bluuebunny/crossref_metadata_2025 huggingface dataset:
Decreased accessory cell function by human monocytic cells after infection with HIV.
Authors: Petit A J , Tersmette M , Terpstra F G , de Goede R E , van Lier R A , Miedema F
Published: December 2022

We studied the effect of HIV infection on the human monocytic cell line U937. The cell line was infected with cellfree HIV, strain HTLV-IIIB. After 3 wk, a high reverse transcriptase activity was continuously detected in the supernatant of the cell line. Neither cytopathic effects nor changes in cell growth were observed. After infection, accessory cell function on T cell proliferation induced by anti-CD3 mAb of both IgG1 and IgG2a subclasses and Con A was tested. Accessory cell function provided by U937 cells started to decline 3 wk after inoculation with HIV. This correlated with detectable reverse transcriptase activity. The remaining accessory cell capacity varied between 10 and 60% of accessory cell function mediated by noninfected U937 cells. It was excluded that decreased FcR expression on U937/HIV cells contributed to the accessory cell defect in the anti-CD3-driven system. IL-2R expression on T cells, cocultivated with U937/HIV and anti-CD3, was minimal. The accessory cell defect could only be partly overcome by addition of rIL-2 or IL-1. Addition of high titer (10(4) TCID50) HIV or U937/HIV cells did not affect T cell proliferation, which rules out that the observed inhibition is caused by HIV infection of T cells or suppressive effects of U937/HIV cells. These results suggest that infection of APC may contribute to the induction of immunologic abnormalities in early HIV infection. Thus, monocytes/macrophages may not only serve as a reservoir for the dissemination of HIV, but may be an important target cell through which the immune system is affected.
IL-4 (B cell stimulatory factor 1) exhibits thymocyte growth factor activity in the presence of IL-2.
Authors: Carding S R , Bottomly K
Published: December 2022

The proliferative activity of thymocytes cultured with IL-2 and submitogenic concentrations of PHA is increased by 3- to 10-fold in the presence of IL-4. In contrast, IL-4 alone is unable to induce proliferative activity in thymocyte cultures and its synergistic activity is only apparent to concentrations of IL-2 above 1 U/ml. The costimulatory activity of IL-4 is abrogated by the monoclonal anti-IL-4 antibody 11B11. Furthermore, potentiation of the IL-2-mediated thymocyte proliferation is not seen with IL-1, IL-3, IFN-gamma, and granulocyte-macrophage CSF. Thymocytes are at least as responsive to IL-4 as B cells and the IL-4 costimulatory activity in fractionated thymocytes appears to be restricted mainly to the Lyt-2+/L3T4- population. In contrast, purified resting mature T cells do not respond to IL-4 plus IL-2, although they did proliferate in response to IL-4 in combination with PMA. These findings indicate that thymocytes and mature T cells are responsive to the costimulatory activity of IL-4 under quite different conditions, and that IL-4 may play an important role in thymocyte maturation in the thymus.
IFN-gamma-regulated expression of a differentiation antigen of human cells.
Authors: Real F X , Carrato A , Schuessler M H , Welt S , Oettgen H F
Published: December 2022

Mouse mAb M111 identifies a cell surface glycoprotein of 115,000 to 135,000 Da. M111 was expressed constitutively in subsets of cells of multiple lineages at discrete stages of cell maturation, suggesting that M111 is a differentiation Ag of the three germ layers. Ag expression could be induced by IFN-gamma but not by IFN-alpha, IFN-beta, or TNF. Induction of M111 expression was maximal at 48 h of culture in 200 U/ml of IFN-gamma and was independent of induction of class II MHC Ag. Induction was dependent on the cell type used. Nine colon cancer cell lines of undifferentiated phenotype were constitutively M111-; IFN-gamma induced M111 expression in seven of them. In contrast, IFN-gamma failed to induce M111 expression in six of six M111- ovarian cancer cell lines. Eight normal fibroblast cultures tested were M111-; they could not be induced to express M111. Three of five sarcoma cell lines were M111+; culture in IFN-gamma induced an increase in M111 expression in all of them. Constitutive and IFN-gamma-induced expression of M111 was independent of constitutive and induced expression of HLA class I and II molecules. IFN-gamma-mediated induction of M111 expression was not accompanied by coordinate changes in the expression of other differentiation traits. These results suggest that expression of the M111 gene is controlled by two mechanisms, one related to differentiation and the other activated by IFN-gamma.
Effect of gangliosides on activation of the alternative pathway of human complement.
Authors: Michalek M T , Bremer E G , Mold C
Published: December 2022

Liposomes as defined model membranes were used to quantitatively study the effects of specific sialic acid containing glycolipids on activation of the alternative pathway of human C. Liposomes containing dimyristoylphosphatidylethanolamine, cholesterol, and cerebrosides at molar ratios of 1.0/0.75/0.33 activated the alternative pathway in human serum treated with MgEGTA. Activation was measured by C3 conversion and the deposition of total C3 and functional C3b on the liposome surface. The monosialoganglioside GM1, when incorporated into the activating liposome membrane at molar ratios between 10(-5) and 10(-2), inhibited activation in a dose-dependent manner. Sialosylparagloboside also inhibited activation in human serum, and inhibition was completely reversed after neuraminidase treatment. The degree of inhibition by GM1 correlated with the relative amount of GM1 exposed on the liposome surface. Sialic acid did not directly inhibit the binding of C3b when liposomes containing gangliosides were incubated with the purified components C3, B, D, and P. GM1 did inhibit activation when liposomes were incubated with a mixture of purified C3, B, D, P, H, and I. Binding assays with radiolabeled H showed increased binding of H to liposome-bound C3b in the presence of GM1. These results establish the ability of sialic acid on glycolipids to promote H binding to C3b and thereby regulate alternative pathway activation on a defined lipid membrane.
Phorbol ester-induced differentiation permits productive human cytomegalovirus infection in a monocytic cell line.
Authors: Weinshenker B G , Wilton S , Rice G P
Published: December 2022

