bluuebunny/crossref_metadata_2025 huggingface dataset:
Broad recognition of cytotoxic T cell epitopes from the HIV-1 envelope protein with multiple class I histocompatibility molecules.
Authors: Shirai M , Pendleton C D , Berzofsky J A
Published: December 2022

A few cases have been described of antigenic determinants that are broadly presented by multiple class II MHC molecules, especially murine I-E or human DR, in which polymorphism is limited to the beta chain, and the alpha chain is conserved. However, no similar cases have been studied for presentation by class I MHC molecules. Because both domains of the MHC peptide binding site are polymorphic in class I molecules, exploring permissiveness in class I presentation would be of interest, and also such broadly presented antigenic determinants would clearly be useful for vaccine development. We had defined an immunodominant determinant, P18, of the HIV-1 gp160 envelope protein recognized by human and murine CTL. To determine the range of class I MHC molecules that could present this peptide and to determine whether two HIV-1 gp160 Th cell determinants, T1 and HP53, could also be presented by class I MHC molecules, we attempted to generate CTL specific for these three peptides in 10 strains of B10 congenic mice, representing 10 MHC types, and BALB/c mice. P18 was presented by at least four different class I MHC molecules from independent haplotypes (H-2d, p, u, and q to CD8+ CTL. In H-2d and H-2q the presentation was mapped to the D-end class I molecule, and for Dd, a requirement for both the alpha 1 and alpha 2 domains of Dd, not Ld, was found. HP53 was also presented by the same four different class I MHC molecules to CD8+ CTL although at higher concentrations. T1 was presented by class I molecules in three different strains of distinct MHC types (B10.M, H-2f; B10.A, H-2a; and B10, H-2b) to CTL. The CTL specific for P18 and HP53 were shown to be CD8+ and CD4- and to kill targets expressing endogenously synthesized whole gp160 as well as targets pulsed with the corresponding peptide. To compare the site within each peptide presented by the different class I molecules, we used overlapping and substituted peptides and found that the critical regions of each peptide are the similar for all four MHC molecules. Thus, antigenic sites are broadly or permissively presented by class I MHC molecules even without a nonpolymorphic domain as found in DR and I-E, and these sequences may be of broad usefulness in a synthetic vaccine.
Characterization of the immune response to a secondary encephalitogenic epitope of basic protein in Lewis rats. I. T cell receptor peptide regulation of T cell clones expressing cross-reactive V beta genes.
Authors: Offner H , Vainiene M , Gold D P , Celnik B , Wang R , Hashim G A , Vandenbark A A
Published: December 2022

In Lewis rats, immunization with myelin basic protein induces two distinct encephalitogenic T cell populations, those responding to the immunodominant 72-89 epitope and those specific for a secondary epitope including residues 87-99. The 72-89 specific T cells were I-A restricted and preferentially expressed V beta 8.2 in their TCR. To determine the fine specificity, MHC restriction, and TCR V beta gene use in T cells reactive to the secondary epitope, we characterized 23 T cell clones from the lymph nodes (LN) and spinal cords (SC) of rats immunized with either whole basic protein or synthetic peptides S85-99 and S87-99 that were found to be functionally similar. The S85-99/S87-99 specific clones from LN and SC were all encephalitogenic despite differences in recognition of intact basic protein and class II MHC restriction. Unlike LN clones that overexpressed V beta 8 (46%+) and V beta 6 (31%+), however, SC clones were strongly biased (86%+) in their expression of V beta 6. This V gene bias raised the possibility of TCR peptide therapy using V beta 6 peptides. The V beta 6 sequence was similar to V beta 8.2 in the CDR2 region, and the corresponding peptides from this region were found to be cross-reactive in vivo. Moreover, both peptides were effective in the treatment of EAE induced with either S85-99, biased in V beta 6+ and V beta 8+ T cells, or guinea pig basic protein, biased only in V beta 8+ T cells. These data demonstrate the presence of common immunogenic epitopes among subsets of TCR V region gene families that possess important regulatory activity on effector T cell function.
IL-4 suppresses cytokine gene expression induced by IFN-gamma and/or IL-2 in murine peritoneal macrophages.
Authors: Gautam S , Tebo J M , Hamilton T A
Published: December 2022

The effect of IL-4 on inflammatory gene expression in murine peritoneal macrophages stimulated with IFN-gamma in combination with IL-2 has been examined. These agents cooperatively induce the expression of mRNA for TNF-alpha and IP-10. Murine rIL-4 suppresses cytokine mRNA expression depending on the stimulus used and the mRNA being measured. Expression of TNF-alpha mRNA in macrophages stimulated with IFN-gamma, IL-2, or the combination is markedly suppressed by IL-4 whereas LPS-induced TNF-alpha mRNA is unaffected. In contrast, IP-10 mRNA expression is more sensitive to suppression by IL-4 when stimulated by LPS than by IFN-gamma/IL-2. IL-4-mediated suppression does not alter the time course of mRNA expression. Treatment of IFN-gamma/IL-2-stimulated macrophages with cycloheximide blocks the suppressive effect of IL-4, suggesting that de novo synthesis of an intermediate protein is part of the suppressive mechanism. The IL-4-mediated suppression of IFN-gamma/IL-2-driven TNF-alpha gene expression appears to be mediated at the level of transcription. These findings support a role for IL-4 as an antiinflammatory cytokine and suggest that macrophage inflammatory function will be dependent on the precise stimulus composition of the tissue microenvironment.
Molecular heterogeneity of Fc alpha receptors detected by receptor-specific monoclonal antibodies.
Authors: Monteiro R C , Cooper M D , Kubagawa H
Published: December 2022

