bluuebunny/crossref_metadata_2025_split huggingface dataset:
The diversity of antigen‐specific monoclonal antibodies from transgenic mice bearing human immunoglobulin gene miniloci
Authors: Wagner Simon D. , Popov Andrei V. , Davies Sarah L. , Xian Jian , Neuberger Michael S. , Brüggemanno Marianne 
Published: March 2007

AbstractAn approach to the preparation of antigen‐specific human monoclonal antibodies focuses on mice transgenic for human immunoglobulin gene miniloci; the V gene segments in these miniloci undergo productive rearrangement to yield mouse B cells expressing human immunoglobulin (Ig) chains. The general usefulness of this strategy hinges on whether it is feasible to obtain specific, high‐affinity antibodies following immunization of such animals with a variety of antigens. To test this, we have investigated the antigen‐specific responses in mice which carry human IgH miniloci (constaining just one or two VH segments) instead of a functional mouse IgH locus. Although serum responses were relatively weak, monoclonal antibodies were readily obtained to all immunogens tested (a hapten, foreign proteins and human lymphoma cells). The affinities of two of the hapten‐specific (anti‐2‐phenyl‐oxazol‐5‐one) antibodies were 60 and 160 nM, values intermediate between what is typically obtained in the primary and secondary response of normal mice. Sequence analysis of the rearranged V genes revealed that junctional events made a major contribution to diversity with a considerable amount of apparently non‐templated sequence at the V‐D and D‐J borders. Somatic hypermutation was also evident within the expressed V gene segments of many of the antigen‐specific hybridomas. These findings augur well for the general usefulness of the transgenic approach for the isolation of high‐affinity human antibodies to a wide range of antigens and suggests that the miniloci need not be particularly large.
An immortalized cell line with features of human follicular dendritic cells. Antigen and cytokine expression analysis
Authors: Orscheschek Karin , Merz Hartmut , Schlegelberger Brigitte , Feller Alfred C. 
Published: March 2007

AbstractFollicular dendritic cells (FDC) are specialized cells residing primarily within lymphoid follicles. They bind immunocomplexes and play an important role in the presentation of antigen to follicular B cells. Isolation of FDC for in vitro studies, however, is difficult because they constitute only about 1% of the cells in lymphoid tissue and form tight clusters entrapping lymphocytes within their dendritic processes. The monoclonal antibody (mAb) Ki‐M4, which is highly restricted in its binding to FDC, is used to identify these cells.In order to establish a new immortalized cell line with features of FDC, we applied a modified procedure to isolate and enrich FDC from human tonsils and fused them with the myeloma cell line SP2/0‐Ag14. The new hybrid cell line, designated FDC‐H1, is of both mouse lymphoid and human FDC origin. FDC‐H1 was found to have unlimited growth potential and to consistently express the Ki‐M4 antigen and other surface antigens of human FDC.Semiquantitative reverse‐transcribed polymerase chain reaction (RT‐PCR) of enriched FDC and FDC‐H1 revealed the same highly restricted cytokine/mRNA profile for both, with detectable levels of interleukin (IL)‐1α and surface CD23 and a lack of mRNA for IL‐1β, IL‐2, IL‐3, IL‐4, IL‐7, IL‐9, IL‐10, interferon‐γ, tumor necrosis factor‐α, transforming growth factor‐β and granulocyte/macrophage‐colony‐stimulating factor. Additionally a weak but constant IL‐6 mRNA expression was found in the cell line FDC‐H1 by RT‐PCR. In situ hybridization experiments in tonsils revealed IL‐6 transcripts in cells with a staining pattern characteristic of a dendritic cell only in a few germinal centers.To our knowledge, FDC‐H1 is the first cell line that constantly expresses surface antigens and a cytokine profile characteristic of FDC. It is, therefore, well suited for studying the biology of FDC and the functional relationship between FDC and normal or neoplastic lymphatic cells.
Two inhibitors of pro‐inflammatory cytokine release, interleukin‐10 and interleukin‐4, have contrasting effects on release of soluble p75 tumor necrosis factor receptor by cultured monocytes
Authors: Joyce David A. , Gibbons Deena P. , Green Patricia , Steer James H. , Feldmann Marc , Brennan Fionula M. 
Published: March 2007

