bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of isotype expression by B cell clones responding to thymus‐dependent and thymus‐independent antigens in vitro
Authors: Hurwitz Julia L. , Tagart Victoria B. , Schweitzer Peter A. , Cebra John J. 
Published: February 2007

AbstractIt was found that the Type 2 thymus‐independent (TI‐2) antigens bacterial levan, trinitrophenyl‐Ficoll, and pneumococcal carbohydrate vaccine (PnC) stimulate clonal expansion and antibody secretion in splenic fragments from either hemocyanin‐primed or unprimed irradiated recipients bearing B cells from unprimed donors. The in vitro stimulation with TI‐2 antigens leads to the expression of isotype switching and provides a more balanced variety of isotypes than is usually observed in vivo. Still, some characteristic patterns of isotypes expressed in vivo to either TI‐2 or thymus‐dependent (TD) antigens are preserved in vitro. Frequencies of phosphocholine (PC)‐reactive B cells responding to either PnC or to PC‐hemocyanin (PC‐Hy) suggest an appreciable overlap in populations responding to these TI and TD forms of antigen. The existence of a population responsive to either form of PC determinant is supported by the observation that many clones arising in the presence of both forms of antigen express patterns of isotypes that appear as summations of those distinct patterns shown by clones responding to only one form or the other. These data suggest that PC‐Hy‐ and PnC‐responding cells may derive from a linear rather than a branched pathway of B cell development and that expression of isotype switching over the lifetime of a developing B cell clone may be regulated in a manner dependent on the form of the stimulating antigen.
Quantitative studies of the secretion of complement component C3 by resident, elicited and activated macrophages. Comparison with C2, C4 and lysosomal enzyme release
Authors: Zimmer Bernd , Hartung Hans‐Peter , Scharfenberger Georg , Bitter‐Suermann Dieter , Hadding Ulrich 
Published: February 2007

AbstractTo quantitate the secretion of complement component C3 by guinea pig peritoneal macrophages an enzyme‐linked immunosorbent assay was developed. C3 secretion was studied in resident, elicited and activated macrophages and compared with release of hemolytically active C2 and C4, as well as the lysosomal enzyme β‐D‐2‐acetamido‐2‐deoxyglucosidase.Resident macrophages secreted about 6 ng C3/106 cells/h into culture supernatants over a period of 12 h. Corynebacterium parvum‐activated cells were found to secrete 3 times that amount at nearly constant rates. There was a stepwise increase in secretion of functional C2 and C4 when comparing resident, elicited and activated macrophages; secretion was 2‐4 times higher in activated than in resident cells.
Synthesis of λ1, λ2, and λ3 light chains by mouse spleen B cells
Authors: Reilly Edward B. , Frackelton A. Raymond , Eisen Herman N. 
Published: February 2007

AbstractTo determine whether the infrequency of immunoglobulins with λ3 light chains is due to a corresponding scarcity of λ3 B cells, the production of the various λ chain subtypes (λ 1, λ2, and λ3) by normal spleen cells was compared. The results showed that λ1, λ2, and λ3 chains are produced in a ratio of about 1.0 :0.7 : 0.3, respectively. The argument is made that λ1, λ2, and λ3 B cells exist in the same ratio. Results obtained with neonatal and nude mouse spleen cells suggest that these small differences are not due to stimulatory effects of environmental antigens or regulatory T cells. The much greater disparity in the abundance of λ subtypes in various antibody responses and serum Ig suggests that λ1 B cells may be more likely than λ2 or λ3 B cells to differentiate into antibody‐secreting plasma cells.
Expression of cell surface lectins on activated human lymphoid cells
Authors: Apgar John R. , Cresswell Peter 
Published: February 2007

