bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conversion of Hageman factor (Factor XII) of the guinea pig to prekallikrein activator and inhibition of the formed kallikrein by a natural plasma inhibitor
Authors: Takeuchi Y. , Movat H. Z. 
Published: February 2007

AbstractAluminum hydroxide adsorbed guinea pig plasma was fractionated by QAE Sephadex A‐50. Fractions correcting the clotting defect in Factor XII‐deficient plasma (without having an effect on Factor XI‐deficient plasma) were pooled and rechromatographed twice through Sephadex G‐200. By gel filtration Factor XII had an approximate molecular weight of 130 000 – 140 000. Its approximate isoelectric point was 5.2. The partially purified Factor XII had no effect on prekallikrein, but upon trypsinization or adsorption to and desorption from celite, generation of prekallikrein activator was induced. Prekallikrein activator added to prekallikrein activated this pre‐enzyme, which then hydrolyzed BAEe and liberated kinin from heated plasma.An incidental finding was the recovery of an inhibitor of kallikrein. It eluted immediately after the excluded peak by anion exchange chromatography. It was passed twice through Sephadex G‐200 and had an approximate molecular weight of 100 000. The kallikrein inhibitor had a pl of 4.7–5.3. It was found to be heat‐resistant up to 80°C and resistant to acidification (pH 1.4). Under the conditions obtained the inhibitor also inactivated plasmin, trypsin and thrombin.
Induction of antibody‐forming cell clones in microcultures
Authors: Lefkovits I. 
Published: February 2007

AbstractWhen microcultures containing 2 × 105 mouse spleen cells are stimulated with heterologous red cells and the response is measured by the production of plaque‐forming cells or antibodies, some microcultures respond, some do not. Microcultures which do not respond to a given antigen are still capable of responding to another antigen. The response marks the presence of at least one precursor cell, probably a B cell. Most of the responding cultures would receive only one such precursor cell, and hence contain single clones of antibody‐forming cells. The frequency of these precursor cells is calculated to be 5.5 × 10−6. Methods for handling and assaying large numbers of cultures in very small volumes (10 μl) are given in detail.
Direct evidence for immunoglobulins on the surface of thymus lymphocytes of amphibian larvae
Authors: Du Pasquier L. , Weiss N. , Loor F. 
Published: February 2007

AbstractImmunoglobulins associated with the membrane of amphibian lymphocytes are easily detectable by immunofluorescence and behave very much like membrane immunoglobulins on mammalian lymphocytes. Ontogenic studies of the thymus and spleen in larvae show a sharp increase (from less than 1 % to 80 %) in the level of lymphocytes carrying immunoglobulins in the thymus at very early stages of their development. This level remains constant during the entire larval and early adult life, and is significantly higher than that in the thymus of older adults (9 %). Splenic lymphocytes having immunoglobulins on their membrane remain at a constant level (40–60 %).
The effect of embryonic bursectomy on the rosette‐forming cells in the chicken
Authors: Hemmingsson E. J. , Alm G. V. 
Published: February 2007

AbstractSurgical bursectomy in 17‐day old chicken embryos drastically impaired both the rosette‐forming cell and plaque‐forming cell responses later in life. Thus, both these responses are primarily bursa‐dependent.
The effect of antigen and mode of immunization on the allotypic distribution of enhanceable plaque‐forming antibody
Authors: Chou C.‐T. , Cinader B. , Dubiski S. 
Published: February 2007

AbstractThe relation between the genotypic control and phenotypic expression of antibody formation and between gene dose and product concentration depends on and is modified by antigen‐mediated selection and by antigen‐induced cell division. This dependence was studied in terms of allotypic specificities of rabbit light chain as markers and with different antigens and. regimens of immunization. The number of enhanceable plaque‐forming cells of the same allotype was measured in the spleens of rabbits, homozygous and heterozygous at the Ab locus. A significant departure from a simple gene‐dose relationship was observed. The regular preponderance of one allotype over another (“pecking order”: A4>A6>A5>A9) was confirmed. The preponderance in A4/A5 animals was found to persist whether the allotype ratio of enhanceable plaques was tested after one, two or ten injections with SRBC, after immunization with chemically modified SRBC or with DNP‐HGG. There was no significant difference in the cross‐reactivity of A4 and AS plaque‐forming SRBC antibody. The distribution of allotype ratios of responding A4/A5 animals changed with prolonged immunization from trimodal to bimodal and finally approached unimodality. After two injections with SRBC, the incidence of individual heterozygotes, making a monoallotypic enhanceable plaque response, was greatest among animals with allotypes from the extremes of the pecking order (i.e. A4/A9).We can account for our observations and for the distribution of allotype ratios in the response to strong and to weak antigen on the basis of the following assumptions:

a small number of receptor‐carrying precursors of antibody‐forming cells is involved in the response to one cr two injections with antigen;
the specificity spectrum for antigens which evoke a heterogeneous response is the same for plaque‐forming antibodies of different allotypic specificity (A4 or A5);
in heterozygotes, the ratio of receptors with different allotypic specificities is different from 1 and is related to the distance in the pecking order; the greater the distance, the greater the difference from 1;
there is continuous recruitment from precursor cells during prolonged immunization.
Dose‐ and time‐dependent changes in the binding capacity of IgM antibody
Authors: Wu C.‐Y. , Cinader B. 
Published: February 2007

AbstractPast experiments have revealed antigen dose‐dependent changes in IgG but not in IgM affinity. This is of importance to the general validity of the receptor concept and led us to investigate IgM affinity as a function of antigen dose and of time after antigen administration.Rabbits were immunized with proteins conjugated with p‐azobenzene arsonate and the hapten response was assessed by plaque formation. Dose‐ and time‐dependent changes in binding properties of IgM were determined by inhibition with hapten. The quantity of hapten which led to inhibition of 50% of the plaques, I50, was independent of the amount of hapten antibody in the system. All direct plaques could be inhibited by antibody directed against μ chains, but were not inhibited by antibody against γ chains. The amount of antibody against μ chain which inhibited 50 % of the plaques was the same in the early as in the late plaque‐forming response.In the initial stages of antibody response, there was no change in I50, over a considerable range of immunizing doses, including doses sufficient to trigger a plaque‐forming response, but insufficient to maintain it. Dose related changes in IgM affinity were observed fifteen days after antigen injection. In general, the avidity of IgM plaque‐forming antibody increased with time. However, at a very high dose of antigen, there were no changes in average affinity. After a second administration of antigen, plaque‐forming cells were detected earlier than in the primary response, though not in greater numbers. The first plaque forming antibody to be detected was of relatively high affinity; antibody detected subsequently was of the same affinity as the antibody formed in the primary response.Results were discussed in terms of cooperation between receptor binding sites and in terms of interference with this cooperation when antigen antibody complexes trigger antibody formation.
The long‐term distribution of antibody‐forming cells
Authors: Anderson H. R. , Dresser D. W. 
Published: February 2007

AbstractPrevious experiments suggested that the spleen might not be the chief source of serum antibody synthesized several months after the immunization of mice by sheep erythrocytes; this has been confirmed for classes other than γM. The anatomical location of the cells making the antibody is not the same for each class. The thymus contains a relatively greater number of non‐γM antibody‐producing cells late in the response than it does in the first three weeks after immunization.
Position of a locus determining mixed lymphocyte reaction distinct from the known HL‐A loci
Authors: Eijsvoogel V. P. , Van Rood J. J. , Du Toit E. D. , Schellekens P. T. H. A. 
Published: February 2007

AbstractBilateral and unilateral mixed lymphocyte culture (MLC) tests were performed in five families, each containing one sibling in which recombination between the genes determining the antigens of the LA and Four segregant series of IIL‐A had occurred. The results confirm the very weak or non‐stimulatory effect of antigens of the LA segregant series, bringing to seven the total number of alleles for which this has been shown so far. Further anomalies in one of the families, however, indicate that the antigens of the Four segregant series are not fully responsible for MLC activation either. Of a group of three HL‐A identical siblings, one proved to be MLC‐positive with the other two, but MLC‐negative with another group of two HL‐A identical siblings, which group displayed a one‐allelic difference for HL‐A with the former group. Furthermore, the child showing this unexpected MLC reaction pattern proved also to be MLC‐negative with the earlier mentioned sibling who had the serologically demonstrable recombination between the LA and Four series, notwithstanding a difference for three HL‐A antigens.These findings are interpreted as strong evidence for the occurrence of a recombination between the HL‐A loci and a MLC determining locus, which can thus be localize outside the previously recognized HL‐A region close to the Four locus. The relationships between HL‐A, MLC, skin graft rejection and organ transplantation are reexamined in the light of this concept.
The synthesis of radioactively labeled sulfanyl‐N‐chloracetyl tyrosine and its use for determinations of quantities and affinities of anti‐p‐azobenzenesulfonate antibodies
Authors: Schirrmacher V. 
Published: February 2007