AbstractThe biological activity of the pro‐inflammatory cytokine, tumor necrosis factor (TNF)‐α depends on the level of TNF‐α itself, the expression of the p55 and p75 cell surface receptors for TNF on target cells and the concentrations of the natural inhibitors of TNF‐α, the soluble p55 and p75 TNF receptors (TNF‐R). Interleukin (IL)‐10 and IL‐4 are known to inhibit TNF‐α production by monocytes. We, therefore, investigated the effects of IL‐10 and IL‐4 on the cell surface expression and release of TNF‐R by human monocytes to determine whether these cytokines also indirectly modulated the biological activity of TNF‐α. Exposure to IL‐10 (1‐10 U/ml) for 24 or 48 h increased soluble p75 TNF‐R expression and concomitantly reduced surface expression of p75 TNF‐R. Further, IL‐l α‐stimulated production of TNF‐α was diminished by IL‐10 and only a small proportion of this TNF‐α was bioactive, consistent with increased production of inhibitory soluble TNF‐R. IL‐10 also induced down‐regulation of surface p55 TNF‐R on monocytes, and increased release of soluble p55 TNF‐R. However, the expression of soluble p55 TNF‐R was much lower than soluble p75 TNF‐R, indicating that it contributed less importantly to neutralization of TNF‐α under these conditions. Like IL‐10, IL‐4 supressed the release of TNF‐α by monocytes. In contrast to IL‐10, however, IL‐4 (0.1‐10 ng/ml) supressed the release of soluble p75 TNF‐R from monocytes in a dose‐dependent manner. Release of soluble p55 TNF‐R was also supressed by IL‐4. IL‐10, therefore, reduces the pro‐inflammatory potential of TNF in three ways: by down‐regulating surface TNF‐R expression whilst increasing production of soluble TNF‐R and inhibiting the release of TNF‐α itself. This suggests that IL‐10 may be useful in the treatment of diseases where overexpression of TNF‐α occurs.
Evidence for the continuous recruitment and activation of T cells into the joints of patients with rheumatoid arthritis
Authors: Iannone Florenzo , Corrigall Valerie M. , Kingsley Gabrielle H. , Panayi Gabriel S. 
Published: March 2007

AbstractRheumatoid arthritis (RA) synovial fluid (SF) T cells express the activation markers CD69, HLA‐DR and very late antigen (VLA)‐1, but surprisingly few bear interleukin‐2 receptors (CD25). This unusual activation state is commonly assumed to be due to stimulation by local antigen, yet T cells activated in vitro express activation antigens in the clearly defined sequence: CD69, CD25, HLA‐DR and finally VLA‐1. Two possible explanations for the activation state of SF cells are: first, they comprise several subpopulations each expressing different activation antigens or, second, activation markers are up‐regulated by mechanisms other than antigen stimulation. To examine these hypotheses, double‐ and triple‐color immunofluorescence techniques were applied to four T cell populations: normal peripheral blood T cells activated in vitro, RA SF T cells, T cells from an in vivo model of migration [tuberculin purified protein derivative (PPD)‐induced skin blisters] and T cells co‐cultured with endothelial cells (EC). The results confirmed that in vitro activated T cells expressed activation markers in the sequence described above, with significant CD25 expression and few cells co‐expressing CD69 with HLA‐DR or VLA‐1. In contrast, almost half the SF T cells were CD69+HLA‐DR+ but CD25−; a significant minority were CD69+VLA−l+, T cells from PPD‐induced skin blisters were already HLA‐DR+ and VLA‐1+ at 24 h, although, in vitro, PPD‐activated T cells up‐regulated HLA‐DR and VLA‐1 only after 1 week, suggesting that pre‐activated T cells were preferentially recruited into the blisters. Finally, T cells were found to up‐regulate CD69 and, to a lesser extent, HLA‐DR after adhering to EC in vitro. In summary, the paradoxical activation state of SF T cells cannot be explained solely by single or multiple rounds of activation in situ. At least two other mechanisms, the preferential recruitment of pre‐activated T cells and the induction of HLA‐DR and especially CD69 by endothelial contact during migration, may also play a role.
Raf‐1 and ERK2 kinases are required for phorbol 12,13‐dibutyrate‐stimulated proliferation of rat lymphoblasts. ERK2 activation precedes Raf‐1 hyperphosphorylation
Authors: Lisbona Carlos , Alemany Susana , Calvo Victor , Fernandez‐Renart Margarita 
Published: March 2007

