bluuebunny/crossref_metadata_2025_split huggingface dataset:
Independently derived IgG anti-DNA autoantibodies from two lupus-prone mouse strains express a VH gene that is not present in most murine strains.
Authors: Gangemi R M , Singh A K , Barrett K J 
Published: January 2023

Abstract
The origin and structure of two clonally unrelated IgG anti-DNA autoantibodies from lupus-prone MRL/Ipr mice were examined. One of these antibodies, H241, binds dsDNA and glomeruli and deposits in the kidneys of normal mice, whereas the other, H102, binds only ssDNA and does not deposit in kidneys. The VH genes of these two antibodies were almost identical to each other and were frequently expressed in anti-DNA antibodies derived from lupus-prone mice. Six other clonally unrelated anti-DNA antibodies from the literature or from data banks expressed nearly identical VH genes (&lt; or = 4 nucleotide differences) and eight others had nearly identical protein sequences (&lt; or = 3 amino acid differences). Analysis of the germ line with oligonucleotide probes from the CDR regions suggests that all 10 autoantibodies are derived from a single member of the J558 gene family, which is present only in mice with the j haplotype for the J558 gene family. The amount of somatic mutation in these VH genes appears to be low, suggesting that some V, N, and D gene combinations can generate high affinity IgG anti-DNA auto-antibodies with little or no somatic mutation. Unusual reading frames, D-D fusions, and inversions were common in the IgG antibodies and may have been co-selected. Although the N and D regions of one IgM and all five IgG autoantibodies contained Arg residues, the presence of Arg residues was not correlated with binding to dsDNA or with pathogenicity. These results suggest that differences in the Ag-binding properties and the pathogenicity of these antibodies are determined by the CDR3 region and the L chain.
Endogenous expression of delta on the surface of WEHI-231. Characterization of its expression and signaling properties.
Authors: Haggerty H G , Wechsler R J , Lentz V M , Monroe J G 
Published: January 2023

Abstract
WEHI-231 is a murine B cell lymphoma that has been used extensively as a model for the immature stage B cell and its functional response to Ag receptor cross-linking as a model for immature B cell tolerance. This cell line expresses sIgM, CD5, and FcR gamma, but lacks the B cell-specific isoform of CD45 (B220). This study demonstrates for the first time that WEHI-231, in contrast to classically defined immature B cells, expresses delta on its surface. Analysis of delta on WEHI-231 revealed structural differences with respect to that on BAL-17 or primary splenic B cells. Although the m.w. of delta on the latter two B cell populations was similar, delta on WEHI-231 manifested a marked increase in its apparent m.w. deduced by SDS-PAGE. This difference was found to be due primarily to differential N-linked glycosylation. Signal transduction through the endogenous sIgD on WEHI-231 was investigated. In contrast to cross-linking of sIgM, cross-linking of the endogenous surface IgD on WEHI-231 was unable to generate a negative growth response in these cells. This inability may be due to uncoupling from normal surface Ig signaling pathways. The signaling properties of the endogenous sIgD on WEHI-231 differ from that on primary B cells and other sIgD-expressing cell lines. Whereas sIgD on splenic B lymphocytes or the mature B cell line BAL-17 is coupled to inositol phospholipid hydrolysis and calcium mobilization, cross-linking of sIgD on WEHI-231 failed to elicit these events, although induced changes in tyrosine phosphorylation were observed. Thus, endogenous expression of surface IgD on WEHI-231 is inconsistent with its representing the classically defined immature stage B cell. The structural and signaling differences associated with delta on these cells suggest the potential for developmentally regulated delta function and model for study of sIgD signal transduction.
Characterization of a novel high affinity human IL-7 receptor. Expression on T cells and association with IL-7 driven proliferation.
Authors: Page T H , Willcocks J L , Taylor-Fishwick D A , Foxwell B M 
Published: January 2023