Fc alpha receptors (Fc alpha R) were isolated from a human monocytic cell line and used to raise four mAb with receptor specificity. The antibodies were used to identify the types of white blood cells that express Fc alpha R and the molecular heterogeneity of the receptor molecules. Nonpolymorphic epitopes, outside of the Fc alpha-binding site, were recognized only on blood cells of granulocyte and monocyte/macrophage lineages. The molecules identified, both by the antibodies and by the IgA ligand, were glycoproteins ranging in relative molecular mass from 55 to 75 kDa. However, one antibody detected a subpopulation of Fc alpha R molecules characterized by relatively restricted size heterogeneity. A complex glycosylation pattern was revealed by the resolution of discrete 32- and 36-kDa molecular species after removal of N-linked oligosaccharides and by evidence for O-linked carbohydrate moieties on at least a portion of the Fc alpha R molecules. In biosynthetic studies, all four anti-Fc alpha R antibodies and the IgA ligand bound a single 32-kDa core protein present in tunicamycin-treated cells, and the exceptional antibody again recognized molecules with relatively restricted glycosylation in the nontreated cells. These antibodies and native IgA ligands thus provide complementary reagents for definition of the complex structure and function of Fc alpha R in systemic IgA antibody responses.
Acquired resistance and granuloma formation in experimental visceral leishmaniasis. Differential T cell and lymphokine roles in initial versus established immunity.
Authors: Murray H W , Squires K E , Miralles C D , Stoeckle M Y , Granger A M , Granelli-Piperno A , Bogdan C
Published: December 2022

In naive BALB/c mice, acquisition of resistance to Leishmania donovani and formation of antileishmanial tissue granulomas are linked expressions that require both L3T4+ and Lyt 2+ cells as well as both IL-2 and IFN-gamma. To determine the mechanisms of established resistance to L. donovani, rechallenged immune BALB/c mice were treated with T cell- and lymphokine-depleting mAb or cyclosporin A. In the liver, resistance to rechallenge was inhibited by treatment with anti-Lyt 2 but not anti-L3T4 mAb. Resistance was also impaired by anti-IL-2 treatment but not by anti-IFN-gamma mAb. The hepatic granulomatous response to rechallenge, however, was not impaired by either anti-Lyt 2 or anti-IL-2 mAb nor by anti-L3T4 or anti-IFN-gamma treatment. In contrast, cyclosporin A suppressed granuloma formation but not antileishmanial activity. These results indicate a particularly important antileishmanial host defense role for Lyt 2+ cells and IL-2 in sensitized animals, and when compared to prior observations in L. donovani-infected naive mice, suggest that 1) discrete T cell- and lymphokine-dependent mechanisms are involved in initial acquisition of resistance vs established immunity, 2) more than one mechanism can mediate the development of tissue granulomas, and 3) granuloma formation by itself may not be required nor necessarily sufficient to confer antimicrobial activity.
Phenotypic and functional studies on ocular T cells during herpetic infections of the eye.
Authors: Niemialtowski M G , Rouse B T
Published: December 2022

Herpetic stromal keratitis an inflammatory disease of the eye resulting from herpes simplex virus type 1 infection, is a common cause of blindness. The disease is generally considered to represent an immunopathologic response, but the exact mechanism remains in doubt and is subject to debate. We have investigated the nature of inflammatory cells in the eye and have isolated ocular cells to establish their phenotype and determine some of their functions. By means of immunocytochemistry and cytofluorography, the only T lymphocyte subset detectable at any stage of infection of BALB/c mice were CD4+ cells. However CD8+ T cells were readily detectable in draining lymph nodes (DLN). Assays for cells with HSV-1-specific cytotoxic function of both CD4+ class II restricted and CD8+ class I-restricted activity were performed. Although in DLN both cell types were found, among ocular cells only CD4+ cytotoxic cells were evident. The frequencies of CD4+ CTL-precursor in eyes were determined and found to be at least 8- to 10-fold less than found in DLN. The number of CTL-precursor in an individual eye was estimated to be 20 or less. Our results further support the notion that CD4+ mediate the immunopathology of herpetic stromal keratitis, but on quantitative grounds cast doubt on the idea that cytotoxicity is the principal mechanism involved.
Isolation and characterization of nuclear proteins that bind to T cell receptor V beta decamer motif.
Authors: Lee M R , Chung C S , Liou M L , Wu M , Li W F , Hsueh Y P , Lai M Z
Published: December 2022

TCR V beta promoter contains a highly conserved decamer homologous to cAMP response element (CRE). Recent studies have identified this CRE decamer as the dominant transcription-activating element within the TCR V beta promoter. We have isolated cDNA clones, TCR-ATF1 and TCR-ATF2, encoding DNA-binding proteins that recognize this CRE motif. The nucleotide sequence of TCR-ATF1 has not previously been reported, whereas that of TCR-ATF2 was homologous to CRE-BP1, ATF-2, and mXBP. Both TCR-ATF1 and TCR-ATF2 shared a conserved leucine zipper and DNA binding motif with other CRE-binding proteins. TCR-ATF1 and TCR-ATF2 were expressed in all cell lines examined and in mouse embryos as early as 12.5 days. Despite binding to the same CRE motif, TCR-ATF1 and TCR-ATF2 were different from CREB in the fine nucleotide specificity. TCR-ATF bound methylated CRE and CRE mutant M4 (4C----G) that were not recognized by CREB. Additionally, TCR-ATF1 weakly recognized two other single nucleotide mutants of V beta-CRE that were not bound by TCR-ATF2 and CREB. We have further demonstrated that TCR beta-chain expression was immediately activated by cAMP. Such induction is likely mediated through V beta-CRE sequence, because the inclusion of V beta-CRE in a vector with minimum promoter (pBLCAT2) conferred the cAMP inducibility of CAT activity.
The Ig VH repertoire of fetal liver-derived pre-B cells is influenced by the expression of a gene linked to X-linked immune deficiency.
Authors: Osman G E , Brodeur P H , Rosenberg N , Wortis H H
Published: December 2022