AbstractRat lymphoblasts are arrested in the G1 phase of the cell cycle and can be promoted to proceed up to the S phase, when they are stimulated by phorbol ester. In this work, we have studied some details of the phorbol 12,13‐dibutyrate (PBu2)‐stimulated proliferation. We show that in response to PBu2 at least four different protein kinase C (PKC) isoforms translocate to the membrane. A specific PKC ζ antibody recognizes two bands of 75 and 82 kDa. These two activities are separated using a Mono Q chromatography and we show that p75 is the classical PKC ζ isoform, while p82 might be a related isoform which is PBu2 sensitive. Our data show that there is a correlation between the ability of PBu2 to promote mitogenesis and to activate ERK2 kinase, suggesting that ERK2 kinase might be the limiting step of the process. We also show that ERK kinase activation precedes Raf‐1 kinase hyperphosphorylation, suggesting that Raf‐1 kinase activation is not required for ERK kinase activation. This idea was checked using a Raf‐1 kinase antisense (AS) oligonucleotide. The results obtained with the Raf‐1 AS oligonucleotide indicate that this serine/threonine kinase is dispensable for ERK kinase activation, but needed for the PBu2 mitogenic signaling even as late as 7 h after the delivery of the signal.
CR1(CD35) and CR2(CD21) complement C3 receptors are expressed on normal human thymocytes and mediate infection of thymocytes with opsonized human immunodeficiency virus
Authors: Delibrias Catherine‐Charlotte , Mouhoub Amal , Fischer Elizabeth , Kazatchkine Michel D. 
Published: March 2007

AbstractThe present study demonstrates that the C3b receptor CR1 (CD35) and the C3dg/Epstein‐Barr virus receptor CR2 (CD21) are expressed by 25% and 70% of normal human thymocytes, respectively. The expression of CR2 extends to both CD1+ and CD1− cells in the thymus. Two subsets of CR2+ thymocytes were defined expressing low and high density of the receptor. The CR2++ subset represented 20% of CR2+ thymocytes and co‐expressed the CR1 receptor. CR2++ thymocytes expressed an immature CD1dull, CD3−, CD4dull, CD8−, CD7++ phenotype and included a subpopulation of large cells expressing CD34. Twenty percent of thymocytes expressed the CD21 epitope defined by monoclonal antibody BU32, which is involved in the binding of CD23 to CD21. These observations provide a basis for a role for CD21 in the proliferation and differentiation of thymocytes at early stages of maturation. The functionality of CR1 and CR2 on thymocytes was evidenced by the ability of the receptors to mediate infection of cells with complement‐opsonized human immunodeficiency virus (HIV). The results may be relevant to the immunopathogenesis of HIV infection.
Expression of major histocompatibility complex class II molecules in rat T cells
Authors: Reizis Boris , Schramm Christoph , Cohen Irun R. , Mor Felix 
Published: March 2007

AbstractThe expression of major histocompatibility complex (MHC) class II molecules in murine T cells has been controversial. We therefore reexamined the transcription, synthesis and surface expression of MHC class II determinants in rat T cells both in vivo and in vitro. In naive rats, a large proportion of small CD4+8+ and mature CD4+8−/CD4−8+ thymocytes was found to be MHC class II positive. At least some of the MHC class II molecules found on thymocytes were actively synthesized. The synthesis of MHC class II proteins was detected in peripheral T cells activated in vivo during induction of experimental allergic encephalomyelitis (EAE). A proportion of T cells from the inflammatory lesion of EAE exhibited MHC class II on the surface. A panel of helper T cell lines and clones was shown to synthesize MHC class II proteins. In a prototypic clone, a weak constitutive expression of MHC class II was observed. During activation, the rate of endogenous MHC class II synthesis increased and passive absorption of surface MHC class II from other cells occurred. Our data demonstrate the expression of MHC class II molecules in rat T cells in both the thymus and periphery. Since the primary function of MHC class II molecules is the presentation of peptide epitopes to T cells, these results call attention to the possible role of MHC class II molecules in T‐T interactions during T cell maturation and activation.
Leishmania major infection in mice primes for specific major histocompatibility complex class I‐restricted CD8+ cytotoxic T cell responses
Authors: da Conceição‐Silva Fátima , Perlaza Blanca L. , Louis Jacques A. , Romero Pedro 
Published: March 2007

