bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced synthesis of factor B induced by tumor necrosis factor in human skin fibroblasts is decreased by IL-4.
Authors: Katz Y , Strunk R C
Published: December 2022

IL-4 is a T cell-derived lymphokine that has multiple biologic functions, affecting B cells, T cells, mast cells, monocytes, macrophages, and hematopoietic progenitor cells. We report that IL-4 also affects human skin fibroblasts. These effects were primarily in modulating the effects of other mediators of inflammation on these cells, with IL-4 producing little or no effects by itself. Synthesis of C proteins in human skin fibroblasts is modulated by TNF and other mediators of inflammation. TNF increased synthesis of factor B by 18.6-fold; IL-4 reduced the TNF effect on factor B synthesis by 83%. This effect started with concentrations of IL-4 as low as 0.1 ng/ml. The effect of IL-4 on the TNF-induced increase in synthesis of factor B occurred after 2 h incubation, the time when the effects of TNF alone were first observed. IL-4 also abrogated the effects of IL-1 and LPS on factor B synthesis, but did not affect the increase in synthesis of factor B induced by IFN-gamma. In contrast to the pattern for effect of IL-4 on factor B synthesis, the TNF-induced rate of synthesis of C3 was augmented by IL-4. The specificity of the IL-4 effect was also apparent when comparing the effect of IL-4 on the TNF-induced synthesis of factor B to the effects on total protein synthesis (increased 1.5-fold) and the TNF-induced increases in synthesis in C1r, C1s, C1 inhibitor, C2, and factor H (no changes). The IL-4-induced decrease in synthesis of factor B was mediated at a pretranslational level and was dependent on synthesis of a new protein. This interaction between IL-4 and mediators of inflammation can potentially modulate the inflammatory response in the setting of activation of Th cells.
Activation of latent EBV via anti-IgG-triggered, second messenger pathways in the Burkitt's lymphoma cell line Akata.
Authors: Daibata M , Humphreys R E , Takada K , Sairenji T
Published: December 2022

Anti-IgG treatment activated latent EBV genomes in 50 to 70% of the cells of the Burkitt's lymphoma cell line Akata. The EBV-activating role of intracellular Ca2+, as potentiated by diacylglycerol (DAG) and suppressed by cAMP, was analyzed in the cells through effects of agonists and antagonists of these second messenger pathways. Early Ag (EA) was induced in 10% of cells with the calcium ionophore A23187 (A23187). EA induction with anti-IgG or A23187 was blocked by a calmodulin antagonist, trifluoperazine. The DAG pathway had a potentiating but not direct effect on EBV activation because: 1) the DAG analog, dioctanoylglycerol (diC8), an agonist for protein kinase C, alone induced only 2% EA-positive cells, 2) diC8 synergized with A23187 for EA induction, and 3) the protein kinase C antagonist, staurosporine, almost completely inhibited EA induction by anti-IgG. When cells were reincubated in medium with fresh diC8 and A23187 at 3, 6, 9, and 12 h, EA induction at 24 h reached the levels seen with anti-IgG stimulation. A cAMP-mediated pathway suppressed EBV activation because dibutyryl cAMP or 8-bromo-cAMP, plus blockage of phosphodiesterase by theophylline, or use of forskolin, inhibited EA induction with anti-IgG. Although the principal stimulatory role in EBV activation of a Ca2(+)-mediated, second messenger pathway, as synergized by DAG and inhibited by cAMP, was established, we did not explain the significant lag in EA induction by A23187 and diC8 as compared with anti-IgG induction of EA. We conclude that EBV genome activation with anti-IgG is mediated by Ca2+/calmodulin and DAG pathways in Akata cells, that the cAMP pathway suppresses EA induction by anti-IgG, and that a mechanism regulating the speed of EA induction remains unexplained.
Macrophage killing of Leishmania parasite in vivo is mediated by nitric oxide from L-arginine.
Authors: Liew F Y , Millott S , Parkinson C , Palmer R M , Moncada S
Published: December 2022

Peritoneal macrophages from CBA mice incubated with rIFN-gamma are effective in killing the protozoal parasite Leishmania major in vitro. This leishmanicidal activity can be completely inhibited by L-NG-monomethyl arginine (L-NMMA), a specific inhibitor of the L-arginine:nitric oxide (NO) pathway. The culture supernatants of macrophage activated by IFN-gamma contain increased levels of NO2-, the production of which is inhibited by L-NMMA, but not by its D-enantiomer. L. major promastigotes are killed when incubated at room temperature in PBS containing NO. These data demonstrate that NO is an effector mechanism in macrophage killing of intracellular protozoa. The importance of NO in vivo is demonstrated by the finding that CBA mice infected with L. major developed exacerbated disease when L-NMMA was injected into the lesions, resulting in 10(4)-fold increases in the number of parasites extractable from the lesions.
Docosahexaenoic acid, a constituent of rodent fetal serum and fish oil diets, inhibits acquisition of macrophage tumoricidal function.
Authors: Dustin L B , Shea C M , Soberman R J , Lu C Y
Published: December 2022