Ig VH repertoire differences between normal and x-linked immune deficiency- (xid) expressing mice are well established. To test the hypothesis that such differences might exist as early as the pre-B stage of ontogeny we generated panels of xid fetal liver derived Abelson murine leukemia virus transformants with H chain Ig VDJ rearrangements. Cells from CBA/Tufts.xid mice used VH genes from many families, with no demonstrable preference for 3' genes. Analysis of cells derived from (CBA/Tufts.xid X CBA/Tufts)F1 mice showed preferential usage of 3' family genes in the phenotypically normal females, even though V to DJ joins were made in vivo. The defective male mice did not show this marked preferential usage. A similar, but less marked, effect on VH gene usage was seen in mice with X-linked immune deficiency and a BALB/c background. Taken together, these results show that either X-linked immune deficiency, or a closely linked gene, affects fetal pre-B cells such that the usual pattern of predominant usage of 3' family genes is altered.
Mouse genotype affects inducible expression of cytokine genes.
Authors: Raj N B , Cheung S C , Rosztoczy I , Pitha P M
Published: December 2022

The levels of circulating IFN in mice infected with Newcastle disease virus (NDV) are regulated by the If-1 locus. In this study we show that in NDV-infected C57BL/6 mice, which carry the If-1h allele and produce high levels of IFN, high levels of both IFN-alpha and -beta mRNA can be detected in the spleen. In contrast, only very low levels of IFN mRNA could be detected in spleens of infected BALB/c mice containing the If-1l allele and producing low levels of IFN or in B6.C-H28c mice that are congenic for the If-1l allele. The relative levels of all individual IFN-alpha 1, alpha 4, and alpha 6 mRNA in spleens of infected BALB/c were lower than in spleens of infected C57BL/6 mice, indicating that the If-1 locus affects the expression of all IFN-alpha subtypes and is not associated with the deletion or inactivation of a specific IFN gene. The relative levels of IFN regulatory factor-1 mRNA in infected mice carrying the If-1l and If-1h loci were comparable, suggesting that the If-1 regulation is not associated with the altered expression of the IFN regulatory factor-1 gene. Quantitative difference in the expression of IFN-alpha and -beta genes was also observed in in vitro-infected peritoneal macrophages isolated from either C57BL/6 or BALB/c mice. A surprise finding was that the If-1 locus also affected the NDV-induced expression of two other cytokine genes, TNF-alpha and IL-6. Priming of the macrophage cultures with murine IFN enhanced the expression of all cytokine genes, and the relative levels of IFN, TNF-alpha, and IL-6 mRNA induced by NDV in macrophages derived from C57BL/6 and BALB/c mice were comparable. We propose that the If-1 locus affects the early stages of a signal transduction pathway which are common to the virus-mediated induction of IFN, TNF-alpha, and IL-6 genes.
Specific protein dephosphorylation in apoptosis induced by ionizing radiation and heat shock in human lymphoid tumor lines.
Authors: Baxter G D , Lavin M F
Published: December 2022

Apoptosis or programmed cell death is observed in a variety of organisms and tissues and is characterized by distinct morphologic changes to the cell. Although early indicators of this process have been described, their functional relevance remains unknown. We have used two-dimensional gel electrophoresis to look for characteristic and consistent changes in the phosphorylation state of proteins during apoptosis, induced by different agents, in the B cell lymphoma line, BM13674, and the T cell leukemia line, CEM-C7. We report that apoptosis induced by either heat treatment or by ionizing radiation exposure is accompanied by dephosphorylation of a limited number of specific proteins. The pattern of dephosphorylation was similar after both treatments in BM13674 cells. In CEM-C7 cells, dephosphorylation was also observed after heat and irradiation. One of these proteins corresponded to one dephosphorylated in BM13674 cells. Okadaic acid, an inhibitor of phosphatases 1, 2A, and, to a lesser extent, 2B, prevented apoptosis in all cases and inhibited dephosphorylation of this common protein as well as some of the others. It seems likely that activation of a phosphatase(s) or loss of activity of a kinase is of central importance in apoptosis in these systems.
Spontaneous recovery from Friend retrovirus-induced leukemia. Mapping of the Rfv-2 gene in the Q/TL region of mouse MHC.
Authors: Miyazawa M , Nishio J , Wehrly K , David C S , Chesebro B
Published: December 2022

The Rfv-2 gene that influences the rate of spontaneous recovery from erythroleukemia induced by a low dose of Friend retrovirus complex was mapped to the Q/TL region of mouse MHC. Rfv-2 was physically and functionally distinct from the I-A-linked Ir gene that has been shown to control the responsiveness of Th cells to the envelope glycoprotein of Friend murine leukemia helper virus. The negative effect of the Rfv-2s allele was overcome by the B10.D2-H-2dm1 mutation of the D-L genes of H-2, suggesting functional similarities between the D-L and Q/TL genes in influencing resistance against Friend murine leukemia retrovirus complex infection or possible modification of Q/TL expression by genes in the D-L region.
Cyclic AMP-independent effects of cholera toxin on B cell activation. II. Binding of ganglioside GM1 induces B cell activation.
Authors: Francis M L , Ryan J , Jobling M G , Holmes R K , Moss J , Mond J J
Published: December 2022

