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B Blomberg

Publications and source records attributed to B Blomberg.

At least 37 records · Page 2Linked to original sources
PubMed1989

Detection of antibody responses in rabbits hyperimmunized with Campylobacter pylori. Enzyme immunoassay indicates extensive antigenic similarities.

Acid glycine extracts from four Campylobacter pylori strains and one GCLO strain were used as antigens in enzyme immunoassay (EIA). Immune responses of rabbits immunized with C. pylori strains, the GCLO-strain and other campylobacter strains were studied. All 14 rabbit antisera against C. pylori reacted with all four C. pylori extracts and there were extensive cross-reactions between these extracts. Antisera against C. jejuni and C. coli strains did not react with a C. pylori extract but reached with the GCLO antigen. Acid glycine extracts proved to be very satisfactory in C. pylori serology and the use of an extract prepared from only one strain instead of a combination of strains seems justified.

Animals↗
PubMed1988

Prevalence of Campylobacter pylori in an unselected Swedish population of patients referred for gastroscopy.

A survey of the prevalence of Campylobacter pylori in an unselected series of 117 patients referred for gastroscopy showed that 49.6% of the patients were infected. In 87% of infected patients both the antrum and the body of the stomach were involved. Duodenal infection occurred in only 9% of 102 studied patients. C. pylori could usually be demonstrated in mucosa showing signs of active chronic inflammation, whereas it was rarely found in histologically normal mucosa. The acridine orange staining method for demonstration of bacilli correlated well with bacteriology; identical results were obtained in 92.8% of the samples.

Adolescent↗
PubMed1988

Heterogeneity of Campylobacter pylori as demonstrated by co-agglutination testing with rabbit antibodies.

The indirect immunofluorescence (IFL) and the co-agglutination (CoA) methods were used to study the serology of Campylobacter pylori strains isolated from patients in different countries (Sweden, Finland, Canada and Australia). Antisera were obtained from rabbits immunized with whole cell antigens. With IFL tests the highest serum titers were obtained with C. pylori strains and their homologous antisera. These tests also showed that all the tested strains contained cross-reactive antigens. With the use of the CoA technique strain or type specific heat labile and heat stable antigens were demonstrated, and a provisional "seropattern" of a particular strain could be defined with selected CoA reagents. With the use of such reagents we were able to show that a patient may be infected with multiple C. pylori strains with different sets of surface antigens. The clinical and epidemiological implications of this serological heterogeneity of C. pylori are discussed.

Agglutination Tests↗
PubMed1987

Human lambda light chain locus: organization and DNA sequences of three genomic J regions.

Evidence for the genomic organization of human lambda light chain joining (J) region gene segments is presented. A mouse J lambda probe was used in Southern hybridizations to localize joining region sequences in a cosmid clone containing the genomic cluster of six human lambda constant (C) region gene segments. The results of these hybridizations suggest the presence of at least one J gene segment upstream from each constant region gene segment. The DNA sequences indicate that the human J lambda 1, J lambda 2, and J lambda 3 gene segments have consensus nonamer and heptamer sequences, proposed to be involved in V-J joining, are capable of encoding the known amino acid sequences for the respective J peptides, and have a sequence which could give a functional RNA splice site at the end of their coding regions. Our data show that a single functional J is located 1.3 or 1.6 kb upstream of each of the C lambda gene segments known to encode the Mcg, Kern- Oz-, and Kern- Oz+ isotypes. Therefore, the gene organization of this region of the human lambda locus is J1C1-J2C2-J3C3. The DNA sequences of J lambda 1, J lambda 2, and J lambda 3 presented in this paper establish that a single J lambda gene segment precedes each expressed C lambda gene segment, and support a model for the evolution of the human lambda JC clusters where J1C1 and J2C2-J3C3 arose from different ancestral JC units.

Animals↗
PubMed1986

The WI-L2-729-HF2 human hybridoma system. Arrangement of lambda genes in monoclonal hybrids.