Macrophage (M phi) activation is deficient in the fetus and neonate, at times when the serum concentration of docosahexaenoic acid (DHA; 22:6n3) is approximately 10-fold higher than in the adult. We tested the effects of highly purified DHA on M phi activation in vitro. M phi were stimulated with rIFN-gamma plus either of two second or "triggering" signals, LPS or heat-killed Listeria monocytogenes. M phi activation was assayed as the lysis of P815 mastocytoma cells, which are resistant to TNF-alpha. DNA inhibited the activation of peritoneal M phi and the M phi line RAW264.7 in a dose-dependent manner at concentrations between 20 and 160 microM. These concentrations are found in fetal and neonatal rodent sera. Another polyunsaturated fatty acid, arachidonic acid (20:4n6), was much less inhibitory. In contrast to its profound effect on tumoricidal activation, DHA did not inhibit phagocytosis and catabolism of 125I-heat-killed Listeria monocytogenes. Increasing the rIFN-gamma or second signals reduced the inhibition of tumoricidal activation by DHA but not M phi incorporation of 14C-DHA. When the rIFN-gamma and second signals were separated in time, DHA was far more inhibitory if delivered with the triggering signal than if delivered with the rIFN-gamma. However, the incorporation of 14C-DHA was the same under these two conditions. In M phi treated with DHA during LPS stimulation, the inhibition was time-dependent, requiring more than 2 h. Although DHA inhibits cyclooxygenase activity, its inhibition of M phi activation was not reversed with the following cyclooxygenase products: PGE2, a stable TXA2 analog (U-46, 619) or a stable PGI2 analog (Iloprost). Although DHA is metabolized by lipoxygenases, the inhibition was not reversed by the lipoxygenase inhibitors 5, 8, 11, 14-eicosatetraynoic acid and nordihydroguaiaretic acid. Altogether, the data indicate that DHA, at concentrations present in fetal and neonatal sera, inhibits M phi activation and may contribute to the previously observed deficits in M phi function in the fetus and neonate.
Characterization of tumor-infiltrating CD4+ T cells as Th1 cells based on lymphokine secretion and functional properties.
Authors: Nagarkatti M , Clary S R , Nagarkatti P S
Published: December 2022

Recent studies have subdivided the Th cells into mutually exclusive Th1 subset producing IL-2 and IFN-gamma and Th2 cells producing IL-4 and IL-5. The relative role played by these two subsets in the antitumor immunity is not clear. We earlier demonstrated that treatment of C57BL/6 mice bearing a syngeneic Ia- T cell lymphoma, LSA, with 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) resulted in 90 to 100% survival of the mice. Furthermore, host's T cell responses were critical for successful BCNU-mediated cures. In our study we observed that immediately after BCNU treatment, there was a dramatic increase in the percentage of CD4+ T cells at the site of tumor growth in the peritoneal cavity. The percentage of CD4+ T cells increased from approximately 3 to 4% found in normal or tumor-bearing mice to approximately 41% in BCNU-treated tumor-bearing mice. The percentage of CD8+ T cells also increased although to a lesser degree. Also, these alterations were primarily restricted to the site of tumor-growth inasmuch as they were not seen in the thymus and were less pronounced in the spleen. The tumor-infiltrating CD4+ T cells obtained after BCNU-treatment, when further characterized, were found to secrete only IL-2 and IFN-gamma but not IL-4, after tumor-specific stimulation. Furthermore, the supernatants from LSA-activated CD4+ T cell cultures failed to provide help to the B cells but were able to activate the macrophages to inhibit the tumor cell proliferation. The CD4+ T cells when adoptively transferred could also protect the nude mice from LSA tumor challenge and induced tumor-specific delayed-type hypersensitivity reaction. Together our data suggest that in the LSA tumor model, the tumor-infiltrating CD4+ T cells have the properties of Th1 cells and these cells can mediate tumor-rejection independent of the CD8+ T cells by activating the macrophages.
Stimulation of mouse lymphocytes by a mitogen derived from Mycoplasma arthritidis (MAM). VIII. Selective activation of T cells expressing distinct V beta T cell receptors from various strains of mice by the "superantigen" MAM.
Authors: Cole B C , Kartchner D R , Wells D J
Published: December 2022

Mycoplasma arthritidis T cell mitogen (MAM), in association with its MHC ligand, is recognized by T cells that express TCR-alpha/beta assembled with a product(s) of the V beta 8 gene family. We show here that lymphocytes from mice which fail to express V beta 8 products can also be activated by MAM and the resulting cultures exhibit a marked increase in V beta 6 TCR-bearing cells. Evidence was also obtained that MAM can activate T cells that express all three V beta 8 TCR. The mAb, F23.1, which recognizes all V beta 8 gene products, was strongly inhibitory for MAM-induced proliferation of CBA cells whose T cell repertoire for MAM consists of T cells that express V beta 8.2 and 8.3 TCR. In contrast, the F23.1 mAb was only weakly inhibitory for BALB/c splenocytes which express V beta 6 TCR in addition to all three V beta 8 TCR. Involvement of V beta 8.1, 8.2, 8.3, and V beta 6 in MAM-induced proliferation was confirmed by expanding lymphocyte cultures in the presence of MAM and phenotyping the activated cells for expression of individual V beta TCR. There was also evidence for a selective activation of T cells bearing specific V beta TCR because BALB/c T cell populations expanded with MAM were comprised of 46.2% V beta 8.2+ cells, 18.6% V beta 8.1+ cells, 7.6% V beta 8.3+ cells and 6.7% V beta 6+ cells. Recent studies suggest that the newly described "superantigens" including the staphylococcal enterotoxins and the self minor lymphocyte-stimulating Ag activate T cells in a manner similar to that described earlier for MAM. The discovery of shared recognition of these proteins by specific V beta TCR strongly suggests that MAM belongs to the superantigen protein family, the members of which may share cross-reactive epitopes. Inasmuch as MAM is produced by an organism which induces chronic joint disease, our findings provide the basis for a new model to study the role of superantigens in the development of chronic autoimmune type diseases.
Characterization and genetic restriction of suppressor-effector cells induced by staphylococcal enterotoxin B.
Authors: Taub D D , Lin Y S , Rogers T J
Published: December 2022