The susceptibility of four different human cell lines (HUT 102, THP-1, MOLT-4, and HL-60) to infection by human CMV (HCMV) was studied. Only HUT 102 was susceptible and only immediate-early gene products were produced. However, THP-1, a monocytic cell line, could be infected by HCMV with a full cycle of replication after treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which produced differentiation of the cell line into cells with characteristics of mature macrophages. Late (structural) Ag were demonstrated, as were infectious virions as detected by electron microscopy and infectious center assay. HL-60, a promyelocytic cell line, was not susceptible to HCMV infection after treatment with TPA despite differentiation into adherent cells with properties of macrophages, suggesting that cellular lineage was important. Treatment with TPA after infection resulted in a greatly reduced frequency of infected cells, suggesting that pretreatment was essential. Furthermore, continued presence of TPA was unnecessary after differentiation was induced. This study establishes the precedent of productive HCMV infection in human monocytic cells. The potential mechanism and relevance of enhanced replication induced by TPA are discussed.
Parasite polymorphism present within minimal T cell epitopes of Plasmodium falciparum circumsporozoite protein.
Authors: Good M F , Pombo D , Maloy W L , de la Cruz V F , Miller L H , Berzofsky J A
Published: December 2022

Identification of T cell antigenic sites is critical for antisporozoite malarial vaccine design. Here, we present data that define two minimal functional T cell sites present in an immunogenic domain of the circumsporozoite protein of Plasmodium falciparum. These two sites overlap one another and correlate with polymorphic regions of the molecule. This suggests that these polymorphisms may be a result of pressure from immune T cells.
Regulation of HLA-DR gene by IFN-gamma. Transcriptional and post-transcriptional control.
Authors: Rosa F M , Fellous M
Published: December 2022

IFN-gamma increases the synthesis and level of mRNA of the HLA class I and II genes, in human cells such as melanomas which normally express both classes of molecules. It also induces the surface expression and mRNA synthesis of HLA-DR genes on cells which normally do not express HLA class II genes such as skin fibroblasts. We have investigated the mechanism by which IFN-gamma increases mRNA levels for class II MHC antigens in human cells. For this purpose, we have studied the effect of IFN-gamma on HLA-DR-alpha transcription rate in two different human cell types: VAL melanoma and JDA2 skin fibroblasts. HLA-DR-alpha mRNA is spontaneously produced in VAL cells and its level is enhanced upon IFN-gamma treatment. We demonstrate here that IFN-gamma increases the transcription of HLA-DR-alpha gene in this cell line. However, the discrepancy observed between HLA-DR-alpha mRNA and transcriptional rates led us to postulate that IFN-gamma also regulates the HLA-DR-alpha gene post-transcriptionally. In the course of these experiments, we found also that human skin fibroblasts, which do not contain detectable amounts of HLA-DR-alpha mRNA, spontaneously transcribe the HLA-DR-alpha gene.
Characterization of natural killer activity in sponge matrix allografts.
Authors: Hoffman R A , Ascher N L , Jordan M L , Migliori R J , Simmons R L
Published: December 2022

NK cell activity, defined by the ability of infiltrating host cells to lyse the YAC-1 tumor target, can be detected in sponge matrix allografts across all genetic barriers tested. Nonspecific tumor cell killing cannot be detected either within bulk populations of host-infiltrating cells or in populations enriched for non-adherent lymphocytes. NK activity is also detected in cells infiltrating a syngeneic sponge matrix graft although to a much lesser extent than an allogeneic graft. NK cell functional activity at the graft site precedes the appearance of alloimmune CTL by several days. The surface phenotype of the NK cell is Thy-1.2+ and L3T4- as determined by depleting the various subpopulations with antibody and C. Systemic treatment of sponge-bearing animals with repeated injections of anti-asialo GM1 (AGM1) results in inhibition of both NK activity and CTL activity recovered from the graft on days 5 to 9 after grafting, but on days 11 to 13 after grafting both NK activity and CTL activity are found within the sponge graft. Treatment of sponge-associated cells with anti-AGM1 in vitro or intrasponge injection of anti-AGM1 at various times after grafting eliminates NK activity more readily than alloimmune CTL activity. The intimate association observed between NK cells and alloimmune CTL at the graft site prompts further investigation into the role of NK cells in the allograft response.
Human epidermal cells from ultraviolet light-exposed skin preferentially activate autoreactive CD4+2H4+ suppressor-inducer lymphocytes and CD8+ suppressor/cytotoxic lymphocytes.
Authors: Baadsgaard O , Fox D A , Cooper K D
Published: December 2022