Abstract
Although both unstimulated and activated human T cells express high affinity IL-7R, only activated T cells can proliferate to IL-7. This responsiveness may occur as a direct result of changes in the structure of the IL-7R during T-cell activation. We have previously demonstrated such changes by affinity cross-linking studies, and have shown that unstimulated human T cells express a single IL-7R of 90 kDa, whereas activated T cells express an additional 76-kDa IL-7 binding protein. In this study the origin and function of the p90 and p76 molecules have been investigated. To determine the role of each of these receptors in IL-7 driven proliferation, IL-7R expression and proliferative capacity were monitored during mitogenic stimulation. These analyses showed that the ability of PBMC to proliferate to IL-7 correlated with expression of the p76 IL-7R, and not with expression of the p90 IL-7R. IL-7-driven proliferation is mediated via high affinity IL-7R, and accordingly, Scatchard analysis revealed that, like the p90 IL-7R, the p76 IL-7R bound IL-7 with dual (high; Kd 38 pM and low; Kd 360 pM) affinity. Deglycosylation studies showed that the p90 and p76 IL-7R are not simply differently glycosylated isoforms of a single receptor. In agreement, mAb to the previously cloned IL-7R were found to stain unstimulated T cells that express only the p90 IL-7R but not T-cell clones that express predominantly the p76 IL-7R. These antibodies also immunoprecipitated the cloned IL-7R as a 90-kDa species from both 125-I-surface-labeled resting and activated T cells, but were unable to precipitate the 76-kDa IL-7R. In addition, PCR analysis of p76-expressing cells could not detect splicing of the extracellular domain of the cloned IL-7R, thereby excluding the possibility that the p76 IL-7R is a previously undescribed splice variant of the cloned IL-7R. These data demonstrate that the p90 IL-7R is the T-cell homologue of the cloned IL-7R, and imply that the p90 and p76 IL-7R have different extracellular domains. Taken together these data suggest that the 76-kDa receptor is a novel high affinity IL-7R that may be necessary for IL-7 driven proliferation in human T cells.
Stimulation of human basophils results in homotypic aggregation. A response independent of degranulation.
Authors: Knol E F , Kuijpers T W , Mul F P , Roos D 
Published: January 2023

Abstract
For a better insight into the mechanisms determining the recruitment of human basophilic granulocytes from the circulation to sites of allergic reactions, we studied the homotypic aggregation of these cells. The aggregation was studied with &gt; 95% pure basophil suspensions obtained from peripheral blood in a double-color flow cytometric analysis. Homotypic aggregation was induced by treatment of the basophils with anti-IgE, house dust mite allergen, the chemoattractant FMLP, PMA, or IL-3. The aggregation by anti-IgE was, in part, mediated by interactions with Fc gamma R-II as indicated by 43 +/- 15% inhibition after pretreatment with CD32 antibodies. The aggregation was mediated by beta 2-integrins, as was shown by inhibition of the response by CD18 antibodies. The aggregation induced by anti-IgE, allergen, and PMA displayed comparable kinetics (t1/2 max, 3 to 4 min), in contrast to the degranulation of basophils. FMLP induced the most rapid response (t1/2max, 1.6 min). Inhibition of protein kinase C by staurosporine resulted in a strong (&gt; 90%) inhibition of the PMA-induced aggregation, whereas the FMLP-induced aggregation was more than doubled (from 11.7 +/- 1.9 to 24.4 +/- 1.9%). Staurosporine did not affect the extent of the anti-IgE-induced aggregation, but it induced a retardation of congruent to 10 min. In most experiments, no clear correlation was found between degranulation and aggregation of human basophils. Most strikingly, IL-3 did not induce degranulation but did induce aggregation. Thus, the homotypic aggregation response of human basophils is induced by intracellular signals not necessarily leading to degranulation. This might be important in the physiologic appearance of basophils at sites of allergic late-phase responses or inflammation.
Interactions of soluble CD59 with the terminal complement complexes. CD59 and C9 compete for a nascent epitope on C8.
Authors: Lehto T , Meri S 
Published: January 2023

Abstract
Human CD59-Ag is a glycophosphoinositol lipid-anchored inhibitor of the membrane attack complex of complement (MAC). We have examined the interactions of CD59 with the terminal complement complexes using soluble CD59 purified from human urine (CD59U). CD59U bound to SC5b-8, SC5b-9, and MAC complexes when present during their formation. When SC5b-8, SC5b-9, and MAC were allowed to perform, progressively less 125I-CD59U bound to the complexes. Terminal SC5b-9 complexes isolated from activated sera no longer bound CD59U, indicating that the binding sites had become inaccessible in the fully assembled SC5b-9 complex. Unlike acylated myocardial CD59 (CD59H) neither CD59U nor PIPLC-treated CD59H became incorporated into poly-C9 complexes, suggesting that the interaction of CD59 with C9 requires the lipid anchor. Human C9 and heterologous C9 from guinea pig serum, as well as the YTH53.1 anti-CD59 mAb, inhibited the binding of CD59U to SC5b-8. On the other hand, soluble CD59U did not inhibit binding of C9 to SC5b-8, although CD59E has been shown to limit the number of C9 molecules entering into MAC. This suggests that two interaction sites between C5b-8 and C9 exist: one conferring the initial binding of C9 into the C5b-8 complex, and a second directing the insertion of C9 into the lipid bilayer. The latter interaction is the prerequisite for C9 polymerization and the target for interference by CD59.
P-selectin blockade does not impair leukocyte host defense against bacterial peritonitis and soft tissue infection in rabbits.
Authors: Sharar S R , Sasaki S S , Flaherty L C , Paulson J C , Harlan J M , Winn R K 
Published: January 2023