AbstractA cell surface lectin found on activated human lymphoid cells has been identified and characterized using membrane glycoprotein micelles as probes. These micelles, which are large, water‐soluble aggregates, are composed of glycoproteins isolated from detergent‐solubilized membranes of human B lymphoblastoid cell lines by Lens culinaris hemagglutinin affinity chromatography. The micelles have an average apparent molecular weight of 4 × 106 estimated by gel filtration and range in diameter from 25‐100 nm. Micelles bind to B and T lymphoblastoid cell line cells and peripheral blood lymphocytes activated with concanavalin A or in a mixed lymphocyte response. Unactivated peripheral blood lymphocytes and red blood cells bind very low levels of the micelles. The binding is saturable, reversible, and temperature‐dependent, with poor binding below 15 °C. Glycoproteins such as fetuin and porcine thyroglobulin, which contain complex oligosaccharide side chains, inhibit the binding, whereas glycoproteins containing only high mannose or simple serine‐linked carbohydrate side chains do not. In addition, binding can be inhibited by complex asparagine‐linked glycopeptides purified from pronase‐digested fetuin, but not by the simple serine‐linked glycopeptides. Membrane glycoprotein micelles are bound to the surface of the cells but are not internalized or degraded. The potential role of this cell surface lectin in lymphocyte function is discussed.
Postirradiation thymocyte regeneration after bone marrow transplantation. III Intrathymic differentiation and development of thymocyte subpopulations
Authors: Boersma Wim J. A. , Kokenberg Esther , van der Westen Gerard , Haaijman Joost J. 
Published: February 2007

AbstractFluorescence distributions of thymocytes stained for Thy‐1 as well as size measurements were used to discriminate between thymocyte subpopulations during regeneration of the thymus after irradiation and bone marrow transplantation.Subpopulations with “low” and “high” Thy‐1 density of donor‐ and recipient‐derived progeny were quantitated. They were continuously present in the thymus and developed simultaneously but at different rates of growth. A similar developmental pattern was observed for donor‐ and host‐derived “high” Thy‐1+ cells, whereas “low” Thy‐1+ cells of donor and recipient origin showed markedly different growth patterns. This indicated that development of the two subpopulations took place independently. During early regeneration donor‐derived “low” and “high” Thy‐1+ cells contain a high proportion of large cells, indicating the presence of cycling cells in both subpopulations.
A monoclonal antibody recognizing a human thymus leukemia‐like antigen associated with β2‐microglobulin
Authors: Knowles Robert W. , Bodmer Walter F. 
Published: February 2007

AbstractA monoclonal antibody, M241, was produced which binds to a human cell surface molecule with properties similar to the murine thymus leukemia (TL) antigen. This human TL‐like antigen was found on thymocytes and some T cell lines derived from patients with acute lymphocytic leukemia, but was not found on peripheral blood lymphocytes or B cell lines. The monoclonal antibody M241 was used to immuno‐precipitate a molecule from lysates of 125I surface‐labeled MOLT 4 cells which had two subunits, a 43‐kDa chain and a 12‐kDa chain. The small subunit was shown to be β2‐microglobulin (β2m) by immunoprecipitation with a monoclonal antibody, BBM.1, which recognizes human β2m. The TL‐like molecule recognized by M241 was shown to be serologically distinct from the HLA‐A, B, C molecules recognized by three monoclonal antibodies W6/32, PA2.6 and BB7.8, and distinct from another human thymocyte antigen, the 49 kDa HTA 1 molecule, recognized by the monoclonal antibody NA1 / 34. Following removal of the HLA‐A, B, C molecules, the HTA 1 molecules, and the M241‐defined TL‐like molecules from MOLT 4 lysates, additional β2m‐associated molecules were immunoprecipitated with BBM.1. These molecules contained a 45‐kDa subunit attached to β2m.
Inhibition of autologous mixed lymphocyte reaction by aggregated IgG molecules
Authors: Kabelitz Dieter , Canonica Giorgio Walter , Sjöberg Olof , Klareskog Lars , Wigzell Hans 
Published: February 2007

AbstractHuman autologous and allogeneic mixed lymphocyte reactions (MLR) were studied using various T cell subsets as responding cells. T cells expressing Fcγ receptor for IgG (TG) were weak responder while T cells with Fcμ receptor and T cells lacking Fc receptor responded vigorously in both types of MLR. Percoll‐separated T cells of low density (TL) enriched for TG cells were, however, excellent responders in autologous MLR, whereas T cells of high density (TH) were the major responders in allogeneic MLR. Continuous presence of or short‐term pulse with aggregated IgG significantly reduced the autologous MLR of unfractionated T and TL cells while largely sparing proliferation in allogeneic MLR. These findings are discussed with respect to diminished autologous MLR reactivity in certain autoimmune diseases.
Fine antigenic specificity and genetic restriction of lysozyme‐specific suppressor T cell factor produced by radiation leukemia virus‐transformed suppressor T cells
Authors: Adorini Luciano , Doria Gino , Ricciardi‐Castagnoli Paola 
Published: February 2007