In vivo exposure of human epidermis to UV abrogates the function of T6+DR+ Langerhans cells and induces the appearance of Ag-presenting T6-DR+ OKM5+ cells in the epidermis. Since UV exposure of murine skin results in Ts lymphocyte activation, we investigated the capacity of human epidermal cells (EC) harvested 3 days after in vivo UV exposure to activate regulatory and effector autologous T lymphocyte subsets. T lymphocytes were separated into CD8+ suppressor/cytotoxic lymphocytes and CD4+ helper/inducer lymphocytes by C lysis and panning. The CD4+ subset was further divided by using the 2H4 mAB to obtain CD4+2H4+ lymphocytes (inducers of TS lymphocytes) and CD4+2H4- lymphocytes (inducers of B cell Ig production and inducers of cytotoxic T cells). Unirradiated suction blister-derived EC from control skin (C-EC) and from skin exposed in vivo to UV (UV-EC) were cultured with purified autologous T lymphocyte subsets in the absence of added Ag. The resultant T lymphocyte proliferation was detected by [3H]thymidine uptake. UV-EC were highly effective in the stimulation of CD4+ lymphocytes, whereas C-EC were poor stimulators. The stimulator effect of UV-EC was abrogated after depletion of DR+ UV-EC. When CD4+ lymphocytes were fractionated, UV-EC consistently demonstrated enhanced ability to stimulate suppressor-inducer CD4+2H4+ lymphocytes relative to C-EC. Although less responsive than CD4+2H4+ lymphocytes, CD4+2H4- lymphocytes also demonstrated greater proliferation to UV-EC than to C-EC. Neither UV-EC nor C-EC were able to activate CD8+ lymphocytes devoid of CD4+ lymphocytes. However, after addition of rIL-2 at concentrations that allow binding only to the high affinity IL-2R on T lymphocytes, UV-EC induced vigorous proliferation of CD8+ lymphocytes, whereas C-EC induced only background levels of proliferation. C lysis of leukocytes resident within UV-EC resulted in 66 to 70% reduction of CD8+ lymphocyte proliferation. In conclusion, UV-EC may activate CD8+ lymphocytes by at least two pathways: (1) UV-EC activation of CD4+2H4+ lymphocytes may induce differentiation/proliferation of CD8+ suppressor cells and (2) UV-EC activation of CD4+ cells may induce IL-2 production, that, in combination with UV-induced epidermal leukocytes, stimulates CD8+ cells.
Effects of tobacco glycoprotein (TGP) on the immune system. II. TGP stimulates the proliferation of human T cells and the differentiation of human B cells into Ig secreting cells.
Authors: Francus T , Klein R F , Staiano-Coico L , Becker C G , Siskind G W
Published: December 2022

We have been studying the effects of tobacco glycoprotein (TGP), a polyphenol-rich glycoprotein isolated from cured tobacco leaves, on the immune system. We have shown previously that mice immunized with TGP produce preferentially antibodies of the IgE isotype and that TGP is a T cell-independent B cell mitogen for mice, which stimulates B cell proliferation and B cell differentiation into Ig-secreting cells. We report herein that TGP stimulates a significant increase in [3H]TdR incorporation by human PBL and by human cord blood lymphocytes. The magnitude of the proliferative response of PBL to TGP does not correlate with the donor's titer of IgE antibodies to TGP, as assayed by a wheal and flare response after an i.d. injection of TGP, neither does it correlate with the donor's smoking history. [3H]TdR uptake is not observed before day 5 of culture, and the response peaks between days 5 and 10 of culture. Analysis of the cellular basis for the proliferative response suggests that T cells are proliferating. Two-parameter analysis by flow cytometry shows that CD3+, CD4+, and CD8+ cells are in the S + G2 + M phases, but not Ig-bearing cells or monocytes. A significant increase in HLA-DR (Ia)-bearing cells is observed on cells in all of the cell cycle phases. This increase coincides with cells entering the S phase. No increase is observed in the expression of the IL-2-R as assayed by the anti-Tac antibody. TGP also stimulates human PBL to differentiate and to produce Ig of the IgM, IgG, and IgA isotypes, without stimulating a detectable B cell proliferative response. The proliferative response of PBL is clearly due to TGP and not to contamination with LPS, because by the limulus amebocyte assay the TGP preparation contains less than 2% LPS, which could not account for the stimulation observed.
Specificity of the T cell immune response to acetylcholine receptor in experimental autoimmune myasthenia gravis. Response to subunits and synthetic peptides.
Authors: Fujii Y , Lindstrom J
Published: December 2022

Myasthenia gravis (MG) and its animal model, experimental autoimmune MG (EAMG), are T cell-dependent diseases mediated by antibodies against acetylcholine receptor (AChR) on skeletal muscle. Most of the antibodies are directed toward conformation-dependent epitopes on the AChR, whereas T cells recognize denatured AChR. In search of T cell epitopes in EAMG, we tested 24 synthetic peptides covering 62% of the alpha-subunit sequence of Torpedo californica electric organ AChR in the T cell proliferation assay with lymph node cells from rats immunized with AChR. In Lewis rats, 2 of these peptides, [Tyr 100]alpha 100-116 and [Gly 89, Tyr 90]alpha 73-90, strongly stimulated T cells and, of these, [Tyr 100]alpha 100-116 was much more potent; 4 other peptides were weakly mitogenic and 18 were ineffective. None of the 24 synthetic peptides alone stimulated anti-AChR production and, when added to cultures along with AChR, [Tyr 100]alpha 100-116 and [Gly 89, Tyr 90]alpha 73-90 suppressed antibody production. Of twelve cloned T cell lines specific to AChR, 4 responded to [Tyr 100]alpha 100-116, indicating the importance of the epitope in alpha 101-116 in Lewis rats. In three other strains of rats whose responses to AChR and its subunits were similar to those in the Lewis rat, neither [Tyr 100]alpha 100-116 nor [Gly 89, Tyr 90]alpha 73-90 was stimulatory. Instead, completely different sets of peptides stimulated their T cells. When peptides were used as immunogens, each strain (except Lewis rats) responded only to the peptides that stimulated AChR-immune T cells from the same strain. Genetically restricted T cell recognition of AChR peptides in rats suggests that T cells from MG patients with different major histocompatibility haplotypes may recognize different AChR peptides.
Flow cytometric analysis of human bone marrow. IV. Differential quantitative expression of T-200 common leukocyte antigen during normal hemopoiesis.
Authors: Shah V O , Civin C I , Loken M R
Published: December 2022

