bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nature of the ligand recognized by a hapten- and carrier-specific, MHC-restricted T cell receptor.
Authors: Nalefski E A , Rao A 
Published: December 2022

Abstract
The hapten- and carrier-specific T lymphocyte clone D5 and a T hybridoma (D5h) derived from D5 cells recognize several different protein Ag conjugated with p-azobenzenearsonate (arsonate) presented by the class II MHC protein I-Ad. We show here that the ligand recognized by the D5 TCR is a complex of a haptenated peptide bound to I-Ad. We have identified a peptide fragment generated by enzymatic cleavage of arsonate-conjugated OVA (Ars-OVA), which stimulates D5 cells when presented by I-Ad-bearing APC. A synthetic peptide corresponding to this fragment, OVA(36-50), forms a ligand for D5h cells when it is conjugated with arsonate and presented by cells bearing I-Ad. Paraformaldehyde-fixed, I-Ad-bearing cells present Ars-OVA(36-50), or the longer stimulatory peptide Ars-OVA(33-49), to D5h cells, demonstrating that haptenated synthetic peptides can substitute for naturally processed antigenic peptides. The peptide Ars-OVA(33-49) binds to the major peptide-binding site of I-Ad because it competitively inhibited presentation of the peptide OVA(323-339), previously demonstrated to bind to I-Ad directly in vitro, to the OVA/I-Ad-specific T cell hybridoma 3DO-54.8. The unconjugated OVA(33-49) peptide failed to inhibit the presentation of OVA(323-339), demonstrating that the hapten facilities binding of the peptide to I-Ad. Conversely, the peptide OVA(323-339) competitively inhibited the presentation of Ars-OVA(33-49) to D5h cells, indicating that the two peptides Ars-OVA(33-49) and OVA(323-339) bind to overlapping sites on I-Ad. Amino acid substitutions introduced into the beta 1 domain of I-Ad that affected recognition of OVA(323-339) by 3DO-54.8 cells also affected recognition of Ars-OVA(33-50) by D5h cells, demonstrating that similar regions on I-Ad are required for TCR recognition of conventional as well as haptenated peptides. These results represent the first demonstration that the ligand recognized by a hapten- and carrier-specific T cell clone restricted to an MHC class II protein is a haptenated peptide Ag bound to the MHC molecule.
Strain-dependent leakiness of mice with severe combined immune deficiency.
Authors: Nonoyama S , Smith F O , Bernstein I D , Ochs H D 
Published: December 2022

Abstract
Mice with immunodeficiency provide an excellent in vivo model for cell transfer experiments. In this study, we compare the extent of immune deficiency of the original CB17 severe combined immune-deficient (SCID) mice with that of two other strains of immune-deficient mice, the recently developed C3H SCID mice and the beige/nude/X-linked immune-deficient (BNX) mice. Detectable levels of serum lg (higher than 0.4 microgram/ml) were found in 79% of CB17 SCID mice studied (n = 24) and in all BNX mice (n = 12); some leaky CB17 SCID mice had normal levels of Ig. In contrast, only 15% of C3H SCID mice (n = 61) had detectable serum lg; the highest Ig level in this strain was 9.6 micrograms/ml. Age had no effect on serum Ig concentrations of C3H SCID mice; in contrast, all old (&gt; 1-year-old) CB17 SCID mice studied had detectable levels of serum Ig. Transfer of syngeneic, normal, neonatal thymocytes increased serum Ig of SCID mouse origin to near-normal levels in all CB17 SCID mice but had no effect on serum lg concentrations in C3H SCID mice. Treatment with anti-asialo-GM-1 antiserum to abrogate NK cell activity increased serum Ig levels in 37% of CB17 SCID mice but had no effect on Ig production in C3H SCID mice. Flow cytometric analysis failed to identify mature T or B cells in C3H SCID mice; in contrast, some leaky CB17 SCID mice had detectable numbers of T and B cells in the peritoneal cavity. After immunization with bacteriophage phi X 174, neither C3H nor CB17 SCID mice, including leaky mice, produced specific antibody to phage. In contrast, BNX mice produced small but significant amounts of anti-phage antibody. These results indicate that, of the three strains of immune-deficient mice, C3H SCID mice have the most severe immune defect. We predict that C3H SCID mice will be best suited for cell transfer experiments.
Differential activation of antigen-stimulated suicide and cytokine production pathways in CD4+ T cells is regulated by the antigen-presenting cell.
Authors: Wang R , Murphy K M , Loh D Y , Weaver C , Russell J H 
Published: December 2022