AbstractThis report shows that lymphoid tissues of mice which have resolved a primary infection with Leishmania major contain parasite‐specific major histocompatibility complex (MHC) class I‐restricted cytolytic CD8+ T cell precusors that can be expanded after specific restimulation in vitro with syngeneic antigen‐presenting cells pulsed with a cyanogen bromide digest of L. major. In H‐2b mice, two distinct populations of CD8+ T cells were identified which both lysed target cells pulsed with L. major‐derived peptides but were restricted by a different H‐2b class I gene product. Interestingly, these two populations appear to recognize different parasite‐derived peptides. It is noteworthy that one K°‐restricted CD8+ T cell line was able to specifically lyse syngeneic macrophages infected with viable L. major, indicating that some L. major‐derived peptides may reach the MHC class I pathway of presentation from the phagolysosomal compartment where the parasites are confined in infected macrophages. The importance of these parasite‐specific MHC class I restricted cytolytic CD8+ T cells for the elimination of L. major by the infected host remains to be determined.
B cell antigen receptor cross‐linking induces tyrosine phosphorylation and membrane translocation of a multimeric Shc complex that is augmented by CD19 co‐ligation
Authors: Lankester Arjan C. , Van Schijndel Gijs M. W. , Rood Pauline M. L. , Verhoeven Arthur J. , Van Lier René A. W. 
Published: March 2007

AbstractThe SH2 domain‐containing transforming Shc protein has been implicated in mitogenic signaling via several surface receptors through p21ras. Following tyrosine phosphorylation by either receptor or non‐receptor tyrosine kinases, Shc may interact with the adaptor protein Grb2, which is linked to Sos1, a guanine nucleotide exchange factor for human ras. Ligation of the antigen receptor complex on B cells (BCR) is known to activate various intracellular signaling pathways, which may accumulate in mitogenic responses. With respect to the initial steps, the activation of BCR‐associated non‐receptor tyrosine kinases appears to be indispensible. In this report we show that Shc proteins become tyrosine phosphorylated after BCR ligation on both transformed and normal human B cells. This is accompanied by the association of Shc with Grb2 proteins and a yet unidentified 145‐kDa tyrosine phosphorylated protein. Subcellular fractionation revealed that this activation‐induced multimeric Shc complex rapidly translocates towards the plasma membrane. Co‐ligation of the BCR with the CD19 molecule results in a marked increase of these events, whereas CD19 cross‐linking alone does not induce Shc tyrosine phosphorylation or translocation. Thus, in B cells the Shc complex may represent a molecular junction between the BCR and the mitogenic p21ras cascade.
Transfer of Sjögren's syndrome‐like autoimmune lesions into SCID mice and prevention of lesions by anti‐CD4 and anti‐T cell receptor antibody treatment
Authors: Hayashi Yoshio , Haneji Norio , Hamano Hironori , Yanagi Kumiko 
Published: March 2007

AbstractWe describe the successful transfer of murine Sjögren's syndrome‐like autoimmune lesions from MRL/lpr mice (H‐2k) to severe combined immunodeficiency (SCID) mice (H‐2d) and prevention of lesions by anti‐CD4 and ‐T cell receptor Vβ8 antibody treatment. Mononuclear cells (1 × 106) isolated from the inflammed submandibular salivary gland tissues of MRL/lpr mice were transferred intraperitoneally into SCID mice. Autoimmune lesions resembling those seen in Sjögren's syndrome developed in the salivary and lacrimal glands of SCID mice 8 weeks after the injection, whereas other organs did not show any lesion. This pathology resembles Sjögren's syndrome in humans involving both the salivary and lacrimal glands. Immunohistochemically, a major proportion of these infiltrating cells in transferred SCID mice were CD4+ and Vβ8+. When the spleen cells from MRL/lpr mice were injected, severe inflammatory lesions, probably resulting from a graft‐versus host reaction, were observed in multiple organs of SCID mice. The disease could not be induced by intraperitoneal administration of the sera from MRL/lpr mice, or of the spleen cells from C3H/He (H‐2k) and BALB/c (H‐2d) mice. We detected autoantibody production specific for the salivary gland tissue in sera from transferred SCID mice. Moreover, we found that the lesions were prevented by administration of the isolated cells treated in vitro with anti‐CD4 and anti‐Vβ8 monoclonal antibodies. These results suggest that CD4‐ and Vβ8‐bearing T cells are involved in recognizing an autopeptide and triggering autoimmunity in the salivary and lacrimal glands, and therapies designed with anti‐CD4 and anti‐Vβ8 antibodies may prove effective in treating the murine autoimmune disease.
Monoclonal IgA class‐switch variants against bacterial surface antigens: molecular forms and transport into murine respiratory secretions
Authors: Steinmetz Ivo , Albrecht Frank , Häußler Susanne , Brenneke Birgit 
Published: March 2007

