of sodium cromoglycate in treatment of varioliform gastritis: comparison with cimetidine.

Eighteen patients with diffuse varioliform gastritis were enrolled in a double-blind, placebo-controlled trial of sodium cromoglycate, 200 mg a day, and sodium cromoglycate, 400 mg a day, for 28 days. An additional six patients were treated with cimetidine 1 g daily for 28 days. The improvement in terms of patient's subjective assessment, endoscopic assessment, and immunohistochemical measurements of IgE cells in the mucosa was significantly greater in patients given sodium cromoglycate than that in those given cimetidine or placebo. The results provide evidence that type 1 hypersensitivity plays some part in the pathogenesis of varioliform gastritis. It is, therefore, important to differentiate this condition from other types of gastritis, as treatment with sodium cromoglycate appears to be affective.

Reduced immunological responsiveness induced by oral immunization in nude mice.

Nude mice (Nu-Nu) were immunized orally by intragastric administration of sheep red blood cells (SRBC) repeated daily for 4 days. This oral immunization resulted in the appearance in the animals serum of anti-SRBC antibodies and of IgA Plaque Forming Cells (PFC) in spleen and intestine. Two weeks after the first intragastric administration mice were given one parenteral injection of SRBC. In these mice the immunological response was reduced to 60% in relation to the results obtained in mice which had not any previous digestive contact with the antigen. These results support the view that thymus does not play a role in the induction of intragastrically induced immunosuppression.

[Relationship between orally induced immune tolerance and local immune response (author's transl)]. / Relation entre tolérance immunitaire induite par voie digestive et réponse immune locale.

BALB/c mice were immunized by intragastric immunization with sheep red blood cells repeated daily for 4 days. This immunization resulted in the appearance of circulating antibodies which were predominantly of the IgA class. When serum from intragastrically immunized mice was administered intraperitoneally to recipient animals 8 h before parenteral immunization with sheep red blood cells, the subsequent immune response was depressed proportionally to the dose of serum injected. When intragastrically immunized mice were challenged intraperitoneally with sheep red blood cells, the level of the IgM response to the parenteral stimulation was in inverse ratio to the IgA response induced by the oral route. These results suggest that orally induced IgA production is related to orally induced immune tolerance and that systemic hyporesponsiveness is achieved while gut plasma cells are producing specific IgA.

Response of anamnestic IgA-producing cells in the mouse gut after repeated intragastric immunization.

1) Repeated intragastric immunization after a 90-day interval results in a local immunologic memory. 2) Repeated intragastric immunization does not induce the same circulation of gut lymphocytes as does the initial oral immunization. 3) Measurement of circulating antibodies is a poor criterion for gauging the local immune status. 4) A gastric intubation dose of 4 X 10(9) SRBC given daily for 4 days appears to be suboptimal for the induction of a local immune response.