Tolerance induction by the peroral administration of protein antigens

The possibility of inducing systemic tolerance in animals by feeding them with ovalbumin and human serum was studied on mice, rats and rabbits. Antibodies to ovalbumin, human serum albumin and immunoglobulins (IgG, IgA, IgM) were determined by the passive hemagglutination test in the sera of the test and control animals after the second immunization made through a parenteral route. Tolerance to all the antigens under study was obtained in mice and rats, while in rabbits such feeding was found to produce the priming effect. The degree of tolerance was the greater, the more was the dose of the antigen and the longer was the period of feeding. Different proteins showed varying tolerogenic activity; the same degree of tolerance in mice was obtained by feeding them with IgG in a dose of 0.3-0.5 mg and with ovalbumin or human serum albumin in a dose of 6-12 mg (per gram of body weight). Tolerance was determined on day 3 after the course of feeding was over; in 3 weeks tolerance essentially decreased, and in 1.5-2 months it was replaced by normal reactiveness. Tolerance induced by the oral administration of antigens proved to be immunologically specific.     

Population Changes of Heterodera glycines and Soybean Yields Resulting from Soil Treatment with Alachlor,Fenamiphos, and Ethoprop

The population dynamics of Heterodera glycines as influenced by alachlor, fenamiphos, and ethoprop alone and in herbicide-nematicide combinations were studied in the field. Numbers of H. glycines juveniles and eggs were higher at midseason and harvest where nematicides were applied. Fenamiphos alone or in combination with alachlor provided better control of H. glycines and greater seed yields than treatments with ethoprop. Numbers of H. glycines eggs at harvest in 1980 were positively correlated with numbers of juveniles at planting in 1981 and negatively related to seed yield in 1981.     

Involvement of glutathione in the inhibition of sea urchin egg mitosis by phenyl glyoxal

Cell division in fertilized sea urchin eggs was reversibly inhibited when the ketoaldehyde phenyl glyoxal (PG) at a concentration of 0.1 mM was added to eggs for ten minutes prior to the formation of the mitotic spindle. We investigated whether inhibition of mitosis was due to PG binding to the cell surface (as previously suggested by Stein and Berestecky, '74) or to some intracellular effect. When 14C-PG was added to eggs, label was readily taken up into the egg cytoplasm; very little label was associated with the egg surface. In the cytoplasm PG combined with equimolar amounts of reduced glutathione (GSH), decreasing the levels of cellular GSH to less than 15% of normal and accounting for at least 50% of the PG taken up by eggs. The concentrations of oxidized and protein-bound glutathione were unaffected by PG treatment. We showed that glyoxalase enzymes were present in sea urchin eggs and were capable of metabolizing the PG-GSH complex, thereby restoring GSH to normal levels after PG was removed from the sea water. Though some other effect of PG cannot be ruled out, the major fate of PG in eggs was to combine with GSH, and the transient decrease in GSH which resulted could lead to inhibition of mitosis. While other reports (Nath and Rebhun, '76; Oliver et al., '76) have shown that reagents which oxidize GSH disrupt microtubule-related events, our results showed that such inhibition could be caused by decreased GSH levels alone.     

The Coccidian Genus Calyptospora n. g. and Family Calyptosporidae n. fam. (Apicomplexa), with Members Infecting Primarily Fishes1

Calyptospora n. g. was erected for Eimeria funduli because the sporocyst of that species lacks Stieda and sub-Stieda bodies, has a veil supported by sporopodia, and has an anterior apical opening. A suture may be present, but it does not completely divide the sporocyst into two valves. Because C. funduli has an obligatory invertebrate intermediate host, we established Calyptosporidae n. fam. to accommodate Calyptospora and tentatively to accept Goussia. A new subgenus, Plagula, is erected for species of Goussia with a sporocystic veil not supported by sporopodia. We consider the family more primitive than Eimeriidae, Sarcocystidae, and possibly Lankesterellidae.     

Profile of the alpha-bungarotoxin-binding regions on the extracellular part of the alpha-chain of Torpedo californica acetylcholine receptor.