We have correlated the intensity of expression of CD45 Ag (T200 common leukocyte Ag) with mAb reactive with various lineages of hemopoietic cells in normal human bone marrow by using two-color immunofluorescence on a flow cytometer. Mature T lymphocytes (CD3+) and NK cells (CD16+ or CD11b+) expressed CD45 at the highest intensity. B lymphoid cells (CD19+) had three distinct levels of CD45 Ag expression. The bright CD45(3+) cells were mature B cells (CD19+, CD20+), whereas the less intense CD45(2+) cells were less mature B lymphoid cells (CD19+, CD10+). The dim CD45+ cells were very early, B lymphoid precursor cells (CD19+, CD10(2+), CD34+). The intensity of CD45 expression increased as cells matured in the monocytic lineage (CD14+, CD11b+). Among marrow granulocytic cells, CD45 intensity did not change on cells during maturation. Within the erythroid lineage, the most immature cells were CD45+ dim, and CD45 expression decreased during erythroid maturation to become undetectable on mature E. Hemopoietic progenitor cells (CD34+) expressed low levels of CD45 Ag. Expression of CD45R on marrow cells also showed intensity differences on different lineages. All NK cells (CD16+) were positive for CD45R, whereas only about one-half of the T lymphocytes (CD3+) were positive for CD45R. Almost all the cells in the erythroid and myelomonocytic lineages were CD45R-. Quantitative differences in expression of CD45R were observed on marrow B lymphoid cells which were correlated with the expression of CD45. The results show that quantitative changes in CD45 Ag expression accompany the differentiation and maturation of cells in the bone marrow. Comparisons with CD45R showed that this Ag was not always correlated with CD45. Since these Ag are the products of the same gene, these data indicate that the regulation of expression of the T200 molecules during normal hemopoietic development must be both quantitative and qualitative.
Regulation of IgA secretion by T cell clones derived from the human gastrointestinal tract.
Authors: Benson E B , Strober W
Published: December 2022

The role of T cells in Ig isotype regulation is still unclear. To address this question, we generated mitogen-stimulated T cell clones from normal human lymphoid follicles of the gut-associated lymphoid tissue (appendix). Both the T cell clones and clonal supernatants provided preferential help for IgA secretion by PWM-stimulated B cells. Many of these CD3+, CD4+, 4B4+, DR+ helper clones co-expressed Fc-gamma and Fc-alpha R, but there was poor correlation between the expression of Fc-alpha R and IgA help (p = 0.31). Most of the T cell clones helped both IgM+A- and IgM-A+ B cell populations to secrete IgA, suggesting that they mediate switch of isotype-uncommitted B cells as well as post-switch expansion of IgA-committed B cells; however, some of the T cell clones helped IgM+A- B cell populations much more than IgM-A+ B cell populations, suggesting that, in this case, the regulatory effect is predominantly at the level of B cell switch. In all, these results show that the mucosal immune system contains individual T cells which are capable of positively regulating IgA-specific isotype differentiation at two levels of B cell development, thus allowing for efficient generation of IgA-secreting B cells.
Increased binding of IL-2 and increased IL-2 receptor mRNA synthesis are expressed by an NK-like cell line in response to IL-1.
Authors: Lubinski J , Fong T C , Babbitt J T , Ransone L , Yodoi J J , Bloom E T
Published: December 2022

An NK-like cell line (YTN10 cells) was stimulated with IL-1, and the IL-2R, as detected by flow cytometry analysis using fluorescein-labeled anti-IL-2R (Tac) antibody, increased displaying a dose-response curve in the shape of an inverted "U." This was associated with increases in 1) the number of high affinity binding sites for IL-2 (Kd approximately 45 pM) which increased from 1270 to 4220 sites per cell, and 2) the number of binding sites for anti-Tac antibody, which increased from 999 to 6763 sites per cell. They were both detected by using radiolabeled ligand-binding methods which are one to three orders of magnitude more sensitive than flow cytometry analysis. No binding sites with low affinity for IL-2 could be detected on untreated or treated cells. However, a change was noted in the number of IL-2 binding sites with intermediate affinity (Kd approximately 1000 pM), which increased from 54,000 to 67,000 sites per cell. This binding affinity is equivalent to that of the p70 IL-2-binding protein detected on YT cells and on large granular lymphocytes by other investigators. This suggests that the increase in the Tac peptide was the limiting factor in the combination of the Tac and p70 components to form the high affinity IL-2R. The corollary is that all new Tac molecules were incorporated into these R. The IL-1 treatment also induced an increase in production of Tac mRNA as detected by Northern blots. Comparison of the relative amounts of Tac mRNA by dot blots verified the quantitative difference between treated and untreated cells. These data demonstrate that the IL-1-induced positive regulation of the Tac protein and high affinity IL-2R on YTN10 cells may operate at the level of gene transcription.
Generation of leukotriene C4, leukotriene B4, and prostaglandin D2 by immunologically activated rat intestinal mucosa mast cells.
Authors: Heavey D J , Ernst P B , Stevens R L , Befus A D , Bienenstock J , Austen K F
Published: December 2022