Abstract
Stimulation of the TCR of activated, mature T cells by an APC produces a spectrum of functional responses. Most of those responses positively promote immunity and inflammation. However, death of the responding T cell, which would limit subsequent inflammation, can also result from such stimulation. We compare the Ag threshold necessary to promote inflammation through cytokine production with the Ag threshold necessary to limit inflammation through T cell death. These two responses are independently regulated by the APC and this regulation is selective for both different APC products and different T cell subsets. The costimulator B7 selectively decreases the Ag threshold for cytokine production in Th1 cells with no effect on the Ag threshold for Th1 death. B7 has no effect on the Th2 Ag threshold for cytokine production or death. In contrast, IFN-gamma negatively modulates a macrophage product that selectively increases the threshold of Ag necessary to stimulate death in Th2 cells, but has no effect on cytokine production by Th2 cells or cytokine production or death of Th1 cells. This selective regulation of cytokine production and T cell death may play an important role in both shaping the quality of a given immune response and in providing a general mechanism for the regulation of the immune response by limiting inflammation and through peripheral deletion of inappropriate T cell specificities.
p21ras function is important for T cell antigen receptor and protein kinase C regulation of nuclear factor of activated T cells.
Authors: Woodrow M A , Rayter S , Downward J , Cantrell D A 
Published: December 2022

Abstract
In T cells, signals initiated at the TCR, and in particular activation of protein kinase C (PKC), can activate the p21ras proteins. Triggering of the TCR and PKC is required for the efficient production of the T cell growth factor, IL-2. IL-2 gene transcription is controlled by a 275-bp enhancer that is known to contain binding sites for many transcription factors including the octamer family of proteins, NF kappa B, AP-1, and a T cell-specific factor, NFAT (nuclear factor of activated T cells). NFAT binds to a region of the IL-2 enhancer that has been defined as a TCR response element (ARRE-2), and is induced in response to increases in intracellular calcium, stimulation of PKC, or triggering of the TCR. To determine whether p21ras is involved in the signals that regulate NFAT, we examined the effect of expression of a constitutively active p21ras mutant, v-Ha-ras, and a dominant inhibitory mutant of p21ras, c-Ha-ras(asn)17, on the induction of a NFAT-driven reporter gene (NFAT CAT) during T cell activation. The constitutively active Ras mutant could synergize with the calcium ionophore ionomycin to induce NFAT. In addition, expression of p21v-Ha-ras could enhance NFAT CAT induction in response to TCR and PKC agonists. The dominant inhibitory mutant of p21ras could prevent NFAT CAT expression in response to PKC or TCR triggering. These data show that Ras regulates NFAT, and that p21ras function is important for the TCR- and PKC-regulated pathways that regulate NFAT.
Isolation and characterization of a novel B cell activation gene.
Authors: Hong J X , Wilson G L , Fox C H , Kehrl J H 
Published: December 2022

Abstract
Using subtractive cDNA cloning, we have isolated a series of cDNA clones that are differentially expressed between B and T lymphocytes. Whereas some of the isolated cDNA are from known B cell-specific genes, many of them represent previously uncharacterized genes. One of these unknown genes was denoted as BL34. Northern blot analysis performed with the BL34 cDNA revealed a 1.6-kb mRNA transcript that was present at low levels in RNA extracted from resting B lymphocytes, but whose expression was markedly increased in RNA prepared from mitogen-activated B cells. Similarly, RNA prepared from several B cell lines treated with phorbol myristate acetate (PMA) contained high levels of BL34 mRNA. In contrast, RNA from purified T cells treated with phytohemagglutinin and PMA had undetectable amounts of BL34 mRNA. In addition, high levels of BL34 mRNA were detected in RNA purified from PBMC of a patient with B cell acute lymphocytic leukemia. Southern blot analysis of human DNA from various tissues and cells lines demonstrated that BL34 is a single-copy gene without evidence of rearrangement. Two full length BL34 cDNA were sequenced, and an open reading frame of 588 bp was identified that was predicted to encode for a 196 amino acid protein. Searches of several protein data bases failed to find any homologous proteins. To directly analyze the expression of BL34 mRNA in lymphoid tissues in situ, hybridization studies with human tonsil tissue sections were performed. BL34 mRNA was detected in a portion of the cells in the germinal center region and adjacent to the mantle region. Further characterization of the BL34 gene and its protein should lead to insights to its role in B cell function and the consequences of its over-expression in acute lymphocytic leukemia.
IL-2 is necessary for the progression of leishmaniasis in susceptible murine hosts.
Authors: Heinzel F P , Rerko R M , Hatam F , Locksley R M 
Published: December 2022

