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Biomedical subjects

J Ivanyi

Publications and source records attributed to J Ivanyi.

At least 199 records · Page 11Linked to original sources
PubMed1977

A heterophile carbohydrate moiety common to mammalian IgM and erythrocytes detected by chicken IgM antibody.

Sequential treatment of chicken lymphocytes with normal sheep serum (NSS), chicken antiserum against sheep erythrocytes (SE) and formaldehyde results in rosette formation with SE. The identity of reactive components and the mechanism of rosette formation has been elucidated. The binding activity of NSS to chicken lymphocytes was ascribed to "natural" IgM anti-species antibodies. Subsequently, chicken IgM anti-SE antibody reacted with sheep IgM bound to the lymphocyte surface, and, following formaldehyde fixation, rosettes were formed by the addition of SE. The reaction of chicken anti-SE antibody was competitively inhibited with a hog blood group substance suggesting that it had binding specificity for a carbohydrate moiety which is shared by sheep IgM and SE. This specificity represented only a fraction of the bulk of chicken IgM anti-SE antibodies and was not manifested by antibodies of the IgG class. The analysis by the above-described "sandwich rosette assay" was extended to chicken antisera against horse, rat and mouse red cells and to normal sera from these species. Cross-matching of chicken antisera, with the normal sera and red cells from the tested species revealed a distinct pattern of cross-reactivities. These results imply that the saccharide epitope which is shared by IgM and red cells has a wide distribution between various mammalian species and may be classified as a new system of heterophile antigens.

Animals↗
PubMed1977

Immunofluorescent detection of differentiation alloantigens (CA1) in the chicken.

Lymphoid cell surface alloantigens were detected by a triple-layer immunofluorescence technique. An antiserum raised against B locus-incompatible lymphoid cells also reacted with previously undefined differentiation antigens (CA1) which segregated between B locus homozygous (B14/B14) chickens of the same strain as the antiserum donor. CA1-positive chickens reacted with the antiserum by agglutination of red cells and staining of all peripheral lymphocytes and thymocytes but not bursal cells. Cross-absorption experiments have demonstrated that antigens expressed by red cells, T cells (both thymic and peripheral) and B cells (peripheral only) respectively, were of distinct specificity.

Animals↗
PubMed1977

Detection of bursa and thymus-specific alloantigens in the chicken.

CH strain chickens selected from the F2 progeny of a cross between CH (B10/10) and B14B (B14/14) strains carried bursa (BA) and thymus (TA)-specific alloantigens of B14B parental origin. The BA marker was present on 95% of bursal cells but only on 10% of splenic and blood B lymphocytes. The TA marker was expressed by 80% of thymus cells and weakly by 45% of splenic and 70% of blood T lymphocytes. The adopted immunological and genetic protocol offers a feasible approach towards detection of differentiation antigens in major histocompatibility complex-homozygous but 'minor' alloantigen-segregating populations.

Animals↗
PubMed1977

An immunofluorescent technique for the detection of lymphocyte alloantigens.

A triple-layer immunofluorescent technique for the detection of cell surface alloantigens has been developed. Chicken lymphoid cells were treated in sequence with: 1) chicken alloantibody, 2) rabbit anti-chicken Fc or anti-gamma chain serum and 3) FITC-labelled sheep anti-rabbit globulin. The second layer was diluted to that point where normal serum treated lymphocytes were no longer stained but without diminishing the degree of specific staining. This method enables the study of alloantigens expressed on B cells, avoiding the problem of staining of surface Ig-bearing lymphocytes.

Animals↗
PubMed1977

Inhibition of B-cell function by concanavalin-A-induced suppressor cells.

The in vitro immune response of normal spleen cells to the thymus-independent antigen dinitrophenylated levan (DNP-LE) was found to be inhibited by suppressor cells induced previously by concanavalin A (Con A) in vitro. At various suppressor to target cell ratios, the level of suppression observed was comparable to that seen in anti-sheep erythrocyte (SRBC) responses. Consequently, it is suggested that B cells constitute a direct target for Con-A-induced suppressor cell activity.

Animals↗
PubMed1976

Close linkage between genes coding for allotypic markers on chicken IgG and IgM.

The allotypic markers Gla and Gld (present on chicken IgG molecules) and Mla and Mlc (present on IgM) have previously been defined. The inheritance of these markers was studied in the F2 progeny of a cross between birds of the inbred lines CB (Gla+,d-,Mla+,c-) and WA (Gla-,d+,Mla-,c+). The results suggest that antigens Gla and Gld, and Mla and Mlc, are genetically controlled by alleles at two loci (Gl and Ml, respectively) and also show that these loci are closely linked.

Alleles↗
PubMed1976

Rapid recovery of antigen-binding receptors on chicken B cells following anti-Ig serum treatment.