Fusion of WI-L2-729-HF2 human lymphoblastoid cells and human B-cell blasts provides a very efficient and rapid means of isolating stable B-cell hybridomas that secrete high levels of new human immunoglobulins. By titrating the plating density of fused cells into microwells immediately following fusion, it has been possible to obtain monoclonal hybrids. In this communication, proof of monoclonality is provided based on subcloning, karyotyping, and Southern blot analyses of lambda light chain immunoglobulin genes. The results reveal rearranged lambda genes in hybridoma subclones that produce both kappa (the WI-L2-729-HF2 isotype) and new lambda light chains. In contrast, the WI-L2-729-HF2 parental cell line and kappa-producing hybrids exhibit a germline configuration of lambda genes. The results provide evidence that stable, monoclonally derived hybridomas may be obtained upon initial plating of fused cells, without subsequent subcloning. The data further demonstrate the WI-L2-729-HF2 system to be ideal for rapidly generating, at very high frequency, clonal human B-cell hybridomas that stably secrete human monoclonal antibodies.

B-Lymphocytes↗
PubMed1984

Restricted association of V and J-C gene segments for mouse lambda chains.

The frequencies of diverse rearrangements of variable (V)lambda to joining (J)lambda gene segments were examined by Southern blot hybridization in 30 murine B-cell lines, each producing an immunoglobulin lambda light chain of known subtype (lambda 1, lambda 2, or lambda 3). For 11 out of 12 lambda 1 chains, the rearrangement was V lambda 1----J lambda 1; for 9 out of 9 lambda 2 chains, it was V lambda 2----J lambda 2; and for 8 out of 9 lambda 3 chains, it was V lambda 1----J lambda 3. Similar results were obtained by considering the partial or complete sequences at the amino acid or cDNA level of 44 other lambda chains (24 previously described): for 43 of these chains the rearranged V-J gene segments were evidently V lambda 1-J lambda 1 for 28 lambda 1 chains, V lambda 2-J lambda 2 for 10 lambda 2 chains, and V lambda 1-J lambda 3 for 5 lambda 3 chains. Of the combined total of 74 chains there were 3 with unusual V lambda rearrangements, all involving the V lambda 2 gene segment: for 2 of these unusual chains, the encoding segments were V lambda 2-J lambda 1-C lambda 1 and for one they were V lambda 2-J lambda 3-C lambda 3. Thus, the results for all 74 lambda chains show that, in contrast to the apparently unrestricted V kappa----J kappa rearrangements for kappa chains, for each of the 3 murine lambda-chain subtypes V-J recombination is severely restricted: the V lambda gene segment expressed in lambda 1 and lambda 3 chains was nearly always V lambda 1 (95% and 93%, respectively), whereas in lambda 2 chains it was without exception V lambda 2 (19 out of 19 chains). Therefore V lambda-J lambda combinatorial variation is not a significant source of amino acid sequence diversity of lambda chains of inbred mice. If the order of the lambda gene segments is 5' V lambda 2-J lambda 2C lambda 2J lambda 4C lambda 4-V lambda 1-J lambda 3C lambda 3J lambda 1C lambda 1 3', as suggested previously and by the present findings, it appears that (i) when a V lambda gene segment rearranges in a developing B cell it ordinarily recombines with a J lambda gene segment in the nearest downstream (3') cluster of J lambda C lambda segments, and (ii) V lambda rearrangement to the upstream (5') cluster is very rare and possibly may not take place at all.

Animals↗
PubMed1982

The expression of antibody diversity in natural and laboratory-made polyploid individuals of the clawed toad Xenopus.

