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Variation in the expression of blood group antigen A in different areas of the human oral mucous membrane was investigated using a double layer immunofluorescence staining technique. The expression of the antigen was semiquantitated by a serial two-fold dilution titration. Comparison between cheek, commissure, lower lip, and hard palate was made. It was not possible to demonstrate any difference in expression of blood group antigen between cheek, commissure, and lower lip. However, in most cases a marked difference in blood group antigen A was found between cheek and hard palate, the latter demonstrating a much weaker expression. [ABSTRACT FROM AUTHOR]

The lymphocyte transformation test is commonly employed as a correlate of delayed hypersensitivity in vitro. As a generalization it is a good correlate, although there are some exceptions. Venous blood is collected in heparin and lymphocytes are collected and placed in a culture with or without antigen. After an appropriate duration of incubation, the precursor of DNA, tritiated thymidine, is added to the cultures. The cells are then harvested and the radioactivity incorporated by the antigen-stimulated cultures and compare it to the counts in the unstimulated cultures. The difference in the counts reflects the increment of DNA synthesis by cells responding to the antigen.

Detergent-soluble antigens from rat liver microsomes and plasma membranes were separated by two-dimensional immunoelectrophoresis. Enzyme activities in the immunoprecipitates were assayed by different staining reactions. Nine different microsomal esterases were detected. Six of these, including one esterase shared with plasma membranes, were inhibited by 0.1 mM difluorophosphate. but not by 1 mM eserine. Plasma membranes and microsomes each contained at least ten nucleoside diphosphatase and triphosphatase-active antigens. Only three precipitates with these activities were detected when plasma membrane extracts were tested against anti-microsomal sera or microsomal extracts against anti-plasma membrane sera. Although the possible immunological identity of these antigens remains to be established these findings suggest that plasma membranes and microsomes have at most three of these nucleoside diphosphatases and triphosphatases in common. Seven microsomal nucleoside diphosphatases and triphosphatases were intimately associated with both acid phosphatase and NADH-neotetrazolium reductase activities. These complexes also contained phospholipids as shown by incorporation experiments either in vivo or in vitro with [14C]-choline or [14C]ethanolamine. Three microsomal UDPase-active antigens did not hydrolyze ATP or ADP and were not associated with acid phosphatase or NADH-neotetrazolium reductase activities. Furthermore, these antigens did not contain any of the labelled phospholipids. Lipid-containing multienzyme complexes of different composition were also detected in the plasma membranes. The nucleoside diphosphatases and triphosphatases in plasma membrane extracts were associated with NADH-neotetrazolium reductase activity and two of them also contained L-leucyl-β-naphthylamidase activity. p-Chloromercuribenzoate (0.1 mM) inhibited all NADH-neotetrazolium reductase activity in the plasma membrane and microsomal precipitates and 10 mM tartrate all acid phosphatase activity in the microsomal precipitates, leaving the other activities intact. This indicated that the various enzyme activities present in the multienzyme complexes depended on separate catalytic sites. The plasma membrane extracts contained three and the microsomal extracts two L-leucyl-β-naphthylamidase-active antigens, respectively. The latter two and one of the plasma membrane antigens were not found to be associated with any other enzyme activities or phospholipids, in contrast to the two plasma membrane antigens mentioned above. [ABSTRACT FROM AUTHOR]

The activity of a large number of human erythrocyte antigens was monitored through a procedure which fractionates the erythrocyte membrane proteins. A significant amount of the erythrocyte "ghost" protein could be removed by aqueous extractants without affecting the activity of any antigen. Subsequent extraction of the residual "ghosts" with pyridine solution resulted in a separation of blood group M, N and Pr activities from blood group A, P1, P and I activities. A number of antigens including c, C, D, k, Kpb, Jka and Fya were labile to this treatment. Gel filtration in the presence of detergent showed that the MN and Pr activity was associated with the erythrocyte sialoglycoprotein. In agreement with Whittemore et al. (1969) two types of blood-group-A antigen could be distinguished on the basis of their partition properties on butanol extraction. Type OS-A antigen can be extracted into butanol, while type WS-A antigen is retained in the aqueous phase. The characteristics of blood-group-P antigen were similar to that of type OS-A antigen, while blood-group-I antigen and type WS-A antigen showed similar behaviour.

Salmonella typhimurium 1195 mutant bacteria were allowed to produce clusters of lipopolysaccharide with new, wild-type specificity over the export sites. Ferritin­labeling experiments showed that the lipopolysaccharide diffuses away from the export sites at 37 °C and is found dispersed on the cell surface, whereas at 0 °C it remains immobile. The density of lipopolysaccharide molecules on the bacterial surface, measured as number of lipopolysaccharide molecules per μm2, or as percentage of the bacterial surface covered by lipopolysaccharide was determined in two wild-type S. typhimurium strains and one mutant strain, which was grown under conditions either permissive or nonpermissive for the formation of wild-type lipopolysaccharide. There are 0.7—1.0×105 lipopolysaccharide molecules per μm2 surface area. About 15—25% of the bacterial surface was found to be covered by lipopolysaccharide. The mean intermolecular distance at hypothetical uniform distribution of lipopolysaccharide was calculated to be in the range of 3—4nm. It was of no consequence to the lipopolysaccharide surface density whether the mutant strain produced wild-type or mutant lipopolysaccharide. An estimate of the lateral diffusion constant D (D ≈ 3 × 10-13 cm2/s) of lipopolysaccharide in the outer membrane was made from earlier published data [2]. Possible reasons for the low order of magnitude of D, based on the observed surface density, are discussed. [ABSTRACT FROM AUTHOR]

