Study of the nature of the binding sites of some allergens interacting with IgE

The nature of one of the binding sites of interacting macromolecules was studied by employing a model system consisting of immobilized allergens and specific reaginic antibodies present in the sera of allergen sensitive patients. Prior to their interaction with reaginic antibodies, the immobilized allergens were treated with a variety of enzymes in order to determine their susceptibility to enzymatic hydrolysis.

Structure of the lymphocyte membrane. 3. Chemical nature of the guinea-pig lymphocyte membrane macromolecules reacting with heterologous ALS

Behaviour of normal and hydrolase-treated guinea-pig lymph node lymphocytes versus heterologous ALS was studied by means of biophysical and immunological techniques i.e. electrophoretic mobility, leucoagglutination, cytotoxicity and visualization of antigen–antibody reaction in electron microscopy.

Our results clearly revealed that heterologous ALS antibodies reacted with mannose and sialic acid containing glycoproteins located on the lymphocyte surface. Sialic acid and other main constituents of the lymphocyte cell coat, i.e. the sulphated mucopolysaccharides have an important role in the electronegative charges of the cell and in binding of the ALS antibodies.

β-Glycosidase as well as α-maltase treatment of the lymph node lymphocyte increased from 45% to 100% the reactivity to ALS as revealed by the peroxidase reaction in electron microscopy.

These results suggest that all lymph node lymphocytes can react with ALS antibodies, but that the reactive sites of 45% of these cells are masked by glucidic sub-units.

Metabolism of intravenously administered 17 -(6,7- 3 H)estradiol-17-glucoside in normal women

17α-[6,7-3H]estradiol-17-glucoside was injected intravenously into two normal young women. Within 72 h, 60 and 46% of the 3H dose was excreted in the urine in the two experiments. In the first 6 h, 4 and 1.4% of the dose was excreted as the unchanged glucoside, together with 14 and 5% in the form of a double conjugate, identified as 17α-estradiol-3-glucuronide-17-glucoside. Over the periods 6–24 h and 24–48 h none of the injected glucoside and only minor amounts of the double conjugate were present in the urine. The main excretory product after 6 h was 17 α-estradiol-17-glucuronide. This latter result contrasts with that obtained in previous experiments in which 17β-estradiol-6,7-3H-17-glucoside was injected, and in which the main monoconjugates excreted were the 3-glucuronides of 17β-estradiol and estrone.

Mechanism of biosynthesis of thio- -D-glucuronides and thio- -D-glucosides

1. The thio-beta-d-glucosiduronic acids (thio-beta-glucuronides) of o-aminothiophenol, diethyldithiocarbamic acid, p-nitrothiophenol and thiophenol are formed biosynthetically in broken- and intact-cell preparations of mouse liver. 2. For this biosynthesis to occur in homogenates or microsomal fractions, UDP-glucuronic acid was required during incubation; glucose, glucuronic acid or UDP could not replace it. UDP was a product of the reaction. 3. The biosynthetic mechanism linking glucuronic acid to thiol and carbodithioic groups therefore requires UDP-glucuronyltransferase activity and resembles that forming the various types of O-glucuronides. 4. An analogous enzymic mechanism employing UDP-glucose synthesizes the thio-beta-d-glucosides of diethyldithiocarbamic acid and thiophenol in gut preparations of the mollusc Arion ater; this mechanism resembles that forming the O-glucosides. The thio-beta-d-glucosides are formed also in intact cells. 5. As expected from the distribution of O-glycosides, S-glucuronides of these aglycones were not detectable with the invertebrate, nor were the S-glucosides with the vertebrate. 6. Despite their similar biosyntheses, S- and O-beta-glycosides differ in susceptibility to hydrolysis by beta-glycosidases. Rat preputial-gland beta-glucuronidase hydrolysed thioglucuronides of o-aminothiophenol, diethyldithiocarbamic acid and p-nitrothiophenol, hydrolysis being inhibited by glucarolactone; the thioglucuronide of thiophenol was not hydrolysed by preputial-gland or liver beta-glucuronidase. The two S-glucosides resisted hydrolysis by beta-glucosidase from almond emulsin.

Gross cardiac involvement in glycogen storage disease type 3

Images