Antibody diversity, as measured by isoelectric focusing of dinitrophenol-specific antibodies, was compared in different polyploid species of the clawed toad Xenopus. Antibody heterogeneity increased with chromosome number and DNA content from Xenopus tropicalis (2n = 20 chromosome) to Xenopus ruwenzoriensis (2n = 108 chromosomes). Laboratory allopolyploids made by hybridization between two species showing different antibody diversities and different chromosome numbers gave antibody patterns intermediate between the two parents. On the other hand, autopolyploid individuals showed no increase in antibody diversity, showing that increased polyploidy alone cannot be responsible for increased heterogeneity. In contrast to the increase in antibody diversity following polyploidization, the number of expressed major histocompatibility complex alleles, as measured by a mixed lymphocyte reaction, did not increase. This locus appeared to be diploid or in the process of rediploidization in all the Xenopus species studied. Selection has thus operated differentially on the polyploid immunoglobulin and major histocompatibility loci. It apparently preserved the additional heterogeneity acquired for immunoglobulins favoring the expression of an expanded antibody repertoire in polyploid species.

Animals↗
PubMed1982

DNA sequences of the joining regions of mouse lambda light chain immunoglobulin genes.

The joining (J) segments of mouse immunoglobulin lambda light chain genes, lambda 2, lambda 3, and a presumptive lambda 4, were cloned, and their sequences were determined and compared with that of lambda 1. Although all the lambda J segments share sequence homology, the J1 and J4 segments and the J2 and J3 segments, respectively, are more homologous. These sequence data, together with the fact that present day lambda genes occur in two clusters, 5' J3C3J1C1 3' and 5' J2C2J4C4 3', further substantiates a probable evolutionary duplication unit, JIICIIJICI, with II the precursor of lambda 3 and lambda 2 and I the precursor of lambda I and lambda 4. From the J4 sequence, we conclude that the lambda 4 gene is most likely nonfunctional (i.e., a pseudogene). The signal nonamer sequence 5' to J3 differs from that of J1 in two consecutive base pairs. This difference could account in part for the lower level of expression of lambda 3 as compared with lambda 1 in mouse serum.

Animals↗
PubMed1981

Genetic control of T helper cell function in the clawed toad Xenopus laevis.

The genetic control of the collaboration between Xenopus T and B cells has been analyzed in vivo using cells from five strains of major histocompatibility complex-defined Xenopus. When carrier (fowl gamma-globulin)-primed T cells and hapten (dinitrophenylated keyhole limpet hemocyanin)-primed B cells differed by minor histocompatibility antigens or by only one haplotype of the major histocompatibility complex, the collaboration was efficient in the sense that large numbers of plaques, low-molecular weight antibodies and high-affinity IgM antibodies could be recorded in the cultures challenged with dinitrophenylated fowl gamma-globulin. However, when T and B cells differed at both alleles of the major histocompatibility complex, lower numbers of plaques were obtained, no low-molecular weight anti-hapten antibodies could be detected, and the IgM antibodies that were sometimes synthesized were of low affinity. This suggests that the major histocompatibility complex, or a gene linked with it, affects the collaboration between Xenopus T and B cells in a way perhaps similar to that described in mammals.

Animals↗
PubMed1981

Organization of four mouse lambda light chain immunoglobulin genes.

We have cloned four lambda light chain constant region (C) genes from mouse embryo DNA. Each carries its own joining (J) segment approximately 1.3 kilobases to its 5' side. The four C genes occur in two clusters, 5' J3C3J1C13' and 5' J2C2J4C43', with C4 being a new C lambda gene. We have also shown that V lambda 1 is joined productively with C lambda 3 in a lambda 3-producing myeloma, and it is most likely that V lambda 1 and V lambda 2 are the only V lambda genes. Based on the analysis of the germ line and rearranged variable region (V) lambda genes in myelomas we argue that the V lambda 1 and V lambda 2 genes are at the 5' side of the C3C1 and C2C4 clusters, respectively. We propose that the two clusters arose by duplication. We also speculate on the role of J-associated DNA sequences in regulation of expression of the lambda subtypes.

Animals↗
PubMed1980

In vitro evidence for T-B lymphocyte collaboration in the clawed toad, Xenopus.