A purification procedure applied to H-2 antigens (controlled by the H-2 locus) was used for the characterization of HL-A substances (HL-A2 and HL-AT)(controlled by the HL-A locus) solubilized from lymphoid cell membranes by delipidation. Upon Sephadex chromatography the serologiealty active material had an apparent Mr of 32000, and displayed, in relation to H-2 antigens, a faster electrophoretic mobility and higher pI values. One sulfhydryl group and one (intrachain) disulfide bond were present in partially purified HL-A preparations. Reduction and aminoethytation in 4 M urea did not influence the electrophoretic migration of HL-A active substances, suggesting that, as already demonstrated for H-2 alloantigens, in HL-A molecules the genetic determinants are present on single polypeptide chains. Highly purified HL-A alloantigens, like H-2 substances, revealed a high degree of microheterogeneity. These findings further support the concept of the genetic and structural homology of the main histocompatibility systems in mouse and man. [ABSTRACT FROM AUTHOR]

The conformation of rabbit antibody specific for the p-azophenyl-β-lactoside group was studied by small-angle X-ray scattering and the effect of interaction with hapten evaluated. The binding of hapten to the antibody caused a change in the conformation of the protein. The experimental findings indicate that the radius of gyration and the volume of the antibody become smaller by 2 to 3% as a result of interaction with hapten when 50% of the combining sites are occupied. Since the typical shape of the scattering curves remains the same it is inferred that the change of conformation consists mainly of a volume contraction whereas the overall shape, which is best described by T-shaped models, is not essentially modified. [ABSTRACT FROM AUTHOR]

The glycopeptides containing either the disaccharide or the heteropolysaccharide chains were purified, after enzymatic digestion of glomerular basement-membrane antigens, by gel filtration and ion-exchange chromatography. Their antigenicity was investigated in seven patients with anti-glomerular-basement-membrane antibody-mediated glomerulonephritis, by the leukocyte migration test and radioimmunoassay. The leukocyte migration of the seven patients is inhibited in presence of membrane antigens with both types of oligosaccharide chains. The disaccharide-containing glycopeptide inhibits the leukocyte migration of these patients using 10-times less antigenic material; the heteropolysaccharide-containing glycopeptide does not modify the leukocyte migration of the same patients. Similarly, only the disaccharide-containing glycopeptide decreases the binding of labelled membrane antigens with anti-glomerular-basement-membrane antibodies, using the radioimmunoassay. This glycopeptide carries therefore the major antigenic determinants of humoral and cellular anti-basement-membrane auto-immunization. The amino acid sequence of the glycopeptide is Hyl-Gly-Glu-Asp-Gly the disaccharide prosthetic group being linked to the hydrolysine residue of the peptidic chain; its immunodominant antigenic site is formed by the Galp-Hyl unit. [ABSTRACT FROM AUTHOR]

Mouse histocompatibility antigens were solubilized from lymphocyte membranes by limited papain degradation. Spleens from Balb/c mice (H-2d), enlarged by administration of lymphoma cells, were used for the membrane preparations. The solubilized protein components were purified by ion-exchange chromatography, gel filtration and discontinuous polyacrylamide-gel electrophoresis. A further characterization was achieved in a two-dimensional protein mapping system using disc-electrophoresis and isotachophoresis in the first and second dimension, respectively. The purification was monitored for alloantigens H-2.4(D) and H-3.21(K) (H-2D and H-2K represent two regions of the H-2 system). On Sephadex G-100 partially purified H-2-alloantigen chromatographed in a region of Mr = 35500. The pI of these substances showed a maximum at pH 5.5 and 5.3 for H-2.4 and at 5.2 for H-2.31. Free SH- and dithio-groups were determined with 5,5′-dithiobis(2-nitrobenzoic acid). 1.56 μmol SH/μmol alloantigenic material was found, but no SS-bond could be detected after alkaline cleavage. This suggests the absence of covalently linked protein subunits in papain-solubilized molecules bearing single private specificites. This was confirmed after reduction and alkylation in 4 M urea: 30-50% of the alloantigenic activity was retained and shown, in polyacrylamide-gel electrophoresis, to migrate in the original region of activity (RBPB 0.29 and 0.33 for H-2.4; about 0.33 for H-2.31, BPB = bromophenol blue). After reductive alkylation gel filtration resulted in a further purification of the alloantigenic material. Highly purified substances showed a diffuse staining pattern and a broad serological profile after electrophoresis. We assume this heterogenity to be a genuine property of H-2 antigens. Structural and genetic implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

By applying analytical gel chromatography technique the association behaviour of human erythrocyte phosphofructokinase has been studied. The molecular weight distribution of the polymerized forms of this enzyme covers a range of 380000 to about six millions. The degree of polymerization has been found to depend on the protein concentration, on the presence of various substrates and effectors and on the pH-value. ATP favours the aggregation of the enzyme with increasing pH, whereas in presence of fructose 6-phosphate or fructose 1,6-bisphosphate respectively the degree of association appears to be independent of the pH value between pH 6 and 9. In the microgram range the specific activity of the enzyme decreases with an increase of the enzyme concentration. [ABSTRACT FROM AUTHOR]

A three-step mild procedure is described, that permits isolation of an adenovirus type-2 soluble hexon, penton and fiber antigens in an extensively purified form. This procedure comprises ammonium sulfate precipitation. Sephadex ion-exchange chromatography and adsorption chromatography on an hydroxyapatite column. The final antigen preparations were homogeneous with regard to immunological, electrophoretic and electron microscopic criteria. [ABSTRACT FROM AUTHOR]

