bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epstein‐Barr virus mediates a switch in responsiveness to transforming growth factor, type beta, in cells of the B cell lineage
Authors: Blomhoff Heidi Kiil , Smeland Erlend , Mustafa Abu Salim , Godal Tore , Ohlsson Rolf 
Published: March 2007

AbstractThe functional performance of the transforming growth factor beta (TGFβ), appears to depend on the target cell phenotype as well as in vitro culture conditions. We show here that Epstein‐Barr virus (EBV) infection may induce a change in responsiveness to TGFβ, since TGFβ inhibits traverse of the cell cycle of activated normal human B cells, but promotes cell proliferation of EBV‐positive Burkitt's lymphoma cell lines as well as EBV‐infected B cells. We present evidence that the switch in the responsiveness to TGFβ is mediated by EBV infection, irrespective of the proliferative status of target cells, and thus may contribute to the initiation as well as the maintenance of certain B cell neoplasias.
C3 convertase of the human alternative pathway of complement: modulation of enzyme activity and stability by mouse monoclonal antibodies to Bb
Authors: Fishelson Zvi , Müller‐Eberhard Hans J. 
Published: March 2007

AbstractTo further characterize functional sites on C3b, Bb, the C3 convertase of the alternative pathway of complement, we examined the effect of four monoclonal antibodies on its activity and stability. These antibodies recognized antigenic epitopes on human Bb which were not fully exposed in intact factor B. Three of the monoclonal antibodies inhibited lysis of rabbit erythrocytes by normal human serum in the presence of Mg2+ and EGTA. Two of these antibodies markedly inhibited the activity of purified C3b, Bb deposited on rabbit erythrocytes. However, all four monoclonal antibodies increased the half‐life of the C3 convertase. Thus, these results demonstrate that binding of antibodies to Bb may concomitantly stabilize C3b, Bb and abate its activity. It is likely that such antibodies induce in Bb conformational changes which increase the C3b, Bb complex stability but may also hinder its catalytic site.
Deficient tumor‐specific immunity in old mice: in vivo mediation by suppressor cells, and correction of the defect by interleukin 2 supplementation in vitro but not in vivo
Authors: Bruley‐Rosset Martine , Payelle Béatrice 
Published: March 2007

AbstractThe capacity of old (18–24 months) C57BL/6 mice to develop an immune reaction against MC‐B6‐1 fibrosarcoma cells was studied using in vivo adoptive transfer experiments (Winn assay) and in vitro T cell‐mediated cytotoxicity test. Anti‐tumor immunity was found to decline with age, as indicated by a decreased anti‐tumor growth T cell activity. A suppressive activity was also found present in the splenic T cell population of old mice which can inhibit the in vivo generation of immune T cells in young mice.These suppressors, or their precursors, were resistant to cyclophosphamide treatment and were effective only when administered 3 days before the immunization of young mice. These mice developed immune T cells perfectly when the suppressors were administered 3 days after immunization, indicating that suppressors may act at an early phase of T cell activation. The protective activity of T cells in vivo correlated well with the in vitro T cell cytotoxicity for MC‐B6‐1 tumor cells, as both were depressed in old mice. Exogenous interleukin 2 (IL 2) addition during the 4‐day culture period partially restored the low cytotoxic activity of old immunized lymphocytes, suggesting that specific clones were present but that a lack of IL 2 limited their expansion. However, in vivo supplementation with IL 2 administered after immunization did not increase the protection mediated by old immunized T cells but, rather, increased the suppression. This work demonstrates the presence of a T cell suppressive activity in the spleen of old mice but also indicates that precursors of cytotoxic cells are generated by the immunization. It seems that in vitro IL 2 addition increases cytotoxic cells while in vivo IL 2 administration amplifies the development of suppressor cells generated during immunization of aged mice.
Selective immunosuppression with anti‐interleukin 2 receptor‐targeted therapy: helper and suppressor cell activity in rat recipients of cardiac allografts
Authors: Kupiec‐Weglinski Jerzy W. , Padberg Winfried , Uhteg Lawrence C. , Ma Lan , Lord Roseanne H. , Araneda Dorian , Strom Terry B. , Diamantstein Tibor , Tilney Nicholas L. 
Published: March 2007