The capacity of the staphylococcal enterotoxins to stimulate all T cells bearing certain (but not all) TCR has generated a great deal of interest. This stimulation appears to involve specific binding of the toxin to class II Ags and subsequent stimulation via the TCR. Previous studies from this laboratory have demonstrated that staphylococcal enterotoxin B (SEB) induces multiple T suppressor cell populations that inhibit both primary and secondary plaque-forming cell responses. Efforts to characterize these suppressor cell populations have demonstrated that the suppressor population active early in the antibody response expresses the Lyt-1-2+ cell surface phenotype, whereas depletion analysis suggests that the population active late in an ongoing response bears the Lyt-1+2+ cell-surface markers. In the present study, enrichment for this late acting effector population with the use of sequential panning with anti-Lyt mAb reveals significant suppressive activity at both the initiation and effector phases of a 5-day Mishell-Dutton coculture. Additional experiments using I-J disparate strains of mice have demonstrated a genetic restriction at the "I-J" gene locus between the cells mediating SEB-induced suppression and their target. Depletion of SEB-primed splenocytes with anti-I-J mAb suggests that both the early and late effector cells bear I-J molecules on their surface. Taken together, these results show that SEB induces suppressor cell populations with properties similar to those exhibited by Ag-specific cell circuits.
Importance of suppressor T cells in cyclophosphamide-induced tolerance to the non-H-2-encoded alloantigens. Is mixed chimerism really required in maintaining a skin allograft tolerance?
Authors: Tomita Y , Mayumi H , Eto M , Nomoto K
Published: December 2022

Mechanisms of cyclophosphamide (CP)-induced tolerance were studied. When AKR/J Sea (AKR: H-2k) mice were primed i.v. with 5 x 10(7) spleen cells plus 1 x 10(7) bone marrow cells from [C57BL/6 Slc (B6; H-2b) x C3H/He Slc (C3H; H-2k)]F1 (B6C3F1) mice and treated i.p. with 200 mg/kg CP 2 days later, the survival of C3H skin was moderately prolonged, but the survival of either B6 or B6C3F1 skin was not prolonged. By this treatment, however, mixed chimerism of B6C3F1 cells in the AKR mice was not established. When C3H cells were used as the tolerogen, a minimal degree of mixed chimerism associated with profound tolerance to C3H skin was established. Similar results were observed in various donor-recipient combinations. When C3H skin was grafted in the AKR mice 12 wk after the treatment with C3H cells and CP, or B6C3F1 cells and CP, survival of the grafted C3H skin was prolonged remarkably or moderately, respectively, although mixed chimerism was not detectable at the timing of grafting in either of the groups. In this late stage of tolerance, a strong level of tolerogen-specific suppressor cell activity was observed in those tolerant AKR mice. The suppressor activity was mainly attributable to T cells. These results suggest that the role of Ts cells in order to maintain skin tolerance is important in our CP-induced tolerance system, especially in the late stage of tolerance. Moreover, the generation of the Ts cells does not necessarily require the establishment of a long term mixed chimeric state.
A mouse lymphoid endothelial cell line immortalized by simian virus 40 binds lymphocytes and retains functional characteristics of normal endothelial cells.
Authors: O'Connell K A , Edidin M
Published: December 2022

Leukocyte-endothelial cell (EC) interactions regulate the entry of immune effectors into the tissues. This interaction occurs in lymphoid tissues and inflammatory sites at post-capillary high endothelial venules, as opposed to large capacitance vessels lined with flat EC. Transient SV40 infection of mouse EC derived from lymph node stroma has resulted in a cell line, SVEC4-10, that retains morphological and functional characteristics of normal EC. SVEC4-10 cells grow efficiently on plastic as a monolayer with a characteristic epithelioid morphology. They require as little as 2% FCS and are independent of other exogenous growth factors or matrix components. When grown on a synthetic basement membrane, SVEC4-10 forms branching tube-like networks. SVEC4-10 expresses Factor VIII related Ag as measured by indirect immunofluorescence using a rabbit antiserum to human FVIII-associated protein and incorporates acetylated low density lipoprotein. SVEC4-10 specifically binds mouse lymphocytes in vitro. IFN-gamma induces expression of MHC class II Ag in a time course identical to normal EC and the cell line is susceptible to lysis by anti SV40 H-2k CTL clones. Thus, this SV40 immortalized line retains much of the normal cellular physiology of EC.
Requirements for the adoptive transfer of antibody responses to a priming antigen in man.
Authors: Wimperis J Z , Gottlieb D , Duncombe A S , Heslop H E , Prentice H G , Brenner M K
Published: December 2022