Although the physiologic function of gangliosides is unknown, evidence suggests they play a role in the regulation of cell growth. The binding of ganglioside GM1 by recombinant B subunit of cholera toxin (rCT-B) inhibited mitogen-stimulated B cell proliferation without elevating intracellular cAMP. CT-B paradoxically enhanced the expression of MHC class II (Ia) molecules and minor lymphocyte-stimulating determinants without altering the expression of some other immunologically relevant B cell surface Ag. Increased expression of Ia was not detected until 4 h after stimulation, kinetics similar to those seen when B cells are stimulated with anti-Ig antibody or IL-4, suggesting that the enhancement was not the result of redistribution of existing cell surface markers but rather the result of a new metabolic event. Both the inhibitory and stimulatory effects of CT-B could be blocked by incubation of CT-B with ganglioside GM1. Furthermore, enhancement of the CT-B-mediated effect was seen when additional ganglioside GM1 was incorporated into the B cell membrane. rCT-B with a mutation that interfered with its binding to ganglioside GM1 did not enhance Ia expression. Taken together, these results indicate that the observed effects of CT-B were most likely mediated through the binding of cell surface ganglioside GM1. CT-B-mediated stimulation of Ia expression provides a potential explanation for the previously described ability of CT-B to act as an immunoadjuvant. These results suggest that the binding of ganglioside GM1 has multiple B cell growth-regulating effects.
A pathogenic monoclonal antibody, G8, is characteristic of antierythrocyte autoantibodies from Coombs'-positive NZB mice.
Authors: Caulfield M J , Stanko D
Published: December 2022

With age, NZB mice develop anti-RBC autoantibodies resulting in the development of autoimmune hemolytic anemia. We now have evidence that this spontaneous autoantibody response consists of antibodies that are similar in specificity and Id expression to a pathogenic autoantibody (G8) that was cloned from an autoimmune NZB mouse. Similar to autoantibodies eluted from Coombs'-positive mouse E (MRBC), the G8 mAb recognizes native (unmodified) MRBC but not RBC from other species. Interestingly, G8 and four additional mAb bind with a higher titer to bromelain-treated MRBC than to native MRBC. Nucleotide sequence analysis reveals, however, that unlike "natural" antibodies that react solely with bromelain-MRBC, G8 is encoded by a J558 VH gene and a V kappa 12,13 L-chain gene. Thus G8 is clearly distinct from antibodies to bromelain-MRBC which are encoded by unrelated V genes. Instead, the sequence of the G8 VH chain was found to be nearly identical to that of an anti-DNA mAb derived from an MRL-lpr/lpr mouse. The results suggest Coombs'-positive autoantibodies from NZB mice are not derived from "natural" antibodies, but rather, consist of a restricted set of autoantibodies expressing the G8 IdX.
Association of the human Fc epsilon RI gamma subunit with novel cell surface polypeptides.
Authors: Schöneich J T , Wilkinson V L , Kado-Fong H , Presky D H , Kochan J P
Published: December 2022

It has recently been demonstrated that the gamma-subunits of the high affinity Fc epsilon RI are required for the cell surface expression of not only the Fc epsilon RI alpha-subunit, but also for the low affinity Fc gamma RIIIA alpha (CD16). In addition, formation of heterodimeric complexes of the gamma-subunit with the zeta- and eta-chains of the TCR have also been reported. The exact role of the gamma-subunit in the function of these receptors is not known. To gain additional insight into the association of the gamma-subunit with these and other cell surface polypeptides, we have generated a mAb, 4D8, directed against the human Fc epsilon RI gamma-subunit. Using this antibody we have been able to demonstrate that Fc epsilon RI alpha and Fc gamma RIIIA alpha are associated with Fc epsilon RI gamma at the cell surface. Furthermore, we have identified the expression of Fc epsilon RI gamma in HL60 and U937 cells, which are negative for the TCR, Fc epsilon RI, and Fc gamma RIII. Analysis of these cells reveals the presence of novel Fc epsilon RI gamma-associated polypeptides. These results suggest that Fc epsilon RI gamma plays a common functional role in a number of different receptor complexes. The availability of the anti-gamma antibody 4D8 will help to define this role, and allow the characterization of cell surface polypeptides that are associated with the Fc epsilon RI gamma-subunit.
Role of protein tyrosine phosphorylation in monokine induction by the staphylococcal superantigen toxic shock syndrome toxin-1.
Authors: Scholl P R , Trede N , Chatila T A , Geha R S
Published: December 2022

The staphylococcal superantigen toxic shock syndrome toxin-1 (TSST-1) is a potent inducer of IL-1 beta and TNF-alpha synthesis in human monocytes. As superantigens are high affinity ligands for MHC class II molecules, the induction of monokines by TSST-1 provides a biologically relevant model of MHC class II-mediated transmembrane signaling. In this study, we show that TSST-1 induces cytoplasmic protein tyrosine phosphorylation in the human monocytic cell line THP-1. This induction was greatly enhanced by cross-linking TSST-1 with biotin-avidin. The functional relevance of tyrosine phosphorylation induced by TSST-1 was demonstrated by the finding that three specific inhibitors of protein tyrosine kinases strongly inhibited the induction of IL-1 beta mRNA by TSST-1. These data suggest that protein tyrosine kinase activation plays a critical role in MHC class II-mediated transmembrane signalling by staphylococcal superantigens.
Formyl peptide stimulates and ATP gamma S potentiates [3H]cytidine 5'-diphosphate diglyceride accumulation in human neutrophils.
Authors: Stubbs E B , Walker B A , Owens C A , Ward P A , Agranoff B W
Published: December 2022