Abstract(LEW × BN)F1 cardiac allografts are rejected within 8 days in unmodified LEW rats. ART18, a mouse anti‐rat IgG1 monoclonal antibody which binds specifically in vitro to the interleukin 2 receptor (IL2R) molecule expressed primarily on activated T cells, prolongs allograft survival in a dose‐dependent fashion to ca. 3 weeks (p < 0.001) after being administered for 10 days after transplantation. This effect was related to the specificity of the antibody for IL2R, as therapy with ART62 (a monoclonal antibody recognizing MHC class I antigen but not binding the rat IL2R) was ineffectual. Suppressor activity was detected in spleen cells of ART18‐treated grafted hosts: in vivo, splenic T suppressor/cytotoxic fraction adoptively transferred into normal LEW improved donor‐specific but not third‐party test graft survival (17 days, vs. 8 days, respectively, p < 0.001); in vitro, mixed lymphocyte reaction was profoundly but nonspecifically inhibited (< 5% of test mixed lymphocyte reaction, p < 0.001 as compared to acutely rejecting controls). In contrast, splenic T helper (Th) cells from ART18‐treated hosts were functionally depressed, as noted by their passive transfer into immunologically anergic B recipients of cardiac allografts (rejection in ca. 40 days, vs. ca. 13 days after transfer of Th from specifically sensitized rats). ART18 treatment also resulted in diminished elaboration of IL 2 as compared to normal (p < 0.005) or acutely rejecting hosts (p < 0.001); however, a remarkable increase in the production of IL 3 occurred (p < 0.001). These results demonstrate that IL 2R‐targeted therapy of immunocompetent graft recipients produces a selective immune defect in which donor‐specific T suppressor cells are spared, but Th cells attenuated or destroyed. Decreased elaboration of IL 2 concomitantly augments the release of IL 3, a lymphokine which might play a role in suppressor effect in vivo. In addition, IL 2R‐targeted therapy of the immunodeficient graft recipients abrogates the capacity of alloactivated T cells to re‐establish acute immune responsiveness.
Monoclonal antibodies to restricted and cross‐reactive idiotopes on monoclonal rheumatoid factors and their recognition of idiotope‐positive cells
Authors: Ono M. , Winearls C. G. , Amos N. , Grennan D. , Gharavi A. , Peters D. K. , Sissons J. G. P. 
Published: March 2007

AbstractFour human monoclonal rheumatoid factors (MRF) were used to raise a panel of mouse monoclonal antibodies (mAb) which were selected in a solid‐phase radioimmunoassay for binding to MRF but not normal IgM. Three mAb, each raised against a different MRF, bound to the majority of MRF and also to most polyclonal RF. Four other mAb bound selectively to the MRF against which they were raised and to no other MRF, and rarely to any polyclonal RF. Competition studies using cold and radiolabeled mAb further indicated that these mAb recognize distinct and different epitopes on MRF. RF activity of MRF was inhibited by 3 of the 4 mAb binding to a single MRF and 2 of the 3 mAb binding to multiple RF. It was thus concluded that of this panel of mAb 3 recognized cross‐reactive idiotopes and the remainder demonstrated highly restricted idiotopes on MRF. These mAb identified MRF idiotopebearing cells in the peripheral blood of 3 of the MRF donors (and a further subject with type II essential cryoglobulinemia), with a frequency ranging from 0.3–10% of all mononuclear cells with the mAb to restricted idiotopes or 1.5–17% with mAb to cross‐reactive idiotopes. These anti‐idiotopic mAb should thus provide a highly specific means of identifying and monitoring MRF‐producing cells in vivo.
Hybridomas producing human monoclonal antibodies against varicella‐zoster virus
Authors: Sugano Toru , Matsumoto Yoh‐Ichi , Miyamoto Chikako , Masuho Yasuhiko 
Published: March 2007

AbstractHybridomas producing human monoclonal antibodies (mAb) against varicella‐zoster virus (VZV) were generated by fusing human splenic lymphocytes with mouse myeloma cells. Before cell fusion, lymphocytes were stimulated in vitro with viral antigens and pokeweed mitogen. This combination synergistically increased the generation of VZV‐specific hybridomas. Five established hybridomas have been stably producing mAb for at least 9 months. These mAb, designated V1, V2, V6, V8 and V9, were of the IgG1λ isotype. They bound to all 6 tested VZV strains but not to other herpes viruses, with the exception that V1 bound to herpes simplex virus (HSV) as well as VZV. Immunoprecipitation analysis showed that V1, V6 and V9 recognized glycoprotein gpII, whereas V2 and V8 recognized gpI. In addition, V1 reacted with the gB glycoprotein of HSV. All these mAb neutralized viral infectivity. The neutralizations by V2 and V8 were more effective and more complement dependent than those by V1, V6 and V9. Immunofluorescence tests revealed that all these mAb bound to the surface membrane of VZV‐infected cells. These results suggest that cell fusion between in vitro stimulated lymphocytes and mouse myeloma cells is a reliable method for the generation of hybridomas capable of stable production of human mAb. The human mAb thus developed may provide a new means of passive immunization of humans against VZV infection.
Sequences and repertoire of the human T cell receptor α and β chain variable region genes in thymocytes
Authors: Kimura Nobuhiro , Toyonaga Barry , Yoshikai Yasunobu , Du Ran‐Pan , Mak Tak W. 
Published: March 2007

