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Antigenic and allergenic analysis of psyllium seed components.

The outer portions (husk) of psyllium seeds are a concentrated source of natural fiber used in some bulk-fiber laxatives and cereals. They are known to elicit respiratory allergic reactions after inhalation or ingestion among sensitized individuals. Antigenic and allergenic characterization of three psyllium-seed fractions (husk, endosperm, and embryo) was conducted with crossed immunoelectrophoresis (CIE), crossed radioimmunoelectrophoresis, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the source of psyllium allergenicity. Homologous CIE demonstrated psyllium endosperm and embryo extracts contained seven and four antigens, respectively. Husk extracts were too gelatinous to react by CIE. However, heterologous CIE profiles of endosperm or embryo extracts, reacted with antihusk antibodies, resulted in antigen-antibody precipitin peaks that matched the heavy staining precipitin lines of homologous reactions for endosperm and embryo, respectively. These results indicated that commercial-grade husk, endosperm, and embryo contained similar antigens. Extracts of all three seed components contained antigens that bound IgE antibodies in the sera of 11 psyllium RAST-positive individuals, as determined by crossed radioimmunoelectrophoresis. The few prominent husk protein/peptide bands resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were common in either embryo or endosperm. Immunoblots revealed common IgE reactive bands in all three seed fractions. Microscopic examination of the powdered commercial-grade psyllium (95% pure) revealed it contained endosperm and embryo particles. These immunologic, biochemical, and microscopic findings suggest that other contaminating seed components are primarily responsible for the allergenicity of commercial-grade psyllium-husk powder rather than the husk itself.

Allergens↗

On the mechanism of Clq binding to antibody-I. aggregation and/or distortion of IgG vs combining site-transmitted effects.

It was shown previously that in sheep calcium-dependent anti-GAT there is a subpopulation which reacts with and can be precipitated with poly G [Liberti (1975) Immunochemistry 12, 303-310]. This entire subpopulation was also found to react with the cross-reacting polypeptides GA and GT. Furthermore, from hydrogen exchange experiments, it was found that only the immunizing antigen GAT completely filled the combining sites of these antibodies whereas poly G was shown to occupy an average of 47% of all sites, and GA and GT, 75 and 85% respectively. Since precipitins formed with this subpopulation and each of these antigens should have reasonably similar densities and orientations of 'aggregated' IgG but differing combining sites occupancies, we have used this system to explore the relative role of Fc aggregation and/or IgG distortion vs combining site-transmitted effects on the binding of Clq to antibody. For two preparations of this subpopulation (one of high avidity, the other obtained via poly G-Sepharose and of lower avidity) there is only a 5% difference in the delta G (10.2-10.8 kcal/mole) of Clq-IgG interaction for a change in combining site occupancy of 47-100%. For the high-avidity preparation there is a correlation between delta G and degree of ligand occupancy of combining site. This could reflect combining site-transmitted effects or may be related to small differences in the molecular architecture of these precipitins. Clq saturation curves support the latter notion. In view of the very moderate effect of combining site filling (from 47 to 100%) on Clq-IgG interaction for the high-avidity preparation and the absence of any correlation for the lower-avidity preparation. It appears that an allosteric model for antibody initiation of complement is untenable. Unless combining site-originating contributions are completed when less than 50% of an antibody-binding site is occupied by ligand, it would seem that Clq binding to immune complexes must be governed either by enhanced interactions resulting from Fc clustering which occurs via antibody interactions with antigen or by distortion of the antibody molecular upon ligand binding or some combination thereof.

Allosteric Regulation↗

Immunochemical characterization of a high molecular weight basic allergen (HMBA) of rye grass (Lolium perenne) pollen.

A high molecular weight basic allergen (HMBA) was isolated from the mixture of non-dialysable components of the aqueous extract of defatted rye grass pollen by a combination of gel filtration and isoelectrofocusing, HMBA, a glycoprotein of mol. wt 56,800 (17% carbohydrate) contained all naturally occurring amino acids. A hyperimmune rabbit anti-HMBA serum gave only a single precipitin band with the crude extract of the rye grass pollen in crossed immunoelectrophoresis. Thus, it was concluded that HMBA was a unique and highly purified antigen. The allergenicity of HMBA was revealed by its ability to elicit immediate skin reactions in grass allergic patients. Moreover, all patients' sera tested had IgE antibodies to HMBA detectable by direct RAST with HMBA allergosorbent discs. These observations indicated that HMBA was a major allergenic constituent of rye grass pollen. Treatment of HMBA by 6 M guanidine HCl led to a significant reduction in its ability to combine with human IgE antibodies. The treatment also resulted in the complete loss of allergenicity (i.e. inability to elicit PCA reactions with a murine reaginic antiserum to HMBA) and antigenicity (inability to form precipitins with rabbit anti-HMBA); hence, it would appear that the allergenic and antigenic determinants of HMBA are 'conformational'.