Chemically induced tumors of the rat submaxillary glands were tested for the presence of tumor antigens by in vitro leukocyte mediated cytotoxicity assays. Since it has been reported that the saliva of humans with oral cancer contains markedly elevated levels of secretory antibody, the rats' saliva specimens were also tested for blocking and/or potentiating ‘antibody’ activity. The results indicate that saliva from tumor-bearing animals potentiated tumor cell killing if either the tumor cells or leukocytes were pretreated. The effect was much more marked when tumor cells were pretreated. Furthermore, the addition of saliva to tumor cells imparted an immunologic cross reactivity which was not present with untreated tumor cells. Control saliva occasionally produced a similar effect, but not as consistently. or with the potency of saliva from tumor-bearing animals. Heat inactivation did not abrogate this potentiation. It is inferred that this may indicate a new system of immunologic surveillance, i.e. arming or potentiation of leukocytes by soluble tumor antigens in glandular secretions. [ABSTRACT FROM AUTHOR]

Investigates the reaction of the body's own defense mechanism against cancer. Importance of tumor antigens in detecting the presence of carcinogen in tumor cells; Various approaches developed for immunodiagnosis of neoplasm; Effects of vaccination and other immunotherapeutics in the treatment of cancer.

Soluble extracts of rat lymphoid cells were characterized in order to determine the physical relationship between the major histocompatibility (Ag-B) antigen and species or xenoantigen. Antigenic determinants recognized by rabbit anti-rat antiserum were separated from those recognized by alloantiserum by polyacrylamide gel electrophoresis (PAGE) and selective immunoabsorption. Thus, this species antigen and major H antigen are present as separate molecules on the membrane of rat lymphoid cells. [ABSTRACT FROM AUTHOR]

Spent culture media of all the human cell lines tested have been found to contain the antigenic activity present on the ll,000-Dalton HL-A common portion fragment of the HL-A antigen molecule that appears to be a characteristic, invariant portion of HL-A antigen molecules. From the culture medium of one of these lines, RPMI 1788, a lymphoid cell line, the substance carrying HL-A common activity was isolated, which was shown to be identical to the HL-A common portion fragment with respect to molecular size, electrophoretic mobility, isoelectric focusing patterns, and certain antigenic characteristics. By an isolation procedure involving differential ultrafiltration, gel filtration, and column electrophoresis, 8 litres of the culture medium yielded 1.5-2.0 A280 units of the substance representing 15-20 per cent of the HL-A common antigenic activity originally present. A single protein band with a Rf of 0.47 was obtained by disc electrophoresis. The molecular size was shown to be about 11,000 Daltons by gel filtration and by sodium dodecyl sulphate acrylamide gel electrophoresis. Upon isoelectric focusing two bands were obtained which corresponded exactly to those obtained with HL-A common portion fragment prepared from papain-solubilized HL-A antigen preparations by acid dissociation. The isoelectric point of the major band was 5.0. The reactions of this substance with rabbit antisera against human lymphoid cell membrane and against the substance were essentially identical to the reactions of HL-A common portion fragment with these same antisera. [ABSTRACT FROM AUTHOR]

Bovine peripheral leucocytes were used in a migration inhibition test to detect sensitization to Theileria parva antigens. Seventy-six per cent of animals that were exposed to T. parva antigens yielded sensitive cells. The reaction was most efficiently induced by use of living T. parva. Migration of cells from control animals was not inhibited. In some animals the presence of sensitive cells in the peripheral circulation was shown m persist for up to 8 months after exposure to experimental T. parva infection. The significance of cells that are sensitive to T. parva antigens in East Coast fever is not known. [ABSTRACT FROM AUTHOR]

The presence in each antiserum of different antibody components, with different binding affinities, quantitatively affects the outcome of an inhibition reaction. A detailed analysis permits the recognition of the following conditions. (a) At high antigen concentrations, the antiserum is approaching saturation; the only effect of adding unlabelled antigen is competition with the labelled antigen for the available antibody sites. (b) At intermediate antigen concentrations, only a fraction of the antibody components, those of higher affinity, are contributing to the binding reaction; in addition to competition, unlabelled antigen produces an increase in the number of reacting antibody sites. The resultant of these two counteracting effects can be predicted according to the slope of a simple linear function. (c) Lastly, at low antigen concentrations, the added antigen does not have any significant inhibitory effect. As a result of this analysis, practical indications are available for selecting antisera for radioimmunoassays on the basis of their avidity parameters, for choosing the most suitable antigen range for each antiserum, and for interpreting the shape of inhibition curves in terms of the avidity and heterogeneity of the antiserum. [ABSTRACT FROM AUTHOR]

Elevation of serum IgE levels is highly significant in multitransfused patients as compared to a normal population. Except for subjects with cirrhosis, no significant differences are found among the various categories of patients. Such elevation, about two-fold on average, is observed in 85 per cent of patients who underwent cardiac surgery, within 8-15 days following the operation. The IgE abnormality (levels over 500 u/ml) affects up to 41 per cent of multitransfused patients without antibodies directed against the formed elements of the blood, who developed intolerance reaction to transfusion. [ABSTRACT FROM AUTHOR]

The reactions of two monoclonal IgM lambda cold agglutinins, Sch and Sher, have been studied in detail with human and animal erythrocyte antigens. Although they were unusual in having lambda and not kappa polypeptide chains, they could be assigned to the anti I and anti-Pr1 groups of cold agglutinins. The findings with serum Sher indicated that the Pr1 antigen may be more complex than previously thought. The occurrence of unexpectedly large numbers of specificities among monoclonal anti-I, anti-i and anti-Pr antibodies is discussed and it is suggested that each monoclonal antibody may recognize only a limited portion of a complex red cell antigen. [ABSTRACT FROM AUTHOR]