Mucosal mast cells (MMC) were isolated from the intestine of Nippostrongylus brasiliensis-infected rats and then activated with Ag or with anti-IgE in order to assess their metabolism of arachidonic acid to leukotriene (LT) C4, LTB4, and prostaglandin D2 (PGD2). After challenge of MMC preparations of 19 +/- 1% purity with five worm equivalents of N. brasiliensis Ag, the net formation of immunoreactive equivalents of LTC4, LTB4, and PGD2 was 58 +/- 8.3, 22 +/- 4.5, and 22 +/- 3.4 ng/10(6) mast cells, respectively (mean +/- SE, n = 7). When MMC preparations of 56 +/- 9% purity were activated by Ag, the net generation of immunoreactive equivalents of LTC4, LTB4, and PGD2/10(6) MMC was 107 +/- 15, 17 +/- 5.4, and 35 +/- 18 ng, respectively. These data indicate that the three eicosanoids originated from the MMC rather than from a contaminating cell. Analysis by reverse phase HPLC of the C-6 sulfidopeptide leukotrienes present in the supernatants of the activated MMC preparations of lower purity revealed LTC4, LTD4, and LTE4. In a higher purity MMC preparation only LTC4 was present, suggesting that other cell types in the mucosa are able to metabolize LTC4 to LTD4 and LTE4. The release of histamine and the generation of eicosanoids from intestinal MMC and from peritoneal cavity-derived connective tissue-type mast cells (CTMC) isolated from the same N. brasiliensis-infected rats were compared. When challenged with anti-IgE, these MMC released 165 +/- 41 ng of histamine/10(6) mast cells, and generated 29 +/- 3.6, 12 +/- 4.2, and 4.7 +/- 1.0 ng (mean +/- SE, n = 3) of immunoreactive equivalents of LTC4, LTB4, and PGD2/10(6) mast cells, respectively. In contrast, CTMC isolated from the same animals and activated with the same dose of anti-IgE released approximately 35 times more histamine (5700 +/- 650 ng/10(6) CTMC), generated 7.5 +/- 2.3 ng of PGD2/10(6) mast cells, and failed to release LTC4 or LTB4. These studies establish, that upon immunologic activation, rat MMC and CTMC differ in their quantitative release of histamine and in their metabolism of arachidonic acid to LTC4 and LTB4.
Low calcium concentrations support killing by some but not all cytolytic T lymphocytes, and reveal inhibition of a postconjugation step by calcium antagonists.
Authors: Howell D M , Martz E
Published: December 2022

Previous findings support the prediction that drugs which antagonize the action of calcium should inhibit cytolytic T lymphocyte (CTL)-mediated killing without inhibiting the formation of Ag-specific CTL-target cell conjugates. This would contrast with other CTL-inhibiting drugs, nearly all of which inhibit conjugate formation. Testing this prediction, we found that two calcium channel blockers (verapamil and ruthenium red) inhibit killing only when the extracellular calcium concentration is low (100 microM), and, as predicted, do not inhibit conjugate formation. Surprisingly, the esterase inhibitor N alpha-p-tosyl-L-lysine choloromethylketone also inhibited killing without inhibiting conjugate formation. Unexpectedly, we found that the amount of calcium required by CTL varies by four-fold or more. CTL produced in vivo, or by a single Ag stimulation cycle in vitro, require more than 130 microM calcium for optimal killing, whereas 30 microM suffices for CTL primed in vivo plus boosted in vitro. The rate of admission of calcium into the cytoplasm by physiologic channels did not appear to be the limiting factor for the former type of CTL. Recent findings indicate that allospecific CTL produced in vivo may lack cytoplasmic granules, and may kill by an unidentified mechanism distinct from the exocytosis of granules prominent in CTL lines or clones maintained in vitro. The differences in calcium requirements reported here may reflect differences in mechanisms of killing.
Partial characterization of the cross-reacting determinant, a carbohydrate epitope shared by decay accelerating factor and the variant surface glycoprotein of the African Trypanosoma brucei.
Authors: Shak S , Davitz M A , Wolinsky M L , Nussenzweig V , Turner M J , Gurnett A
Published: December 2022

The variant surface glycoprotein (VSG) of the African trypanosome is anchored in the cell membrane by a complex glycan attached to phosphatidylinositol. The carboxyl terminal portion of VSG contains a cryptic carbohydrate epitope, the cross-reacting determinant (CRD), that is revealed only after removal of the diacylglycerol by phosphatidylinositol-specific phospholipase C (PIPLC) or VSG lipase. Recently, we have shown that after hydrolysis by PIPLC, decay-accelerating factor (DAF)--a mammalian phosphatidylinositol-anchored protein--also contains the CRD epitope. Using a two site immunoradiometric assay in which the capturing antibody is a monoclonal antibody to DAF and the revealing antibody is anti-CRD, we now show that sugar phosphates significantly inhibited the binding of anti-CRD antibody to DAF released by PIPLC. DL-myo-inositol 1,2-cyclic phosphate was the most potent inhibitor of binding (IC50 less than 10(-8) M). Other sugar phosphates, such as alpha-D-glucose-1-phosphate, which also possess adjacent hydroxyl and phosphate moieties in cis also inhibited binding at low concentrations (IC50 = 10(-5) to 10(-4) M). In contrast, sugar phosphates which do not possess adjacent hydroxyl and phosphate moieties in cis and simple sugars weakly inhibited binding (IC50 greater than 10(-3) M). These results suggest that myo-inositol 1,2-cyclic phosphate contributes significantly to the epitope recognized by the anti-CRD antibody and is consistent with analysis of the carboxyl terminus of VSG, which also suggested the presence of the cyclic inositol phosphate. In light of the recent findings that human serum contains a glycan-phosphatidyl-inositol-specific phospholipase D, which converts DAF from a hydrophobic to a hydrophilic form lacking the CRD, the observation that the phosphate is crucial for expression of the epitope may be relevant in understanding the origin of CRD-negative DAF in urine and plasma.
Lymphocyte-virus interactions. Identification of a restriction fragment permitting virus replication in lymphocytes.
Authors: Strayer D S , Mulloy J , Leibowitz J L
Published: December 2022