Amino Acids↗

The heterogeneity of bovine IgG2--IV. Structural differences between IgG2a molecules of the A1 and A2 allotypes.

The major product of digestion of bovine IgG2a(A1) with immobilized pepsin is F(ab')2 while similar treatment of IgG2a(A2) yields Fab, Fc and other products. It is postulated that structural differences in the hinge region, including the absence of the most N-terminal disulfide bridge in IgG2a(A2) and a displacement of the primary pepsin cleavage site toward the Fd, can explain this effect. The immunodominant A1 allotope(s) appears to be located in the CH3 domain of IgG2a(A1) while the A2 allotopes are located elsewhere and are apparently affected by digestion. The allotypic bias of rabbit anti-IgG2a is also present in anti-IgG2a raised in goats. However, the A2 allotypic determinants of bovine IgG2a are recognized by goat precipitins although precipitins of this specificity are not detectable in rabbits immunized with IgG2a(A2). Rabbit anti-A2 antibodies are detectable using the ELISA in rabbits immunized with IgG2a(A2).

Animals↗

A simple procedure for the isolation of human secretory IgA of IgA1 and IgA2 subclass by a jackfruit lectin, jacalin, affinity chromatography.

Jackfruit lectin, jacalin, prepared from two batches of jackfruit seeds showed a different specificity in precipitating reaction in Agarose gel with various purified immunoglobulins and secretory components. Jacalin-P, extracted from jackfruit seeds from the Philippines, reacts only with serum IgA and secretory IgA of IgA1 subclass. Jacalin-O, extracted from jackfruit seeds from Okinawa prefecture in Japan, makes a strong precipitin are with IgA1 subclass and a weak precipitin arc with IgA2 subclass of IgA2m(2) allotype, IgM, IgD and IgE. Human secretory IgA of IgA1 subclass was isolated from human milk by a single jacalin-P affinity chromatography using D-galactose as a dissociating agent. From conventionally purified human secretory IgA preparation, secretory IgA of IgA1 subclass and of IgA2 subclass were separated from each other. The former was separated as jacalin-P adsorbed fraction and the latter as jacalin-P non-adsorbed fraction by the affinity chromatography. Subclass composition of secretory IgA in human milk was determined by the affinity column and was calculated to be 70% for IgA1 and 30% for IgA2 subclass. Jacalin affinity chromatography has several advantages compared with antibody coupled affinity chromatography, notably, high capacity, inexpensiveness, and very mild extraction of IgA1 subclass.

Chromatography, Affinity↗

IgA binding lectins isolated from distinct Artocarpus species demonstrate differential specificity.

The discovery of jacalin, a group of lectins from jackfruit seeds (Artocarpus heterophyllus), has attracted considerable attention due to its numerous interesting immunological properties as well as its usefulness in the isolation of various serum proteins. We have further identified a similar lectin from the seeds of Champedak (Artocarpus integer) which we refer to as lectin-C and performed comparative studies with two types of jacalin isolated from different batches of the Malaysian jackfruit seeds (jacalin-M1 and jacalin-M2). The three purified lectins demonstrated equivalent apparent Mr of about 52,500, each of which comprised of a combination of two types of non-covalently-linked subunits with apparent Mr of approximately 13,300 and 16,000. The lectins demonstrated equal haemagglutinating activity against human erythrocytes of blood groups A, B, AB and O. Our data also demonstrated that lectin-C, jacalin-M1 and jacalin-M2 are similar by selectively precipitating human serum IgA1 and colostral sIgA but not IgA2, IgD, IgG and IgM. When immunoelectrophoresis was performed on normal human sera and reacted with the lectins, single precipitin arcs corresponding to IgA immunoprecipitates were detected with lectin-C and jacalin-MI. Jacalin-M2, however, exhibited two closely associated precipitin arcs. The binding of these lectins with IgA was pronouncedly inhibited in the presence of p-nitrophenyl-beta-D-galactopyranoside, 1-o-methyl-alpha-D-galactopyranoside, D-melibiose, N-acetyl-D-galactosamine and D-galactose. The data therefore provide evidence on the differential specificity of IgA binding lectins isolated from seeds of similar as well as distinct Artocarpus species.