Although it is evident that the chemotactic peptide FMLP activates O2-formation in neutrophils via the phosphoinositidase-mediated second messenger system, it is less clear how endogenous priming agents such as ATP and platelet activating factor potentiate FMLP action. In our study, we have examined the possible effects of the stable ATP analog adenosine 5'-O-[3-thiotriphosphate] (ATP gamma S) on cellular levels of inositol 1,4,5-trisphosphate, [Ca2+]i and diglyceride (DG), in resting and in FMLP-stimulated neutrophils. Although all three measures were increased in the presence of FMLP, only the increase in DG was enhanced by pretreatment (priming) with ATP gamma S. We also measured the accumulation of the phosphoinositide cycle intermediate cytidine 5'-diphosphate (CDP)-DG to assess possible effects of priming on phosphoinositide resynthesis. The addition of FMLP to [3H]cytidine-prelabeled neutrophils elicited an increase in the accumulation of [3H]CDP-DG that was maximally enhanced in cells that were pretreated with cytochalasin B. The stimulated accumulation of [3H]CDP-DG was completely reversed by the addition of myo-inositol. Treatment of [3H]cytidine-prelabeled neutrophils with ATP gamma S (10-100 microM) resulted in a dose-dependent synergistic increase in FMLP-stimulated [3H]CDP-DG accumulation, whereas ATP gamma S alone had no effect. The observed increases in DG and in [3H]CDP-DG, in contrast to inositol 1,4,5-trisphosphate and [Ca2+]i responses, correlates well with the ATP gamma S-priming of FMLP-induced O2-formation. A similar potentiation of FMLP-induced stimulation of CDP-DG formation was also observed with platelet-activating factor. It is proposed that the priming of FMLP responses in neutrophils proceeds via a mechanism that selectively enhances DG production through a mechanism that is independent of FMLP-induced breakdown of phosphatidylinositol bisphosphate.
In vivo molecular analysis of lymphokines involved in the murine immune response during Schistosoma mansoni infection. II. Quantification of IL-4 mRNA, IFN-gamma mRNA, and IL-2 mRNA levels in the granulomatous livers, mesenteric lymph nodes, and spleens during the course of modulation.
Authors: Henderson G S , Lu X , McCurley T L , Colley D G
Published: December 2022

Parasite egg-induced granulomas are the primary pathogenic lesions in murine schistosomiasis mansoni. This cell-mediated granulomatous response is specific for soluble egg Ag and appears to be mediated predominantly by CD4+ Th2 cells. As infection progresses from the acute to the chronic phase, the cell-mediated anti-soluble egg Ag responses attenuate in a process termed modulation. In this study the hypothesis that modulation is effected by a chronic phase increase in Th2-inhibiting Th1 cell activity was investigated. Northern blot quantification of mRNA specific for the Th2 lymphokine, IL-4, and the Th1 lymphokines, IFN-gamma and IL-2, in the spleens, mesenteric lymph nodes, and granulomatous livers of mice infected for various lengths of time over the course of modulation was performed. Also, the capacity of mitogen- and Ag-stimulated spleen cells to produce message for these lymphokines was compared. Peak tissue levels of both IL-4 mRNA and IFN-gamma mRNA were seen in acutely infected mice, and levels of both messages declined as infection became chronic. Stimulated spleen cells from acutely infected mice also produced higher levels of IL-4 and IFN-gamma mRNA than cells from chronically infected mice. IL-2 mRNA was never detected in any tissue sample but was detected in the stimulated spleen cells, again with acute phase levels higher than chronic phase levels. Hence, this study shows no evidence for increased Th1 cell activity during chronic infection and suggests that modulation may be effected by a generalized suppression of lymphokine synthesis.
CD4+ Th2 response induced by Schistosoma mansoni eggs develops rapidly, through an early, transient, Th0-like stage.
Authors: Vella A T , Pearce E J
Published: December 2022

Data from recent studies of murine schistosomiasis mansoni have indicated that certain characteristics of this infection, such as eosinophilia and elevated IgE, are due largely to the induction of Th2-like immune responses by parasite ova. The present study was designed to examine more closely the genesis and development of these skewed Th responses to schistosome eggs. Accordingly, eggs isolated from infected mice were injected s.c. into normal mice. After inoculation, draining lymph node (LN) cells were recovered, phenotyped, and tested for their ability to proliferate and secrete IL-2 and IFN-gamma (as markers of Th1 function) and IL-4, IL-5, and IL-10 (Th2 cytokines). The results show a maximal LN enlargement of 40- to 100-fold by day 3 after egg inoculation. The CD4/CD8/B cell ratio at this time is similar to that in LN from normal mice, but increases in numbers of cells expressing very low levels of MEL-14 and high levels of Pgp-1 are evident by days 3 and 10, respectively. Surprisingly, the initial detectable Ag-specific response to schistosome eggs, observed at day 1, is the production of IFN-gamma. By day 3, LN cells are capable of proliferating and making IFN-gamma plus IL-2, IL-4, IL-5, and IL-10 when stimulated with soluble egg Ag and, therefore, appear Th0-like. After 7 to 10 days, IFN-gamma production is severely depressed but the response continues to be characterized by IL-4, IL-5, IL-10, and IL-2. Depletion studies indicate that CD4 cells are the major population responsible for Ag-mediated proliferation and cytokine production. Results show that schistosome eggs are autonomous inducers of vigorous Th2-like effector responses. Further, our data, from a system that utilizes an in vivo priming step, support the contentions that skewed Th responses develop via an intermediate Th0 stage is accompanied by a loss of the MEL-14 surface marker and an increase in Pgp-1 expression.
Monocyte chemoattractant protein-1 regulates adhesion molecule expression and cytokine production in human monocytes.
Authors: Jiang Y , Beller D I , Frendl G , Graves D T
Published: December 2022