Antibody responses to recall vaccines can be adoptively transferred after marrow transplantation in man. Transfer of responses to priming Ag has not been successful, although this would broaden the range of organisms to which recipients could be protected. To investigate the importance of T cells and Ag in such transfer we primed marrow donors with keyhole limpet hemocyanin (KLH) 1 or 3 wk before marrow harvesting. B cells secreting IgM and IgG anti-KLH antibody were present in donor marrow at both 1 and 3 wk after immunization. After T cell depletion, donor marrow was infused into chemo-irradiated recipients, half of whom were immunized pretransplant with KLH. We found no evidence for the transfer of the IgM component of the response. Clonal expansion of the transferred IgG antibody-secreting cells with a corresponding rise in recipient serum IgG antibody levels was seen only when donors were primed 3 wk before marrow harvest and when the recipients were also immunized. IEF and immunoblotting demonstrated that successful transfer coincided with maturation of the IgG primary response from a polyclonal to an oligoclonal pattern and confirmed that donor oligoclonal bands appeared in the recipient serum. We conclude that the immunization protocols required for the transfer of antibody responses to priming Ag reflect the initial dependence of unprimed B cells on T cell help and on prolonged Ag stimulation. Ag-stimulated primary B cells in T cell-depleted marrow respond only to the noncognate growth and differentiation signals available in the chemo-irradiated recipient after an initial period of clonal selection and expansion in the donor which is both T cell and Ag dependent. Even after this initial selection, continued expansion of antibody-secreting clones in recipients retains an absolute dependence on Ag stimulation. Immunization techniques to protect transplant recipients against organisms such as Pseudomonas and CMV may need to be modified accordingly.
GM-CSF administration augments the survival of ity-resistant A/J mice, but not ity-susceptible C57BL/6 mice, to a lethal challenge with Salmonella typhimurium.
Authors: Morrissey P J , Charrier K
Published: December 2022

Ity resistant A/J mice were challenged with a lethal dose (2 x 10(3) organisms) of Salmonella typhimurium. Infected mice treated with 1 microgram of GM-CSF twice daily showed increased median survival time and had a higher survival fraction than untreated controls. GM-CSF was most effective when given for a brief period (1 to 2 days) after infection. Pretreatment of the mice or delayed treatment with GM-CSF had no effect on the survival of the mice. Studies on the effect of GM-CSF on the bacterial load showed that mice treated with GM-CSF had fewer S. typhimurium in the spleen and peritoneal cavity on day 4 but not on day 2 after infection. GM-CSF treatment of ity-susceptible C57BL/6 mice infected with 10 organisms had no therapeutic effect.
3-deazaadenosine inhibits leukocyte adhesion and ICAM-1 biosynthesis in tumor necrosis factor-stimulated human endothelial cells.
Authors: Jurgensen C H , Huber B E , Zimmerman T P , Wolberg G
Published: December 2022

Previous reports demonstrate that cultured human umbilical vein endothelial cells (HEC) treated with TNF and other inflammatory mediators show an increased capacity to adhere human neutrophils. This increase is associated with the up-regulation of intercellular adhesion molecule 1 (ICAM-1) and other adhesion molecules on the HEC surface. We have found that 200 microM 3-deazaadenosine (c3Ado) prevented this TNF-induced increase in HEC adhesiveness. This effect resulted from interactions of c3Ado with HEC and not with polymorphonuclear neutrophils. Transport of c3Ado into the HEC was required for its activity, as evidenced by antagonism with the nucleoside transport inhibitor, nitrobenzylthioinosine. Treatment of HEC with c3Ado led to the intracellular buildup of S-adenosylhomocysteine and to the metabolic formation of S-3-deazaadenosylhomocysteine and 3-deazaadenosine 5'-triphosphate, events that appeared not to contribute to c3Ado activity. Exogenous L-homocysteine potentiated c3Ado activity, and this potentiation was prevented by the S-adenosylhomocysteine hydrolase inhibitor, periodate-oxidized adenosine. By using the mAb RR1/1, we have determined that c3Ado also inhibited the TNF-induced expression of ICAM-1 on the surface of the HEC, as well as cytosol-associated ICAM-1. Northern blot and in vitro translation analyses of poly(A+) RNA from c3Ado-treated HEC revealed that this nucleoside analog selectively decreased steady-state levels of ICAM-1 mRNA. The capacity of c3Ado to selectively inhibit HEC adhesiveness, ICAM-1 production, and steady-state levels of ICAM-1 mRNA may contribute to the drug's activity as an anti-inflammatory agent.
Different effects of native Candida albicans mannan and mannan-derived oligosaccharides on antigen-stimulated lymphoproliferation in vitro.
Authors: Podzorski R P , Gray G R , Nelson R D
Published: December 2022

Yeast cell wall mannan polysaccharide has been proposed to contribute to immune dysfunction associated with chronic infections involving Candida albicans. This influence of mannan has been suggested based partially upon studies of the in vitro immunoinhibitory effects of mannans prepared from Saccharomyces cerevisiae or C. albicans by precipitation with Fehling's reagent, which provides a structurally modified product contaminated with copper. We have therefore evaluated the immunoinhibitory influence of a more native C. albicans mannan prepared by complexation with cetyltrimethylammonium bromide (CTAB). CTAB mannan was a potent stimulator of lymphoproliferation when added to human PMBC from donors responsive to Candida; it has no inhibitory influence on lympho-proliferation induced by Candida or other Ag. In contrast, members of a family of mannose oligosaccharides (disaccharide through hexasaccharide) derived from the CTAB mannan by weak alkaline degradation did not stimulate lymphoproliferation, but were potent inhibitors of lymphoproliferation stimulated by Candida and other Ag. Fifty percent inhibitory doses were 260 to 34 microM, respectively. Compositional analyses of these immunoinhibitory oligomers showed them to be composed of mannose and free of contaminating protein. We propose that mannan-derived oligosaccharides produced by catabolism of mannan in vivo are immunoinhibitory and contribute to the deficit in cell-mediated immune function associated with chronic candidiasis.
Coordinate expression of src family protooncogenes in T cell activation and its modulation by cyclosporine.
Authors: Furue M , Katz S I , Kawakami Y , Kawakami T
Published: December 2022