Abstract35S‐labeled sulfany l‐N‐chloracetyl‐L‐tyrosine is presented as a valuable hapten for binding studies on anti‐p‐azo‐benzenesulfonate antibodies. The capacities of individual rabbit anti‐sulf antisera to bind this hapten were correlated with their 7 S passive hemagglutination titers. Affinities of anti‐sulf antibodies to the hapten were determined by two methods, a) by directly measuring the binding constants and b) by calculating the ratios of the hapten‐binding capacities of the sera determined at two different hapten concentrations. The values obtained by the latter, much simpler method, were correlated with the binding constants determined for the same sera.
The rosette cell response of several mouse strains to immunization with both sheep and pigeon erythrocytes; magnitude of errors caused by cytophilic antibody
Authors: Kapp Judith , Benacerraf B. 
Published: February 2007

AbstractImmunization of mice with two non‐cross‐reacting red cells, sheep and pigeon, gave rise to rosette‐forming spleen cells (RFC) capable of binding both types of erythrocytes. These double rosettes occurred in random bred mice and ininbred strains. The double RFC response vaned from strain to strain, from 6‐32% of the total RFC response. Serum taken from mice during the peak response was able to passively sensitize normal mice, resulting in a considerable number of RFC and double RFC recovered in their spleens. Strain differences in the number of double KFC determined following immunization were found to be related to the ability of individual strains to be passively sensitized with cytophilic antibody. The transfer could be performed in vivo or in vitro. It has also been shown that this cytophilic antibody can belong to the IgM or IgC class. This data indicates that cytophilic antibodies are responsible for all double RFC and for a significant varying number of the RFC in actively immunized mice depending upon the strain.
Serum immunoglobulin levels in nude mice
Authors: Luzzati Alma L. , Jacobson Ethel B. 
Published: February 2007

AbstractA quantitative evaluation of Ig classes in the serum of “nude” mice(nu/nu) in comparison with nu/+ and +/+ animals is reported. IgA and IgG classes are shown to be reduced in “nude” mice, the reduction being particularly severe in the case of IgG1. On the other hand these animals have normal IgM levels.
Anti‐hapten antibodies in normal sera. II. Species difference in amounts and characteristics
Authors: Jormalainen Seija 
Published: February 2007

AbstractThe relationship between anti‐NIP (4‐hydroxy‐3‐iodo‐5‐nitrophenacetyl) and anti‐DNP (2,4‐dinitrophenyl) antibodies was studied in 158 sera of seven species. Evidence was found suggesting that anti‐NIP and anti‐DNP antibodies are generally different populations of molecules. It was shown that some species had higher average levels of natural antibodies than other species and some individuals of a species had a generally higher level of natural antibodies than other individuals of the same species.Fine specificity of natural antibodies was studied by using the related haptens NIP, NNP (4‐hydroxy‐3, Sdinitrophenacetyl) and NP (4‐hydroxy‐3‐nitrophenacetyl). A positive correlation was found between anti‐NIP and anti‐NP titers in individual sera as well as between the mean titers within the species. By using hapten inhibition and immunoadsorbents the antibody populations which inactivated NIP‐ and NP‐phages were shown to be represented in a different way in rabbits, pigs and rainbow trout. Rabbits appeared to have distinct NP‐specific antibodies, whereas pigs and rainbow trout did not.
Factors affecting the propagation of a B Cell Clone forming antibody to the 2,4‐dinitrophenyl group
Authors: Askonas Brigitte A. , Williamson A. R. 
Published: February 2007