Monocytes play a critical role in defending the host against foreign organisms and in regulating the behavior of other cells. Monocytes circulate as nonadherent cells in the blood and migrate as adherent cells through tissues. Adhesion molecules mediate not only cell adhesion, but also migration, phagocytosis, and many other adhesion-dependent functions. Monocyte chemoattractant protein-1 (MCP-1) is thought to be responsible for monocyte recruitment in acute inflammatory conditions and may be an important mediator in chronic inflammation. In this study, immunofluorescence flow cytometry was used to determine whether MCP-1 can regulate the cell surface expression of adhesion molecules, particularly beta-2 and alpha-4 integrins and the leukocyte adhesion molecule-1. We found that MCP-1 induced expression of CD11c (p150,95 alpha-subunit) and CD11b (Mac-1 alpha-subunit), and caused little or no change of CD11a (lymphocyte function-associated Ag-1 alpha-subunit), very late activation Ag-4, or leukocyte adhesion molecule-1. We demonstrated that antibodies to beta-2 and alpha-4 integrins inhibited MCP-1-induced monocyte chemotaxis. We also showed that MCP-1 is capable of inducing IL-1 and IL-6, but not TNF production of monocytes. These results indicate that MCP-1 is not only a chemoattractant but also a novel cytokine with the capacity to regulate several parameters of monocyte function.
Preliminary identification and role of phosphodiesterase isozymes in human basophils.
Authors: Peachell P T , Undem B J , Schleimer R P , MacGlashan D W , Lichtenstein L M , Cieslinski L B , Torphy T J
Published: December 2022

We attempted to identify and establish the role of cyclic nucleotide phosphodiesterase (PDE) isozymes in human basophils by using standard biochemical techniques as well as describing the effects of isozyme-selective and nonselective inhibitors of PDE. The nonselective PDE inhibitors, theophylline and 3-isobutyl-1-methylxanthine, inhibited anti-IgE-induced release of histamine and leukotriene C4 (LTC4) from basophils. This inhibition was accompanied by elevations in cAMP levels. Rolipram, an inhibitor of the low Km cAMP-specific PDE (PDE IV), inhibited the release of both histamine and LTC4 from activated basophils and increased cAMP levels in these cells. In contrast, mediator release from basophils was not inhibited by either siguazodan or SK&F 95654, inhibitors of the cGMP-inhibited PDE (PDE III) or zaprinast, an inhibitor of the cGMP-specific PDE (PDE V). SK&F 95654 failed to elevate basophil cAMP in these experiments whereas zaprinast induced significant increases in cAMP content. The inhibitory effect of rolipram on mediator release was potentiated by siguazodan or SK&F 95654, but not by zaprinast. SK&F 95654 also enhanced the ability of rolipram to increase cAMP content. Forskolin, a direct activator of adenylate cyclase, inhibited IgE-dependent release of mediators from basophils and increased cAMP levels in these cells. These effects were enhanced by rolipram, but not by SK&F 95654 or zaprinast. The cell permeant analog of cAMP, dibutyryl cAMP, inhibited mediator release from these cells, a property not shared by either dibutyryl-cGMP or sodium nitroprusside, an activator of soluble guanylate cyclase. The presence of both PDE III and PDE IV was confirmed by partially purifying and characterizing PDE activity in broken cell preparations. Overall, these data lend support to the hypothesis that cAMP inhibits mediator release from basophils and suggest that the major PDE isozyme responsible for regulating cyclic AMP content in these cells is PDE IV, with a minor contribution from PDE III. However, the finding that zaprinast caused increases in cAMP without inhibiting mediator release indicates that cAMP accumulation is not invariably linked to an inhibition of basophil activation.
cis-acting regulatory elements abrogate allele-specific HLA class I gene expression in healthy individuals.
Authors: Lardy N M , Bakas R M , van der Horst A R , van Twuyver E , Bontrop R E , de Waal L P
Published: December 2022

Pedigree analysis of a Dutch family revealed the presence of an HLA-A "blanc" allele segregating with the HLA-B8, -Cw7, -DR3, -DR52, -DQ2 haplotype. Precipitation studies, using selected mAb and sera directed against conserved epitopes of HLA class I products, failed to detect the expression of a corresponding HLA-A locus product. cDNA nucleotide sequence analysis of the HLA-A "blanc" specificity showed that the obtained sequence was identical to the authentic HLA-A1 gene revealing no mutations, deletions or recombinations that could influence translation or transport of a putative translation product to the cell surface. Mitogen stimulation, EBV transformation, or treatment with rIFN-gamma and rTNF-alpha did not induce HLA-A1 expression. Furthermore, cell-mediated lympholysis analysis revealed that individuals carrying the nonexpressed HLA-A1 gene could mount a strong anti-HLA-A1 T cell response, indicating that HLA-A1 was not expressed during T cell ontogeny. Therefore, this study describes for the first time the allele-specific down-regulation of the expression of a classical HLA class I gene segregating in healthy individuals.
The antigen-processing mutant T2 suggests a role for MHC-linked genes in class II antigen presentation.
Authors: Riberdy J M , Cresswell P
Published: December 2022

