An immunological approach to prion diseases.

Ovine scrapie and bovine spongiform encephalopathy are genetic diseases, presenting probably autoimmunity transmissible by the oral route. The absence of immune response in prion diseases indicates a tolerant state for PrP(C) and PrP(SC). The tolerant state against these diseases should be overcome before immunizing animals.

Mice ascites as a source of polyclonal and monoclonal antibodies.

A large quantity of polyclonal anti-ovalbumin antibodies was obtained from mice by a simple modification of the method described by Kurpisz et al. (1988). In addition, the cells from ascitic fluid were used to produce monoclonal antibodies.

Common antigenic properties of a g-type (goose) and a c-type (duck) egg white lysozyme: antibody responses in rabbits and mice.

Embden goose (GEWL) and Barbary duck (DEWL) egg white lysozymes possess different amino acid sequences corresponding to the g-type and c-type, respectively. GEWL was shown to be a better immunogen than DEWL in both rabbits and mice. The antigenicity of the two lysozymes was tested using different techniques (i.

Ultrasound treatment for harvesting an aminopeptidase from lactic Acid bacteria and quantitation of the enzyme by enzyme-linked immunosorbent assays.

Ultrasound treatment of Lactococcus lactis subsp. cremoris AM2 was optimized to release a maximum amount of intracellular aminopeptidase without modifying the antigenicity of the enzyme. The cells were sonicated three times for 30 s at 23 W.

Immunochemical probes for food proteins after heat processing.

While better hygiene controls and vaccinations have diminished the occurrence of infectious diseases in humans, food-borne diseases have increased. Thus sterilization of food products is of prime importance. The introduction of new technologies applied to food has necessitated new methods for the control of food safety and food quality.

[Immunochemical analysis of structural changes in ovalbumin caused by heat: possible application to the quick control of food sterilization].

Bacteriological methods, to determine proper hygiene control for food for human consumption suffers from inordinate delay (1-4 days) in the methodology before an accurate answer can be given regarding the food safety. In contrast by immunochemistry results can be obtained in 15 to 30 minutes. As it is known that during heating processing protein structure is modified, a careful identification of epitopic changes by monoclonal antibodies could be of help.

[Are industrial toxic substances a risk factor in gallbladder cancer?].

Increased prevalence of gallbladder cancer has been related to specific occupations and suggests a possible professional exposure to carcinogens. The authors report the case of a 64-year-old woman who had a squamous cell carcinoma of the gallbladder with hepatic metastases, and professional exposure to trichloroethylene in a degreasing metal laboratory. Although trichlorothylene could not be assumed to be a true carcinogen for gallbladder cancer, this case underscores that epidemiologic studies taking into account professional exposure, in addition to the usual risk factors of gallbladder cancer, are requested, in order to detect a new patient group at risk for gallbladder cancer.

Natural killer (NK) activity and interferon (IFN) production by a fraction of spleen and blood lymphocytes in swine.

After carbonyl iron treatment and gradient isolation, spleen and blood pig lymphocytes exhibited NK activity and produced IFN after viral induction. Removal of plastic-adherent cells, including the majority of B cells, did not change these activities. The plastic-non-adherent cells were further separated into two subsets of roughly similar size by panning using a monoclonal, anti-T, and anti-null cell antibodies (81 + cells).

[Rapid collection of swine lymphocyte subpopulations in large quantity].

Lymphocyte subpopulations derived from different pig organs (blood, spleen, mesenteric lymph nodes) were separated by a simple, rapid and cheap panning technique, using either normal or ozone treated Petri dishes with bovine serum albumin. Slg+ lymphocytes could thus be obtained with a purity of up to 95% by adhesion onto Corning plastic dishes. The purified cells retained their proliferative activity with regard to lectins.

A cytotoxic murine monoclonal antibody that recognizes a porcine T cell subset involved in lectin-induced proliferation.

A panel of cytotoxic monoclonal antibodies (Moab) derived from mice immunized with porcine thymocytes has been developed which reacts with monomorphic determinants on porcine peripheral blood lymphocytes (PBL). These Moab recognized from 25% to 100% of PBL as tested by flow microfluorimetry One of the Moab (PT 81) that bound 39% of PBL, 30% of splenocytes and 65% of thymocytes as determined by flow microfluorimetry was selected for initial characterization. PT 81 specifically lysed 37% of Ficoll/Hypaque-prepared PBL depleted of monocytes by carbonyl iron ingestion.

Phospholipid outside-inside translocation in lymphocyte plasma membranes is a protein-mediated phenomenon.

We have measured the transbilayer diffusion of spin-labeled analogs of sphingomyelin, phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine in pig lymphocyte plasma membrane. At 4 degrees C and 37 degrees C the aminophospholipids are rapidly transported from the outer to the inner leaflet of the membrane, whereas the choline-containing phospholipids experience a slower diffusion. This selectivity is abolished after cell treatment by SH-group reagents indicating that the aminophospholipid translocation is protein-dependent and must be driven by a system analogous to the one existing in the human red cell membrane.

Purification of three porcine immunoglobulin classes from the same biological source.

Porcine IgG, IgA and IgM were isolated from sow milk. They were systematically purified by a combination of gel filtration and ion exchange chromatography. The yields were 85%, 64% and 32%, respectively.

A method of purifying sheep sIg+ lymphocytes as a tool for class II MHC antigen analysis.

A method is described for the purification of sheep lymphocytes carrying class II MHC antigens. After incubation of purified blood lymphocytes on anti-IgM-coated petri dishes, the adherent fraction contained 95% sIg-positive cells determined by immunofluorescence. When tested with cross-reacting anti-class II (bovine and human) monoclonal antibodies, more than 95% of these cells were positive either by immunofluorescence or cytotoxicity.

[Granulopoiesis in the alcoholic and cirrhotic patient. Exploration of neutropenia in cirrhosis using bone marrow cultures and a hydrocortisone test].

Twenty per cent of 60 patients with cirrhosis (55 alcoholic patients) had neutropenia (defined as neutrophil polymorphonuclear (NP) count under 2,000/mm3). The authors tried to define the mechanism of this neutropenia and compared it with the acute bone marrow cytotoxicity of alcohol. They found that bone marrow neutrophil colony growth was normal in 7 cases of cirrhosis compared to 7 controls (with and without cirrhotic serum incubation).

Hepatoma after thorotrast. Morphological and autoradiographic data.

Two women, respectively given thorotrast 30 and 40 years ago, died of hepatoma. The spleen and liver of one and the liver of the other were studied by morphological, macro- and micro-autoradiographic methods. The part played by thorotrast in the neoplasic process and its effect on the mechanism of tumour induction are discussed.

[Erythrocyte filtrability in liver cirrhosis].

In view of the frequent erythrocyte abnormalities found in liver cirrhosis, erythrocyte deformability was studied in 62 patients. Deformability was determined by the initial filtration flow technique using a Hemorheometer. Results are given as a rigidity index (IR), which is characteristic of the average individual RBC.