bluuebunny/crossref_metadata_2025_split huggingface dataset:
E alpha u and E beta u chain association: where lies the anomaly?
Authors: Ayane M , Mengle-Gaw L , McDevitt H O , Benoist C , Mathis D 
Published: December 2022

Abstract
H-2u haplotype mice are unique among all E alpha+ strains because they do not provide in heterozygotes an E alpha chain that interacts with E betak,s,etc. sufficiently well to allow certain E-restricted immune responses. As a first step in understanding this peculiarity, we have sequenced E alpha u and E beta u cDNA and compared the derived amino acid sequences with those of previously analyzed alleles. Although no glaring structural abnormalities were found, we have identified some u-specific residues and suggest which are the most likely to provoke a pairing anomaly.
Nonspecific T suppressor factor (nsTsF) cascade in contact sensitivity: nsTsF-1 causes an Ly-1+2- I-A+ immune T cell to produce a second, genetically restricted, nsTsF-2.
Authors: Zembala M , Romano G C , Colizzi V , Little J A , Asherson G L 
Published: December 2022

Abstract
We studied the mode of action of the nonspecific T suppressor factor (nsTsF-1) made in the picryl (TNP) system when T acceptor cells armed with antigen-specific TsF are triggered by antigen in the context of I-J. This suppressor factor does not inhibit the passive transfer of contact sensitivity directly, as shown by its failure to inhibit passive transfer by immune cells deprived of I-A+ cells. Its immediate target is an immune, antigen-specific, Ly-1+2-, I-A+ T cell. This cell, which may be regarded as a T suppressor effector cell (Ts-eff-2), produces nsTsF-2 when exposed sequentially to nsTsF-1 and antigen. This nsTsF subsequently inhibits the passive transfer of contact sensitivity. The action of nsTsF-2 is MHC genetically restricted. As the nsTsF-2 bears I-A determinant(s), this raises the possibility that it may act by combining with the recognition site for I-A on the T cell that mediates contact sensitivity.
Effect of human syncytiotrophoblast plasma membrane-soluble extracts on in vitro mitogen-induced lymphocyte proliferation. A possible inhibition mechanism involving the transferrin receptor.
Authors: Khalfoun B , Degenne D , Crouzat-Reynes G , Bardos P 
Published: December 2022

Abstract
Transferrin (Tf) binding to lymphocytes and to syncytiotrophoblast plasma membranes (STPM) and their soluble extracts (STPM-SE) was examined, as well as the effect of the latter on mitogen-induced lymphoproliferation. Lymphocytes only express Tf receptors (Rtf) after mitogen (phytohemagglutinin or concanavalin A) stimulation, and the percentage of Tf bound by stimulated lymphocytes increased as a function of contact time with the mitogen, reaching a maximum at 72 hr. Studies of Tf binding to STPM-SE showed that the percentage of bound Tf increased proportionally to the protein concentration, but was additionally enhanced by a factor of three when STPM were pretreated with 3 M KCl. Scatchard analysis of Tf binding to lymphocytes cultured for 72 hr in the presence of mitogen, as well as to STPM and STPM-SE, revealed that this binding was specific and occurs via a single category of identical and independent receptors the numbers and affinity constants (Ka) of which have been determined. The results obtained by using STPM indicate that the Ka does not vary significantly from one preparation to another, but that the number of sites per milligram of protein increases by a factor of 10 when the STPM are pretreated with 3 M KCl (KCl-STPM). Finally, STPM-SE inhibited the mitogen-induced lymphoproliferative response whether or not they were treated with 3 M KCl. This inhibition was not due to lymphocytotoxicity, was dose dependent regardless of the preparation used, but was maximized with the KCl-STPM-SE fraction. The correlation between the inhibitory capacities of the soluble STPM extracts and the numbers of RTf sites present on their membranes leads to the hypothesis that the observed inhibition could involve the RTf. This effect may help in protecting the fetus from the maternal immune system at the time of the semi-allogenic fetal graft.
Monoclonal antibody (H107) inhibiting IgE binding to Fc epsilon R(+) human lymphocytes.
Authors: Noro N , Yoshioka A , Adachi M , Yasuda K , Masuda T , Yodoi J 
Published: December 2022