.174xCEM.T2 (T2) is a human cell hybrid that has a large homozygous deletion within the MHC, including all of the functional class II genes. We have generated stable HLA-DR3 and H-2 I-Ak transfectants of T2 that express parental levels of class II molecules at the cell surface. T2.Ak transfectants fail to stimulate a hen egg lysozyme (HEL)-specific, I-Ak-restricted T cell when incubated with intact HEL. However, stimulation occurs if the appropriate HEL peptide is provided. The T2 cell line therefore has a defect in class II-restricted Ag processing. Biosynthetic studies demonstrate that the kinetics of I-Ak transport in T2.Ak are similar to the parental rates of transport, although the percentage of I-Ak molecules transported appears somewhat lower. I-Ak glycoproteins in T2.Ak associate normally with the I-chain, which appears to be proteolytically cleaved after transport through the Golgi apparatus in a similar fashion to that in the parent cell line, .174xCEM.T1 (T1). The DR alpha beta heterodimers in T2 differ from the parental phenotype in two ways. First, HLA-DR3 expressed in T2 does not have the epitope recognized by the DR3-specific mAb 16.23, although DR3 expressed in the parent does have the epitope. Second, the alpha beta subunits in the parent remain associated when exposed to SDS at room temperature, although those in T2 dissociate.
Identification and molecular cloning of tactile. A novel human T cell activation antigen that is a member of the Ig gene superfamily.
Authors: Wang P L , O'Farrell S , Clayberger C , Krensky A M
Published: December 2022

We have identified and cloned cDNA for a novel cell-surface protein that we have named Tactile for T cell activation, increased late expression. It is expressed on normal T cell lines and clones, and some transformed T cells, but no other cultured cell lines tested. It is expressed at low levels on peripheral T cells and is strongly up-regulated after activation, peaking 6 to 9 days after the activating stimulus. It is also up-regulated on NK cells activated in allogeneic cultures. It is not found on peripheral B cells but is expressed at very low levels on activated B cells. Tactile-specific mAb immunoprecipitates a band of 160 kDa when reduced and bands of 240, 180, and 160 kDa nonreduced. Using an antiserum produced with affinity-purified Tactile protein to screen a lambda gt11 library, we have identified Tactile cDNA. Northern blot analysis shows an expression pattern similar to that of the protein and transfection of COS cells with the full-length 5.2-kb cDNA results in cell-surface expression. Comparison with the sequence databanks show that Tactile is a member of the immunoglobulin gene superfamily, with similarity to Drosophila amalgam, the melanoma Ag MUC-18, members of the carcinoembryonic Ag family, the poliovirus receptor, and the neural cell adhesion molecule. The deduced primary sequence encodes a protein with three Ig domains, a long serine/threonine/proline-rich region typical of an extensively O-glycosylated domain, a transmembrane domain, and a 45 residue cytoplasmic domain. These data suggest that Tactile may be involved in adhesive interactions of activated T and NK cells during the late phase of the immune response.
Regulation of locomotion and cell-cell contact area by the LFA-1 and ICAM-1 adhesion receptors.
Authors: Dustin M L , Carpen O , Springer T A
Published: December 2022

We demonstrate complementary differences in the behavior of B lymphoblastoid cells adhering to LFA-1 or its counter-receptor ICAM-1. The interaction of B lymphoblastoid cells with glass-supported planar bilayers bearing LFA-1 or ICAM-1 was observed by time-lapse video microscopy, and the distribution of adhesion receptors on cells interacting with the planar bilayers was studied by immunofluorescence microscopy. B lymphoblasts formed a large contact area and crawled rapidly (up to 25 microns/min) on planar bilayers bearing ICAM-1. In contrast, these cells attached to planar bilayers bearing LFA-1 through a fixed point about which the cells actively pivoted, using a single stalk-like projection. Phorbol ester-stimulated lymphoblasts, which adhere more strongly to ICAM-1-bearing substrates than unstimulated lymphoblasts, were still capable of locomotion on ICAM-1. Phorbol ester stimulation of B lymphoblasts on planar bilayers bearing LFA-1 promoted a rapid conversion from "stalk" attachment to symmetrical spreading of the cell on the substrate. Cellular LFA-1 remained uniformly distributed on the cell surface during interaction with bilayers bearing purified ICAM-1 as determined by immunofluorescence. In contrast, ICAM-1 was concentrated in the stalk-like structure through which the unstimulated B lymphoblasts adhered to LFA-1 in planar bilayers, but ICAM-1 immunofluorescence became more uniformly distributed over the cell surface within minutes of phorbol ester addition. Neither LFA-1 or ICAM-1 colocalized with the prominent staining of filamentous actin in the ruffling membrane regions. Interaction through cell surface LFA-1 and ICAM-1, 2, or 3 promotes different cellular morphologies and behaviors, the correlation of which with previously observed patterns of lymphocyte interaction with different cell types is discussed.
CD4 epitope masking by gp120/anti-gp120 antibody complexes. A potential mechanism for CD4+ cell function down-regulation in AIDS patients.
Authors: Amadori A , De Silvestro G , Zamarchi R , Veronese M L , Mazza M R , Schiavo G , Panozzo M , De Rossi A , Ometto L , Mous J
Published: December 2022