Abstract
Adhesion molecules are responsible for PMN-endothelial cell interactions involved in both PMN-mediated endothelial injury (e.g., after ischemia-reperfusion injury) and PMN-mediated host defense against bacterial infection. Inhibition of PMN-endothelial adherence with CD18 and P-selectin mAb has been shown to ameliorate the tissue injury resulting from ischemia and reperfusion under a variety of experimental conditions. However, interference with PMN function may result in an increased risk of bacterial infection. Previous investigations suggest that CD18 blockade can lead to increased infectious risk. Little is known of the infectious risks associated with selectin blockade. We report the effects of P-selectin blockade (using mAb PB1.3) on bacteria-induced PMN emigration into the peritoneum and subcutaneous (s.c.) tissue in rabbits. Leukocyte and PMN emigration into the peritoneum 4 h after inoculation with 10 ml of 10(9) CFU/ml Escherichia coli was significant in saline-treated animals, and not different in animals pretreated with mAb PB1.3. Similarly, the incidence and severity of abscess formation 7 days after s.c. inoculation with Staphylococcus aureus (10(7), 10(8), or 10(9) CFU) was not increased in rabbits pretreated with mAb PB1.3 compared to saline. PMN emigration to the s.c. S. aureus was also similar in both saline and mAb PB1.3-treated animals, as determined by light microscopy. We conclude that P-selectin blockade with mAb PB1.3: 1) does not interfere with acute, E. coli-induced PMN emigration into the peritoneum, 2) does not increase the incidence or severity of S. aureus abscess formation in s.c. tissue, and 3) interferes less with PMN antibacterial host defense mechanisms than inhibition of CD18-mediated PMN adherence.
Human antilipid A monoclonal antibodies bind to human B cells and the i antigen on cord red blood cells.
Authors: Bhat N M , Bieber M M , Chapman C J , Stevenson F K , Teng N N 
Published: January 2023

Abstract
We describe two independently derived human mAb, A6(H4C5) and 216, initially selected for their reactivity to the lipid A domain of bacterial LPS, which also react with the following Ag: the i Ag present on cord RBC, a ligand on human B lymphocytes, and to certain autoantigens, defining these mAb as polyreactive. Both mAb have specific affinity for a carbohydrate epitope consisting minimally of a disaccharide with an acyl substitution at the 2-carbon position. Structural examination of the diverse Ag recognized by the two antibodies reveals the presence of this carbohydrate structure required for antibody binding. A6(H4C5) and 216 are IgM in isotype, but differ in their L chain expression. Molecular analysis shows that both the mAb are encoded by a highly conserved VH4 gene, designated VH4-21. This gene encodes a number of autoantibodies, particularly cold agglutinins. Specific recognition of lipid A and of a carbohydrate epitope on B lymphocytes by the two human mAb suggests a dual function for the highly conserved VH4-21 gene in antibacterial response and in B cell development and regulation.
Heterogeneity of dermal microvascular endothelial cell antigen expression and cytokine responsiveness in situ and in cell culture.
Authors: Petzelbauer P , Bender J R , Wilson J , Pober J S 
Published: January 2023