AbstractTo compare and contrast the human T cell antigen receptor (TcR) α and β chain messages found in human thymocytes to those previously isolated from human peripheral blood T lymphocytes and other nonthymic sources, 13 TcR α and 13 TcR β cDNA were isolated from a human thymocyte library and the nucleotide sequences were determined. The data indicate that, as was found in the peripheral T lymphocytes, the majority of the TcR α and TcRβ chain thymocyte cDNA were derived from potentially functional messages. Although the thymocyte‐derived TcR cDNA do not contain any unique structural features when compared to TcR cDNA from mature T lymphocytes, 4 new Jα segments, 17 new V‐gene segments (9 Vα; 8 Vβ) and 7 additional V‐gene families (4 Vα and 3 Vβ) and sequences had been identified. The exon CβO, found in many murine thymocyte TcR β messages, was not found in over 75 human β chain messages. Based on these new data, a revised estimate of human TcR Vα, Jα and Vβ repertoires is calculated. The most significant change has been the increase in the estimated number of human TcR Vβ‐gene segments to a total of about 100 distributed among about 18 families. The Vα families are now revised upward to 16, with a total number of Vα segments of 50. The estimate of the Jα segments in humans remains between 50–100.
Degranulation of in vitro differentiated mast cells stimulated by two monoclonal IgE specificities
Authors: Rofolovitch Michal , Amira Milly , Ginsburg Haim 
Published: March 2007

AbstractConfluent spread of mature nondividing mast cells is obtained after 1 month's growth of lymph node cells taken from mice immunized with horse serum and plated on embryonic fibroblast monolayers. The degranulation capacity of these mast cells and histamine release stimulated by monoclonal IgE antibodies and their antigens were studied. The mast cells were first incubated with either anti‐2,4‐dinitrophenyl (DNP) IgE or with anti‐ovalbumin (OVA) IgE and then with the other IgE to study the ability of one IgE specificity to saturate the receptors and block the ability of the other IgE to bind and evoke degranulation.Saturation of the receptors and maximal histamine release (86–92%) were obtained within 2–3 h incubation with excess IgE (1–10 μg/ml). No histamine was released after incubation for 3–4 h with the other IgE (0.38–4.0% histamine release). Seventeen days after the excess, unbound, saturating IgE anti‐DNP was washed away, 75% of the histamine was still released after antigen DNP‐bovine serum albumin was added. However, these mast cells were still effectively blocked from sensitization with IgE anti‐OVA (1.71% histamine release).The blocking could be broken if the second IgE molecules were allowed to stay longer than 4 h in culture. From 10 h onwards, the degranulation capacity steadily increased (from 59.6% histamine release after 10 h to 79.5% after 42 h). In studies with 125I‐labeled IgE, there was a direct correlation between the rate of binding of the second IgE to the mast cells (from 1.7% binding after 3 h to 75% after 48 h) and the increase in degranulation rate with the second antigen (from 2.40% histamine release to 65.4%). In contrast, only slight binding of the 125I‐labeled IgE of the saturating specificity occurred (4.2% after 3 h to 12.7% binding after 48 h).Incubation of mast cells, previously saturated with 125I‐labeled IgE, with cold IgE of either specificity did not proportionally reduce the cell‐bound label. This suggests that no substitution of IgE molecules on the receptors occurred. When the mast cells saturated with anti‐OVA were incubated with IgE anti‐DNP together with tunicamycin, the development of the degranulation capacity by DNP‐bovine serum albumin was inhibited. The results suggest that IgE molecules of the other specificity stimulated the appearance of new receptors on the mast cell surface.
Identification of a uveitogenic cyanogen bromide peptide of bovine retinal S‐antigen and preparation of a uveitogenic, peptide‐specific T cell line
Authors: Gregerson Dale S. , Obritsch Wesley F. , Fling Steven P. 
Published: March 2007