AbstractWe have studied the factors controlling the propagation and sequential transfer of B cell clone, E9, forming IgGI antibody to DNP in syngeneic CBA/H mice. The history of this clone is documented here in detail. E9 antibody was recognized by its isoelectric spectrum, detected by binding of 131‐DNP hapten after isoelectric focusing.During the life of this clone, induction of anti‐DNP depended on the presence of antigen (1 – 10 μg provided an optimum dose) and on cooperation with T‐derived cells recognizing carrier molecules. T cells contribute no information towards antibody formed by the B cells.During the first three transfer generations the clone produced high levels of E9 anti‐DNP (2 – 3 mg/ml serum) and the reliability of clonal transfer was high; 53/54 recipient mice formed large amounts of E9 antibody. As the proliferative capacity of the clone decreased, transfer became less reliable.The optimum interval between consecutive spleen cell transfers was 3 – 5 weeks, although successful transfer of memory cells could still be accomplished 65 days after last contact with antigen.The pI spectrum of E9 anti‐DNP remained constant throughout the life span of the clone, covering a period of one year and eight transfer generations and passage into 300 mice. We have therefore no evidence for any change or improvement in antibody produced by a single clone due to selective pressure.In other experimental series, limiting numbers (0.5 × 106 ‐ 2 × 106) of spleen cells primed with DNP‐BGG were distributed into irradiated syngeneic CBA/H mice. The incidence of single anti‐DNP‐forming clones sufficiently expanded for reliable sequential transfer is low; in 300 irradiated recipients we found 9 clones which produced high levels (0.3 ‐ 3 mg/ml) of anti‐DNP; some of these have been propagated by serial transfer. The high protein production appears to reflect overall expansion of the clone and to be a useful indicator of large numbers of memory cells. In general, low producing clones are not sufficiently expanded for effective propagation of the clone by serial spleen cell transfer.
Identification and genetic control of allotypic specificites on two variable region subgroups of rabbit immunoglobulin heavy chains
Authors: Kim B. S. , Dray S. 
Published: February 2007

AbstractAfter absorption with selected individual rabbit sera, allo‐antibodies directed against the a‐negative IgG from homozygous a2‐suppressed rabbit resulted in the separation of three distinct antibody populations which are designated anti‐A31, anti‐x32 and anti‐y33. The mating studies indicated that the x32 and y33 allotypic specificities are not controlled by allelic alternatives. The inheritance of the x32 and y33 allotypes was found to be closely linked to that of the al, a2 or a3 allotypes. Five allogroups were identified: a1, x−,y−;a1,x−,y33;a1,x32,y33;a2x32,y33; and a3,x32,y−. As was found for the a1, a2 and a3 allotypic specificities, the x32 and y33 allotypic specificities are present on IgA and IgM as well as on IgG suggesting that the x32 and y33 allotypic specificities are located on the variable region of immunoglobulin heavy chains. Our results indicate that three closely linked VH genes code for the variable regions of rabbit Ig heavy chain subgroups.
“Spontaneous” B cell activation due to loss of normal mouse serum suppressor
Authors: Bullock W. W. , Möller Erna 
Published: February 2007

AbstractNormal mouse spleen cells initiate synthesis of immunoglobulins in vitro in the presence of fetal calf serum and in the absence of specific antigen following the removal of regulatory suppressor(s) present in normal syngeneic mouse serum.
Sulfanilic acid as surface antigen on mouse lymphoid cells. I. Properties of hapten‐labeled cells and effects of antihapten antiserum in vitro and in vivo
Authors: Seiler H. 
Published: February 2007

AbstractThe conventional hapten sulfanilic acid (sulf) was coupled covalently to mouse spleen cells via an azobridge. Survival and functional behavior of the coupled cells were assayed by determining their capacity to exclude trypan blue, to secrete antibody and to produce a secondary immune response in an adoptive transfer system. Conditions have been found under which the cells were not affected by the coupling procedure but could be specifically lysed or inactivated in vitro and in vivo by anti‐sulf antiserum. Inactivation in vivo appeared to require complement, since F(ab')2 fragments of anti‐sulf antibody did not inactivate coupled cells. The effects of antibody and complement were shown to depend strongly on the amount of hapten coupled to the cells.The potential of this method is twofold. The hapten can serve as a surface marker, which can be detected by the effect of antiserum in vitro and in vivo. In addition the coupled hapten may be used as an artificial histocompatibility antigen, which can be manipulated to a certain extent for experimental analysis of its function.
Leucocyte mobilizing factor: A new biological activity derived from the third component of complement
Authors: Rother K. 
Published: February 2007