The continuous alpha-neurotoxin-binding regions on the extracellular part (residues 1-210) of the alpha-chain of Torpedo californica acetylcholine receptor were localized by reaction of 125I-labelled alpha-bungarotoxin with synthetic overlapping peptides spanning this entire part of the chain. The specificity of the binding was confirmed by inhibition with unlabelled toxin and, for appropriate peptides, with unlabelled anti-(acetylcholine receptor) antibodies. Five toxin-binding regions were localized within residues 1-10, 32-41, 100-115, 122-150 and 182-198. The third, fourth and fifth (and to a lesser extent the first and second) toxin-binding regions overlapped with regions recognized by anti-(acetylcholine receptor) antibodies. The five toxin-binding regions may be distinct sites or, alternatively, different 'faces' in one (or more) sites.     

Endocytosis of aggregated immunoglobulin G by rat basophilic leukemia cells; rate, extent, and effects on the endocytosis of immunoglobulin E

Rat basophilic leukemia (RBL) cells have distinct receptors for IgE and IgG. We assessed the endocytosis of chemically and immunochemically cross-linked mouse-IgG and its influence on the simultaneous endocytosis of IgE. We found that at 37 degrees C, aggregates of IgG and IgE were endocytosed at about the same rate with one-half of the maximal endocytosis occurring in 5 to 13 min, and the efficiency of endocytosis for both ligands ranging from 40 to 70%. We also found that endocytosis of cross-linked IgE and IgG occurred simultaneously and neither ligand significantly affected the rate or extent of endocytosis of the other. The cells accumulated the cross-linked IgG, and then released it to the extracellular environment, at a rate (less than 3%/hr) slower than the released endocytosed IgE (greater than 10%/hr). Using an assay that discriminates between unbound and receptor-bound oligomeric IgG, we found that oligomeric IgG is endocytosed with its receptor, and that the bulk of the ligand remains bound to its receptor for greater than 120 min after endocytosis. The differences in the rate of release of endocytosed IgG vs IgE suggests that the intracellular fate or pathway of these two oligomeric ligands may differ.     

Immunochemical subfractionation of a microsomal fraction of rat liver with antibody-coated Staphylococcus aureus cells

The procedure for immunochemical adsorption of vesicles with specific antigen on their outer surfaces was improved. When microsomal vesicles were mixed with Staphylococcus aureus cells coated with the antibody against NADPH-cytochrome c reductase, more than 90% of the enzyme activity was adsorbed on the cell, whereas, only about 10% of the activity was adsorbed on cells coated with the same amount of anti-ovalbumin antibody. NADH-cytochrome c reductase and aldehyde dehydrogenase activities were adsorbed on the cell to the same extent as was NADPH-cytochrome c reductase activity. Under this condition, there was no adsorption of the activities of the marker enzymes of lysosomes and Golgi apparatus, whereas large amounts of the activities of the plasma membrane enzymes were adsorbed. The specific activity of NADPH-cytochrome c reductase in the adsorbed vesicles from the microsomal fractions increased considerably. In contrast, marker enzymes of the Golgi or of the plasma membranes could be enriched in unadsorbed vesicles from the Golgi fractions.     

Physiological assay of liposome-mediated transport of a drug across Xenopus intestine: cell-liposome interaction

(1) The antagonistic effect of atropine methyl bromide entrapped in liposomes on contraction of Xenopus intestine in vitro induced by acetylcholine was studied. The results provided some insight into cell-liposome interaction. (2) Acetylcholine (0.1 mM) was added to the medium in the bath (serosal solution), while liposomes containing atropine methyl bromide in their internal and external phases were added on the mucosal side of the intestine. Large multilamellar liposomes were prepared from egg lecithin (phosphatidylcholine, PC) and cholesterol in various molar ratios. Atropine methyl bromide had most effect in liposomes composed of PC and cholesterol in a ratio of 7:3, less in those with a ratio of 4:5, and none in those with a ratio of 9:1. These effects were parallel with the sizes of these liposomes, determined by quasi-elastic light-scattering; that is, the larger the liposomes, the greater was their effect. Addition (to the liposomes) of phosphatidic acid, the negative charge of which increases the distance between the lamellar layers, increased the effect, indicating that atropine methyl bromide in the space between lamellar layers was effective. Another type of liposomes in which atropine methyl bromide was present only in the external phase of liposomes was as effective as liposomes in which atropine methyl bromide was present in both the internal and external phases. (3) From these results the following new model for liposome-mediated stimulation of transport of atropine methyl bromide is proposed. Large multilamellar liposomes have structural defects in their external lamellae through which atropine methyl bromide in the mucosal solution can penetrate into the space between the external lamellar layers and move into intestinal cells through regions of fusion between the outermost layers of the liposomes and the cell membrane.