We are interested in understanding the effects of virus infection on lymphocyte function. To approach this question, we used a unique system of two genetically related leporipoxviruses to generate recombinants. One of these viruses, malignant fibroma virus (MV), replicates in many different cell types, including lymphocytes. The other, Shope fibroma virus (SFV), replicates principally in fibroblasts, but cannot replicate in lymphocytes. Fibroblasts infected with SFV received restriction fragments from MV by transfection. Recombinant viruses were selected in vitro for their ability to replicate in lymphocytes. By these means we have identified one restriction fragment, the 10.8-kb BamHI "C" fragment, capable of transferring from MV to SFV the ability to replicate in lymphocytes. A family of recombinants bearing different sized inserts of this restriction fragment has been isolated and is being characterized. Lymphocytotropic recombinants bearing portions of this restriction fragment produce colony morphology in vitro intermediate between MV's plaques and SFV's foci. On the basis of their ability to grow in and suppress mitogen responsiveness of lymphocytes, these recombinants may be classified into four different groups. Group 1 viruses are the most immunosuppressive, whereas those of group 4 are least. These traits correlate with ability to replicate in lymphocytes. Genetic analysis of recombinants indicates that the most immunosuppressive recombinants do not necessarily contain the most fragment C DNA. Therefore, we have identified a restriction fragment, one or more of the genes of which are sufficient to allow an otherwise nonlymphocytotropic virus to replicate in lymphocytes. Additional genetic and immunologic analysis should permit us to determine the structure and function of the protein responsible for this effect.
Arginine vasopressin (AVP) replacement of helper cell requirement in IFN-gamma production. Evidence for a novel AVP receptor on mouse lymphocytes.
Authors: Torres B A , Johnson H M
Published: December 2022

Arginine vasopressin (AVP), a nine-amino acid neurohypophyseal hormone, is capable of replacing the helper cell requirement for IFN-gamma production by Lyt-2+ mouse splenic lymphocytes. We present data here showing that the AVP helper signal occurs via interaction with a novel R on splenic lymphocytes and involves primarily the N-terminal six-amino acid cyclic ring (pressinoic acid) with the C-terminal three-amino acid end of AVP playing a minor role. Pressinoic acid was capable of providing help at concentrations similar to those of AVP, whereas oxytocin and isoleucine pressinoic acid were 10- and 100-fold less effective, respectively. Isoleucine pressinoic acid has the same structure as pressinoic acid except for the substitution of isoleucine for phenylalanine in position 3 of the sequence. Consistent with the function data, R binding competitions with splenic lymphocyte membrane preparations showed that AVP and pressinoic acid competed similarly with [3H]AVP, whereas oxytocin and isoleucine pressinoic acid were much less effective competitors. Further characterization of the AVP lymphocyte R was performed using AVP analogues having well defined agonist and antagonist activities on either V1 (vasopressor) R or V2 (antidiuretic) R. The AVP helper signal was blocked by the V1 antagonist [d(CH2)1(5) Tyr(methyl)]AVP but not by another V1 antagonist, [d(CH2)1(5)D-Tyr(ethyl)2Val4]AVP. Both V1-R antagonists were able to block [3H]AVP binding to the V1-R on liver cells, whereas only the V1 antagonist that blocked AVP help was able to compete effectively for the spleen AVP-R. Neither a V2 agonist nor a V2 antagonist had any effect on AVP help in IFN-gamma production. These data strongly indicate the presence of a novel AVP-R on spleen lymphocytes, which is related to the classic V1-R on liver cell membranes.
CD4+ T cell lines with selective patterns of autoreactivity as well as CD4- CD8- T helper cell lines augment the production of idiotypes shared by pathogenic anti-DNA autoantibodies in the NZB x SWR model of lupus nephritis.
Authors: Sainis K , Datta S K
Published: December 2022

The (NZB x SWR)F1 hybrid mice (SNF1) uniformly develop lethal glomerulonephritis in marked contrast to their parents and produce nephritogenic autoantibodies that consist of highly cationic, IgG anti-DNA antibodies that share distinct cross-reactive idiotypes called IdLNF1 (idiotypes-lupus nephritis-SNF1). Herein we found that spleen cells of SNF1 mice at the late prenephritic stage, contained CD4+/CD8- and CD4-/CD8- Th that not only induced their B cells in vitro to produce highly cationic IgG autoantibodies to DNA but IdLNF1-positive IgG antibodies as well. The double-negative Th were unexpected in the SNF1 mice because they lack the lpr (lymphoproliferation) gene. We also derived IL-2-dependent CD4+/CD8- as well as CD4-/CD8- T cell lines from nephritic SNF1 mice, that could simultaneously induce IdLNF1-positive and cationic anti-DNA antibodies of IgG class. The CD4+ T cell lines consisted of "autoreactive" T cells, but not all of the lines were equal in autoantibody-inducing capability. Remarkably, the T cell lines that preferentially responded to F1-hybrid-MHC determinants, had a significantly greater ability to augment the production of pathogenic autoantibodies. The SNF1-Th could also augment autoantibody production by the NZB or SWR parent's B cells; however, IdLNF1-positive and cationic anti-DNA autoantibodies of IgG class were not induced, suggesting that the SNF1 mice possess a select population of inducible (susceptible) B cells that are committed to produce nephritogenic autoantibodies and the parental strains are deficient in such B cells. Thus, production of nephritogenic autoantibodies with IdLNF1 markers in the SNF1 mice could result from an interaction between a select population of B cells and CD4+ Th that preferentially recognize unique F1-hybrid-MHC determinants, as well as double-negative auxiliary Th.
Interaction of recombinant IL-1 and recombinant tumor necrosis factor in the induction of mouse acute phase proteins.
Authors: Mortensen R F , Shapiro J , Lin B F , Douches S , Neta R
Published: December 2022