AbstractA simple method is described to assay for factors that mobilize leucocytes in the bone marrow. Guinea pig or rat femura were slowly perfused with Medium 199 and the cell concentration in the effluent was determined. Leucocyte mobilizing factor (LMF) was recognized by an increase in the effluent cell concentration following addition of the material to the perfusion medium.By reaction with C 142, the rabbit C3 molecule was cleaved, releasing a fragment with LMF activity. A purification procedure is described. The factor was devoid of chemotactic activity. It was negatively charged at pH 8.6.LMF may be involved in the pathogenesis of the leucocytosis associated with C dependent immune reactions in vivo.
The molecular requirements for chemotactic attraction of leucocytes by proteins. Studies of proteins with synthetic side groups
Authors: Wilkinson P. C. , McKay I. C. 
Published: February 2007

AbstractVarious small organic molecules were covalently linked to human serum albumin (HSA) and other proteins, and the products were tested for their ability to attract human peripheral blood neutrophil leucocytes in vitro. It was found that many substances, when attached to HSA, could increase its chemotactic activity. The chemotactic activity of the conjugates was not specifically inhibited by the presence of the conjugated substance in free solution. Thus it seems unlikely that chemotactic recognition of structurally altered proteins depends on a close stereospecific bonding between a cell surface receptor and the side group on the protein.In general, non‐polar side groups such as tosyl, propionyl and butyryl groups made the protein more chemotactic, than did polar side groups such as picryl, p‐sulphobenzylazo, guanidyl and carbamoylmethyl groups. We suggest that the chemotactic recognition of structurally altered proteins by neutrophils depends on hydrophobic bonding between non‐polar groups on the protein and those on the cell surface. Ionic groups would also be necessary for activity if the protein had many surface non‐polar groups: if there were no coulombic repulsions the non‐polar groups would become concealed by adhering to one another.
The occurrence of antigenic determinants common to flagella of different salmonella strains
Authors: Langman R. E. 
Published: February 2007

AbstractFive Salmonella proteins, hitherto regarded as antigenically distinct, have been shown to share common antigenic determinants. It is proposed that the flagellar (H) antigens be designated as either Hv (variable) or Hc (common); in these terms the Kauffmann‐White schema describes the Hv determinants only. Antibodies to Hc determinants could be demonstrated by precipitation reactions detected by the Ouchterlony gel diffusion technique and by passive hemagglutination assays.To account for the finding that antibody to Hc determinants is not detected by bacterial immobilization assays it was proposed that Hv determinants are distributed along the flagella so that antibody can bind with two sites on the one flagella, thus disrupting the wave motion; in contrast, antibody to Hc determinants can only bind to one flagella at a time and therefore acts as a crosslink and does not cause immobilization.
Carrier specificity and the allogeneic effect in mice
Authors: Rajewsky K. , Roelants G. E. , Askonas Brigitte A. 
Published: February 2007

AbstractThe findings of several investigators suggest thatin vitrosoluble T cell factors, non‐antigen specific, can replace helper T cells in the induction of antibodies. The present experiments set limits to the possible range of action of such factors in thein vivoinduction process.Murine cells primed with a hapten‐carrier complex could not be efficiently stimulated to produce anti‐hapten antibody by injection of the carrier alone or together with the hapten on an unrelated carrier. This reconfirms the requirement of physical union between hapten and carrier for efficient secondary stimulation.Even under conditions of presumably maximal production of non‐antigen specific T cell product, namely in a graft‐versus‐host reaction, there was no evidence for the systemic appearance of such a factor. A graft‐versus‐host reaction could substitute for specific helper cells only when the hapten‐primed cells were the targets in the cellular reaction and did not belong to the aggressor cell population.The allogeneic effect was shown to be T cell‐dependent and to correlate with reactivity in mixed lymphocyte reaction. In most instances, efficient allogeneic stimulation of the secondary anti‐hapten response required the presence of both allogeneic aggressor cells and hapten on a heterologous carrier.Very low numbers of allogeneic cells (around 104T cells per host) sufficed to abrogate carrier specificity almost completely. This suggests that some type of amplification mechanism is involved in mediating the allogeneic effect.The results support the concept thatin vivo, efficient antibody induction relies on cell‐cell interaction mediated by antigen bridging or by allogeneic recognition.