Binding, Competitive↗

Structural, immunological and functional comparisons of factor H, rheumatoid arthritis protein (RHP), and its apparent normal counterpart (N-RHP).

The isolation and characterization of two human serum proteins, RHP and N-RHP, are described. N-RHP appears to be the normal counterpart of RHP which is found at elevated levels in sera of patients with rheumatoid arthritis [Rosano et al. (1988b) Inflammation 12, 351 - 360]. Although both proteins crossreact with anti-Factor H and have identical N-terminal amino acid sequences, they differ from Factor H in pI, solubility at low ionic strength, and in glycosylation. RHP differs from Factor H and N-RHP in antigenicity in the rabbit, in effect on the C1q-anti-C1q precipitin reaction, and in ability to disaggregate C1, the first component of the complement system. Removal of RHP, N-RHP and Factor H from binding to C1q is a prerequesite for separation of RHP and N-RHP from Factor H by anion exchange chromatography and isoelectric focusing. The finding of uniquely demonstrable RHP activity (enhancement of C1q-anti-C1q precipitin activity) in unfractionated sera from patients with rheumatoid arthritis, but not in normal sera, suggests that RHP is not an artefact of Factor H produced during isolation.

Amino Acids↗

Isolation and characterization of two constitutive forms of microsomal cytochrome P-450 from a single bovine liver.

Two constitutive forms of cytochrome P-450 isozyme were isolated from microsomes prepared from a single bovine liver. The two highly purified isozymes were electrophoretically homogeneous on SDS-polyacrylamide gel and their apparent minimum molecular weights were estimated to be 50 000 and 55 000. The isozyme of smaller molecular weight, designated cytochrome P-450A, and the one of large molecular weight, designated cytochrome P-450B, were distinct proteins by the criteria, SDS-polyacrylamide gel electrophoresis, peptide maps, amino acid contents. To reveal the immunochemical relation between these two isozymes, antibodies to each isozyme was raised in rabbit. Antibodies to cytochrome P-450A gave a single precipitin line against its antigen in Ouchterlony double-diffusion plates, but did not cross-react against cytochrome P-450B. On the other hand, antibodies to cytochrome P-450B formed a single precipitin line with its antigen and did not show any cross-reactivity against cytochrome P-450B. These results indicate that two isozymes are immunochemically distinct. This conclusion was supported by the results from immunochemical staining of the SDS-polyacrylamide gel electrophoretogram of the purified isozymes and detergent-solubilized bovine liver microsomes transferred to the nitrocellulose sheet. Both cytochromes P-450 showed high catalytic activities toward (+)-benzphetamine and aminopyrine in reconstituted systems, indicating that both enzymes have a high turnover number for N-demethylation.

Amino Acids↗

Differentiation between stains of human blood and blood of monkey.

The precipitin tube test fails to differentiate between blood stains of closely related animals such as man and monkey because of the close similarity between antigenic determinants of serum proteins of such closely related species. The quantitative precipitin technique cannot be applied to forensic work. This paper cites a case where definite opinion on the species of origin of some blood stains suspected to have come from a monkey was possible. In the method used, extracts of the questioned stain were tested with similar extracts of known human and known monkey blood stains against human globulin antiserum, by comparative double diffusion method in agar gel on microslides.

Animals↗

Immunological evidence for the capability of free-living Rhizobium japonicum to synthesize a portion of a nitrogenase component.