Abstract
BALB/c mice are highly susceptible to disseminated infection with the intracellular protozoa Leishmania major. Progression of disease requires in vivo expansion of Th2 CD4+ lymphocytes and is reversed by treatment with anti-IL-4 monoclonal antibody. Inasmuch as IL-2 may be necessary for both the production of IL-4 and differentiation of Th2 cells, the possible contribution of IL-2 to progressive infection was examined. Four weekly injections of anti-IL-2 mAb (S4B6) cured more than 80% of BALB/c mice infected with L. major, as determined by diminished footpad swelling and decreased numbers of parasites in infected tissues. Multiple doses of S4B6 were necessary for benefit; a single dose given at the time of infection was ineffective. The anti-IL-2R mAb PC61 demonstrated a similar protective effect when administered twice weekly for 4 wk. Anti-IL-2-mediated cure of cutaneous leishmaniasis was associated with increased IFN-gamma and decreased IL-4 production by regional lymph node cells compared to untreated BALB/c mice with progressive illness. Both CD4+ and CD8+ T lymphocytes contributed to the increased expression of IFN-gamma mRNA in cured mice. These data suggest that levels of IL-2 suboptimal for Th2 expansion in vivo do not inhibit Th1 CD4+ and CD8+ T cell activation and IFN-gamma synthesis. Other cytokines or activation pathways that are either IL-2-independent or synergistic with low levels of IL-2 may account for the appearance of curative T cell responses during treatment with anti-IL-2 antibodies.
Regulation of expression of IL-1 receptor antagonist protein in human synovial and dermal fibroblasts.
Authors: Krzesicki R F , Hatfield C A , Bienkowski M J , McGuire J C , Winterrowd G E , Chapman D L , Berger A E , McEwan R N , Carter D B , Chosay J G 
Published: December 2022

Abstract
The IL-1R antagonist protein (IRAP) is a competitive inhibitor of IL-1, which is predominantly synthesized by monocytes. We show that this molecule is also expressed in human synovial fibroblasts and dermal fibroblasts (CRL 1445). IRAP mRNA was regulated in a time- and dose-dependent manner by IL-1 alpha, TNF-alpha, LPS, and PMA. Maximal induction of IRAP mRNA was observed between 8 and 16 h after stimulation with IL-1 alpha (1 U/ml), TNF-alpha (10 U/ml), LPS (50 ng/ml), and PMA (10 ng/ml). Their relative efficacy was as follows: PMA &gt; LPS &gt; IL-1 alpha &gt; TNF-alpha. Potentiation was observed when fibroblasts were treated with IL-1 alpha plus basic fibroblast growth factor and IL-1 alpha plus platelet-derived growth factor-BB homodimer. Although LPS and PMA were the best inducers of IRAP mRNA, quantitation of the IRAP protein revealed that its synthesis and release were differentially regulated. Immunoprecipitation and SDS-PAGE of culture supernatant from LPS-treated cells and cell lysates of fibroblasts treated with LPS or PMA showed a single IRAP band with a molecular mass of approximately 22 kDa. Very little IRAP was detected in culture supernatants of cells treated with PMA. Quantitation of IRAP revealed that LPS induced the synthesis of secreted IRAP that was released, whereas the majority of the protein induced by PMA remained cell-associated. Reverse transcriptase-polymerase chain reaction amplification demonstrated that although LPS and PMA induced both transcripts, LPS preferentially induced secreted IRAP, whereas PMA differentially induced intracellular IRAP mRNA. Fibroblasts synthesize at least two different forms of IRAP depending on the inducing signal, and may regulate the inflammatory response by dampening the proinflammatory effects of IL-1 via a negative feedback mechanism with IRAP. The relative importance of fibroblast sIRAP vs intracellular IRAP in regulating the inflammatory response by the connective tissue remains to be determined.
Priming of human monocytes with leukotriene B4 enhances their sensitivity in IL-2-driven tumor necrosis factor-alpha production. Transcriptional and post-transcriptional up-regulation of IL-2 receptors.
Authors: Stanková J , Dupuis G , Gagnon N , Thivierge M , Turcotte S , Rola-Pleszczynski M 
Published: December 2022