Antigenic determinants of Australia antigen (AuAg) may be determined by haemagglutination inhibition with ease and high sensitivity. The reaction depends on the inhibitory effect of the test antigen-positive sample on the agglutination by specific antibody of glutaraldehyde-fixed sheep erythrocytes which have been tanned and coated with AuAg of different specificities. The standard monospecific antibody reactants are directed against one or other of the common antigens, a and Re, or against the subtypic determinants, d,y,w and r. Because it is more sensitive than conventional immunodiffusion or electrosyneresis, and more convenient than radioimmunoassay, haemagglutination inhibition is most suited to large-scale determinations of AuAg subtypes in samples of relatively low antigenic activity. [ABSTRACT FROM AUTHOR]

Intestinal immunoglobulins and antibodies in the local immune response to E. coli O somatic antigens have been studied in young fistulated pigs. Antibody levels in intestinal secretion were raised for approximately 2-3 weeks following a single local antigenic challenge with a heat-killed aqueous suspension of E. coli. A second challenge provoked a similar response suggesting a lack of immunological memory. Antibody activity in the secretions was predominantly associated with IgA and immunofluorescent studies of biopsy specimens from young fistulated animals indicated that intestinal synthesis and secretion of IgA had commenced by the 10th day of life. Studies of piglets reared with the sow indicated that oral immunization with E. coli antigen after 10 days of age stimulated intestinal antibody secretion before weaning at 3 weeks. The response of gnotobiotic pigs to oral immunization and infection was evaluated by immunofluorescent histology of the intestinal mucosa. Repeated oral administration of heat-killed E. coli O8 resulted in an immunocyte response in the lamina propria numerically comparable with that produced by infection with the live organism. The early response was dominated by cells of the IgM class whereas after 3 weeks IgA cells predominated. In the germ-free animal very few immunoglobulin-containing cells were detected. In vitro studies of antibacterial activity indicated that the most probable mechanism of immunological control in the alimentary tract is bacteriostasis. [ABSTRACT FROM AUTHOR]

The target cell of in vitro stimulation of primed spleen cells by hapten-carrier complexes was studied. The antigens DNP28-bovine serum albumin (DNP28-BSA), which gives only 2,4-dinitrophenyl (DNP) specific responses and DNP14-mouse immunoglobulin (DNP14-MIg), which probably reveals DNP as well as carrier specificity (new antigenic determinant) were used. Educated T cells could be stimulated with the antigens used for activation. A similar experiment with educated B cells, however, gave no indication that these B cells could be stimulated with antigen in the absence of T cells. Cortisone treatment of primed mice yielded spleen cells which had a higher activity than spleen cells from unprimed, cortisone-treated mice. This also points to stimulation oft cells by antigen. Treatment of primed spleen cells with anti-thymocyte serum (ATS) and complement (C) abolished stimulation by phytohaemagglutinin (PHA) completely, by lipopolysaccharide (LPS) slightly, while the antigenspecific activity was 90 per cent reduced. This indicates a mainly T cell-specific stimulation by the antigen. A corresponding experiment with anti-plasma cell serum (APCS) and C revealed a complete reduction of LPS activity and a small impairment of the PHA and conavalin A (Con A) activity. However, the antigenspecific activity was reduced by one-third to a half for the different antigens. This is an indication for a specific B-cell stimulation by the antigen, although it is on a lower level than the T-cell stimulation. The role of the hapten in the T-cell stimulation is discussed. [ABSTRACT FROM AUTHOR]

The pinocytosis of radioactive colloidal gold by peritoneal exudate cells from guinea-pigs sensitized against tuberculin or ovalbumin was enhanced by specific antigen. The effect was mediated by soluble material (gold uptake stimulator (GUS) produced by lymphocytes and acting upon macrophages. GUS production began within the first 18 hours of culture and required 24 hours contact to maximally stimulate normal peritoneal exudate cells. Comparison of the gold uptake and migration inhibition assays on identical populations of sensitive exudate cells showed in terms of minimum effective antigen dose that the gold uptake assay was considerably more sensitive. Similarly, when sensitive lymph node cells were incubated with antigen, activity could be detected in the culture supernatants at about sixty-four-fold greater dilution by the uptake of gold. At low concentrations of GUS a log-linear dose response relationship held. At high concentrations, gold uptake levelled off or even fell, and this was true for concentrations of antigen greater than optimal when added to sensitive exudate cells. Chromium uptake varied little at the concentrations of antigen and supernatant factors tested. Hence the effects of gold uptake are unlikely to be indirect effects on cell proliferation or viability. [ABSTRACT FROM AUTHOR]

Guinea-pig erythrocytes are cleared very rapidly from the circulating blood of 10-day-old rabbits; in contrast, sheep and mouse erythrocytes are cleared twelve to thirteen times more slowly, while rat erythrocytes are cleared six times more slowly, The differential rates of blood clearance of these xenogeneic erythrocytes largely substantiate differences between low titres of haemagglutinins or haemolysins, either naturally acquired or of maternal origin. Interference by such antibody in induction of the plaque-forming cell response and the minimum time antigen must persist in the circulation for successful induction of a haemolytic antibody-forming cell response are discussed. [ABSTRACT FROM AUTHOR]

Thirty-five weak A samples including fourteen A3, eight Ax, seven Aend, three Am and three Am were studied in order to determine their A antigen site density, using an IgG anti-A labelled with 125I. The values obtained ranged between 30,000 A antigen sites for A3 individuals, and 700 sites for the Ae1 red cells. The hierarchy of values observed made it possible to establish a quantitative relationship between the red cell agglutinability of these phenotypes measured under standard conditions, and their antigen site density. [ABSTRACT FROM AUTHOR]