AbstractCulture supernatants obtained from a radiation leukemia virus‐transformed, hen egg‐white lysozyme (HEL)‐specific, suppressor T cell line are able, when injected into mice, to specifically suppress the anti‐HEL antibody response. Suppression is observed on both primary and secondary anti‐HEL antibody responses evaluated by direct and developed hemolytic plaque assays. Culture supernatants from this HEL‐specific suppressor T cell line do not suppress the antibody response induced by a structurally related lysozyme, demonstrating the presence in the culture supernatant of a suppressor factor endowed with fine antigenic specificity. The suppressor factor is able to selectively suppress the anti‐HEL antibody response induced by the N‐terminal C‐terminal peptide of the HEL molecule indicating that the fine specificity of this factor is restricted to an antigenic epitope present in this region of the HEL molecule. The suppressive activity is restricted by genes located within the H‐2 complex and analysis of the suppression induced in recombinant mice demonstrates that the interaction between HEL‐specific suppressor T cell factor and its cellular target requires identity in the I‐J region of the H‐2 complex.
B cell subpopulations in the mouse: Analysis with monoclonal antibodies NIM‐R2 and NIM‐R3
Authors: Chayen Ann , Parkhouse R. M. E. 
Published: February 2007

AbstractTwo rat monoclonal antibodies, NIM‐R2 and NIM‐R3, have been produced using the rat myeloma line 210RCY3‐Agl.2.3 and spleen cells from Lou rats immunized with mouse spleen cell plasma membrane or cells. The antibodies identify nonoverlapping populations of surface Ig‐positive cells in the spleen and a large (95%) proportion of bone marrow cells. Both recognize differentiation antigens in that the surface representation of the markers changes during the development of the cell. The NIM‐R3 specificity does not appear until three weeks of age in both the spleen and bone marrow and may be on a more mature set of cells. In contrast, the NIM‐R2 antibody, which stains the pre‐B cell line 70Z/3 and binds to neonatal cells, may recognize pre‐B cells in the bone marrow.There was no Clear‐cut correlation between the presence or absence of surface IgM, surface IgD or complement receptors on B cells positive or negative for either NIM‐R2 or NIM‐R3. Most interesting was the finding of identical total surface Ig densities on cells which stained weakly or strongly with NIM‐R2, since these two B cell sub‐populations are shown to be enriched for memory and virgin B cells, respectively. To bias the production of monoclonal antibodies to distinct populations of cells, the immunogen for the NIM‐R3 fusion was depleted of cells strongly reactive with NIM‐R2. This method is of general applicability in the production of monoclonal antibodies to complementary populations of cells.
Recognition of self, balance of growth and competition: Horizontal networks regulate immune responsiveness
Authors: Grossman Zvi 
Published: February 2007

AbstractThis report addresses itself to two fundamental questions: the generation of immunologic specificity, and the regulation of cellular growth. The classical clonal selection theory and later schemes involving lymphocyte networks or “circuits” postulate sets of specific “recognition” events which directly determine the nature of the immune response. An alternative principle is offered to apply to the analysis of immune phenomena: namely, that of a Darwinian dynamic selection among lymphocyte populations differing in their relative “fitness”. Incremental selection pressure upon a diverse population is, in theory, capable of producing a precisely specific outcome, and this can account for the fine specificity of the immune response.The immune system is described in terms of “horizontal” networks. A network consists of lymphocyte clones regulated by feedback mechanisms which manifest cross‐reactivity, resulting in competition and selection. The relative “fitness” of clones within a network depends primarily on their growth capacities, as assessed by the “balance of growth” hypothesis: accordingly, the number of divisions of an antigen‐responsive lymphocyte and the probability of maturation depend on regulatory factors. In particular, (a) activated, but not “resting” cells, can be further induced to mature or regenerate the relative probability of maturation increases with antigen dose and with affinity (avidity); (c) the in vivo induction of “terminal differentiation” of both B and T cells is antagonistic to clonal expansion; and (d) both activation and maturation are threshold‐dependent in terms of antigen dose and avidity, the threshold for maturation being generally higher. The hypothesis implies that proliferation can be uncoupled from differentiation under certain predictable conditions. Moreover, clones that proliferate for prolonged periods of time without significant maturation into effector cells may reach prominence. This mode of “latent proliferation” plays a major role in the selection and expression of the immune repertoire: those T or B cells are selected that react “proliferatively” with certain classes of self antigens and this constraint ensures tolerance to self. Major histocompatibility complex restriction and alloreactivity follow essentially as expressions of heteroclicity in this selection. Proliferative, latent reactions can mediate generation and maintenance of memory and tolerance and determine the ratio of helper to suppressor cells. The proposed scheme is amenable to testing and has many theoretical and experimental implications.
α‐Bungarotoxin binding to the nicotinic acetylcholine receptor is inhibited by two distinct subpopulations of anti‐receptor antibodies
Authors: Barkas Thomas , Gairns Jan Mcphail , Kerr Helen Jackson , Coggins John Richard , Simpson John Alexander 
Published: February 2007