Requirements for an in vitro secondary antibody response to the soluble antigens dinitrophenylated keyhole limpet hemocyanin and dinitrophenylated flow gamma-globulin are described for the clawed toad, Xenopus. Priming of both hapten and carrier-specific cells is required in order to obtain good responses to the hapten. The carrier-reactive ("helper") cells do not adhere to nylon wool, are X ray-resistant and surface Ig-negative. The cell adherence and X ray sensitivity characteristics of these Xenopus "T" cells and their ability to generate a mixed lymphocyte response, allogeneic cytotoxic and helper activities, are identical to those of thymus-derived (T) cells in higher vertebrates. The hapten-reactive, antibody-secreting cell precursors are nylon-adherent, X ray-sensitive and surface Ig-positive. In the absence of other distinguishing serological markers for T cells in frogs, and considering the thymus dependency of the helper activity described here, the evidence presented is interpreted as demonstrating the requirement for antigen-specific T-B cell cooperation in response to soluble protein antigens in vitro for Xenopus.

Animals↗
PubMed1979

Determination of the kappa anti-alpha(1,3) dextran immune response difference by A gene(s) in the VKappa-locus of mice.

Mice lacking the V(alpha(1,3) (h gamma1)-gene do not produce a gamma1 anti-alpha(1,3) dextran response. However, on hyperimmunization some strains mount a kappa-anti-alpha(1,3) dextran response, whereas other remain nonresponder. Responsiveness in dominant. The kappa-anti-alpha(1,3) response difference is linked to the Ly-3 locus on chromosone 6 and is likely the result of a structural Vkappa-gene(s). In conjunction with previous work, three Vkappa-allogroups can now be distinguished. At present, this is the only example of an immune responsiveness difference associated with the Vkappa-locus.

Animals↗
PubMed1979

Ontogeny of immunity in amphibians: changes in antibody repertoires and appearance of adult major histocompatibility antigens in Xenopus.

Larval Xenopus anti-2,4-dinitrophenyl antibodies of the low-molecular weight type can be analyzed by isoelectric focusing (IEF). Within a clone of genetically identical animals, tadpoles make antibodies whose IEF spectrotypes are shared by most of the individuals. Adults of the same clone also make antibodies of identical spectrotype, but the adult pattern can be very different from the larval one, although both responses are heterogeneous. The larval spectrotypes that one cannot see in a primary adult response can be found if the adult has been primed during larval life and boosted after metamorphosis. The heterogeneity of the response is somewhat lower in tadpoles (up to 12 antibody IEF bands) than in adults (up to 20 antibody IEF bands). The change in the repertoire occurs during metamorphosis at the time of the appearance of two major histocompatibility complex antigens. One, a lymphocyte antigen, appears 10-15 days before the end of metamorphosis, the other, present on red cells (and presumably also on lymphocytes), appears 1.5 month after the end of metamorphosis, as determined by immunofluorescence analysis. During the same period, the syngeneic mixed leukocyte reaction switches from a larval anti-adult to an adult anti-larval reaction.

Animals↗
PubMed1978

Shared antigenic determinants by mitogen receptors and antibody molecules to the same thymus-independent antigen.

The antibody response to dextran B1355 is thymus independent, and in high responder mice, over 90% of the antibodies carry the idiotype of an alpha-1,3 binding myeloma protein (J558). The present experiments demonstrate: (a) dextran B1355 is a B-cell mitogen both in a strain which carries the J558 idiotype on antibodies and in a low-responder strain which does not express that idiotype on antibodies to dextran; (b) anti-idiotypic antibodies to J558 recognize a dextran-specific surface receptor on 10--15% of all splenic B cells in those two strains as well as in all strains so far tested; (c) as shown by inhibition experiments such surface receptors cross-react with J558, and (d) anti-idiotypic antibodies are mitogenic for spleen cells of both strains resulting in B-cell proliferation and maturation to polyclonal antibody secretion.

Antibodies↗