Recombinant mouse and human IL-1 (alpha and beta forms), as well as rTNF-alpha when administered in vivo, induced the production of the mouse acute phase reactants: serum amyloid P-component (SAP), C3, and fibrinogen. The SAP response to all three rIL-1 proteins reached a maximum at a dose of 10(4) U/mouse, which corresponds to 1 to 10 micrograms of protein. The maximum in vivo response consisted of a 10-fold increase in SAP levels, a 2-fold increase in C3 levels, and a 3-fold increase in fibrinogen concentration. By contrast, rTNF-alpha induced a much smaller acute phase (AP) protein response (4-fold increase in SAP) when administered in vivo. Administration of a combination if rIL-1 and rTNF resulted in an AP response that was additive for SAP, synergistic for fibrinogen, but resulted in only the same amount of C3 induced by IL-1 alone. Both recombinant monokines induced new SAP synthesis by isolated hepatocytes in vitro with an optimal response occurring with either 1 U of rIL-1/ml per 2 x 10(5) hepatocytes or 10(-3) U/ml of rTNF. The hepatocyte response to IL-1 was of the same magnitude as the response of intact mice; however, the response to TNF was approximately 10(4) times more efficient in vitro. A mixture of the monokines induced an in vitro SAP response that was additive when suboptimal doses of rIL-1 were combined with optimal amounts of rTNF-alpha. Overall, the findings indicate that both monokines directly trigger hepatocyte synthesis of SAP and that their combined effect probably accounts for a substantial portion of the synthesis of these AP proteins in mice.
Identification of a novel human B cell activation antigen involved in B cell growth factor-dependent proliferation.
Authors: Tseng C T , Springgate C F , Tadmori W , Choi Y S
Published: December 2022

The B6.4 mAb we present here identifies a novel activation Ag of B cell lineage. The B6.4 mAb was generated by immunizing mice with B cell growth factor (BCGF)-responding BA3 cells, and selected by its capability to block BCGF-induced proliferation of BA3 cells. The inhibitory effect of this antibody on BCGF-dependent proliferation was further confirmed by using normal activated B cells in the presence of exogenous BCGF derived from T cells or B cells. Furthermore, it did not affect IL-2-dependent proliferation of B cells. The expression of the B6.4 Ag, as analyzed by FACS, is restricted to in vitro activated B cells, and remains undetectable on resting B or T cells, PHA-activated T cells, and monocytes. The B6.4 Ag is also expressed on some lymphoblastoid B cell lines and most of the lymphomas and CLL of B cell origin; however, it did not express on pre-B cell ALL and plasma cell leukemias. The B6.4 Ag has a Mr of 35,000 Da, as determined by SDS-PAGE of radiolabeled immunoprecipitates from activated B cells. The B6.4 Ag is detectable on B cells as early as 8 h after activation, and precedes that of the IL-2R or transferrin R. All of these results suggest that the B6.4 Ag is an early activation Ag of B cells and is functionally related to a receptor of BCGF, but not IL-2.
The role of the C9b domain in the binding of C9 molecules to EAC1-8 defined by monoclonal antibodies to C9.
Authors: Yoden A , Moriyama T , Inoue K , Inai S
Published: December 2022

Three mAb to human C9, X195, X197, and P40 were used to analyze the roles of the C9a and C9b domains in the reaction of the C9 molecule with sensitized sheep E bearing C1 to C8 (EAC1-8). X195 bound to NH2-terminal (C9a) fragments, and X197 bound to COOH-terminal (C9b) fragments obtained by cleavage of C9 with alpha-thrombin or trypsin. P40 recognized the epitope on the C9b fragment obtained by alpha-thrombin cleavage but did not react with the NH2-terminal or COOH-terminal fragment obtained by trypsin cleavage. In this respect, P40 differed from mAb to C9 reported previously. P40 almost completely inhibited the hemolytic activity of C9. X195 and X197 also inhibited C9 activity, but less effectively than P40. C9 molecules bound to P40 could not bind to EAC1-8 cells. C9 bound to X197 could not bind rapidly to EAC1-8, but prolonged incubation of the C9-X197 complex with EAC1-8 caused considerable lysis of the cells. C9 molecules bound to X195 could bind rapidly to EAC1-8, but their lytic activity was partially inhibited by the bound antibody. From these results, it is concluded that the C9b but not C9a domain contributes to the binding of C9 to EAC1-8 and that the epitope recognized by P40 or a closely adjacent site may be the binding site of C9 molecule to EAC1-8.
Characterization of an antigen expressed on activated human T cells and platelets.
Authors: Brashem-Stein C , Nugent D , Bernstein I D
Published: December 2022

We have identified a protein complex on the surface of activated human T cells and platelets. This Ag, detected by the murine mAb 1B3, is not expressed on resting human T cells or platelets or on other hematopoeitic cells. The majority of T cells express the Ag after stimulation with PHA, Con A, or allogeneic cells. Platelets express the Ag after activation with 1 U/ml thrombin. Immunoprecipitation of 125I-labeled activated T cells with antibody 1B3 shows a heterodimer of 180,000 and 155,000 Mr. An additional protein of 130,000 Mr is very faintly seen depending on the cell type. On platelets, the 180,000 Mr protein is the predominant protein immunoprecipitated under both nonreducing and reducing conditions. Antibody 1B3 may prove useful in identification of activated T cells and platelets as well as definition of specific mechanisms of T cell and platelet activation.
Pleiotropic effects of the Bcg gene. I. Antigen presentation in genetically susceptible and resistant congenic mouse strains.
Authors: Denis M , Forget A , Pelletier M , Skamene E
Published: December 2022