Abstract
Microvascular endothelial cells (EC) recruit circulating leukocytes at sites of inflammation, in part through cytokine-regulated expression of endothelial-leukocyte adhesion molecules. Adhesion molecule expression varies among vascular beds and among EC within microvessels of a particular vascular bed. In the present study, we have examined the patterns of antigen expression and cytokine responsiveness of dermal microvascular endothelial cells (DMEC) in a skin organ culture model and, for comparison, in cell culture. Within the superficial vascular plexus (SVP) of normal skin, CD36 molecule expression is undetectable on capillary loops and is expressed on DMEC in only 20% of the larger, horizontal vessels. CD36 expression is not modulated by cytokines. Endothelial-leukocyte adhesion molecule-1 (ELAM-1) expression induced at 6 and 24 h by TNF or IL-1, is restricted to the venular side of the capillary loop and to the venules proper. Vascular cell adhesion molecule-1 (VCAM-1) expression is not inducible on EC of the SVP in normal skin by TNF, IL-1, or IL-4, alone or in combination at either time point. When inflamed skin is examined in organ culture, SVP EC are cytokine responsive regarding VCAM-1 expression. Within the deep vascular plexus (DVP). CD36 molecules are expressed on EC in all capillaries and small vessels. Both ELAM-1 and, to a lesser extent, VCAM-1 expression are inducible by TNF, IL-1, and/or IL-4 on capillaries and larger microvessels at 6 and 24 h. The larger vessels at the dermal-subcutaneous border were found to be CD36-/ELAM-1+/VCAM-1+ after cytokine treatment. CD36 expression of DMEC in cell culture varies from 47 to 98% of cells (mean 75%) in seven separate isolates and is not modified by cytokines. Upon TNF or IL-1 activation, 50 to 90% of DMEC express ELAM-1 molecules at 6 h and expression persists at high levels for 24 h. VCAM-1 expression is negligible at both times. These results with DMEC differ from human umbilical vein EC analyzed in parallel, which are completely CD36- and show transient ELAM-1 and sustained VCAM-1 expression in response to TNF and IL-1. In summary, we have demonstrated that DMEC comprise a heterogeneous population that differ from umbilical vein EC.
Abnormal selection of antibody repertoires in retrovirus-induced murine AIDS.
Authors: Portnoï D , Viale A C , Colle J H 
Published: January 2023

Abstract
The mature B cell repertoire in the course of murine AIDS (MAIDS) was investigated. The polymerase chain reaction (PCR) was used to amplify a large diversity of rearranged Ig H chain genes in normal or infected mice, 2 and 8 wk after virus inoculation. Libraries were constructed from the polymerase chain reaction products. By sequencing V-D-J clones in these libraries and analyzing the respective complementary determining region 3 (CDR3), we have shown at 8 wk the emergence of a population of B cells with significantly less N diversity, some sequences lacking any N addition, a typical feature of fetal repertoires known for degeneracy, and autoreactivities. This decreased N diversity was not present 2 wk after inoculation and could not be related to a defect in terminal deoxytransferase expression because the steady-state levels of terminal deoxytransferase mRNA were found normal in MAIDS bone marrow 8 wk after inoculation. FACS analyses revealed a decreased number of bone marrow B cells (B220+, sIgM+) in MAIDS already present at 2 wk, suggesting an alteration in the pathway of B cell differentiation and resulting in a decrease of peripheral B cells renewal. A relative enrichment of spleen cells in long lived B cells as a consequence of this blockade may participate in the abnormal antibody repertoire selection occurring in MAIDS. These data suggest in the MAIDS pathogeny the relationship between an abnormal repertoire selection and the pathologic process.
Activation of T cells by superantigen in class II-negative mice.
Authors: Avery A C , Markowitz J S , Grusby M J , Glimcher L H , Cantor H 
Published: January 2023

Abstract
The ability of the staphylococcal enterotoxins to stimulate T cells has been thought to depend on their association with class II MHC products. Here, we demonstrate that a subgroup of staphylococcal enterotoxins, which includes staphylococcal enterotoxin C and staphylococcal enterotoxin E, stimulates strong MHC-independent responses, thereby resulting in T cell expansion and generation of CTL. The immunologic consequences of MHC-independent activation of T cells by superantigens differ from those of class II-dependent activation, inasmuch as this pathway does not result in detectable T cell deletion. These findings delineate a novel MHC-independent T cell activation pathway that leads to both clonal expansion and expression of CTL effector function in response to a subgroup of bacterial superantigens.
C-C chemokines induce the chemotaxis of NK and IL-2-activated NK cells. Role for G proteins.
Authors: Maghazachi A A , al-Aoukaty A , Schall T J 
Published: January 2023