Poly A:U, a complex of synthetic polyadenylic polyuridylic acids, prevented tolerance induction to bovine gamma-globulin (BGG) in mice when administered 0-12 hours after a tolerogenic dose (500 µg) of BGG, as shown by haemagglutinin production and immune elimination of labelled antigen after challenge with 300 µg of aggregated BGG. Administration of poly A:U 3-6 hours after tolerogen appeared to be the most effective. It was found further that two doses of poly A:U given at 3 and 6 or 3 and 12 hours, or a double dose of 600 µg given at 3 hours after tolerogen did not increase its effectiveness beyond that of a single dose of 300 µg given at 3 hours. The finding that poly A:U, which may affect thymus-derived (T) cell function, prevented tolerance induction to a T cell-dependent antigen suggests that the action of poly A:U is on the T cell, For comparison, Salmonella endotoxin, thought to affect bone marrow-derived (B) cell function, was included and it interfered with tolerance induction when given 0-72 hours after soluble BGG. This interval is in marked contrast to poly A:U which is effective at 0-12 hours after tolerogen and probably reflects a difference in mechanism of the two agents. [ABSTRACT FROM AUTHOR]

The conditions have been studied for induction of tolerance in mice to two thymus-independent multichain synthetic polypeptides, poly(DTyr,DGlu)polyDPro—polyDLys, and poly(DTyr,DGlu)-polyLPro—polyLLys. The antigens are of very similar structure, differing only in the optical configuration of proline and lysine residues. The tolerance thresholds were established by giving a single injection of antigen in solution in saline, followed later by challenge of antigen in adjuvant. For both antigens it was possible to induce high dose tolerance, which was preceded by a zone of priming at lower doses. In neither case was low zone tolerance observed. The induction of high zone tolerance was accompanied by a passing phase of antibody production in the case of poly(DTyr,DGlu)-polyDPro—polyDLys, but not in the case of poly(DTyr,DGlu)-polyLPro—polyLLys. Furthermore, the threshold doses for high zone tolerance for the two antigens differed by two orders of magnitude, being at about 100 µg per mouse for the former and at 1 µg per mouse for the latter. It appears that thymus-independent antigens, even if very similar structurally, can differ very markedly in the characteristics of their interaction with B cells. [ABSTRACT FROM AUTHOR]

The repeated administration of bovine serum albumin by stomach tube to Charles River and Black Norwegian rats resulted in a state of partial tolerance to the antigen. A very small amount of antibody was detected in the serum at the end of the oral regime but anti-BSA-producing cells could not be demonstrated in the lamina propria, in the Peyer's patches of the small intestine, in the mesenteric nodes or in the spleen of these animals. Antibody was not demonstrated in the small intestinal contents or in the faeces of the same animals. The antigen was absorbed in the native form and not as constituent peptides bearing antigenic determinants in common with the native protein. Preliminary data, using a radioimmunoassay, indicate that the serum concentration of BSA after the administration of 25 mg of the protein by stomach tube, is in the range 1-10 ng/ml of serum. Preliminary experiments indicate that the state of partial tolerance could not be abrogated by syngeneic spleen cells or peritoneal exudate cells from normal rats. This form of tolerance therefore has some features in common with the state of tolerance induced by the parenteral administration of small amounts of bovine albumin (low zone tolerance). [ABSTRACT FROM AUTHOR]

A saline solution of bovine serum albumin (40 mg/kg) readily stimulated the production of precipitins and passive haemagglutinating (HA) antibodies in adult chickens and pheasants, but not in quail, following a primary (day 0) and secondary (day 38) intravenous injection. In quail a primary injection of BSA in Freund's complete adjuvant produced low passive HA titres but not precipitins; a further injection of soluble antigen intravenously on day 25 resulted in greatly enhanced passive HA titres and the appearance of precipitins. A single intravenous injection of sheep erythrocytes (109/kg) promptly evoked an agglutinin response in all three species, with the chicken yielding the highest and the quail the lowest titres. A second injection, 21 days later, stimulated titres higher than those achieved during the initial response only in the quail. [ABSTRACT FROM AUTHOR]

Normal mice were intravenously injected with 125I-labelled HGG-anti-HGG complexes and 2 weeks later with 131-I-labelled HGG-anti-HGG complexes. One week after the last injection the mice were killed and the localization of 125I and 131I in the spleen was studied using a double isotope autoradiographic stripping technique. It appeared that 125I-labelled HGG-anti-HGG and 131I-labelled HGG-anti-HGG complexes were both localized in exactly the same sites of the splenic follicle centres. It was concluded that both immune complexes were retained by the same dendritic cells. 131I-labelled HGG-anti-HGG complexes however were still localized in the periphery of the follicles shortly after injection at a time when 125I-labelled HGG-anti-HGG complexes were already present in the follicle centres. If indeed cells carry immune complexes from the periphery of the follicles towards the follicle centres as suggested by previous studies, the present findings confirm that immune complexes are transferred from these cells to other cells (dendritic cells) in the follicle centres. [ABSTRACT FROM AUTHOR]

Evidence is presented to substantiate an earlier report that macrophages are the operative cells in the initiation of lymphocyte trapping. Several procedures which increase phagocytosis in mice of a soluble antigen (BGG), including transfer of specific serum or of adherent and non-adherent immune cells, or the transfer of in vitro sensitized macrophages, enhance the trapping potential of BGG. Animals tolerant to BGG trapped effectively when challenged with aggregated BGG, or when passively immunized and challenged with soluble BGG. The trapping defect in tolerant animals is thus due to a specific defect in immune responsiveness rather than an inherent failure of the trap mechanism. The dissociation between trapping and immune responsiveness is discussed. [ABSTRACT FROM AUTHOR]

