bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a polymorphism of CD4 in miniature swine.
Authors: Sundt T M , LeGuern C , Germana S , Smith C V , Nakajima K , Lunney J K , Sachs D H
Published: January 2023

A polymorphism of CD4 in miniature swine has been identified by failure of cells from some animals to react with mAb 74-12-4. The phenotypic, molecular genetic, and functional characteristics of these animals have been defined. Cells from heterozygous animals bear approximately 50% the number of 74-12-4-reactive molecules on their surface as do cells from animals homozygous for the wild type. Animals of both phenotypes demonstrate similar flow cytometric profiles for CD8+ T cells. Northern blot analysis confirms the presence of mRNA for CD4 among PBL of animals failing to stain with 74-12-4. CD4 allelism is confirmed by Southern blot analysis, revealing RFLP. Function of the CD4 subset in vivo, as demonstrated by antibody production against a T cell-dependent Ag, is similar between animals of both phenotypes. Proliferative responses to PHA and alloantigen stimulation by a full haplotype mismatch or a class II mismatch alone are equivalent for animals of both phenotypes. These data suggest that the allelic form of CD4, designated CD4.2 in contrast to the wild-type CD4.1, is capable of performing normally as an accessory molecule in the generation of immune responses. Furthermore, antixenogeneic responses to C57B10.BR were equivalent, suggesting that both CD4 molecular types may be capable of interacting with xenogeneic class II molecules. Although the polymorphism includes differences in exons 3 and 4, regions thought to encode portions of the molecule interacting with MHC class II, these results imply that this naturally occurring CD4 polymorphism does not affect the interaction with class II molecules.
Infection with Schistosoma mansoni alters Th1/Th2 cytokine responses to a non-parasite antigen.
Authors: Kullberg M C , Pearce E J , Hieny S E , Sher A , Berzofsky J A
Published: January 2023

Schistosoma mansoni infection in the mouse has been shown to be accompanied by a down-regulation in parasite-Ag- and mitogen-induced Th1 cytokine secretion (IL-2 and IFN-gamma) with a simultaneous increase in the production of Th2 cytokines (IL-4, IL-5, and IL-10), suggesting a generalized imbalance in lymphocyte function. In the present study, we examined whether infection with S. mansoni would also influence the character of immune responses to a non-parasite Ag, sperm whale myoglobin (SwMb). When spleen cells (SC) from schistosome-infected SwMb-immunized animals were stimulated with SwMb, their production of IL-2 and IFN-gamma per CD4+ cell was found to be significantly reduced (by 45% and 59%, respectively) compared with the responses observed in immunized uninfected animals. Moreover, SwMb-induced secretion of IL-4 per CD4+ cell was increased threefold in SC cultures from infected mice. No myoglobin-induced IL-5 was detected in the same cultures. Addition to SC cultures of a neutralizing mAb specific for IL-10 partly restored the suppressed IFN-gamma response to SwMb seen in infected mice, suggesting a role for IL-10 in the observed down-regulation. S. mansoni-infected mice also showed an impaired antibody response to SwMb, with levels ranging from 10% to 27% of those observed in uninfected mice, although no differences in IgG isotype were evident. Taken together, these results suggest that infection with S. mansoni induces a down-regulation of Th1 responses and elevation of Th2 responses to unrelated foreign immunogens as well as to parasite Ag themselves. One implication of these findings is that helminth-infected individuals may have altered cell-mediated immune function to other microbial agents.
Clonally related IgM rheumatoid factors undergo affinity maturation in the rheumatoid synovial tissue.
Authors: Randen I , Brown D , Thompson K M , Hughes-Jones N , Pascual V , Victor K , Capra J D , Førre O , Natvig J B
Published: January 2023

Using hybridoma technology we established a panel of human monoclonal rheumatoid factors (RF) from the synovial tissues of two patients with rheumatoid arthritis (RA), and one patient with polyarticular juvenile RA. Nucleotide sequence analysis of the V regions of these RF indicates that two independently derived antibodies from one of the RA patients are clonally related. One of these antibodies appears to be close to germ-line configuration, whereas the other has accumulated a total of 36 substitutions in both H and L chains. Measurements of the affinity for human IgG of the two RF show that the extensively mutated RF has 100-fold higher affinity for IgG than the RF close to germline. These findings indicate that IgM RF in RA can undergo affinity maturation and suggest that certain RF may be the product of an Ag-driven immune response.
Identification and analysis of a novel human surface CD5- B lymphocyte subset producing natural antibodies.
Authors: Kasaian M T , Ikematsu H , Casali P
Published: January 2023