Abstract
The C-C chemokines MIP-1 alpha, MCP-1, and RANTES, but not MIP-1 beta, induce the chemotaxis of NK and IL-2-activated NK (IANK) cells, as determined in microchemotaxis assay. Only RANTES and MCP-1, but not MIP-1 alpha were able to induce the chemokinesis of NK cells. In contrast, none of the C-C chemokines tested was able to induce the chemokinesis of IANK cells. IANK cell chemotaxis in response to MCP-1 or RANTES but not MIP-1 alpha, was inhibited by pertussis toxin (PT). In contrast, cholera toxin (CT) inhibited the ability of all three chemokines to induce the chemotaxis of IANK cells. IANK cells intoxicated with PT lost their ability to migrate in response to RANTES and MCP-1 but not MIP-1 alpha, whereas those intoxicated with CT lost their ability to migrate in response to the three C-C chemokines tested. These results suggest that guanine nucleotide binding (G) proteins are coupled to C-C chemokine receptors in IANK cells. Subsequently, we observed that MIP-1 alpha, MCP-1, and RANTES, but not MIP-1 beta, enhance the binding of guanosine 5'-O-(thiotriphosphate), and increase the hydrolysis of [32P]GTP in IANK cell membranes. Further analysis showed that MIP-1 alpha, RANTES, or MCP-1 did not enhance GTP binding in membranes prepared from IANK cells intoxicated with CT, whereas only RANTES and MCP-1 but not MIP-1 alpha lost their ability to enhance GTP binding to IANK cell membranes prepared from PT-intoxicated cells. The differential inhibitory activity of CT and PT suggests that C-C chemokine receptors are coupled to different G proteins in IANK cells.
Tepoxalin, a novel immunosuppressive agent with a different mechanism of action from cyclosporin A.
Authors: Zhou L , Ritchie D , Wang E Y , Barbone A G , Argentieri D , Lau C Y 
Published: January 2023

Abstract
Tepoxalin, a compound previously identified as a dual cyclooxygenase/lipoxygenase (CO/LO) inhibitor, is a potent inhibitor of T cell proliferation. Comparing the suppressive effects of tepoxalin and cyclosporin A (CsA) on OKT3-, PMA-, IL-2-, and PMA+ionomycin-induced T cell proliferations revealed marked differences in the mechanism of action between the two compounds. Whereas CsA was most effective in suppressing OKT3-stimulated proliferation, tepoxalin was more potent in inhibiting PMA-, PMA+ionomycin-, and IL-2-induced proliferation. Quantitative PCR (QPCR) assays used to detect cytokine messages showed that tepoxalin blocked IL-2 mRNA transcription in PMA- and PMA+ionomycin-, but not OKT3-stimulated T cells whereas CsA was most potent in inhibiting OKT3-induced IL-2 mRNA induction in these cells. Both tepoxalin and CsA did not inhibit the expression of IL-2R; however, only tepoxalin, but not CsA, inhibited the proliferation of IL-2-dependent blasts and the transcription of IFN-gamma, an IL-2-dependent target gene. Moreover, addition of exogenous IL-2 restored OKT3-induced proliferation to CsA- but not tepoxalin-treated cells. These data suggest that tepoxalin, but not CsA, suppressed T cell proliferation by inhibiting IL-2-induced signal transduction. Consistent with these findings, tepoxalin, unlike CsA, which was most potent when added at the initiation of OKT3 stimulation, was equally active, regardless of whether it was added at the beginning or 48 h after culture initiation. The difference in mechanism of action between tepoxalin and CsA was confirmed further by the synergistic suppressive effects on T cell proliferation upon co-administration of the two compounds.
The second kappa B element, kappa B2, of the HLA-A class I regulatory complex is an essential part of the promoter.
Authors: Mansky P , Brown W M , Park J H , Choi J W , Yang S Y 
Published: January 2023

Abstract
The MHC class I regulatory complex (CRC) contains the well characterized palindromic kappa B element, kappa B1, to which a number of nuclear factors are known to bind. This cis element plays an important role in controlling the transcription of MHC class I genes. In addition, the CRC contains a second kappa B element, kappa B2, which is located in tandem with the kappa B1 site, 5 bp upstream. In this study, from reporter gene transfection experiments, we present evidence that this kappa B2 site is as important as kappa B1 in regulating HLA-A locus transcription. Mutations introduced into either kappa B site reduced promoter activity to approximately the level obtained when the entire CRC was deleted. Electrophoretic mobility shift and supershift assays showed that the kappa B2-binding complex (BIII) contained a p65-like subunit, but apparently not the p50 subunit of NF-kappa B. Complex BIII also bound to the kappa B1 site, but the kappa B2 sequence was poorly recognized by the kappa B1-binding complex, BI, probably KBF1, the p50 homodimer. These results demonstrate that both kappa B sites are essential components of the promoter and suggest that they may function together to control MHC class I gene transcription.