The effects of Ca++ on primary and secondary immune responses to SRBC in vitro was investigated using the Marbrook technique. During the primary immune response three periods could be distinguished: first, a Ca++-independent lag period (0-24 hours after antigenic stimulation); second, a period with an absolute requirement for Ca++ (24-36 hours after antigenic stimulation), which is related to a proliferative phase of antigenically stimulated cells; and third, a period (later than 48 hours and up to 72 hours after antigenic stimulation), which is inhibited by Ca++ and which can be enhanced by removing Ca++ from the medium. This third period is related to the differentiation step(s) leading to antibody-forming cells. During the secondary immune response only a partial inhibition of immune response was observed after removing Ca++ from the medium at the time of antigenic stimulation. Addition of Ca++ to EGTA-containing culture medium at any time relative to the initiation of the secondary immune response enhanced the response, but, in contrast to its effects on a primary immune response, never completely restored it. Removal of Ca++ later than 6 hours after initiation of the response resulted in a decreased inhibition of the immune response and in an increased switch from 19S to 7S antibody-forming cells. This differentiation step was enhanced by removing Ca++ from the medium and was inhibited by Ca++ added to the medium. The results suggest that Ca++ controls the mechanisms involved in the antibody formation by an antagonistic action on cell proliferation and cell differentiation. [ABSTRACT FROM AUTHOR]

Immunological reactions, both immediate and delayed. were induced in guinea-pigs immunized with two sequential polyheptapeptides, poly-(Leu- Glu-Lys-Ma-Glu-Ser-Gly) and poly- (Leu-Glu-Lys-AIa-Glu-AIa-Gly). The serine-containing polymer was moderately efficient at inducing both types of immune response (7/16 immediate and 12/16 delayed), whereas the polymer containing alanine in place of serine was almost incapable of inducing a humoral response, but invariably induced cell-mediated immunity (1/15 immediate and 15/15 delayed) on primary immunization. The difference is attributed to the lower polarity of the alanine-containing polymer since other evidence exists indicating preferential stimulation of cell-mediated immunity with decreasing polarity of the antigen. [ABSTRACT FROM AUTHOR]

Rabbit antibodies formed in response to Rhesus monkey cell membranes react with a structure found on papain-solubilized HL-A molecular fragments of 48,000 Daltons. The structure or structures responsible for the reaction is common to HL-A antigen molecules of different alloantigenic specificities and appears to be one or more of the HL-A antigenic determinants shown earlier to be characteristic structural features of different HL-A antigen molecules. The structure appears to be very closely associated functionally with the alloantigenic activity. Its pH and temperature stability characteristics are very similar to those of the alloantigenic activity and it is not found on the HL-A common portion fragment of 11,000 Daltons which does not carry HL-A alloantigenic activity In Rhesus monkeys the antigenic determinant appears to be on the major histocompatibility antigens, since it is found only on the 48,000-Dalton molecular fragment of papain-solubilized cell membrane as it. is in man. The antigenic determinant of Rhesus monkey and the similar, if not identical, cross-reacting structure on the HL-A antigen molecule, may be a common, characteristic marker for the major histocompatibility antigens of man and Rhesus and possibly of other primates This antigenic marker is not an alloantigenic determinant which is present in only certain individuals in each species. [ABSTRACT FROM AUTHOR]

The in vitro assay of inhibition of Ieucocyte migration was used in two forms for the study of the specificity of transplantation immunity in mice. In one system thymus cells (antigen) were mixed with peritoneal exudate cells (PEC) from mice immunized with skin grafts and inhibition of migration was detected only when the antigenic cells were of donor origin or were from a third-party strain which shared an H-2 region (K or D) with the graft donor. However, in another form of the assay, in which sensitized lymph node cells (LNC) were mixed with antigenic PEC, inhibition of migration was detected also using antigenic cells from third- party strains which did not share an H-2 region with the donor and possessed only few H-2 specificities of the donor, The inhibition of migration mediated by LNC was abrogated with the use of anti-θ sen. Transplantation immunity was studied in vivo with an assay of resistance to the growth of a third-party tumour (SaI) in mice pre-immunized with skin grafts from congenic strains having different H-2 antigens. Resistance was found in cases where the tumour cells did not share an H-2 region with the graft donor, but was weaker than the resistance obtained upon immunization with grafts from strains sharing an H-2 region with the tumour donor. [ABSTRACT FROM AUTHOR]

Rabbit appendix cells were injected into horses at weekly intervals, after which the horses were bled and the sera tested for cytotoxic activity. The unabsorbed antiserum was cytotoxic to the lymphocytes of all the lymphoid organs tested Following absorption with bone marrow and thymus cells, the antiserum lost all cytotoxic activity directed toward these cells but displayed almost undiminished cytotoxic activity toward the cells of the SAPP organs (sacculus rotundus, appendix and Peyer's patches). The absorbed antiserum also demonstrated cytotoxic activity toward certain lymphocytes present in the spleen, lymph node and circulation. Thus, the antibodies directed toward the antigens common to all lymphoid cells were removed by the thymus and bone marrow cells, leaving behind cytotoxic antibodies directed toss aid antigens present on appendix and appendix-derived cells only, We have therefore succeeded in preparing antisera specific for rabbit thymus, bone marrow and appendix cells, respectively. [ABSTRACT FROM AUTHOR]

Horse anti-rabbit bone marrow cell antiserum was tested for its cytotoxic activity with respect to the lymphocytes of the various lymphoid organs. The unabsorbed antiserum was highly cytotoxic with respect to the circulating WBC and cells of the bone marrow and thymus but demonstrated low cytotoxic activity with respect to spleen, lymph node and SAPP cells (sacculus rotundus, appendix and Peyer's patches). However, following absorption with thymocytes, lymph node cells or SAPP cells, cytotoxic activity directed toward any of these cell types disappeared without affecting the cytotoxic activity with respect to bone marrow and circulating lymphocytes. On the other hand, bone marrow and spleen cells and circulating white blood cells were capable of absorbing out completely the cytotoxic activity directed toward these cells, On the basis of a comparison of efficiency of absorption of anti-bone marrow cell activity by cells of the different lymphoid organs and cytotoxicity assays of the absorbed antiserum, it is concluded that approximately 15-25 per cent of the spleen lymphocytes and 20-40 per cent of the circulating lymphocytes in the rabbit are bone marrow-derived cells. The other lymphoid organs do not normally appear to possess these cells. [ABSTRACT FROM AUTHOR]