The production of "natural" autoantibodies or antibodies, i.e., Ig that bind a variety of self- and/or exogenous Ag and arise independently of known immunization, is though to be a feature of CD5+ B lymphocytes. To determine whether other lymphocyte subsets exist that might be committed to the production of natural antibodies, human peripheral blood B cells were sorted on the basis of surface CD5 expression and differential expression of surface CD45RA (CD5+CD45RAintermediate(int), CD5-CD45RAlow(lo), and CD5-CD45RAhigh(hi)), and analyzed for the type of Ig produced after EBV infection and culture. Like their CD5+ counterparts, most CD5-CD45RAlo B lymphocytes were precursors of cells producing IgM, a major proportion of which displayed the Ag-binding features of natural antibodies. In contrast, CD5-CD45RAhi B cells comprised a high frequency of IgG-producing cell precursors, possibly including memory B lymphocytes. Six of seven IgM mAb generated from sorted CD5-CD45RAlo B cells and three of four IgM mAb from sorted CD5+ B cells were polyreactive, binding with different affinities (Kd, 10(-5) to 10(-8) M) to two or more Ag; the remaining mAb from CD5-CD45RAlo and the mAb from CD5+ B cells each bound to a single Ag (Kd, 10(-7) to 10(-8) M), beta-galactosidase and ssDNA, respectively. CD5-CD45RAlo B cells account for 4.1 +/- 1.2% (mean +/- SD in 11 healthy subjects; CD5+ B cells, 23.3 +/- 6.9%) of total B lymphocytes and display the features of quiescent cells. In a given individual, the number of CD5-CD45RAlo B cells remains constant over time. CD5-CD45RAlo and CD5+ B cells bear surface CD11b and CD14, at densities and/or frequencies apparently higher than those of CD5-CD45RAhi B lymphocytes. Despite their surface CD5- phenotype, CD45RAlo B cells express CD5+ mRNA at levels comparable with those of CD5+ B lymphocytes, whereas CD5-CD45RAhi B cells express only trace amounts of CD5 mRNA. The commitment to natural antibody production and the degree of CD5 mRNA expression suggest that the newly defined CD5-CD45RAlo B cell subset is related to CD5+ B lymphocytes, and may constitute the human homologue of the mouse Ly-1-"sister" B cell population.
Cloning and functional expression of the T cell activation antigen CD26.
Authors: Tanaka T , Camerini D , Seed B , Torimoto Y , Dang N H , Kameoka J , Dahlberg H N , Schlossman S F , Morimoto C
Published: January 2023

A cDNA encoding the T cell activation Ag CD26 was isolated from human PHA-activated T cells by using an expression cloning method. The nucleotide sequence obtained predicts a protein of 766 amino acids of type II membrane topology, with six amino acids in the cytoplasmic region. The predicted amino acid sequence of the Ag was 85% homologous to that of the dipeptidyl peptidase IV enzyme isolated from rat liver. Derivatives of the human leukemic T cell line Jurkat transfected with a CD26 expression plasmid were established. Characterization of the CD26 Ag expressed by the transfected Jurkat cells revealed that the Ag could be immunoprecipitated as a 110-kDa molecule similar to that found on peripheral blood T cells and that the Ag had dipeptidyl peptidase IV activity. Functional analysis of these Jurkat transfectants showed that cross-linking of the CD26 and CD3 Ag with their respective antibodies resulted in enhanced intracellular calcium mobilization and IL-2 production. These results provide direct evidence that the CD26 Ag plays a role in T cell activation.
Rat secretory component binds poorly to rodent IgM.
Authors: Underdown B J , Switzer I , Jackson G D
Published: January 2023

Our previous studies and those of others indicated that human secretory component (SC), the five domain extracellular portion of the poly Ig receptor, binds avidly to both pIgA and IgM. In this study we report that in rodents, SC binds primarily to pIgA. Rat secretory component was isolated from bile and radiolabeled to known specific activity with 125I. Radiolabeled rat SC was incubated with rat and mouse monoclonal proteins for 1 h at room temperature and overnight at 4 degrees D. Binding of 125I-rat SC to Ig was determined in two ways: 1) immunoprecipitation of putative 125I-rat SC-Ig complexes with anti-L chain antibodies; 2) HPLC gel filtration on an analytical TSK 4000 column that separated free 125I-rat SC from 125I-rat SC bound to Ig. Both methods of analysis yielded similar results. Rat and mouse polymeric (p) IgA bound rat SC with high avidity, although the binding activity of the IgM from either species was virtually nil. The number of SC-binding sites on rat polymeric Ig was determined by immunoprecipitation of mixtures of rat pIg with saturating concentrations of 125I-rat SC and yielded values of 1.0 and 0.05 for rat pIgA and IgM, respectively. The significance of these findings with respect to the biologic function of the pIg R in rodents and the nature of the pIg R-binding site on pIg is discussed.
Role of binding pockets for amino-terminal peptide residues in HLA-B27 allorecognition.
Authors: Villadangos J A , Galocha B , López D , Calvo V , López de Castro J A
Published: January 2023

The peptide binding site of HLA-B27 and other class I Ag consists of a series of pockets that bind peptide side chains. Two of these pockets interact with the amino-terminal peptide residue (pocket A) and with the highly conserved second residue (pocket B). In this study, the role of pockets A and B in HLA-B27-specific T cell allorecognition has been analyzed. Four HLA-B27 mutants with single or double changes in pocket B (24T----A, 45E----M, 67C----V, and 24,67T,C----A,V) and three mutants with single changes in pocket A (163E----T, 167W----S, and 171Y----H) were constructed by site-directed mutagenesis and expressed in HMy2.C1R cells after DNA-mediated gene transfer. These transfectants were used as target cells in cytotoxicity assays with a series of HLA-B27-specific CTL. All the mutations analyzed affected allorecognition by a significant proportion of the CTL tested, but no single change abrogated recognition by all CTL. The global effects of each mutation on allorecognition were comparable to one another, except for the effect of the change at position 67, which was smaller. The behavior of individual CTL with the mutants was very diverse, ranging from CTL that did not recognize most of the mutants to CTL recognizing all of them. Thus, some alloreactive CTL can withstand drastic alterations in pockets A and B. Two CTL showed heteroclytic effects towards the V67 and M45 mutants. CTL behavior with the H171 mutant was closely parallel to that with the B*2703 subtype, having a single Y----H change at position 59. This parallelism correlates with the similar role of Tyr59 and Tyr171 in establishing hydrogen bonds with the amino termini of HLA-B27-bound peptides. The results demonstrate that altering the structure of pockets that interact with the amino-terminal first and second residues of HLA-B27-bound peptides significantly affects recognition by alloreactive CTL, and they strongly suggest widespread peptide involvement in HLA-B27 allorecognition.
Release of granule proteins from eosinophils cultured with IL-5.
Authors: Kita H , Weiler D A , Abu-Ghazaleh R , Sanderson C J , Gleich G J
Published: January 2023