Activation of T lymphocytes induces transcription of several important genes which encode lymphokines and lymphokine receptors as well as "proliferation complementary" protooncogenes like c-myc or c-fos. Recently, the expression of lck gene, one of the src family gene, has also been shown to be modulated during T cell activation. We, therefore, assessed the question of whether other src family genes are expressed during the activation of T cells and of whether cyclosporine, a potent immunosuppressive drug, affects expression of these genes. We examined the expression of four different src family genes (lck, c-src, fyn, and c-fgr) in addition to the expression of IL-2, c-fos, c-myc, and actin genes in murine T cells which were activated with PMA plus ionomycin or PMA plus anti-CD3 mAb. We found that T cell activation was associated with the up-regulation of these src family genes and that the expression of these genes was specifically blocked in the presence of cyclosporine indicating that these activation-related genes were coordinately regulated.
Structure of the gene for human complement protein decay accelerating factor.
Authors: Post T W , Arce M A , Liszewski M K , Thompson E S , Atkinson J P , Lublin D M
Published: December 2022

Decay accelerating factor (DAF) is a glycophospholipid-anchored membrane protein that is part of the regulators of complement activation (RCA) gene family located on human chromosome 1, band q32. These proteins, beginning at their amino terminus, consist largely of multiple copies of an approximately 60 amino acid short consensus repeat (SCR). A DAF cDNA clone was used to identify overlapping bacteriophage genomic clones. The human DAF gene spans approximately 40 kb and consists of 11 exons. The length of these exons and introns varies considerably, with the exons ranging from 21 to 956 bp and the introns ranging from approximately 0.5 to 19.8 kb. SCR I, II, and IV are all encoded by single exons; however, SCR III is encoded by two separate exons, with the splice junction occurring after the second nucleotide of the codon for the glycine residue at position 34 of the consensus sequence. This feature has also been found in CR1, CR2, membrane cofactor protein, and murine factor H. Following the SCR in DAF is a 76 amino acid serine/threonine-rich domain encoded on three separate exons. Exon 10 encodes the Alu family sequence that has been found as an insert in a minor class of DAF cDNA, thus indicating that this mRNA arises by standard alternative splicing. The last DAF exon, which comes after the largest intron of 19.8 kb, encodes the hydrophobic carboxy terminus and the 3'UT region. The nature of the signal that directs posttranslational attachment of a glycophospholipid anchor to DAF is not known, but that signal is apparently spread over three exons and greater than 20 kb. An analysis of the DAF gene provides additional evidence for the common evolutionary heritage of the RCA gene family. The exon/intron structure of this gene will facilitate experiments aimed at understanding the functions of the various domains of DAF.
Activation of human T lymphocytes via the CD2 antigen results in tyrosine phosphorylation of T cell antigen receptor zeta-chains.
Authors: Monostori E , Desai D , Brown M H , Cantrell D A , Crumpton M J
Published: December 2022

The phosphorylation of the invariant chains associated with the human TCR has been investigated after the stimulation of T lymphocytes with CD2 mAb T11(2) and T11(3), PHA, or phorbol 12,13-dibutyrate. As described previously, stimulation of T cells with either CD2 mAb or phorbol 12,13-dibutyrate resulted in the phosphorylation of the CD3 gamma-chain. The combination of T11(2) and T11(3) mAb also induced phosphorylation of the TCR zeta-chain. The phosphorylated zeta-polypeptide of CD2-activated cells was immunoprecipitated with antiphosphotyrosine antibodies and migrated to a 21- to 23-kDa position during SDS/PAGE. These results indicate that stimulation of human T cells via the CD2 Ag with the T11(2) and T11(3) mAb activates not only protein kinase C but also tyrosine kinase(s), resulting in the phosphorylation of the CD3 gamma-chain and the tyrosine phosphorylation of the zeta-chain, respectively.
Human and mouse LSP1 genes code for highly conserved phosphoproteins.
Authors: Jongstra-Bilen J , Young A J , Chong R , Jongstra J
Published: December 2022

With use of the mouse LSP1 cDNA we isolated a human homologue of the mouse LSP1 gene from a human CTL cDNA library. The predicted protein sequence of human LSP1 is compared with the predicted mouse LSP1 protein sequence and regions of homology are identified in order to predict structural features of the LSP1 protein that might be important for its function. Both the human and mouse LSP1 proteins consist of two domains, an N-terminal acidic domain and a C-terminal basic domain. The C-terminal domains of the mouse and human LSP1 proteins are highly conserved and include several conserved, putative serine/threonine phosphorylation sites. Immunoprecipitation of LSP1 protein from 32P-orthophosphate-loaded cells show that both the mouse and human LSP1 proteins are phosphoproteins. The sequences of the putative Ca2(+)-binding sites present in the N-terminal domain of the mouse LSP1 protein are not conserved in the human LSP1 protein; however, a different Ca2(+)-binding site may exist in the human protein, indicating a functional conservation rather than a strict sequence conservation of the two proteins. The expression of the human LSP1 gene follows the same pattern as the expression of the mouse LSP1 gene. Southern analysis of human genomic DNA shows multiple LSP1-related fragments of varying intensity in contrast to the simple pattern found after similar analysis of mouse genomic DNA. By using different parts of the human LSP1 cDNA as a probe, we show that most of these multiple bands contain sequences homologous to the conserved C-terminal region of the LSP1 cDNA. This suggests that there are several LSP1-related genes present in the human genome.
Distinct tumor cell membrane constituents activate human monocytes for tumor necrosis factor synthesis.
Authors: Jänicke R , Männel D N
Published: December 2022