Abstract
Cytotoxic activity of monocytes may be mediated by their production of TNF-alpha, and IL-2 has been shown to induce TNF-alpha production in monocytes and alveolar macrophages. Unstimulated human monocytes constitutively express the beta-chain of the IL-2R (IL-2R beta), but little or no IL-2R alpha. When monocytes were pretreated with leukotriene (LT) B4, they responded to IL-2 with both enhanced production of TNF-alpha (two- to threefold) and, more strikingly, with augmented sensitivity (1000-fold) to IL-2. Treatment of monocytes with LTB4 induced IL-2R alpha gene transcription at 30 min and augmented expression of IL-2R alpha gene transcripts by 3 h, maximal at 10(-8) M LTB4. LTB4 induced increased shedding of the IL-2R alpha in the culture supernatants and a modest induction of IL-2R alpha protein expression on monocytes. On the other hand, although LTB4 could stimulate the cell membrane expression of IL-2R beta and the accumulation of IL-2R beta mRNA, LTB4 did not significantly affect IL-2R beta gene transcription. The augmented expression of IL-2R on monocytes was associated with augmented binding of 125I-labeled IL-2 to LTB4-pretreated monocytes. Our data present direct evidence that the inflammatory lipid mediator LTB4 can induce the expression of IL-2R alpha in human monocytes by activating IL-2R alpha gene transcription; it can also stimulate the expression of IL-2R beta, through post-transcriptional regulation; this augmented expression of both alpha- and beta-chains of the IL-2R is associated with enhanced sensitivity of monocytes to IL-2 in terms of TNF-alpha production and may be relevant to the proinflammatory actions of LTB4.
Preferential usage of T cell antigen receptor V region gene segment V beta 5.1 by Borrelia burgdorferi antigen-reactive T cell clones isolated from a patient with Lyme disease.
Authors: Lahesmaa R , Shanafelt M C , Allsup A , Soderberg C , Anzola J , Freitas V , Turck C , Steinman L , Peltz G 
Published: December 2022

Abstract
Forty-three CD3+4+8- TCR alpha beta+ Borrelia burgdorferi-reactive T cell clones isolated from the peripheral blood of a single patient with clinically active chronic Lyme arthritis were characterized. The spirochetal Ag recognized by 16 of these T cell clones was determined by reactivity with a panel of recombinant spirochetal Ag, which included the OspA, OspB, flagellin, Hsp60 and Hsp70 proteins. All three T cell clones reactive with heat shock proteins recognized a non-cross-reactive epitope unique to the spirochetal Ag. Analysis of the TCR V regions revealed preferential usage of V beta 5.1; 5 of 15 T cell clones that recognized an unidentified spirochetal Ag utilized this V beta gene segment. Most of the T cell clones recognized a given spirochetal Ag exclusively within the context of one HLA class II allele. However, two T cell clones, which recognized an unidentified Ag in the spirochetal lysate within the context of different HLA class II alleles, were both TCR V beta 5.1+, although each displayed a distinct alpha-chain. Moreover, in vitro incubation of this patient's PBMC with B. burgdorferi Ag resulted in a specific increase in the percentage of T cells expressing TCR V beta 5.1. These results indicate that B. burgdorferi has a V beta-selective factor influencing the cellular immune response in a patient with clinically active Lyme disease.
Superantigen can reactivate bacterial cell wall-induced arthritis.
Authors: Schwab J H , Brown R R , Anderle S K , Schlievert P M 
Published: December 2022

Abstract
Intravenous injection of toxic shock syndrome toxin-1 (TSST-1) produced by Staphylococcus aureus, can reactivate arthritis in a rat ankle joint that has been previously inflamed by injection of peptidoglycanpolysaccharide polymers isolated from the cell walls of group A streptococci. The severity and chronicity of this renewed arthritis is dose dependent and at higher doses (125 micrograms/kg) a prolonged joint inflammation with pannus formation and marginal erosion of cartilage and bone is induced after a single injection of TSST-1. Only modest synovial hyperplasia is induced in control ankle joints by systemic injection of TSST-1. Another superantigen, streptococcal pyrogenic exotoxin induces a much weaker, acute reactivation of arthritis that resolves by 2 days. Repeated injections of TSST-1 at 7-day intervals give the same undiminished pattern of joint response, but the joint swelling persists at a higher level with each succeeding injection. Cyclosporin A suppresses all phases of the recurrent arthritis, indicating that TSST-1 could be functioning through its property of a superantigen activating T lymphocytes. II-1 receptor antagonist and anti-TNF-alpha neutralizing antibody, which reduce reactivation of arthritis by peptidoglycan-polysaccharide polymers, have no effect on reactivation by TSST-1. This experimental model provides a means to examine in vivo the possible role of superantigens in rheumatoid arthritis and related diseases, and to analyze the cellular and molecular pathways induced by this family of microbial products.
Susceptibility to inflammatory disease in HLA-B27 transgenic rat lines correlates with the level of B27 expression.
Authors: Taurog J D , Maika S D , Simmons W A , Breban M , Hammer R E 
Published: December 2022