Eosinophils isolated from normal individuals were cultured in the presence of human rIL-5 (hrIL-5) for up to 14 days, and the effects of this exposure were determined. First, the hrIL-5-cultured eosinophils were activated and degranulated more readily than freshly isolated eosinophils. For example, eosinophils cultured for 7 days with hrIL-5 released 30 and 10% of granule eosinophil-derived neurotoxin (EDN) when exposed to Sepharose 4B beads coupled to secretory IgA and IgG, respectively, whereas freshly isolated eosinophils released only 19 and 4%, respectively, of their EDN in response to the same stimuli. Degranulation of hrIL-5-cultured eosinophils was not augmented by further exposure to hrIL-5, whereas degranulation of freshly isolated cells to secretory IgA and IgG beads was increased by exposure to hrIL-5. Second, eosinophils cultured with hrIL-5 had prolonged viability in vitro. For example, after four days of culture with 50 U/ml of hrIL-5, 86% of eosinophils were viable compared to 12% in medium alone. Third, hrIL-5-cultured eosinophils became hypodense, and electron microscopy showed that they contained granules with core and matrix lucency and with evidence of granule fusion. Fourth, hrIL-5-cultured eosinophils spontaneously lost 30 to 60% of their EDN, eosinophil cationic protein, and eosinophil peroxidase and about 50% of their eosinophil granule major basic protein content compared to freshly isolated eosinophils, and all four of the granule proteins were released into the culture medium. Fifth, detailed studies of eosinophils cultured in hrIL-5 showed that 89 +/- 10% of the starting quantity of EDN could be recovered at 7 days. Whereas 99 +/- 1% of the EDN at day 0 was cell associated, by 7 days 60 +/- 9% was in the cell supernatants. Thus, hrIL-5 activates eosinophils, increases their viability, decreases their density, and their content of granule proteins and causes release of the granule proteins into culture fluids. The striking loss of granule proteins during culture with hrIL-5 may be an important mechanism for deposition of these cationic toxins in various diseases where IL-5 plays a role.
Eosinophil granule cationic proteins regulate complement. I. Activity on the alternative pathway.
Authors: Weiler J M , Edens R E , Gleich G J
Published: January 2023

Eosinophil granules contain several cationic proteins that mediate tissue damage in allergic disease. The present study examined the capacity and mechanisms by which these cationic proteins regulate activity of the alternative pathway of C. Eosinophil peroxidase and eosinophil cationic protein inhibited formation of cell-bound alternative pathway C3 convertase, causing 50% inhibition of lysis at about 0.19 and 0.75 microgram/10(7) cellular intermediates, respectively. Major basic protein inhibited alternative pathway C3 activity by only 19% at 1.5 micrograms/10(7) cellular intermediates. Eosinophil-derived neurotoxin had no activity on the alternative pathway. The eosinophil granule proteins were examined for the mechanism by which they inhibited alternative pathway activity. Eosinophil peroxidase and major basic protein inhibited fluid phase factor B consumption in a reaction mixture that also contained factors D and C3b, eosinophil-derived neurotoxin had no activity on factor B consumption, and eosinophil cationic protein consumed factor B in the absence of C3b and factor D. Both eosinophil cationic protein and eosinophil peroxidase enhanced the decay of preformed alternative pathway convertase. Lysis of EAC4b,3b cellular intermediates formed to contain a low surface amount of C3b was more inhibited than was lysis of cells formed with a standard amount of C3b on the surface. This suggests that these eosinophil proteins acted predominantly on C3b to regulate alternative pathway activity. We also found that none of the eosinophil granule cationic proteins had any effect on later events after the formation of the C3 convertase. We conclude that although eosinophil-derived neurotoxin (isoelectric pH value (pI) = 8.9) does not regulate alternative pathway activity, the more highly charged eosinophil granule cationic proteins--major basic protein (pI = 10.9), eosinophil cationic protein (pI = 10.8), and eosinophil peroxidase (pI = 10.8)--do share the capacity to regulate C activity and may exert this activity in vivo.
A novel cell-surface molecule expressed by human interdigitating reticulum cells, Langerhans cells, and activated lymphocytes is a new member of the Ig superfamily.
Authors: Zhou L J , Schwarting R , Smith H M , Tedder T F
Published: January 2023