Several lines of evidence point to an activation mechanism of monocytes/macrophages by tumor cells. In this study we present data for distinct surface structures on K562 and Jurkat cells to directly induce TNF-mRNA expression and TNF production by human peripheral blood monocytes. Northern analysis showed that incubation of monocytes with either K562 or Jurkat cells led to a significant increase in TNF-mRNA expression. In addition, enhanced TNF production was detected in supernatants of monocyte cultures activated by Jurkat cells. Not only viable tumor cells but also metabolically inactivated tumor cells, cytoblasts, and membrane preparations from Jurkat and K562 cells induced TNF-mRNA expression. We identified two different membrane protein fractions with relative molecular mass of 32 to 38 kDa for Jurkat cells and 46 to 54 kDa for K562 cells that were responsible for monocyte activation.
A monoclonal antibody to VLA-4 alpha-chain (CDw49d) induces homotypic lymphocyte aggregation.
Authors: Bednarczyk J L , McIntyre B W
Published: December 2022

The complex processes of cellular adhesion involve a variety of receptor to ligand interactions that are extremely important during the development of immune function. Lymphocyte activation by Ag or mitogen, CTL- and NK-mediated cytolysis, homing to lymphoid-associated tissue, and the attachment of lymphocytes to extracellular matrix proteins are all governed, at least in part, by cell surface adhesion receptors. During the analysis of mAb for the ability to block human cytotoxic T lymphocyte-mediated killing an inhibitory mAb was noted that caused rapid and vigorous aggregation among the CTL. This antibody, mAb L25, also induced aggregation among human T and B tumor cell lines. mAb L25 binds to an epitope on the alpha 4 subunit of the integrin protein VLA-4 and induced an adhesion event requiring divalent cations, energy, a fluid plasma membrane, and an intact cytoskeleton. The Ag-independent homotypic adhesion induced by mAb L25 was not inhibited by mAb to the lymphocyte function associated Ag-1 (CD11a/CD18), CD2, CD4, and CD8, or to their ligands ICAM-1, LFA-3, MHC class I, or MHC class II. We believe that these experiments suggest a role for VLA-4 in a novel system of leukocyte adhesion.
Neonatal tolerance induction by class II alloantigens activates IL-4-secreting, tolerogen-responsive T cells.
Authors: Powell T J , Streilein J W
Published: December 2022

Neonatally induced tolerance of class II MHC alloantigens in mice of the A/J strain background is achieved without evident clonal deletion, because lymphoid cells from tolerant animals proliferate in mixed lymphocyte reactions against tolerogen-bearing stimulators. However, the pattern of lymphokines produced in bulk cultures by these tolerogen-reactive cells is unusual in that, unlike lymphocytes from nontolerant normal mice, lymphocytes from tolerant mice produce measurable amounts of IL-4 when stimulated with tolerogen. Using limit dilution analysis, we have determined that the ability to detect IL-4 in bulk cultures is caused by a high frequency of precursors of Ag-specific IL-4 secreting (pIL-4) cells among tolerant, but not normal, responder lymphocytes. Moreover, after repeated in vitro exposure to class II alloantigens, and after in vivo grafting with class II-disparate skin, the frequency of pIL-4 cells rises among lymphocytes from normal mice, eventually reaching levels similar to those found in class II tolerant mice. Because in normal mice a high frequency of class II-reactive pIL-4 cells reflects the "primed" state, we conclude that a subset of T cells that resemble Th2 cells is similarly primed in neonatally tolerized mice. We propose that this priming is achieved by the neonatal inoculation of semiallogeneic bone marrow cells. Because no expansion in the clone size of tolerogen-specific precursors of Ag-specific IL-2-secreting T cells (pIL-2) is observed among tolerant animals, and because the pIL-2 cells from tolerant mice are incapable of differentiating into cytotoxic and delayed hypersensitivity effector cells, we further propose that the precociously primed pIL-4 cells function as "suppressor" cells, helping to maintain the tolerant state.
Allotype-specific immunoregulation of autoantibody production by host B cells in chronic graft-versus host disease.
Authors: Morris S C , Cheek R L , Cohen P L , Eisenberg R A
Published: December 2022

A chronic graft-vs-host (GVH) reaction induced in nonautoimmune mice by the transfer of Ia-incompatible spleen cells results in a syndrome that closely resembles SLE in the spectrum of autoantibodies and immunopathology. We have utilized Ia- and Igh-congenic strains to study the immunoregulation of autoantibody-producing B cells in this model. We have found that the autoantibodies are produced almost entirely by the host B cells. The transferred donor B cells contributed neither to the autoimmune response nor to the total serum Ig, with rare exceptions. The donor cell population did, however, exert an Igh allotype-specific immunoregulatory effect on the host B cells. For example, in allotype-heterozygous recipients, the autoantibodies were preferentially made by those host cells that expressed the donor allotype, whereas those host B cells that expressed nondonor allotype were relatively suppressed. In allotype-homozygous recipients, the donor cells frequently suppressed the host IgG2a allotype completely. This suppression sometimes prevented the IgG antichromatin response, although in other cases the response occurred with the use of a different isotype. In a final set of experiments, a chronic GVH reaction was induced in which both the donors and the recipients were Igh allotype heterozygous and yet differed at Ia. In this case, no donor influence on allotype should be expected; yet the IgG2a autoantibodies were clearly skewed toward the b allotype. These results show that host B cells play a unique role in the GVH autoimmune syndrome. In addition, they are immunoregulated in allotype-specific manners, some of which presumably involve interaction with donor T cells.
Regulation of human T cell proliferation by IL-7.
Authors: Armitage R J , Namen A E , Sassenfeld H M , Grabstein K H
Published: December 2022