AbstractPeptide fragments of bovine retinal S‐antigen produced by cyanogen bromide (CB) digestion have been purified and tested for their ability to induce experimental autoimmune uveoretinitis (EAU) and pinealitis (EAP) in Lewis rats. Following immunization with the various peptides in complete Freund's adjuvant, one of the peptides, CB123, was found to be potently uveitogenic. A CB123‐specific, class II restricted T helper lymphocyte line (R208) prepared from one of the CB123 peptide‐immunized animals by repeated in vitro selection with purified CB123 was able to transfer severe EAU and EAP to naive rats. Peptides CB36, CB46, CB51 and CB66 were immunogenic as assessed by the presence of antibodies detected in the enzyme‐linked immunosorbent assay and sensitized lymphocytes found in [3H]thymidine incorporation assays using lymphocytes from the peptide‐immunized rats, but they did not induce significant EAU or EAP. Antibodies induced by immunization with the peptides also bound intact S‐antigen, unlike the lymphocytes which were only weakly responsive to S‐antigen. Cross‐reactivity of antibodies and lymphocytes from CB51 and CB66 immune animals suggested that these peptides overlap and contain a common epitope. No measurable immunity to any CB peptide or intact S‐antigen was found in the animals immunized with peptide CB26. Although a T cell line (R17) raised to human S‐antigen was also able to transfer EAU, it was weakly responsive to the CB123 peptide; also, the R208 line did not respond well to human S‐antigen. Since both human and bovine S‐antigen are uveitogenic, these results suggest that the uveitogenic epitope in CB123, which is of bovine origin, is not the same as the uveitogenic epitope of the human antigen.
Isolation of rat immunoglobulin class switch variants of rat‐mouse hybridomas by enzyme‐linked immunosorbent assay and sequential sublining
Authors: Pluschke Gerd , Bordmann Gerard 
Published: March 2007

AbstractThe use of sequential sublining in combination with highly specific and sensitive enzyme‐linked immunosorbent assays for the isolation of spontaneous rat Ig heavy chain class switch variants is described. These methods allowed us to isolate switch variants from mouse‐rat hybridoma lines secreting monoclonal rat antibodies. Switch variants from IgM to IgG2a, from IgG2a or IgG2b to IgE and from IgE to IgA were obtained. Members of the BA1.2 family, which consists of IgG2b, IgE and IgA antibodies are shown to exhibit identical rhamnose‐inhibitable binding to the O18A antigen of Escherichia coli and to the paratope‐associated anti‐idiotypic antibody BA114.
LFA‐1 β‐chain synthesis and degradation in patients with leukocyte‐adhesive proteins deficiency
Authors: Dimanche Marie‐Therèse , Le Deist Franç , Fischer Alain , Arnaout M. Amin , Griscelli Claude , Lisowska‐Grospierre Barbara 
Published: March 2007

AbstractThe defective membrane expression of the adhesive protein family (LFA‐1, Mo1 and p 150, 93) on leukocytes from certain patients with recurrent bacterial infections was shown to be secondary to the absence of synthesis of mature β chain that is common to all three antigens (Springer et al., 1984, Lisowska‐Grospierre et al. 1986). In all patients, studies of β‐chain biosynthesis that lead to this conclusion were performed using the monoclonal anti‐β chain antibody to isolate the β subunit. Since this antibody detects the mature form of β chainonly, the potential presence of a precursor or of an abnormal β chain in the patient's cells could not be tested. the availability of the polyclonal antibody to the purified β subunit allowed us t re‐examine the biosynthesis of the LFA‐1 subunits in 3 affected children. In al 3 patients, the absence of membrane expression of the LFA‐1, CR3 and p150,95 proteins was confirmed. The LFA‐1 α‐chain precursor of 170 kDa was detected in the lysates of PHA blasts of two children, but was not detected in the third. The β‐chain precursor of 85 kDa was isolated by the polyclonal anti‐β chain antiserum from the cytoplasm of phytohemagglutinin and Epstein‐Barr virus‐induced blasts of one patient. The same antibody precipitated some peptides of smaller mol. wt. from the cell lysates of 2 other patients. These results suggest that in this disorder the membrane nonexpression of the adhesive proteins is probably due to the structural abnormality of β chain which, although synthesized, is rapidly degradated.
Antibody diversity in amphibians. Noninbred axolotls used the same unique heavy chain and a limited number of light chains for their anti‐2,4‐dinitrophenyl antibody responses
Authors: Charlemagne Jacques 
Published: March 2007