Immunodiffusion tests conducted under aerobic conditions demonstrated that cross-reactive material to antiserum prepared against the Mo-Fe protein component of nitrogenase from soybean nodule bacteroids was detectable in extracts of free-living Rhizobium japonicum cells cultured in a standard medium under: aerobic conditions; aerobic conditions with nitrate; aerobic conditions with ammonia; anaerobic conditions with nitrate; and anaerobic conditions with nitrate and ammonia. The most intense precipitin bands resulted from cross-reaction of the antiserum with extracts of cells cultured anaerobically with nitrate or anaerobically with ammonia and nitrate. Immunodiffusion experiments with crude bacteroid extract and purified Mo-Fe protein revealed a greater number of precipitin bands in tests conducted under aerobic conditions than those conducted under anaerobic conditions. These results indicate that some of the cross-reactive material observed under aerobic conditions resulted from breakdown of the Mo-Fe protein. Bacteroid extracts of nodules from plants supplied with ammonia exhibited only a trace of nitrogenase activity. The addition of an excess of the Fe protein component of nitrogenase, however, resulted in 270-fold enhancement of activity indication the presence of active Mo-Fe protein in these extracts. Our experiments together with results published elsewhere provide evidence that the genetic information for synthesis of a part of the Mo-Fe component of nitrogenase is carried by Rhizobium.

Aerobiosis↗

A sheep hydatid cyst glycoprotein as receptors for three toxic lectins, as well as Abrus precatorius and Ricinus communis agglutinins.

The binding properties of a glycoprotein with blood group P1 specificity isolated from sheep hydatid cyst fluid with Gal and GalNAc specific lectins was investigated by quantitative precipitin and precipitin inhibition assays. The glycoprotein completely precipitated Ricinus communis agglutinin (RCA1), Abrus precatorius agglutinin (APA) and Mistletoe toxic lectin-I (ML-I). Only 1.0 microgram of P1 glycoprotein was required to precipitate 50% of 5.1 micrograms ML-I nitrogen. It also reacted well with abrin-a and ricin, precipitating over 73% of the lectin nitrogen added, but poorly or weakly with Dolichos biflorus (DBL), Vicia villosa (VVL, a mixture of A4, A2B2 and B4), VVL-B4, Arachis hypogaea (PNA), Maclura pomifera (MPL), Bauchinia purpurea alba (BPL) and Wistaria floribunda (WFL) lectins. When an inhibition assay in the range of 5.1 micrograms N to 5.9 micrograms N of lectins (ML-I, abrin-a; ricin, RCA1, and APA, and 10 micrograms P1 active glycoprotein interaction was performed; from 76 to 100% of the precipitations were inhibited by 0.44 and 0.52 mumol of Gal alpha 1-->4Gal and Gal beta 1-->4GlcNAc, respectively, but not or insignificantly with 1.72 mumol of GlcNAc. The Gal alpha 1-->4Gal disaccharide found in this P1 active glycoprotein is a frequently occurring sequence of many glycosphingolipids located at the surface of mammalian cell membranes, especially human erythrocytes and intestinal cells for ligand binding and microbial toxin attachment. The present finding suggests that the Gal alpha 1-->4Gal beta 1-->4GlcNAc sequence in this P1 active glycoprotein is one of the best glycoprotein receptors for three toxic lectins (ricin, abrin-a, and ML-I) as well as for APA, and RCA1, and the result of inhibition assay implies that these lectins are recognizing part or all of the Gal alpha 1-->4Gal beta 1-->4GlcNAc sequence in the P1 active glycoprotein.

Animals↗

Detection of specific anti-antibodies in patients treated with radiolabeled antibody.

Over 100 patients have received cyclic treatment with polyclonal 131I labeled anti-ferritin and anti-carcinoembryonic antigen (CEA) antibodies from different animal species (rabbit, pig, cynomolgous monkey, bovine, and baboon). Because survival was prolonged from original cyclic treatment, retreatment with original antibodies (recycling) became a necessary consideration. An assay using autoradiography of Ouchterlony gels, with diffusion of patients' sera against the varied radiolabeled antibodies, was developed to detect anti-antibody precipitin bands. Anti-antibody could be detected with a sensitivity to the 60 ng level. Sera from 35 patients given from 1 to 7 separate cycles (2 injections/week, total antibody 6 mg/cycle) of radiolabeled foreign antibody were studied for the production of anti-antibodies. Anti-antibodies were detected in 11 of 22 primary hepatoma patients studied, 3 of 4 intrahepatic biliary cancer patients, and 0 of 9 Hodgkin's disease patients. In all but two of the patients, the anti-antibodies produced were specific for the species used in the treatment of the patient. Eight patients were reinjected (recycled) with previously used antibodies and the presence or absence of precipitin bands correlated with the ability of these antibodies to deposit in the tumor or to be rapidly degraded. The importance of this assay is its simplicity, sensitivity, and the rapid detection of anti-antibody activity for patients requiring treatment with radiolabeled antibodies.