AbstractAffinity‐purified antibodies to the nicotinic acetylcholine receptor of Torpedo marmorata were fractionated into two populations using a covalently cross‐linked receptor‐toxin immunosorbent lacking free toxin‐binding sites.The population of antibodies which bound to and were subsequently eluted from this resin, and which cannot possibly contain antibodies directed to the toxin‐binding site itself, was effective in inhibiting the binding of toxin to receptor in solution. This unequivocally demonstrates that inhibition of toxin binding can be mediated by antibodies which are not directed against the toxin‐binding site. A second minor population of antibodies which did not bind to the affinity resin but which did inhibit the binding of toxin to receptor in solution was detected.Two subpopulations of toxin‐binding inhibitory antibodies can therefore be distinguished. A clear differentiation should be made in future work describing “anti‐toxin site” antibodies between antibodies directly binding to the toxin‐binding site and the pseudo‐anti‐toxin‐binding site antibodies described in this report.
Intrastrain recurrent idiotypes among anti‐DNA antibodies of (NZB X NZW)F1 hybrid mice
Authors: Tron François , Guern Christian Le , Cazenave Pierre‐André , Bach Jean‐François 
Published: February 2007

AbstractImmunization of NZB and A/J mice against an anti‐DNA hybridoma antibody (F227) derived from (NZB x NZW)F1 (B/W) mice allowed the preparation of two anti‐idiotype antisera. These two reagents were shown to recognize different idiotopes of the F227 monoclonal antibody. NZB anti‐idiotypic antibodies recognized non‐ligand‐modifiable idiotypic determinants. These idiotopes were private or present at undetectable level in BW mouse sera since it was found that only two of the 24 B/W mouse sera tested were recognized by these antibodies. Conversely, A/J anti‐idiotypic antibodies recognized partially ligand‐modifiable idiotopes which were found in all B/W mouse sera tested. These results demonstrate that anti‐DNA antibodies share similar idiotypic specificities and suggest that these autoantibodies occur as families of structurally related proteins.
Development and continuous growth in culture of interleukin 2‐producer lymphocytes from athymic nu/nu mice
Authors: Palacios Ronald , Fernandez Carmen , Sideras Paschalis 
Published: February 2007

AbstractSplenocytes of nu/nu mice treated with serum thymic factor (FTS) for 3 or more days followed by stimulation with either phorbol myristate acetate (PMA) or concanavalin A (Con A) produced interleukin 2 (IL2) as determined in two indicator systems, namely, support of growth of IL 2‐dependent T cells and promotion of Con A‐initiated mitogenesis of thymocytes. However, neither mitogens nor FTS alone could induce nude mice cells to produce IL2.Supernatants derived from the tumor cell line WEHI‐3 (WEHI‐3 conditioned media) induced and supported continuous growth in culture of Thy‐1.2+, Lyt‐1+2− lymphocytes from athymic nude mice capable of producing IL2 after their stimulation by either, PMA or Con A. The growth of these IL 2‐producer cell lines strickly depends on the presence of WEHI‐3 conditioned media, as in the absence of it they die 24‐48 h later. In addition, WEHI‐3 conditioned media have been supporting the growth of IL 2‐producer cell lines derived from nude mice for 3 1/2 months.The helper factor contained in WEHI‐3 conditioned media responsible for the above biological activity has an apparent mol. wt. of ∼ 40 000 as determined by Sephadex G‐100 chromatography and lacks IL1 and IL2 activities, but efficiently supports the growth of IL 2‐producer cells derived from nude mice and the peripheral blood of normal human volunteers. These results indicate that the helper factor in WEHI‐3 conditioned media which enables the generation and continuous proliferation in culture of IL 2‐producer cells in nude mice is distinct from interleukin 1, IL2 and FTS (mol. wt. 864). Finally, the possible functional relationship of FTS and the helper factor produced by WEHI‐3 cells is discussed.
The relationship between surface immunoglobulin isotype and immune function of murine B lymphocytes V. IgD‐bearing cells in immunological tolerance
Authors: Zan‐Bar Israel , Barzilay Malka 
Published: February 2007