The regulation of human T cell proliferation by rIL-7 was investigated. Purified peripheral blood T cells were stimulated to proliferate in a short-term assay by IL-7 in the presence of CD3 mAb or lectin. This stimulation was accompanied by a significant increase in the expression of IL-2R on both CD4+ and CD8+ T cells over that seen with mitogen alone. The proliferation of these cells in the presence of exogenous IL-7 involved both IL-2-dependent and - independent mechanisms as shown by the ability of neutralizing IL-2 antibody to partially inhibit the response. Anti-IL-4 and anti-IL-6 antibodies had no effect on IL-7-induced T cell growth. These results suggest that the costimulatory effect of IL-7 on human T cells is primarily direct, not involving other intermediate T cell growth factors. IL-7 was also found to be mitogenic in a long-term assay in the absence of any costimulus, with the onset of proliferation occurring later than that seen in the presence of mitogen. These results demonstrate that IL-7 provides a potent T cell stimulus either alone or in the presence of co-mitogen and, although this stimulus is accompanied by an increase in the level of IL-2R expression, it is not dependent on the action of IL-2 for its effect.
Differential gene expression of IFN-alpha and tumor necrosis factor-alpha in peripheral blood mononuclear cells from patients with AIDS related complex and AIDS.
Authors: Voth R , Rossol S , Klein K , Hess G , Schütt K H , Schröder H C , Meyer zum Büschenfelde K H , Müller W E
Published: December 2022

Human PBMC from HIV-1-infected individuals produced ex vivo in response to vesicular stomatitis virus only low amounts of IFN-alpha. This impairment was significant as early as Walter Reed (WR) stage 2; at WR stage 4-5, the production was almost zero. At WR stage 2 of infection, IFN-alpha mRNA was exclusively found in association with polyribosomes, indicating that IFN-alpha gene was transcriptionally inactive under the experimental conditions used. A similar decrease of the level of transcripts as a function of the progression of the disease was also observed for the IFN-gamma mRNA. In contrast, TNF-alpha production was strongly enhanced in PBMC from HIV-1-infected individuals after stimulation with LPS compared to the TNF-alpha production of activated PBMC from healthy donors. Almost parallel with the increase of the level of the transcript for TNF-alpha, the level of TNF-beta increases as well. Data are presented which show that the increased TNF-alpha production is due to a longer half-life of TNF-alpha transcripts in PBMC from infected individuals. These results let us suggest that the up-regulation of TNF-alpha gene expression in PBMC from HIV-infected individuals is controlled predominantly on the posttranscriptional level, whereas transcriptional events regulate the level of IFN-alpha transcripts. This assumption is supported by run-on experiments which revealed that the extent of transcription of TNF-alpha gene is almost identical in nuclei from stimulated PBMC of noninfected and HIV-infected donors, whereas the transcription of IFN-alpha gene is strongly suppressed in nuclei from HIV-infected individuals at WR stages 3 and 6.
Differential distribution of antigen-specific helper T cells and cytotoxic T cells after antigenic stimulation in vivo. A functional study using limiting dilution analysis.
Authors: Bishop D K , Ferguson R M , Orosz C G
Published: December 2022

We have developed modified limiting dilution analysis (LDA) techniques that distinguish in vivo Ag-stimulated murine helper T lymphocytes (HTL) and CTL from unstimulated precursor T cells, even those with the same Ag specificity. We refer to these cells that are detectable in the modified LDA as "Ag-conditioned" T cells (cHTL and cCTL). We have used the modified LDA techniques in conjunction with conventional LDA techniques (which enumerate all Ag-specific T cells) to evaluate the in vivo distribution of Ag-conditioned cHTL and cCTL following in vivo sensitization to alloantigens via sponge matrix or skin allografts. In general, we observed the following regarding the distribution of cHTL and cCTL: 1) Ag-conditioned HTL and CTL were detectable only after in vivo sensitization with alloantigen: 2) not all Ag-reactive T cells became conditioned T cells after in vivo Ag deposition; 3) the percentage of Ag-reactive T cells that converted to conditioned T cells after Ag deposition varied among different lymphoid compartments; 4) a high percentage of cHTL, but a low percentage of cCTL, accumulated in regional lymph nodes and spleen; 5) cHTL accumulated in peripheral blood, whereas cCTL did not; 6) Ag-conditioned cHTL were detectable in various lymphoid tissues for greater than 60 days following Ag deposition, whereas cCTL were detectable for only 14 to 20 days; and 7) unlike the other lymphoid sites, the site of Ag deposition accumulated a high percentage of both Ag-stimulated cHTL and cCTL. Furthermore, cHTL and cCTL appeared to reside in phenotypically distinct T cell subsets in that in vivo treatment with anti-L3T4 mAb abrogated the accumulation of HTL, but not CTL, at the site of Ag deposition. These data demonstrate differential compartmentalization of Ag-conditioned cHTL and cCTL subsequent to in vivo Ag deposition. The implications of these findings regarding the monitoring of in vivo immune responses are discussed.
Analysis of the donor-specific cytotoxic T lymphocyte repertoire in a patient with a long term surviving allograft. Frequency, specificity, and phenotype of donor-reactive T cell receptor (TCR)-alpha beta+ and TCR-gamma delta+ clones.
Authors: Vandekerckhove B A , Datema G , Koning F , Goulmy E , Persijn G G , Van Rood J J , Claas F H , De Vries J E
Published: December 2022