cDNA isolated from a human lymphocyte library were analyzed and shown to encode a novel cell-surface glycoprotein, termed HB15, expressed by dendritic cell subsets and activated lymphocytes. The predicted mature 186 amino acid protein was composed of a single extracellular V-type Ig-like domain, a transmembrane region, and a 39-amino acid cytoplasmic domain. In contrast to most Ig-like domains, analysis of a partial genomic DNA clone revealed that the extracellular Ig-like domain of HB15 was encoded by at least two exons. Northern blot analysis revealed that HB15 derived from three mRNA transcripts of approximately 1.7, 2.0, and 2.5 kb expressed by lymphoblastoid cell lines. Two mAb reactive with HB15 were produced and used to show that HB15 is expressed as a single chain cell-surface glycoprotein of M(r) 45,000. HB15 expression was specific for lymphoblastoid cell lines and mitogen-activated lymphocytes, and HB15 was not expressed at detectable levels by circulating leukocytes. Immunohistologic analysis revealed that HB15 had a unique pattern of expression, being found predominantly in hemopoietic tissues with strong expression by scattered interfollicular interdigitating reticulum cells and weak expression by germinal center cells. HB15 was also expressed by Langerhans cells within the skin. HB15 therefore serves as a unique marker for the subset of dendritic cells represented by Langerhans cells and interdigitating reticulum cells. Thus, the HB15 glycoprotein represents a newly identified member of the Ig superfamily that may play a significant role in Ag presentation or the cellular interactions that follow lymphocyte activation.
Inducible cell contact signals regulate early activation gene expression during B-T lymphocyte collaboration.
Authors: Klaus S J , Parker D C
Published: January 2023

B cells get help in the antibody response by presenting processed Ag to Th cells. We asked whether the Ag-presenting B cell must induce Th functions before receiving help, or whether B cell activation is a direct consequence of T cell recognition of Ag on the B cell surface. To obtain a prompt and sensitive indication of the receipt of growth signals, we measured mRNA levels of the immediate early genes, c-myc and egr-1, in T and B cells separated from Ag-specific B-T conjugates of normal, resting murine B cells and a Th line. Although Ag-dependent increases in B cell c-myc expression occur as early as 2 h after conjugation, early c-myc expression in the B cell was also seen when the Th cells were activated with immobilized anti-CD3 in the absence of Ag recognition. Therefore, T cell activation rather than Ag recognition per se appears to be responsible for the early c-myc signal in the B cells. The c-myc response in the B cell depends on induction of a contact-dependent helper function in the T cell, which is inhibitable by cyclosporin A acting on the T cell. Delivery of contact help is not blocked by anti-class II MHC antibody. Contact with activated Th cells induces a different pattern of immediate early gene expression from that induced by cross-linking the B cell Ag receptor.
Heterogeneity in antigen processing by different types of antigen-presenting cells. Effect of cell culture on antigen processing ability.
Authors: Vidard L , Rock K L , Benacerraf B
Published: January 2023

The ability of normal B cells, peritoneal macrophages, and splenic APC to process and present OVA to a panel of T-T hybridomas with different specificities was investigated. In all cases, B cells were less efficient than unfractionated splenocytes in presenting OVA or its peptides. However, when the presentation of native Ag was compared to the presentation of peptides, it was obvious that there were marked differences in the ability of these two APC populations to generate different epitopes from OVA. Leupeptin inhibits the processing of selected epitopes from native OVA differently when it was presented by spleen cells or B cells, suggesting that these two APC populations differ in their protease content. The effect of in vitro culture on the ability of splenic and peritoneal APC to process OVA was also investigated. Native OVA presentation by macrophages and spleen cells was affected by in vitro culture, more for some epitopes than for other epitopes. In contrast, presentation of exogenous peptides by paraformaldehyde-fixed APC was either not affected by previous culturing for 3 days, or very much improved. Altogether, these data demonstrate that different epitopes on the same protein may be independently and differentially processed by B cells and spleen cells. Furthermore, the precise peptides that are produced may vary with the physiologic state of the APC.
A Na(+)-dependent Ca2+ exchanger generates the sustained increase in intracellular Ca2+ required for T cell activation.
Authors: Wacholtz M C , Cragoe E J , Lipsky P E
Published: January 2023

Movement of extracellular Ca2+ is required for the sustained increase in [Ca2+]i necessary for T cell activation. However, the mechanisms mediating mitogen-stimulated Ca2+ movement into T cells have not been completely delineated. To explore the possibility that a Na(+)-dependent Ca2+ (Na+/Ca2+) exchanger might play a role in the mitogen-induced increases in [Ca2+]i required for T cell activation, the effects of inhibitors of this exchanger were examined. Inhibitors of Na+/Ca2+ exchange suppressed the sustained increase in [Ca2+]i stimulated by ligation of the CD3-TCR complex, but did not affect mobilization of intracellular Ca2+ stores. Consistent with the importance of this prolonged increase in [Ca2+]i in T cell activation, Na+/Ca2+ exchange inhibitors, but not inhibitors of the Na+/H+ antiporter, inhibited DNA synthesis stimulated by immobilized anti-CD3 mAb. Inhibition only occurred when the agents were present during the first hours after stimulation. These agents also inhibited IL-2 production, but not expression of the IL-2R or of an early activation Ag, 4F2. Inhibition of IL-2 production did not account for the inhibition of T cell proliferation as addition of exogenous IL-2 or phorbol ester (PDB) did not overcome the inhibition. In contrast, activation pathways that are not thought to require an increase in [Ca2+]i such as IL-1 + PDB or engagement of CD28 in the presence of PDB were less sensitive to the suppressive effects of inhibitors of Na+/Ca2+ exchange. Thus, proliferation induced by these stimuli was not suppressed by low concentrations of these inhibitors and IL-2 production induced by mAb to CD28 + PDB was not inhibited by any concentration of inhibitors of Na+/Ca2+ exchange. These results suggest that stimulation of a Ca2+ transporter with the same spectrum of inhibition as the Na+/Ca2+ exchanger in other tissues mediates the sustained increase in [Ca2+]i required for T cell activation after CD3 ligation.
The HLA class I gene family includes at least six genes and twelve pseudogenes and gene fragments.
Authors: Geraghty D E , Koller B H , Hansen J A , Orr H T
Published: January 2023