The experiments described here form part of a series carried out to determine the conditions of antigen presentation which dispose to the production of IgE antibody in the rat. We have found that Hooded Lister rats in comparison with rats of some other strains have an exceptional ability to produce reaginic antibodies responses can be consistently induced with very small doses of antigen and are boosted to high levels with a second dose of antigen. The effect of the dose of antigen on these responses is as follows. [ABSTRACT FROM AUTHOR]

Prednisolone causes a dose-related inhibition of antigen-evoked histamine release from IgE-sensitized human skin in vitro. The effective concentrations are of the same order as are achieved in plasma therapeutically. Analysis of prednisolone inhibition shows that it acts on the second histamine release stage, antigen-antibody combination being unaffected. In contrast with the traditional view, our results show that, at least in human skin, glucocorticoids can inhibit antigen-evoked histamine release [ABSTRACT FROM AUTHOR]

Sheep erythrocyte (SRBC) antigen was delivered directly into the lymphoid component of the appendix or via the appendicular artery, followed by ligation or clamping of appendicular vessels. Antigen was also injected intravenously, into the spleen, or into the thymus. Counts of anti-SRBC plaque-forming cells (PFC) in the appendix were compared with counts in the spleen and thymus. None of the injection routes employed resulted in an elevation of PFC activity above background in the appendix. However, delivery of antigen via the appendicular artery caused a marked increase of PFC activity in the spleen. These results and other available evidence point towards a helper-cell function of lymphocytes in the appendix, and therefore suggest a central role of this organ in humoral immunity. [ABSTRACT FROM AUTHOR]

Intramuscular injection of a non-immunogenic dose (1 mg) of the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) into mice caused a marked and prolonged increase in the amount of the serum IgM and IgG. The increase of IgM after this injection was over 100 times greater than that of antigen-specific IgM antibodies produced by injection of an immunogenic dose of CPS-K (5 μg) or sheep red blood cells SRBC) (2 × 108). The increase in the amount of immunoglobulins was not related to induction of immunological paralysis to the major subcomponent of CPS-K (acidic CPS-K) by. a large dose of antigen, but was induced by non-antigenic stimulation by the minor subcomponent of CPS-K (neutral CPS-K), which was non-immunogenic at any dose. In mice injected with a non-immunogenic dose of CPS-K, antibody levels in tile serum to three kinds of non-cross-reacting antigens, SRBC, bovine serum albumin (BSA) and a possibly autochthonous IgG (IgM-IgG mixed type cryoglobulin) were also increased. The number of plaque-forming cells (PFC) for SRBC in the spleens of mice was also markedly increased after CPS-K injection. These antibodies to SRBC and BSA and PFC for SRBC were exclusively of IgM type and increased to as high levels as those found after specific antigenic stimulation. This marked increase in IgM antibody was neither followed by an increase in IgG antibody nor by immunological memory for a secondary IgG response. [ABSTRACT FROM AUTHOR]

Chickens of four inbred lines were tested for the development of delayed hypersensitivity to mycobacterial antigens. It was found that WA and WB lines failed to develop tuberculin hypersensitivity. On the other hand, IB line was a strong responder, while the response of CB line was intermediate. [ABSTRACT FROM AUTHOR]

Antigen-induced migration inhibition of guinea-pig peritoneal cells was clearly detectable after in vitro irradiation with 5000 to 10,000 rads, but it was weaker than with non-irradiated cells. An attempt was made to quantify this effect by diluting immune cells with non-immune peritoneal cells. The titrations showed a drop of four two-fold dilution steps after 5000 rads and even 2000 rads caused a small drop to 50 per cent efficiency when compared to non-irradiated cells. [ABSTRACT FROM AUTHOR]

The time course of the relative distribution of small lymphocytes binding 125I-labelled human thyroglobulin (HTg) in cell suspensions from the peripheral blood and various lymphoid organs was studied in guinea-pigs at progressive intervals up to 28 days after immunization with an emulsion of HTg and BCG in Freund's incomplete adjuvant (FIA). Small lymphocytes binding 125I-labelled HTg were first detected in peripheral blood, popliteal (draining) lymph node, spleen and bone marrow preparations on the 10th day, and in mesenteric (distant) lymph node and thymus preparations on the 14th day after primary immunization. In general, the percentage of these cells increased progressively thereafter until the end of the period of study. Blocking experiments with unlabelled antigens indicated that the binding of 125I-labelled HTg by small lymphocytes was specific. An anti-HTg antibody cytophilic for guinea-pig small lymphocytes was demonstrated by the passive transfer of antigen-binding capacity to lymphocytes of unimmunized animals with hyperimmune guinea-pig serum. It is proposed that, in these experiments, anti-HTg cytophilic antibody was bound first to small lymphocytes in tile tissues participating actively in the immune response (popliteal node, spleen and bone marrow) before spilling over into the general circulation to coat lymphocytes at other sites (mesenteric node and thymus). [ABSTRACT FROM AUTHOR]