In the present study the transplant specific CTL repertoire of a patient (HLA:A1,3, B8,18, Cw5,7 DR3, DQw2, DPw3) with a long term surviving HLA mismatched kidney graft (HLA: A1,24 B8,27 Cw2,7, DR3, w13 DQw2,6 DPw1,3) has been investigated. This patient was unable to generate specific cytolytic activity against donor-derived PHA-blasts in the MLC in which donor spleen cells or B lymphoblastoid cell line were used as stimulator cells. In addition, the CTL precursor frequencies against donor alloantigens were very low (1/67,000). The patient had otherwise normal immune responses in vivo and in vitro and no signs of transplant rejection. Transplant specific CTL clones were generated in high frequencies (1/195) from T cell bulk cultures activated by PHA in the absence of any sensitization by donor Ag in vitro. The repertoire of 14 donor-reactive CTL clones (12 TCR-alpha beta+ and 2 TCR-gamma delta+) was analyzed. Two TCR-alpha beta+ CD8+ clones were specific for B27. Ten TCR-alpha beta+ CTL clones directed against class II HLA Ag were isolated. Seven of these were CD4+ and recognized DRw13 (3), DQw6 (3), and DPw1 (1), whereas three of these clones were CD4-CD8+ recognizing DRw13 (1) and DQw6 (2). In addition, two donor-specific TCR-gamma delta+ CTL clones were obtained recognizing HLA-A9(23,24) and DQw6. Our data indicate that the precursors of CTL clones specifically directed against donor class I or II HLA Ag are not deleted from the repertoire and that part of this reactivity resides in the TCR-gamma delta+ fraction.
Studies on molecular regulation of phagocytosis and activation of the NADPH oxidase in neutrophils. IgG- and C3b-mediated ingestion and associated respiratory burst independent of phospholipid turnover and Ca2+ transients.
Authors: Della Bianca V , Grzeskowiak M , Rossi F
Published: December 2022

The role of messengers derived from hydrolysis of phosphoinositides and other phospholipids, of the basal level of [Ca2+]i and of the increase in [Ca2+]i in phagocytosis and respiratory burst was investigated, using normal neutrophils and neutrophils Ca2(+)-depleted by pretreatment with Quin2/AM and EGTA. 1) Phagocytosis and respiratory burst in control neutrophils challenged with yeast opsonized with IgG or C3b/bi were associated with a stimulation of the production of inositol phosphates, diacylglycerol, phosphatidic acid, arachidonic acid, and rise in [Ca2+]i. 2) In Ca2(+)-depleted neutrophils (basal [Ca2+]i 10 to 20 nM) the phagocytosis of yeast-IgG was similar to that in control neutrophils, the respiratory burst was slightly depressed (-30%), while the increase in [Ca2+]i and production of inositol phosphates, diacylglycerol, and phosphatidic and arachidonic acid did not occur. 3) In Ca2(+)-depleted neutrophils the phagocytosis of yeast-C3b/bi was slightly lower than that in control neutrophils, and the respiratory burst, related to the same number of particles ingested, was depressed by about 60%, whereas the increase in [Ca2+]i and production of inositol phosphates, diacylglycerol, phosphatidic acid, and arachidonic acid release did not occur. These findings demonstrate that transmembrane signaling pathways involving the hydrolysis of phosphoinositides by phospholipase C and D and of other phospholipids by phospholipase C and Az, and the rise in [Ca2+]i are not essential processes for triggering the ingestion of yeast particles opsonized with IgG and C3b/bi and the activation of the NADPH oxidase.
Cytolytic mechanisms of activated macrophages. Tumor necrosis factor and L-arginine-dependent mechanisms act synergistically as the major cytolytic mechanisms of activated macrophages.
Authors: Higuchi M , Higashi N , Taki H , Osawa T
Published: December 2022

We examined the cytolytic mechanisms of activated macrophages by using proteose peptone- or thioglycollate broth-induced mouse peritoneal macrophages or mouse macrophage hybridomas as effector cells, L.P3 cells, a clone of L929 cells, and P815 cells as target cells, and IFN-gamma and LPS as activators. It was determined that TNF is the main cytolytic molecule against L.P3 cells from the following results: 1) activated macrophages can produce TNF; 2) TNF shows cytotoxic activity against L.P3 cells; 3) the addition of anti-TNF antibody inhibited most of the cytolytic activity of activated macrophages against L.P3 cells. On the other hand, it was concluded that the main cytolytic mechanism against P815 cells is the production of NO2-/NO3- from L-arginine, from the following results: 1) activated macrophages can produce NO2-; 2) NaNO2 shows high cytotoxic activity against P815 cells; 3) the depletion of L-arginine from the medium inhibited most of the cytolytic activity of activated macrophages against P815 cells and NO2- production by activated macrophages. In this study, however, cytostatic effects of L-arginine-dependent effector mechanism were not studied. Thus, these results show that activated macrophages can express at least two cytolytic mechanisms independently, namely, the one that appears to be mediated by the L-arginine-dependent effector mechanism and the second that appears to be mediated directly by TNF. Furthermore, it was demonstrated that TNF and L-arginine-dependent NO2- production act synergistically as killing mechanisms of activated macrophages. These mechanisms can explain the cytolytic activity of activated macrophages against a variety of target cells.