AbstractThe present study describes a new model for passive immunization of the respiratory tract with IgA in comparison to other isotypes. Monoclonal IgA‐isotype‐switch variants were isolated from different IgG‐producing hybridoma clones specific for surface epitopes of bacterial respiratory tract pathogens. Analysis of the molecular form of the IgA variants revealed the simultaneous production of monomeric, dimeric and higher polymeric IgA by a single‐cell line with predominance of the polymeric forms. The specificities of the IgA variants were identical to the parent IgG antibodies as demonstrated by inhibition experiments. The IgA variant antibodies were separated into monomers and polymers by gel filtration. Intravenous injection of the different molecular forms of IgA and of IgG into mice were used to investigate the transport characteristics of IgA into murine upper and lower respiratory tract secretions by the physiological route in comparison to IgG. Polymeric IgA variant, monomeric IgA variant and IgG were detected in immunologically active form in both nasal secretion and bronchoalveolar fluid as evidenced by binding to their antigens in an enzyme‐linked immunosorbent assay. The relative contribution of the specific exogenous monoclonal IgA and monoclonal IgG to total IgA and IgG, respectively, was determined in secretions. Comparison of the secretion to serum transport ratios clearly indicates selective transport of polymeric IgA variant into nasal secretions relative to IgG parent antibody. Molecular and functional characteristics of the IgA variants make them ideal for passive mucosal immunization experiments and identification of protective epitopes in mucosal immunity.
Antigenic and immunogenic mimicry of the HER2/neu oncoprotein by phage‐displayed peptides
Authors: Orlandi Rosaria , Ménard Sylvie , Colnaghi Maria I. , Boyer Cinda M. , Felici Franco 
Published: March 2007

AbstractTo recover peptides that antigenically and immunogenically mimic the p185HER2 oncoprotein, we selected the phage‐peptide libraries pVIII‐9aa and pVIII‐9aa. Cys using murine monoclonal antibodies (mAb) MGr2 and MGr6, directed against two distinct epitopes of the p185HER2 extracellular domain. Phagedisplayed peptides containing consensus amino acid motifs were recovered and shown to compete specifically for mAb binding on tumor cells that overexpress p185HER2. The deduced amino acid sequence of the peptides suggests that both epitopes defined by the mAb on p185HER2 are discontinuous and that hydrophobic interactions are involved in binding with the mAb. A phage clone displaying the GPLDSLFAQ peptide elicited a specific immune response against the p185HER2 in BALB/c mice, demonstrating that this phage‐displayed peptide represents an immunological equivalent of the MGr2 epitope on p185HER2 and might be used as a substitute for this oncoprotein in in vitro and in vivo immunological studies.
Structural profile of idiotype, anti‐idiotype and anti‐anti‐idiotype monoclonal antibodies in the HLA‐DQ3 antigenic system
Authors: Iwasaki Yoshiaki , Takabatake Hiroyuki , Shinji Toshiyuki , Monestier Marc , Ferrone Soldano 
Published: March 2007

AbstractInterest in the characterization of idiotype cascades in the HLA antigenic system has been stimulated by their potential role in the immune response to mismatched HLA allospecificities and in the survival of kidney allografts. Since no information is available about the structural organization of idiotypic cascades in the HLA system, we have sequenced the variable regions of the heavy (VH) and light (VL) chains of mouse anti‐HLA‐DQ3 monoclonal antibody (mAb) KS13 elicited by cell membrane‐bound antigens, of syngeneic anti‐HLA‐DQ3 mAb S2B154 elicited by anti‐idiotypic (anti‐id) mAb K03‐34 and of five syngeneic anti‐id mAb elicited by mAb KS13. mAb KS13 and S2B154, which have been previously shown to be very similar in their specificity and idiotypic profile, share several structural characteristics. Their VH and VL regions are encoded by the same VH. VK and JH genes, display relatively similar V(D)J rearrangements and differ only through a few amino acid substitutions. Among the five anti‐id mAb elicited by mAb KS13, mAb R1‐38 and R18‐9 utilize multiple genetic elements that are different from those used by anti‐id mAb KO3‐34, K03‐256 and K03‐335. These results indicate that diverse V region combinations can confer an anti‐id specificity in the antigenic system analyzed. mAb K03‐34, K03‐256 and K03‐335 originate from the same B cell clone, since they use the same V, D and J genes and possess identical V(D)J rearrangements. The latter three anti‐id mAb differ only by point mutations, which have dramatic effects on the HLA‐DQ3 antigen mimicry properties of the three anti‐id mAb. mAb K03‐34 is the only one to induce anti‐HLA‐DQ3 antibodies both in syngeneic and xenogeneic hosts. The antigen mimicry properties of anti‐id mAb K03‐34 depend upon its three‐dimensional conformation, since no significant amino acid sequence homology has been found between its VH and VL regions and α1 and β1 domains of HLA‐DQ3 antigens.