Abstract
To investigate the role of the class I MHC molecule HLA-B27 in the spondyloarthropathies, we produced rats transgenic for HLA-B27 and human beta 2-microglobulin. Of five lines bearing &gt; 1 copy of each transgene and showing hemizygous expression of both transgenes, two (lines 21-4H and 33-3) developed spontaneous inflammatory disease that closely resembled B27-associated human disease. Two lines, 21-4L and 25-6, remained healthy even when homozygous for the transgene locus, whereas the 21-3 line, bearing the third highest transgene copy number, developed disease similar to that of the 21-4H and 33-3 lines only when homozygous for the transgene locus. The disease-prone lines showed higher expression of B27--thymic mRNA in utero, splenic mRNA by 5 days of age, and splenic cell surface protein by the time of disease onset--than the disease-resistant lines. Disease susceptibility thus appeared to correlate with gene copy number and the quantity of B27 in lymphoid cells. The increase in the amount of B27 protein did not appear to be simply a consequence of the inflammatory disease because 1) there was no similar change in endogenous RT1 class I expression; 2) no alteration of B27 expression occurred in 21-4H rats with adjuvant-induced arthritis; 3) in rats with inflammatory disease transgenic for HLA-A2 and the 21-4H transgene locus, A2 expression was the same as in healthy rats transgenic for A2 but not B27; and 4) the transgenes in disease-prone and disease-resistant lines were equally susceptible to induction by IFN-gamma. Immunocytochemistry of the distal colon, an early site of inflammation, showed that the B27 Ag is expressed at high levels in cells of the lamina propria, but not at all in colonic epithelial cells. Taken together, the data suggest that the B27 transgene is expressed in a copy number dependent, position-independent manner in lymphoid tissue and that disease results from the expression of B27 above a critical threshold level.
Characterization of a novel CD2+ human thymic B cell subset.
Authors: Punnonen J , de Vries J E 
Published: December 2022

Abstract
In the present study, it is demonstrated that functionally mature B cells are present in human thymus early during fetal life. Interestingly, 46 +/- 7% of fetal and postnatal thymic CD19+ B cells co-expressed CD2. Adult peripheral blood or splenic B cells were CD2-, and &lt; 5% of fetal BM or fetal splenic CD19+ cells expressed CD2, indicating that CD2 is expressed preferentially on thymic B cells. Fetal thymic CD2+ B cells have a mature phenotype, because they are CD20+, CD40+, and surface IgM+, but they lack CD34 expression. They are also functionally mature because total thymic cell populations or highly purified CD2+ thymic B cells underwent Ig isotype switching and differentiation into Ig-secreting cells in a similar fashion as conventional B cells after culturing in the presence of IL-4 and activated cloned CD4+ T cells and anti-CD40 mAb cross-linked to Fc gamma RII/CDw32 transfected into murine L cells (Fc gamma RII+/L). Engagement of CD2 on thymic B cells by LFA-3+ L cell transfectants, anti-CD2 mAb cross-linked to Fc gamma RII+/L, or a mitogenic combination of anti-CD2 mAb did not result in proliferation or Ig production under the present conditions. However, anti-CD2 mAb enhanced IL-4 dependent Ig-synthesis by thymic B cells in the presence of activated CD4+ T cells, but they were ineffective when the B cells were activated by anti-CD40 mAb, suggesting that the anti-CD2 mAb stimulated antibody production indirectly via CD4+ T cells. Similarly, IL-7 enhanced IL-4-induced Ig production in the presence of CD4+ T cells. This effect of IL-7 also appeared to be indirect because no enhancement in Ig levels was observed in cultures of purified thymic B cells. Collectively, our results indicate that functionally mature B cells are present in human thymus early during fetal life, and that thymic CD2+, CD19+, sIgM+ cells represent a subset of bona fide B cells, which can be induced to Ig isotype switching and Ig production in vitro in a similar fashion as conventional B cells.