Antibodies, Anti-Idiotypic↗

Extraction of serologic and delayed hypersensitivity antigens from spherules of Coccidioides immitis.

We have used an aqueous toluene extraction procedure to obtain antigens from mature spherules of Coccidioides immitis. This extract contained many antigens as determined by immunoblotting and two-dimensional immunoelectrophoretic studies. These included antigens with specificity for tube precipitin-type antibodies having molecular weights greater than or equal to 100 KDa. The extract also displayed lymphocyte-transforming activity when tested on human peripheral blood mononuclear leukocytes from donors who react to coccidioidal skin tests but elicited no such stimulation of cells from persons whose coccidioidal skin tests were nonreactive. At high concentrations of the extract, lymphocyte transformation did not occur, a finding that could not be explained by nonspecific toxicity. When gel filtration was employed to separate antigens by size, tube precipitin-like activity and specific coccidioidal delayed-type hypersensitivity displayed overlap, although only the latter activity was apparent in lower molecular weight pools.

Animals↗

Binding properties of a blood group Le(a+) active sialoglycoprotein, purified from human ovarian cyst, with applied lectins.

Studies on the structures and binding properties of the glycoproteins, purified from human ovarian cyst fluids, will aid the understanding of the carbohydrate alterations occurring during the biosynthesis of blood group antigens and neoplasm formation. These glycoproteins can also serve as important biological materials to study blood group A, B, H, Le(a), Le(b), Le(x), Le(y), T and Tn determinants, precursor type I and II sequences and cold agglutinin I and i epitopes. In this study, the binding property of a cyst glycoprotein from a human blood group Le(a+) nonsecretor individual, that contains an unusually high amount (18%) of sialic acid (HOC 350) was characterized by quantitative precipitin assay with a panel of lectins exhibiting a broad range of carbohydrate-binding specificities. Native HOC 350 reacted well only with three out of nineteen lectins tested. It precipitated about 80% of Ricinus communis (RCA1), 50% of Triticum vulgaris (WGA) and 37% of Bauhinia purpurea aba (BPA) agglutinins, respectively. However, its asialo product had dramatically enhanced reactivity and reacted well with many I/II (Gal beta1 --> 3/4GcNAc), T(Gal beta1 --> 3GalNAc) and Tn(GaNIAc alphaI --> Ser/Thr) active lectins. It bound best to Jacalin, BPA, and abrin-a and completely precipitated all the lectins added. Asialo-HOC 350 also reacted strongly with Wistaria floribunda, Abrus precatorius agglutinin, ricin and RCA1 and precipitated over 75% of the lectin nitrogen added, and moderately with Arachis hypogaea, Maclura pomifera, WGA, Vicia viosa-B4, Codium fragile tomentosoides and Ulex europaeus-II. But native HOC 350 and its asialo product reacted not at all or poorly with Dolichos biflorus, Helix pomatia, Lotus tetra-gonolobus, Ulex europaeus-I, Lens culinaris lectins and Con A. The lectin-glycoform interactions through bioactive sugars were confirmed by precipitin inhibition assay. Mapping the precipitation profiles of the interactions have led to the conclusion that HOC 350 contains a large number of receptors for I/II, T, and Tn active lectins. But in the untreated (or native) substance, most of these determinants are masked by sialic acids.

Carbohydrate Sequence↗

Purification of two lipovitellins and development of immunoassays for two forms of their precursors (vitellogenins) in medaka (Oryzias latipes).

Two distinct yolk proteins (YP1 and YP2) were purified from the ovary of medaka, and specific antisera against YPs were generated to characterize YPs and reveal their relation to two vitellogenins (Vg1 and Vg2). The molecular masses of purified YP1 and YP2 on gel filtration were 270 and 380 kDa, respectively. YPs were confirmed to be lipoproteins by staining with Sudan black. Amino acid compositions of YP1 and YP2 were similar to those of Vg1 and Vg2, respectively. In double immunodiffusion using anti-Vg1, a precipitin line of YP1 formed a spur against the Vg1 line. YP2 and Vg2 were reacted with anti-Vg2, and a precipitin line of YP2 formed a fuse against the Vg2 line. These biochemical and immunological analyses of purified YPs revealed that YP1 is lipovitellin 1 (Lv1) derived from Vg1 and YP2 is lipovitellin 2 (Lv2) derived from Vg2. Using specific antibodies against Lvs and Vgs, specific, high sensitivity chemiluminescent immunoassays (CLIAs) for two Vgs were developed to reveal basal Vg levels and response to exogenous estradiol-17beta (E2). The measurable range of both CLIAs was from 0.975 to 1000 ng/ml. The cross-reactivity to the alternative Vg in each CLIA was extremely low (<or=0.57%). When immature fish were immersed in water containing E2 for 1 h, both Vgs were induced by 0.5 microg/L of E2 at 24 h after treatment. Vg1 increased in a concentration-dependant manner up to 100 microg/L E2, while Vg2 reached a plateau at 10 microg/L of E2. The ratio of Vg1:Vg2 in E2-treated fish changed in a concentration-dependent manner from 1.5:1 to 8.5:1. The results from E2-treatment suggest that differential regulation may control the expression of medaka Vgs.