We report the characterization of eight HLA class I homologous sequences isolated from cosmid and lambda libraries made from lymphoblastiod cell line 721 DNA. Four of these sequences, each contained within HindIII fragments of 1.7, 2.1, 3.0, and 8.0 kb, have class I homology extending over short intronexon regions. The remaining four are found within 7.5-, 8.0-, 9.0-, and 16.0-kb HindIII fragments, the first having homology to the 5' half of a class I gene whereas the latter three are homologous to the 3' portion of a class I gene. When combined with the characterization of other class I clones, this work brings the total number of HLA class I homologous sequences cloned and characterized to 18. Restriction mapping of cosmid clones showed that some of these sequences are linked to one another and to other class I pseudogenes and genes within 50-kb regions. Reconstruction experiments using the 18 class I genes and pseudogenes were performed that indicated that we had cloned all of the members of the HLA class I gene family detectable using HLA-A2 genomic DNA as probe. An additional 19th member of the class I gene family was identified using an HLA-E cDNA probe. Further Southern analysis with other class I probes indicated the 19 sequences comprise the entire class I gene family in LCL 721. Locus-specific probes were isolated from five of the eight clones and were used in Southern analysis of diverse genomic DNA to examine the polymorphism of the pseudogene sequences, demonstrating that some of them were highly polymorphic and some were missing entirely in certain haplotypes. An additional class I sequence, not contained within the 721 genome, was identified and may be found in association with the HLA-A11-Bw60 haplotype. Sequence comparisons were carried out to examine the evolutionary relationships among the pseudogenes. Hypothetical events in the evolution of the class I region are discussed.
Expression of murine beta 7, alpha 4, and beta 1 integrin genes by rodent mast cells.
Authors: Gurish M F , Bell A F , Smith T J , Ducharme L A , Wang R K , Weis J H
Published: January 2023

The screening of a rat mast cell cDNA library with a probe selected to recognize those genes preferentially or exclusively expressed by mast cells identified a rat gene sequence, RF-17, that shared homology with the beta-integrins. This integrin was expressed in rat tissues enriched for mast cells and T cells. The rat RF-17 sequence was used to isolate the murine homologue from a spleen cDNA library. The murine gene encodes a protein of 806 amino acids that is the probable homologue to the human beta 7 chain. Transcripts specific for the murine gene are found in the thymus, spleen, and lung. To attempt to identify the gene product for this new integrin chain, we examined the murine T cell line TK-1, which expresses a novel integrin heterodimer, lymphocyte Peyer's patch high endothelial venule adhesion molecule (LPAM-1), of a known alpha 4 chain and an unknown beta P chain, for expression of murine beta 7 (RF-17). This cell line expresses high levels of RF-17 transcripts, suggesting that beta P is encoded by the beta 7 gene. Bone marrow cells induced to differentiate into mast cells via IL-3 express the beta 7 gene as well as the genes encoding the murine integrin alpha 4 and beta 1 proteins. Surface staining analysis indicates that these cells express an alpha 4-containing integrin complex throughout the differentiation process. These data suggest that the Peyer's patch homing LPAM-1 receptor expressed by a subset of T cells consists of the beta 7 gene product and the alpha 4 chain, and that this integrin chain complex is also found on the surface of maturing mast cells. The presence of beta 1 transcripts also suggests that these maturing mast cells possess the LPAM-2 integrin complex (alpha 4/beta 1) as well. The experimental strategy described in this manuscript has, thus, identified a novel murine beta-integrin chain that is expressed by rodent T cells and mast cells.
Human IL-1 receptor antagonist promoter. Cell type-specific activity and identification of regulatory regions.
Authors: Smith M F , Eidlen D , Brewer M T , Eisenberg S P , Arend W P , Gutierrez-Hartmann A
Published: January 2023

To study the molecular mechanisms involved in transcriptional regulation of the human IL-1R antagonist (IL-1ra) we have isolated 1680-bp of 5'-flanking region DNA from the IL-1ra gene. This region of DNA was sequenced and cloned into the luciferase expression vector pA3Luc (pRA-1680.Luc) for use in gene transfer studies aimed at determining the cis-acting DNA elements required for IL-1ra expression. Sequence analysis of the IL-1ra promoter revealed a TATAA box at -26, with consensus sequences for possible NF-kB-, NFIL-1 beta A-, AP-1-, and CRE-binding sites located further upstream. When transfected into a variety of human and murine cell lines, the cloned IL-1ra promoter was preferentially active in those cell lines in which expression of the endogenous IL-1ra gene could be detected. The cloned promoter and the endogenous IL-1ra promoter utilized the same transcriptional start site. This promoter activity was LPS-inducible in the RAW 264.7 murine macrophage cell line. In the human monocytic cell line U937, IL-1ra promoter activity was inducible by LPS or PMA treatment, but the combination of LPS and PMA led to the greatest increase in promoter activity, identical to the pattern of expression of endogenous IL-1ra mRNA as detected by polymerase chain reaction analysis. A series of 5'-truncated promoter constructs having a common 3'-end at +27 were created to map potential cis-acting transcriptional elements important for full IL-1ra promoter activity. Removal of sequences between -294 and -148 led to a greater than 90% decrease in both unstimulated and LPS-induced promoter activity; further deletion to -85 led to an almost complete abrogation of promoter activity. These studies demonstrate that the cloned IL-1ra promoter behaves in a manner consistent with that of the endogenous gene. Two regions within the IL-1ra promoter are identified which are required for full promoter activity.
Complex of soluble human IL-6-receptor/IL-6 up-regulates expression of acute-phase proteins.
Authors: Mackiewicz A , Schooltink H , Heinrich P C , Rose-John S
Published: January 2023