Rosette-forming cells (RFC) from the peripheral blood of sheep red blood cell (SRBC)-immunized chickens were characterized as B cells which manifest antigen-binding receptors but no antibody secretion. Lymphocytes were pretreated at 0 degrees C with anti-Ig serum, washed, incubated further at various temperatures and harvested for the rosette-forming cells (RFC) assay. Anti-Ig treatment blocked all RFC formation and providing that the cells were maintained at less than 10 degrees C regeneration did not occur up to 6 h. Complete recovery of RFC formation occurred within 10 min at 37 degrees C following treatment with low but not with high concentrations of anti-Ig serum. However, recovery from inhibition by high-dose anti-Ig treatment was achieved by including chicken IgG in the incubation medium. The recovery of receptors was reduced following "sandwich" treatment of lymphocytes. When cells were treated with anti-Ig antibody, washed and exposed to various drug inhibitors of "capping" the regeneration of RFC was prevented; in contrast, inhibitors of protein synthesis were ineffective. The results were interpreted in terms of dissociation of anti-Ig antibodies from the Ig receptor at an early stage of the ligand-induced receptor redistribution process.

Animals↗
PubMed1976

Immunodeficiency in the chicken. IV. An immunological study of infectious bursal disease.

Chickens inoculated orally with infectious bursal disease virus (IBDV) 1 day after hatching subsequently showed a 50% incidence of immunodeficiency but little mortality. Antibody responses against IBDV and to immunization with sheep red blood cells (SRBC) or human serum albumin (HSA) were suppressed. Serum IgG concentration was decreased while IgM occurred exclusively in its 7S monomeric form (mIgM). An allotypic marker of chicken IgM (Mla) was lacking in mIgM derived from IBDV-infected birds. The loss of Mla occurred gradually in several birds between 3 and 12 weeks after perinatal infection. Inoculation of IBDV into chickens 3 weeks after hatching resulted in 50% mortality level but little immunodeficiency. Paradoxically, the serum IgG concentration was elevated, in comparison with normal birds. Histology of the bursa showed permanent hypo- or aplasia of follicles irrespective of the age of infection. The results suggest that bursal but not peripheral B cells are targets for IBDV, and immunodeficiency results from impaired peripheral seeding of B cells in infected juvenile chickens.

Age Factors↗
PubMed1976

Mechanisms of natural resistance to trypanosomal infection. Role of complement in avian resistance to Trypanosoma cruzi infection.

The natural resistance of chickens to Trypanosoma curzi infection and the capacity of their sera to lyse blood (trypomastigote) forms of the parasite in vitro were found to be complement-dependent phenomena. Parasites given intravenously to decomplemented chickens were detectable in their bloodstream for at least 24 h post-infection, whereas in untreated animals they became undetectable after 1 min (and destroyed flagellates were observed). One millilitre of serum had the capacity to lyse as many as 10-30 X 10(6) organisms. The lytic activity of serum in vitro was not impaired in chickens that had been immunosuppressed by four different procedures and was present in the absence of antibodies. In vitro lysis of T. cruzi by either normal or antibody-free chicken sera occurred in the absence of calcium ions but required magnesium ions, indicating that complement was activated via the alternative pathway. Administration of normal chicken serum to mice infected with T. cruzi provoked a marked decrease in their parasitaemias.

Animals↗
PubMed1975

Immunodeficiency in the chicken. I. Disparity in suppression of antibody responses to various antigens following surgical bursectomy.

The extent of suppression of antibody response by bursectomy (Bx) was examined as a measure of the seeding sequence of different clones from the bursa to peripheral lymphoid tissues. Chickens were bursectomized surgically 1, 4 or 7 days after hatching and immunized later with four antigens: sheep red blood cells (SRBC); Bordetella pertussis (Bp); human serum albumin (HSA); influenza virus (IV). The kinetics of the antibody responses were delayed in bursectomized birds when compared with the control groups. The following order in the degree of immunosuppression was established: Bp greater than HSA greater than SRBC greater than IV. This is discussed in relation to the 'sequential maturation' theory of ontogenesis of immunocyte differentiation. The data also stress the limitation of non-specific markers for assessing partial immunodeficiency states.

Age Factors↗
PubMed1975

Immunodeficiency in the chicken. II. Production of monomeric IgM following testosterone treatment or infection with Gumboro disease.

Chickens were treated at an early embryonal age with testosterone propionate or infected neonatally with the virus producing Gumboro disease. Their sera were subsequently fractionated by Sephadex G-200 chromatography, and showed a complete deficiency of IgG and the presence of IgM which was eluted with the 7S protein fraction. Purified and 125-I-labelled monomeric IgM was examined by SDS-acrylamide gel electrophoresis and found to contain both mu and light chains, together with a chain of intermediary size, which was absent from the patterns of 19S IgM or IgG.

Animals↗
PubMed1975

Immunodeficiency in the chicken. III. Hypoplasia of bursal follicles following intravenous injection of embryos with lipopolysaccharide or allogeneic lymphocytes.

Intravenous injection of LPS or allogeneic lymphocytes resulted in impaired maturation of B cells within the bursa of chick embryos. A gradual decline in the sensitivity of embryos towards both agents was reflected by a decrease in the number and size of bursal follicles following injection between 10 and 15 days of embryonation. The hypoplasia of these follicles in embryos injected with lymphocytes on the 10th day was a more sensitive measure of graft-versus-host reaction than splenomegaly. The relevance of results with this model to the aetiology of immunodeficiency diseases has been briefly discussed.

Animals↗