AbstractNoninbred axolotls (Ambystoma mexicanum, amphibia, urodela) were immunized with trinitrophenylated sheep red blood cells (TNP‐SRBC) and anti‐2,4‐dinitrophenyl (DNP)/TNP antibodies were individually purified by affinity chromatography. The isolated IgM‐like antibodies were analyzed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and isoelectric focusing (IEF) under reducing conditions. The SDS‐PAGE and IEF‐separated heavy (H) and light (L) chains were electroblotted onto nitrocellulose, probed with mouse monoclonal antibodies specific for H or L axolotl Ig chains and stained by a rabbit anti‐mouse Ig horseradish peroxidase conjugate. The specific detection of axolotl anti‐DNP/TNP H chain spectrotypes shows for each of the 14 individually analyzed samples a very similar pattern of 4–5 ordered spaced bands. This suggests that all animals express the same VH chain segment representing the germinal expression of a unique VH gene. When the same analysis was performed starting from a pool of nonimmunized axolotl sera, a low background of natural anti‐DNP antibodies was detected. When analyzed by IEF, the H chains of the pooled anti‐DNP natural antibodies display the same pattern of restricted heterogeneity when compared to the H chain spectrotypes of the individual immune anti‐DNP/TNP antibodies. The specific detection of the axolotl anti‐DNP/TNP L chain spectrotypes indicates at the individual level more heterogeneous and polymorphic patterns compared with H chains, although most animals share the majority of their bands. Our experiments indicate that in axolotl, the production of antibodies to DNP results from the germinal expression of a very limited set of V genes, already expressed as naturally occurring anti‐DNP antibodies before immunization. This seriously restricts the possible extension of the antibody repertoire and perhaps even the nature of antibody “specificity” in this primitive vertebrate.
Induction of an auto‐anti‐IgE response in rats II. Effects on mast cell populations
Authors: Marshall Jean S. , Prout Samantha J. , Jaffery Ghazala , Bell Eric B. 
Published: March 2007

AbstractImmunization of rats with purified rat IgE myeloma (IR2) induces an IgG class atuoantibody directed specifically against the IgE isotype. This has variable stimulatory effects on the serum IgE concentration in high IgE‐producing BN rats but significantly decreases the serum IgE concentration in the conventional PVG.RT1u strain. We have examined the effects of inducing such an auto‐anti‐ϵ response on mast cell populations, as defined by their staining characteristics in BN rats. A persistent anti‐ϵ response changed the proportions of mast cell types. Those containing highly sulfated, Safranin‐positive granules which equate with cells described as connective tissue mast cells (CTMC) were reduced in number in skin, tongue and bone marrow, whereas the less highly sulfated, Alcian Blue‐positive mast cells were increased in number in these tissues as well as in the gut, a site rich in the so‐called mucosal mast cell. The overall number of mast cells in nonmucosal sites was not significantly changed in anti‐IgE‐producing rats.The direct effects of anti‐ϵ antiserum on mast cells in vivo were investigated using an immediate skin response (ISR) technique. The IgG component of serum from IR2‐immunized rats, fractionated by high performance liquid chromatography or eluted from Sepharose 4B‐coupled IR2, gave positive ISR in naive rats. The ISR was inhibited by prior incubation of immuno‐purified rat anti‐IR2 with solid‐phase IR2 or with two unrelated IgE myeloma proteins but not with rat IgG. Histological examination confirmed that degranulation of CTMC had occurred at the ISR sites.
Phenotypic identification of suppressor‐effector, suppressor‐amplifier and suppressor‐inducer T cells of B cell differentiation in man
Authors: Kansa Geoffrey S. , Engleman Edgar G. 
Published: March 2007

AbstractUsing monoclonal anti‐Leu 8 antibody to isolate subpopulations of human helper/inducer (CD4+) and suppressor/cytotoxic (CD8+) T cells, we have investigated the role of these subpopulations in the regulation of B cell differentiation in the human autologous mixed leukocyte reaction (AMLR). Whereas AMLR‐activated CD8+,Leu8− cells were capable of suppressing fresh AMLR cultures in the absence of fresh CD8+ cells, CD8+, Leu8+ cells suppressed only those cultures containing fresh CD8+ cells. On the other hand, CD8+, Leu8− cells became suppressor cells only when cultured in the presence of CD8+,Leu8+ cells. Finally, the development of CD8+ suppressor cells was dependent on the presence of CD4+,Leu8+ cells; CD4+,Leu8− cells were incapable of acting as suppressor‐inducer cells, but have been shown previously to mediate T cell help for B cell differentiation. Thus, at least 3 phenotypically distinct subsets of T cells interact sequentially to generate suppression of B cell differentiation induced in the AMLR: CD4+,Leu8+ suppressor/inducer cells, CD8+,Leu8+ suppressor‐amplifier cells and CD8+Leu8− suppressor‐effector cells.