IL-6 is a major regulator of acute phase protein synthesis in the liver. It exerts its action via a plasma membrane receptor consisting of two subunits, a ligand binding 80-kDa glycoprotein and a 130-kDa glycoprotein involved in signal transduction. We genetically generated a soluble form of the 80-kDa subunit of the human IL-6R (shIL-6R) in mouse fibroblasts (NIH/3T3 cells). The shIL-6R added to human hepatoma cells (HepG2) amplified the induction of alpha 1-antichymotrypsin and haptoglobin by IL-6 at the mRNA and protein level. Moreover, a model for a liver permanently exposed to high IL-6 concentrations has been developed; HepG2 cells were stably transfected with human IL-6-cDNA; 10(6) of the transfected cells (HepG2-IL-6) synthesized and secreted 2 micrograms of IL-6 within 24 h. Incubation of these cells with endogenous or exogenous IL-6 did not result in acute-phase protein induction. However, these IL-6-desensitized cells responded to other cytokines such as leukemia inhibitory factor, transforming growth factor beta 1, and IFN-gamma, known to modulate acute phase protein synthesis in the liver. Incubation of HepG2-IL-6 cells with shIL-6R reconstituted their responsiveness to IL-6 in a dose- and time-dependent manner. The possible biologic role that might be played by the shIL-6R in disease is discussed.
Adherence of infected erythrocytes to venular endothelium selects for antigenic variants of Plasmodium falciparum.
Authors: Biggs B A , Anders R F , Dillon H E , Davern K M , Martin M , Petersen C , Brown G V
Published: January 2023

Erythrocytes (E) infected with asexual forms of malaria parasites exhibit surface antigenic variation. In Plasmodium falciparum infections, the variant Ag is the P. falciparum E membrane protein 1 (PfEMP1). This molecule may also mediate the adherence of infected E to host venular endothelium. We show here that parasite lines selected for increased adherence to endothelial cells have undergone antigenic variation. Three adherent lines selected from the same P. falciparum clone reacted with the same agglutinating antiserum that failed to agglutinate the parental clone. Immunoprecipitation experiments with the agglutinating anti-serum demonstrated that the selected lines expressed cross-reactive forms of PfEMP1 that were of higher m.w. and antigenically distinct from PfEMP1 of the parental clone. When one of the adherent lines was cloned in the absence of selection, a range of variant antigenic types emerged with differing cytoadherence phenotypes. These findings show that selection for cytoadherence in vitro favors the emergence of antigenic variants of P. falciparum and suggest that the requirement for cytoadherence in vivo may restrict the range of antigenic variants of P. falciparum in natural infections.
Cytotoxic activity and production of toxic nitrogen oxides by macrophages treated with IFN-gamma and monoclonal antibodies against the 73-kDa lipopolysaccharide receptor.
Authors: Green S J , Chen T Y , Crawford R M , Nacy C A , Morrison D C , Meltzer M S
Published: January 2023

The hamster IgM mAb 5D3 is specific for an 73-kDa LPS receptor on murine leukocytes. This mAb inhibits binding of radiolabeled LPS to splenocytes and acts as an agonist for induction of LPS-mediated changes in macrophage function. Resident peritoneal macrophages treated with IFN-gamma and mAb 5D3 developed potent cytotoxic activity against tumor cells. Cells treated with IFN-gamma or mAb 5D3 alone were inactive. Macrophage cytotoxic activity induced by IFN-gamma and mAb 5D3 was inhibited by NGMMLA and coincident with high levels of NO2-released into culture fluids. These data show that mAb 5D3 serves as an effective trigger signal for induction of cytotoxic activity with IFN-gamma-primed macrophages. Indeed, mAb 5D3 exactly mimicked the effects of LPS in these same systems. Unlike LPS, effects of mAb 5D3 on induction of macrophage cytotoxic activity and production of nitrogen oxides was abrogated after boiling, and not affected by addition of polymyxin B. The effects of LPS and mAb 5D3 as a trigger signal for IFN-gamma-primed macrophages were associated with production of TNF activity in culture fluids and inhibited by mAb against rTNF-alpha. Expression of class II MHC on macrophages induced by IFN-gamma treatment was suppressed by both LPS and mAb 5D3. These suppressive effects of LPS and mAb 5D3 were not affected by NGMMLA or mAb against rTNF-alpha. Finally, macrophages treated with LPS or mAb 5D3 before exposure to IFN-gamma and LPS or mAb 5D3 did not develop cytotoxic activity or high levels of NO2- in the culture fluids. These same cells developed both effector activities after addition of rTNF-alpha. These results in toto identify the 73-kDa protein as a receptor that mediates LPS-induced changes in macrophage effector function. The mAb 5D3 serves as a specific and defined reagent agonist for analysis of LPS receptor-linked change.
Identification of a new group-specific determinant on hepatitis B surface antigen with a synthetic peptide.
Authors: Manivel V , Panda S K , Rao K V
Published: January 2023

