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Isolated porcine thyroid cells reorganize in culture into various types of multicellular structure, which differ in the orientation of cell polarity and in the surface of the cell layer accessible to molecules present in the culture medium. The types of structure are: (1) follicles: the basal pole is oriented toward the medium; (2) inside-out follicles or monolayers: the apical pole is facing the culture medium; (3) monolayers on a permeable substratum: both sides of the cell layer are accessible to the medium. Follicles can be transformed into inside-out follicles or monolayers and vice versa by manipulation of the external cell environment and without dissociating the cells. Cells concentrate iodide and respond to acute stimulation by thyroid-stimulating hormone (TSH) when the basal pole is accessible, and organification occurs only when cells form a closed follicular lumen. In porous-bottomed culture chambers monolayers are formed with the basal surface accessible to the medium and the apical compartment separated from the medium. Under these conditions 85-95% of the thyroglobulin produced is secreted apically and 5-15% basally. Thyrotropin stimulates (X3) apical accumulation without modifying secretion in the basal compartment. Sodium transport across the cell layer has been characterized. An amiloride-sensitive influx occurs at the apical pole whereas the Na+/K+-ATPase, localized in the basolateral membrane, mediates ouabain-sensitive efflux at the basal pole. The thyroid epithelium in culture appears therefore as a Na+-absorbing epithelium. The role of this transport in the stabilization of cell polarity is discussed.

Very sensitive assays of IgE are required for determining prevalence of allergic reactions in children. In order to develop a sensitive two-site IRMA two kinds of mAb were produced. Antibodies specific for D epsilon 1 determinants were derived from immunization with a 40 kDa papain Fc fragment. They bound equally native and 56 degrees C heated IgE. D epsilon 2 specific mAb were obtained after immunization with IgE anti-D epsilon 1 complex and were selected on the basis of their inability to bind heated IgE. In a two-site assay on plastic plates, D epsilon 1 specific mAb led to the binding of IgE but always prevented further binding of anti-D epsilon 1 mAb, anti-human kappa chain mAb or allergen on bound IgE. This was not true when CNBr activated cellulose was used. The influence of the nature of the solid phase disappeared when D epsilon 2 specific mAb were coated on plastic tubes. In this case, the binding of a second mAb with identical or different fine specificity was observed. The best matched pair was E 164 (anti-D epsilon 2) on the solid phase and 6H10 (anti-D epsilon 1) as a tracer. As little as 0.2 UI/ml of IgE could be detected in a 2 hr test.

RAST interference was used to study the changes in blocking antibodies during hyposensitization. At the onset of desensitization blocking antibodies levels were correlated to IgE antibody titers. They progressively rose during the treatment. IgG isolated by adsorption onto protein A Sepharose were only a part of blocking antibodies. The isolated antibodies gave 80% of RAST interference values. Results showed that RAST interference may be used routinely to determine changes of immunological parameters of immunotherapy.

"Paragerm" is commonly used in hospitals where its bactericide action is well known. Preliminary tests have been carried out in the laboratory in order to study the antifungal power of this product. Variation of the different concentrations in the culture medium, variation of the time of contact between "Paragerm" and the fungus and both the mechanical and chemical effects of the product have shown that, among the species selected, certain were more sensitive and others more resistant to this solution and that, in our experimentation, "Paragerm" had a fungistatic effect.

Whole allergenic extracts (WAE) from plane-tree pollen induces in vitro blastogenesis in splenic lymphocytes from primed and normal rats. Allergen P, the major allergen of plane-tree pollen, induces an early stimulation in primed cells. WAE induced in the same way an early stimulation in primed cells, but a late incorporation of 3H-thymidine occurs at 8 days of culture when lymphocytes from primed or normal rats were used. This late response appears to be non-specific and is not abolished when a short-pulse of antigen is given.

When allergen P was denatured by 8M urea, the modified molecule still reacted with IgE specific for the native allergen but not with hemagglutinating antibodies. Heating at 100 degrees C abolished the reaction in both cases. The results suggested differences between allergenic and antigenic capacities which may be based on structural differences of the antigenic determinants.

The capacity of amoxicillin to elicit allergenic reactions in vitro was determined on benzyl-penicillin sensitive patients. RAST and histamine release were performed on blood of these patients using B pen linked to human serum albumin (BPO-HSA) as allergen. A relationship was noted between the results of the in vitro tests and the date of the allergic manifestations. When results of RAST and histamine release were significant, amoxicillin was tested for its capacity to elicit histamine release and to inhibit RAST performed with BPO-HSA. A cross-allergenicity was observed in six sera out of eight. The results suggested that amoxicillin may be capable to react with cell-bound or serum IgE to give hypersensitive manifestations in some penicillin sensitive patients.

Plane-tree pollen grains were incubated in vitro with alveolar macrophages from inbred Rats, and the possibility of phagocytosis was investigated. No phagocytosis was observed even after 48 hrs incubation. But alveolar cells were bound to pollen grains generally at the apertures. This binding did not require the Fc receptor on the macrophage membrane.

Fraction III (Fr III) mitogen was isolated from the whole aqueous extract (WAE) of plane-tree pollen by Con A-Sepharose chromatography and gel filtration. It stimulated mouse spleen cells, and peripheral blood lymphocytes from plane-tree non-sensitive patients or from cord blood. A 6-day culture gave the best response. The proliferation was not abolished by washing the cells after a short pulse of Fr III given in the initial step but was inhibited by alpha-D-methylmannoside. These results suggested that Fr III bound to a specific site onto spleen cells. This mitogen was not immunogenic in mice and did not bind to human IgE. It induced the proliferation of T lymphocytes in presence of accessory cells and was a polyclonal activator.