The in vitro suppressive effect of gp120 and gp120/anti-gp120 antibody is well known but not yet proven to operate in vivo. We report findings consistent with the presence of gp120/anti-gp120 antibody complexes on CD4+ lymphocytes from HIV-infected patients with advanced disease. PBMC from most AIDS patients showed selective masking of the CD4 epitope associated with the gp120 binding site; immunoprecipitation of PBMC with anti-CD4 mAb disclosed high amounts of IgG bound to CD4 receptors. Antibodies against HIV env proteins, but not other HIV products or CD4 Ag, were detected in purified CD4+ cell culture supernatants; in vitro culture was associated with normalization of both CD4 expression in PBMC and the lymphocyte proliferative response to anti-CD3. gp120 presence could not be directly demonstrated, but findings strongly suggested that CD4+ lymphocytes from most HIV-infected patients with advanced disease were covered with gp120/anti-gp120 antibody complexes, which are responsible for down-regulation of surface CD4 expression as well as functional lymphocyte impairment; this event may represent an important mechanism in the pathogenesis of HIV-associated immunodeficiency.
H chain V region sequences of three human monoclonal IgM with anti-myelin-associated glycoprotein activity.
Authors: Ayadi H , Mihaesco E , Congy N , Roy J P , Gendron M C , Laperriere J , Prelli F , Frangione B , Brouet J C
Published: December 2022

The amino acid sequence corresponding to the V region H chain gene used by three monoclonal IgM directed to the myelin-associated glycoprotein (MAG) is presented. They all belonged to the VHIII variability subgroup, but each may well represent a new member of this family inasmuch as their homology with previously sequenced VHIII genes was less than 80%. Strikingly, there was no greater homology between the H chain V regions of the anti-MAG IgM. Partial amino acid sequence data indicated that these V regions were joined to as yet unidentified DH segments; however, two H chains used very similar DH, possibly indicating that this sequence was involved in the fine specificity of the IgM for MAG. All H chains included a JHIV region. These data, together with results obtained from the sequence of the three kappa L chains of the same IgM molecules (Mihaesco, E., H. Ayadi, N. Congy, M. C. Gendron, J. P. Roy, H. Heyermann, B. Frangione, and J. C. Brouet. 1989. J. Biol. Chem. 264:21481), indicate that the repertoire of VL and VH gene segments used by anti-MAG IgM is quite diverse, in contrast to previous structural data obtained for other human monoclonal IgM autoantibodies. Possibly, these differences reflect distinct pathogenesis.
Murine common acute lymphoblastic leukemia antigen (CD10 neutral endopeptidase 24.11). Molecular characterization, chromosomal localization, and modeling of the active site.
Authors: Chen C Y , Salles G , Seldin M F , Kister A E , Reinherz E L , Shipp M A
Published: December 2022

To further analyze CD10/NEP function in lymphoid and nonlymphoid cells using well characterized murine systems, we isolated the murine CD10/NEP homologue, determined its chromosomal location, and modeled the enzyme's active site. The murine CD10/NEP cDNA predicts a 750-amino acid (aa) type II integral membrane protein with 90% identity to the human CD10 sequence and 100% conservation of critical aa and functional motifs. The latter include the pentapeptide consensus sequence required for zinc binding and catalytic activity, additional aa associated with substrate binding, and the extracellular cysteines that participate in disulfide bonds required for enzymatic activity. Like its human homologue, murine CD10/NEP has multiple alternative 5'-untranslated region sequences. The gene is localized on the proximal half of murine chromosome 3. In Northern analysis, murine CD10/NEP transcripts are abundant in bone marrow stromal cells that support pre-B cell differentiation but are undetectable in representative Abelson transformed pre-B cell lines. The murine CD10/NEP active site was modeled by aligning critical conserved CD10/NEP residues with comparable residues in the active site of thermolysin, a bacterial metalloprotease with similar substrate specificity. The model predicts that the two enzymes have similar clefts that comprise the active site and permit zinc-dependent substrate interactions.
Mast cell proteoglycans modulate the secretagogue, proteoglycanase, and amidolytic activities of dog mast cell chymase.
Authors: Sommerhoff C P , Ruoss S J , Caughey G H
Published: December 2022

Chymase, a potent secretagogue for airway gland serous cells, is stored in secretory granules and released from mast cells together with proteoglycans. To investigate the hypothesis tha tproteoglycans modulate chymase-induced effects, we studied the influence of proteoglycans purified from dog mastocytoma cells on chymase-induced secretion from cultured bovine airway gland serous cells. Heparin proteoglycans reduced the chymase-induced secretory response, whereas glycosaminoglycans and chondroitin sulfate proteoglycans had less of an effect. Chymase released together with proteoglycans from activated mast cells caused secretion comparable to that caused by purified chymase reconstituted with purified proteoglycans. Despite partial inhibition by exocytosed proteoglycans, the secretagogue activity of chymase remains substantial compared to that of histamine. However, proteoglycans virtually abolished chymase-induced degradation of the products of serous cell secretion. Although the secretagogue and proteoglycanase activities of chymase are inhibited by most classes of mast cell granule-associated glycans, the amidolytic activity of chymase toward tripeptide 4-nitroanilide substrates is augmented. These findings suggest that mast cell proteoglycans modulate the secretagogue, proteoglycanase, and peptidase activity of chymase, and the results predict that the extent of this modulation in vivo depends on the nature of the proteoglycans with which chymase is released from mast cells.