In a recent study we demonstrated that a synthetic peptide representing residues 124-147 of the major protein of hepatitis B surface Ag (HBsAg) undergoes spontaneous oligomerization to reconstruct one or more conformational group-specific determinants on HBsAg. The present study was undertaken to identify and characterize the HBsAg-related antigenic determinants on this oligomeric peptide (peptide OS[124-147]). A panel of nine analogs of this peptide was generated by either deleting, substituting, or chemical side chain modification of specific amino acid residues. With HBsAg subtype-specific antisera a single "a" epitope was identified as one that includes Met133 and Lys141. In addition a "d" epitope toward the amino-terminal end of the sequence was also observed. Perturbation of certain amino acid residues was found to enhance a antigenicity and subsequent experiments indicated that maximal expression of this a antigenicity is dependent in part on accessibility of the Lys141 side chain and in part on the primary sequence. With a total of 50 human anti-HBsAg serum samples obtained from individuals vaccinated against hepatitis B, it was demonstrated that these sera recognize the Met133-Lys141-dependent a epitope as the dominant, and in many cases the only, determinant on peptide OS[124-147]. Finally, on immunization, peptide OS[124-147] elicits an anti-HBsAg response that is predominantly anti-a though a lesser contribution from an anti-d response was also obtained.
A T cell clone directed at the circumsporozoite protein which protects mice against both Plasmodium yoelii and Plasmodium berghei.
Authors: Weiss W R , Berzofsky J A , Houghten R A , Sedegah M , Hollindale M , Hoffman S L
Published: January 2023

Clone B is a cytotoxic T cell clone induced by immunization with Plasmodium yoelii sporozoites which recognizes an epitope on both the P. yoelii and Plasmodium berghei circumsporozoite proteins. It is CD8, uses the V beta 8.1 TCR, and is Kd restricted. When adoptively transferred, it protects mice against infection by both species of malaria sporozoites, and this protection is dependent on IFN-gamma. Clone B cells are more broadly reactive and protective than previously described murine T cell clones against malaria. Clone B may be an important model for immune protection against the spectrum of variant parasites in nature.
Both tumor necrosis factor and nitric oxide participate in lysis of simian virus 40-transformed cells by activated macrophages.
Authors: Duerksen-Hughes P J , Day D B , Laster S M , Zachariades N A , Aquino L , Gooding L R
Published: January 2023

SV40 transformation of rodent fibroblasts generally produces cells that are highly sensitive to killing by activated macrophages. The cell line SV-COL-E8 (E8) is typical of SV40-transformed mouse fibroblasts in that it is readily lysed when exposed to activated macrophages. This killing is not due solely to TNF, because soluble TNF alone is incapable of lysing these cells. TNF is, however, necessary for lysis since antibodies to TNF will prevent macrophage-mediated lysis. Similarly, E8 is not sensitive to nitric oxide (NO); however, NO is also necessary for lysis since inhibition of NO generation (by coincubation with the arginine analogue NG-monomethyl-1-arginine) with Fe(II)) blocks lysis of E8 by activated macrophages. Cytolysis by macrophages is contact dependent, suggesting that the cell-associated TNF precursor may be involved in mediating cytolysis. However, transfected cell lines bearing cell-associated TNF precursor do not mediate killing of E8. Thus, killing of E8 either involves both TNF and NO in addition to a third, as yet unidentified, lytic mechanism, or killing requires the contact-dependent delivery of TNF and NO from the macrophage to its target.
Tumor target-derived soluble factor synergizes with IFN-gamma and IL-2 to activate macrophages for tumor necrosis factor and nitric oxide production to mediate cytotoxicity of the same target.
Authors: Jiang H , Stewart C A , Fast D J , Leu R W
Published: January 2023

Inflammatory mouse peritoneal macrophages were activated by IFN-gamma in synergy with IL-2 or Lipid A to mediate TNF production for autocrine generation of cytotoxic nitric oxide (NO) to kill P815 or L1210 tumor targets. It was determined that for IL-2, but not Lipid A, to effectively trigger activation of IFN-gamma-primed macrophages, the tumor targets must be also present for interaction with effector macrophages to mediate the production of TNF and NO. IFN-gamma- and IL-2-activated macrophages from syngeneic DBA/2 and allogeneic C3H mice had identical MHC-unrestricted requirements for interaction with DBA/2 mouse-derived P815 and L1210 targets to mediate production of TNF and NO for tumor cytotoxicity. To further define the mechanistic requirements for macrophage-tumor target interaction, IFN-gamma- and IL-2-activated macrophages were separated from P815 targets in culture by a semipermeable membrane. Under these conditions, both TNF and NO were produced by the macrophage, which indicated that the requirement for tumor target-macrophage interaction may be due to a soluble factor produced by the target rather than to direct physical contact. This was confirmed by experiments in which 24-h cell-free culture fluids, derived from either P815 or L1210 tumor targets, substituted for the intact tumor cells in the stimulation of TNF mRNA synthesis and secretion with NO generation of TNF mRNA synthesis and secretion with NO generation by IFN-gamma- and IL-2-activated C3H or DBA/2 macrophages. The activity in 24-h culture fluids derived from P815 and L1210 tumor targets was tentatively designated as tumor-derived recognition factor(s) (TDRF) since it was produced constitutively by the tumor targets and synergized with IFN-gamma and IL-2 to induce macrophage production of TNF and NO for death of the same targets. A variety of nontransformed human and mouse fibroblasts, mouse spleen lymphocytes, and two adherent mouse fibrosarcomas did not produce detectable TDRF activity, whereas two mouse T lymphomas, EL4 and EL4.IL-2, produced TDRF activity similar to L1210 mouse leukemia and P815 mastocytoma. The C3H/MCA, a TDRF-nonproducing mouse fibrosarcoma, was susceptible to cytotoxicity mediated by macrophages activated by IFN-gamma and Lipid A, but not by IL-2 triggering. Exogenous TDRF derived from L1210 targets reconstituted the cytotoxic activity for C3H/MCA MCA targets mediated by IFN-gamma- and IL-2-activated macrophages accompanied by the production of TNF and cytotoxic NO.(ABSTRACT TRUNCATED AT 400 WORDS)
Potential role of monocyte chemoattractant protein 1/JE in monocyte/macrophage-dependent IgA immune complex alveolitis in the rat.
Authors: Jones M L , Mulligan M S , Flory C M , Ward P A , Warren J S
Published: January 2023