A mean of 6.9 per cent of small lymphocytes in peripheral blood preparations and between 1.8 and 2.4 per cent of small lymphocytes in lymph node, spleen, bone marrow and thymus preparations from unimmunized guinea-pigs bound 125I-labelled purified protein derivative of mammalian tuberculin (mammalian PPD). The percentage of these cells fluctuated but did not alter substantially after immunization with BCG or with BCG emulsified with human thyroglobulin (HTg) in Freund's incomplete adjuvant (FIA). Blocking experiments indicated that the binding of 125I-labelled mammalian PPD was specific and there was tentative evidence that the lymphocyte receptors may be IgG. A comparison is drawn between the observed time course of 125I-labelled mammalian PPD- binding small lymphocytes and the response of lymphocytes sensitive to strong histocompatibility antigens, and it is proposed that the propensity of certain anti- gens to induce a delayed hypersensitivity-type response is related to the presence of substantial numbers of antigen-binding cells in unimmunized animals. A noteworthy incidental finding was an unexplained depression in the cellular and humoral responses to mammalian PPD in guinea-pigs that had been immunized with HTg-BCG-FIA emulsion. [ABSTRACT FROM AUTHOR]

The anti-β-D-galactosidase activating antibody response in lymph node fragment cultures was investigated in an attempt to understand the mechanism determining the magnitude of an immune response towards a natural hapten, which occurs only once in each antigen molecule, under in vitro conditions that preserve the histology of the responding tissue. Fragments were individually challenged for defined tie periods, and washed; cultures with one and two fragments were then set up. Co-cultivation of fragments produced titres higher than predicted from results in single fragment cultures. This happened even, when the latter cultures produced low titres because of excessive antigen dosages. Co-cultivation of fragments also improved the duration of the antibody response. These effects appeared to correlate with the number of memory cells present in the fragments at the beginning of the cultures. These observations, together with data obtained by manipulating different doses and times of antigen exposure suggest that collaboration between cells and determinants with different specificities may occur, not only in the initial induction, but also in the sequential stimulation of antibody-forming clones. It is postulated that the co-operative mechanism shown to act in the initiation of the antibody response by cell suspension toward polyvalent artificial conjugates may also operate when intact lymphoid tissue is reached by a single bacterial determinant in its natural molecular configuration. [ABSTRACT FROM AUTHOR]

Injection of C57B1 mice with endotoxin or other bacterial antigens normally produces (i) a rise in the serum level of a factor that stimulates granulocyte and macrophage colony formation in vitro and (ii) a rise in the numbers of granulocyte and macrophage progenitors in the blood. Preinjection of the mice with polymerized flagellins of Salmonella species specifically depressed both t)'pes of response. After a single injection of fiagellin, depressed responsiveness began within 24 hr, persisted for several months and could be passively transferred to normal mice by injection of immune serum. Responsiveness was partially restored by 850 R whole body irradiation. [ABSTRACT FROM AUTHOR]

Thymus-dependent cells from thymus and peripheral lymphoid organ were preparatively separated by mean of free flow electrophoresis into various subpopulations which were defined in terms of θ (theta) antigen content, negative surface charge, graft-versus-host (GvH) reactivity, hydrocortisone sensitivity, cell volume and morphological details. Most thymocytes in the cortex have a low negative surface charge, high θ antigen content, are hydrocortisone-sensitive and immuno-incompetent. On the basis of electronic cell sizing this group consists of large population of 90 μm³ cells (T1) and a small population of 175 μm³ cells (T2), the latter being less hydrocortisone-sensitive than the former. A minority of thymocytes resides in and around the medulla and has high negative surface change, a medium θ antigen content, is hydrocortisone-resistant and reveals low GvH reactivity. These cells are medium sized (125 μm³)1 electrophoretically bimodal (T3 had a medium and T4 a high negative surface charge) and on the basis of morphological criteria are metabolically more active than the thymocytes of low negative surface charge. In the peripheral lymphoid organs, all thymus-dependent cells show high negative surface charge and have the lowest observed θ antigen content and the highest observed GvH reactivity. These cells fall into two populations of which one is 125 μm³ with lower negative surface charge and the other is 90 μm³ with a somewhat higher negative surface charge. These 125 μm³ cells (T4), which morphologically resemble the 125 μm³ thymocytes, are less GvH-reactive than the 90 μm³ (T5) cells, which seem to be resting cells. On tile basis of these data, a possible sequence of steps in the maturation of T cells was constructed as follows: in the cortex of the thymus T1 thymocytes are transformed into T2 and these develop into T3 and T4 thymocytes which have higher negative surface charge, lower θ antigen content and are in an advanced stage of maturity. After further loss of θ antigen these cells, which are in the medulla, emigrate into the periphery and are finally transformed into highly immunocompetent T5 cells possessing the highest observed negative surface charge. [ABSTRACT FROM AUTHOR]

Xenopus toadlets thymectomized as larvae at 8 days post-fertilization developed relatively normal lymphoid tissues but the spleen was reduced in weight. The increase in numbers of pyroninophilic cells and in the size of the white pulp regions which occurs in the spleen of intact, control Xenopus in response to administration of human γ-globulin (HGG) in adjuvant was less marked in thymectomized animals. HGG localization in an outer zone of the white pulp was demonstrated by immunofluorescence in the spleens of intact Xenopus. Following early thymectomy this reaction was abrogated or severely diminished, as was also the production of circulating antibody to HGG. [ABSTRACT FROM AUTHOR]

Ten rabbits infected with Trypanosoma (Trypanozoon) brucei showed a substantial increase in a natural anti-tissue autoantibody and Wassermann antibody. Absorptions suggest that the liver and Wassermann antibodies are distinct. The liver antibody reacts equally well with homologous and autologous liver. Absorption with trypanosomes and liver show that cross-reacting trypanosomal antibodies are not responsible for the liver activity. These antibodies will contribute to the raised IgM levels of rabbit trypanosomiasis and may be important in this respect but the precise extent of the contribution is not known. It is suggested that a depression of certain T-cell functions may release antibody secreting B-cell descendants from T-cell control resulting in elevated IgM. [ABSTRACT FROM AUTHOR]