AbstractThe role of IgD (δ) in the induction of tolerance in murine B lymphocytes was explored in the in vivo adoptive antibody response to bovine serum albumin (BSA). δ+ or δ− B cells purified on the fluorescence‐activated cell sorter were injected, with or without purified T cells, into lethally irradiated intermediate hosts, which were rendered tolerant by an injection of deaggregated BSA one day after the cell transfer. Spleen cells from the intermediate hosts were treated with anti‐Thy‐1.2 antiserum and complement mixed with normal T cells and were transferred to final hosts. The ability of the B cells of the final hosts to respond to the tolerogen BSA and to dinitrophenylated human gamma globulin antigen was examined. This approach enabled examination of the function of the B cell subpopulations in an environment free of tolerogen and of induced T suppressor cells.The results revealed that in the presence of T cells the δ+ subpopulation was highly resistant to tolerance induction, whereas the δ− subpopulation was highly susceptible to tolerance induction. However, there was no difference in susceptibility to tolerance induction between the two subpopulations when tolerance was induced in the absence of T cells.
An influenza virus matrix protein‐specific human T cell line with helper activity for in vitro anti‐hemagglutinin antibody production
Authors: Fischer Alain , Nash Sue , Beverley Peter C. L. , Feldmann Marc 
Published: February 2007

AbstractA human helper T cell line (F14m) activated by the matrix protein purified from A/X31 influenza virus has been developed. After activation by antigen for 7 days, and reculture with matrix protein and irradiated autologous feeder cells, the cells obtained from an in vivo influenza virus‐immunized donor have been growing in the presence of interleukin 2 for more than 7 months. The cells all belong to the helper‐inducer T cell subset and most of them express surface membrane HLA‐DR antigens. A small number (approximately 103) of F14m T cells provided optimal help for 1 × 105 autologous T‐depleted lymphocytes for production of anti‐A/X31 but not anti‐B/HK antibodies. The F14m T cells produce soluble factors (S14m) able to help B cells to secrete anti‐A/×31 antibodies. F14m and S14m were shown to help antibody production to hemagglutinin when cultured with B cells and the whole virus. The specificity of the T cell line for type‐A matrix protein was confirmed by the ability of S14m to provide help for anti‐A/JAP (A/H2/N2) but not for anti‐B/HK antibody production. These data provide evidence for matrix protein‐specific T helper cells and factors able to provide help for antibody production against hemagglutinin, a distinct protein of the same virus.
Selection of the T cell repertoire during ontogeny: Limiting dilution analysis
Authors: Teh Hung‐Sia , Bennink Jack , von Boehmer Harald 
Published: February 2007

AbstractThe relative frequencies of cytotoxic T lymphocyte precursors (CTL‐P) specific for minor histocompatibility antigens that are restricted to either k or b major histocompatibility complex antigens in normal B6 mice and in B6 → (B6 CBA)F1 radiation chimeras were estimated. The ratio of k‐restricted to b‐restricted CTL‐P determined for the radiation chimeras served as a base value to which the ratio of k: b‐restricted CTL from normal B6 mice can be compared. The frequencies of allorestricted CTL‐P in B6 mice were determined after the B6 cells had been depleted of k‐reactive cells by filtration through irradiated B6.H−2k mice. Lymphocytes from immunized animals were used to obtain frequency estimates of CTL‐P specific for minor H antigens. The cultures contained nu/nu spleen cells syngeneic to the responder, but no exogenous interleukin 2 (T cell growth factor) since a high degree of nonspecific killing was found in IL2‐supplemented cultures. It was found that the CTL‐P frequency of B6 mice to BALB.B antigens in the lymph node cells of normal or immune B6 mice were 1 in 300000 and 1 in 8000, respectively. In B6→ (B6 × CBA)F1 radiation chimeras, the ratio of BALB.B/BALB.K‐specific CTL‐P was 3 :1s ratio was 17 :1 in normal B6 mice. Twenty‐five percent of CTL clones from normal B6 mice lysing BALB.K target also lysed BALB.B target whereas less than 1% of CTL clones lytic on BALB.K target from the chimeras showed this cross‐reaction The results are compatible with the idea of complete positive selection of self MHC‐restricted CTL‐P in the absence of priming effects by foreign antigen.