We have examined the role of monocyte chemoattractant protein 1 (MCP 1) in the pathogenesis of monocyte/macrophage-dependent IgA immune complex alveolitis in the rat. Rat MCP 1 was cloned and expressed in order to facilitate analysis of its function in rat models of human disease. A cDNA library was constructed from rat pulmonary artery endothelial cells stimulated with TNF-alpha. The cDNA library was screened with synthetic oligonucleotide probes based on the recently published rat MCP 1 cDNA sequence. Among numerous MCP 1-positive clones, four full length (approximately 480 bp) cDNA were rescued, amplified by polymerase chain reaction, and ligated into a pJVETLZ baculovirus transfer vector. Spodoptera frugiperda insect cells (Sf-21) infected with baculovirus recombinants (Auto-grapha california nuclear polyhedrosis virus) bearing properly oriented MCP 1 cDNA (AcMCP 1) directed the expression of unique peptides of 18, 21, and 23 kDa. Treatment of AcMCP 1-infected Sf-21 cells with tunicamycin resulted in reduced production of the 21- and 23-kDa proteins and an increase in 16- to 18-kDa products, the predicted size range of uncleaved and nonglycosylated rat MCP 1. Denatured and refolded 23-kDa and 21-kDa rat MCP 1 species exhibited dose-dependent monocyte-specific chemotactic activity at concentrations as low as 10(-10) M whereas the 18-kDa species exhibited negligible activity. Antibodies that react with the immunoblot, block rat rMCP 1-directed monocyte chemotaxis, and neutralize monocyte-specific chemotactic activity secreted by TNF-stimulated rat endothelial cells were raised in rabbits immunized with the 23-kDa MCP 1 species. Intravenous administration of anti-MCP 1 antibodies upon initiation of IgA immune complex lung injury resulted in a marked reduction in lung injury as measured by pulmonary vascular permeability, alveolar hemorrhage, and pulmonary monocyte/macrophage recruitment and pulmonary monocyte/macrophage recruitment. These data suggest that MCP 1 may play an important role in the pathogenesis of monocyte/macrophage-dependent IgA immune complex alveolitis in the rat.
Production of nitric oxide by murine bone marrow cells. Inverse correlation with cellular proliferation.
Authors: Punjabi C J , Laskin D L , Heck D E , Laskin J D
Published: January 2023

The present studies were designed to assess the ability of primary cultures of bone marrow cells to produce nitric oxide. We found that two inflammatory stimuli, IFN-gamma and LPS, were potent inducers of nitric oxide production by bone marrow cells. In addition, the CSF granulocyte-macrophage (GM)-CSF and IL-3 as well as TNF-alpha, while inactive by themselves, were synergistic with LPS and IFN-gamma in inducing nitric oxide production. Maximal effects were observed with combinations of GM-CSF and LPS. Nitric oxide production by bone marrow cells was found to be dependent on the presence of L-arginine in the culture medium and inhibitable by NG-monomethyl-L-arginine and L-canavanine, two nitric oxide synthase inhibitors. Nitric oxide produced by the cells was also suppressed by TGF-beta 1 and the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate. Separation of bone marrow cells by density gradient centrifugation and flow cytometry revealed that the granulocyte-containing fraction was largely responsible for nitric oxide production. In additional experiments we found that treatment of bone marrow cells with GM-CSF significantly stimulated bone marrow cell growth. In contrast, the combination of GM-CSF and LPS or IFN-gamma markedly suppressed cellular proliferation. This suppression was completely reversed by treatment of the cells with NG-monomethyl-L-arginine. Taken together, these data demonstrate that various inflammatory stimuli and cytokines induce nitric oxide production by primary cultures of bone marrow cells and that this mediator may play a role in the regulation of bone marrow cell growth and development.
Absence of T cell tolerance to pancreatic islet cells.
Authors: Burtles S S , Trembleau S , Drexler K , Hurtenbach U
Published: January 2023

To examine whether the lack of self-tolerance to beta cells is responsible for the development of type I diabetes in nonobese diabetic (NOD) mice, we attempted to induce T cell responses to cells from the islets of Langerhans. The data show that all NOD mice, irrespective of age, sex, and disease progression, possess islet cell-specific CD4+, MHC class II-restricted T cells. Both primary and secondary proliferative responses to islet cells were readily induced. The activation of T cells required presentation of islet cell Ag by APC in the responding lymph node cell population. Cells from other tissues, e.g., salivary gland, adrenal gland, and spleen, failed to activate autologous T lymphocytes. T cells specific for other Ag did not respond to islet cells, indicating that the proliferation is not the result of nonspecific stimulation by islet cell products. The presence of islet cell-reactive T cells is, however, not unique to NOD mice, because similar T cell reactivity was also demonstrated in non-diabetes-prone mouse strains. Hence, self-tolerance to islet cells appears to be absent. The results indicate a normal occurrence of islet cell-reactive T cells in both diabetes-prone as well as non-diabetes-prone mice. Thus, the lack of tolerance cannot be the initial cause of diabetes, but the activation of such autoreactive T cells may be important for the development of the disease.