The Ag-presentation ability of Bcgr and Bcgs spleen cells was studied in two sets of Bcg-congenic systems; namely, the BALB/c-BALB/c.Bcgr pair and the B10.A-B10.A-Bcgr pair, by using three sonicated soluble bacterial Ag (mycobacterium bovis bacillus Calmette-Guérin, Salmonella typhimurium, and Brucella abortus) as well as a particulate Ag (heat-killed Escherichia coli). Pulsed Bcgr spleen cells were shown to induce a stronger proliferation of the T cell-indicator system than their Bcgs counterparts. No difference in Ag-presenting ability could be shown between Bcgr and Bcgs peritoneal macrophages from normal animals. However, elicited peritoneal macrophages from immune Bcgr mice were superior in their Ag-presentation ability. Differences at the level of Ag presentation of Bcgr and Bcgs splenic cells were investigated further. Depletion of T cells and B cells did not alter the differences in Ag-presenting ability between Bcgr and Bcgs spleen cells. Furthermore, splenic dendritic cells of Bcgr or Bcgs allelic types were equally efficient in presenting bacillus Calmette-Guérin Ag to accessory cell-depleted T cells. In a final experiment, it was shown that spleen macrophages were the cell type involved in the superior Ag presentation by Bcgr splenic cells.
Immune responses during human schistosomiasis mansoni. XV. Anti-idiotypic T cells can recognize and respond to anti-SEA idiotypes directly.
Authors: Parra J C , Lima M S , Gazzinelli G , Colley D G
Published: December 2022

We previously have shown that former patients and patients with active cases of schistosomiasis mansoni have T lymphocytes in their PBMC that proliferate when exposed to immunoaffinity-purified antibodies against Schistosoma mansoni soluble egg antigens (SEA). These T cell anti-idiotypic responses required the participation of adherent cells, but the role of these cells in the response to the Id has been unclear. We now show that chloroquine does not interfere with Id-elicited stimulation of cells from former patients but completely inhibits their response to the SEA. F(ab')2 fragments of anti-SEA Id are stimulatory, and excess normal human IgG does not alter anti-Id responses. Soluble Id F(ab) fragments are not stimulatory, but rather inhibit stimulation by the intact Id from which they were made. Either intact Id or their F(ab')2 fragments can stimulate non-adherent T cells in the absence of adherent cells if an exogenous source of purified or recombinant human IL-1 is supplied. Nonstimulatory F(ab) fragments can stimulate nonadherent cells if they are bound first to Sepharose 4B and presented in conjunction with IL-1. Thus, T cells from former schistosomiasis patients can react with polyclonal anti-SEA-related Id directly. Under these conditions T cell proliferation requires receptor cross-linking and a source of IL-1 but does not require either "processing" of Id or MHC co-presentation.
Specific inhibition of c-myc protein biosynthesis using an antisense synthetic deoxy-oligonucleotide in human T lymphocytes.
Authors: Harel-Bellan A , Ferris D K , Vinocour M , Holt J T , Farrar W L
Published: December 2022

C-myc protein expression in human T cells was specifically inhibited by a 15-mer deoxy-oligonucleotide complementary to the 5' end of the human c-myc gene second exon. The oligonucleotide penetrates the cells without any treatment, with a plateau of cell association reached in 2 h. The oligonucleotide specifically blocked the de novo synthesis of c-myc protein, induced by PHA in human resting peripheral T cells, without impairing the overall synthesis of other proteins, as shown by two-dimensional analysis of [35S]methionine pulse-labeled proteins. The specific inhibition of c-myc protein synthesis prevented the entry into S phase of resting T cells, induced to proliferate by PHA, or IL-2-dependent T cells induced by IL-2, as shown by [3H]thymidine incorporation. The inhibition of proliferation was specific since it was not observed with the corresponding sense-oligonucleotide and was reversed by preincubation of the cells with an excess of sense oligonucleotide. These results clearly support a role for c-myc protein in the proliferation process and show that inducible protein expression can be blocked by means of synthetic oligonucleotides complementary to a coding exon.
Nucleotide sequence of a DRw10 beta chain cDNA clone. Identity of the third D region with that of the DRw53 allele of the beta 2 locus and as the probable site encoding a polymorphic MHC class II epitope.
Authors: Merryman P , Gregersen P K , Lee S , Silver J , Nuñez-Roldan A , Crapper R , Winchester R
Published: December 2022

The nucleotide and inferred amino acid sequence of a DRw10 beta chain was obtained from cDNA clones isolated from a DR1, DRw10 heterozygous cell line. The sequence of this beta chain gene was distinctive, differing from those of all other defined DR types. The DRw10 beta chain gene was shown by transfection experiments to encode a polymorphic epitope recognized by mAb 109d6 that is also encoded by the DRw53 beta 2 chain gene. Comparison of the nucleotide sequence of both genes revealed that their third D regions (amino acids 67 to 73) were identical. This suggested first that the 109d6 epitope could be encoded by residues of this region, and second, that a putative gene conversion event transferred this sequence along with the information encoding the 109d6 epitope from a donor gene such as DRw53 beta 2. The sequence of the DRw10 beta chain gene was observed to be identical to that of clone pII beta 4 derived from the non-DR3 haplotype in the Raji cell line, which was also demonstrated to express the determinant recognized by antibody 109d6, suggesting that the typing of this cell line is HLA-DR3/DRw10. No evidence was found for the existence of a DR beta 2 chain gene product encoded by the DRw10 haplotype. The DRw10 haplotype was of particular interest because it was present along with a DR1 haplotype in the propositus who had rheumatoid arthritis, and was shared by the DR4-positive son of the propositus, who also had rheumatoid arthritis. This raised the possibility that the DRw10 haplotype, and most probably one or more specific conformations encoded by the DR beta chain, are involved in the definition of the disease susceptibility phenotype.