Animals↗

Precipitation of the D-galactose specific lectin from Erythrina indica by a triantennary complex type oligosaccharide.

We have previously demonstrated that a high mannose type glycopeptide is bivalent for binding Concanavalin A (Con A) and can precipitate the lectin (Bhattacharyya L. and Brewer, C.F. (1986) Biochem. Biophys. Res. Commun. 137, 670-674). The present results show that a triantennary complex type oligosaccharide containing nonreducing terminal galactose residues can precipitate the D-galactose/N-acetyl-D-galactosamine specific lectin from Erythrina indica (EIL). The interactions of the oligosaccharide with EIL was investigated by quantitative precipitin analysis. The equivalence point of the precipitin curve indicated that the glycopeptide is trivalent for EIL binding. These results indicate that each arm of the oligosaccharide can independently bind separate lectin molecules leading to precipitation of the complex. These findings are discussed in terms of the possible biological structure-function properties of complex type oligosaccharides.

Acetylgalactosamine↗

Computer simulation of radial immunodiffusion. I. Selection of an algorithm for the diffusion process.

Theories of diffusion with chemical reaction are reviewed as to their contributions toward developing an algorithm needed for computer simulation of immunodiffusion. The Spiers-Augustin moving sink and the Engelberg stationary sink theories show how the antibody-antigen reaction can be incorporated into boundary conditions of the free diffusion differential equations. For this, a stoichiometric precipitate was assumed and the location of precipitin lines could be predicted. The Hill simultaneous linear adsorption theory provides a mathematical device for including another special type of antibody-antigen reaction in antigen excess regions of the gel. It permits an explanation for the lowered antigen diffusion coefficient, observed in the Oudin arrangement of single linear diffusion, but does not enable prediction of the location of precipitin lines. The most promising mathematical approach for a general solution is implied in the Augustin alternating cycle theory. This assumes the immunodiffusion process can be evaluated by alternating computation cycles: free diffusion without chemical reaction and chemical reaction without diffusion. The algorithm for the free diffusion update cycle, extended to both linear and radial geometries, is given in detail since it was based on gross flow rather than more conventional expressions in terms of net flow. Limitations on the numerical integration process using this algorithm are illustrated for free diffusion from a cylindrical well.

Antigen-Antibody Reactions↗

Fowl cholera; cross-protective turkey antisera and IgG antibodies induced with Pasteurella multocida-infected tissue bacterins.

Turkey antisera induced with formolized Pasteurella multocida-infected tissues (T antisera) passively cross-immunized 48 of 55 chickens against a challenge dose of P. multocida organisms, from which 0 of 15 controls survived. However, turkey antisera induced with formalin-killed, agar-cultured P. multocida cells (A antisera) passively cross-immunized only 4 of 30 chickens. Cross-immunity refers to protection against a different immunologic type of P. multocida. Quantitative precipitin reactions of the A and T antisera with antigens from agar-cultured cells showed that more antibody was present in the A than in the T antisera. However, antigens extracted from the infected tissues reacted with the T and not with the A antisera in the Ouchterlony procedure, demonstrating qualitative differences between the agar-cultured antigens and those extracted from the infected tissue. The gel precipitins isolated from the A and T antisera were characterized as 7S immunoglobulins, which behaved in immunoelectrophoresis as would be expected for a IgG immunoglobulin. The IgG fraction from the T antiserum passively cross-immunized chickens almost as well as the whole antiserum; hence, the IgG antibody is a major factor in cross-immunity.

Animals↗