Abstract
A hybridoma-producing monoclonal antibody blocking the binding of human IgE to lymphocytes Fc receptor (Fc epsilon R) was established by the fusion of murine myeloma cells. P3X63.653.Ag8, with BALB/c spleen cells immunized with Fc epsilon R(+) human B lymphoblastoid cell line cells, RPMI1788. A clone of the hybridoma (H107) produced a monoclonal IgG2b antibody that inhibited the rosette formation of Fc epsilon R(+) human B lymphoblastoid cell line cells (RPMI1788, RPMI8866, CESS, Dakiki, and IM9) with fixed ox red blood cells (ORBC) conjugated with human IgE (IgE-ORBC). In contrast, the rosette formation with IgG-conjugated ORBC (IgG-ORBC) on Fc gamma R(+), Fc epsilon R(-) Daudi cells were not affected by the H107 antibodies. A close association of Fc epsilon R and the antigenic determinant recognized by H107 antibody was suggested by the following results. First, the bindings of 125I-labeled IgE (125I-IgE) or 125I-labeled H107 IgG2b antibody (125I-H107) to RPMI8866 cells were inhibited by cold human IgE and H107 IgG2b but not by other classes of human Ig (IgA and IgG), MPC11 IgG2b, or unrelated monoclonal antibodies. Second, H107 antibody reacted with Fc epsilon R(+) B cell lines but not with Fc epsilon R(-) B cell lines as determined by an indirect immunofluorescence. Third, Fc epsilon R(+) cells were depleted by the incubation in the dish coated with H107 antibody or IgE but not in the dish coated with unrelated antibodies. Finally, there was a correlation between the increase of Fc epsilon R(+) cells and that of H107(+) cells in the peripheral blood lymphocytes of the patients with atopic dermatitis. The surface antigens on Fc epsilon R(+) RPMI8866 cells recognized by H107 antibodies had the molecular size of 45,000 as determined by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.
Noncytolytic terminal complement complexes may serve as calcium gates to elicit leukotriene B4 generation in human polymorphonuclear leukocytes.
Authors: Seeger W , Suttorp N , Hellwig A , Bhakdi S 
Published: December 2022

Abstract
Complement effects on human polymorphonuclear leukocytes (PMN) have generally been ascribed to the anaphylatoxin C5a, which induces degranulation, superoxide anion generation, migration, and cell aggregation via interaction with membrane receptors. We here report that complement activation on the surface of antibody-sensitized human PMN provokes generation of the potent lipid mediator leukotriene B4 (LTB4) in strict dependence on complement component C8, but in the absence of detectable C9. The kinetics of LT generation are rapid, comparable with those observed after challenge with the calcium-ionophore A23187. LTB4 release is a distinct event that is dissociable from cytotoxicity as assessed by lactate dehydrogenase (LDH) release (dependent on C9) and from superoxide generation (independent of C8 and C9). It is dose dependent on extracellular calcium and is not observed in the absence of calcium. It is inhibited by substances interfering with calcium-calmodulin function (trifluoperazine and W7), but not by blockers of physiologic calcium channels (nimodipine, verapamil, and D 888). Addition of purified C8 to cells bearing C5b-7 induces a severalfold increase in their passive permeability to 45calcium. Sieving experiments with the use of marker molecules of different sizes collectively indicate the existence of small hydrophilic channels consisting exclusively or predominantly of C5b-8 complexes, which allow passive transmembrane flux of small molecules with Mr less than 200. Thus, noncytolytic terminal complement complexes may serve as a biological bypass gate for calcium in PMN membranes, triggering the arachidonic acid cascade with generation of LTB4 at doses well below the threshold required to invoke overt cell damage.
Concanavalin A induces Ca2+ mobilization, but only minimal inositol phospholipid breakdown in mouse B cells.
Authors: Bijsterbosch M K , Klaus G G 
Published: December 2022

Abstract
Concanavalin A (Con A) induces DNA synthesis in bulk cultures of murine T cells. In contrast, the lectin has been shown to stimulate purified B cells to leave G0, but not to proliferate. We demonstrate here that Con A induces comparable increases in intracellular Ca2+ levels in the two cell types. In B cells this appears to be due to Ca2+ influx. As expected, the lectin also provokes significant degradation of inositol phospholipids in T cells. However, it causes only minimal release of inositol phosphates in B cells. We therefore postulate that Con A may stimulate B cells by causing influx of Ca2+. In line with this, activation of B cells by the lectin is inhibited by cyclosporine, which preferentially affects stimulation of lymphocytes by Ca2+ mobilizing agents.
Amiloride inhibition of DNA synthesis and immunoglobulin production by activated human peripheral blood mononuclear cells is independent of sodium/hydrogen antiport.
Authors: Yamaguchi D T , Sakai R , Bahn L , Cragoe E J , Jordan S C 
Published: December 2022

Abstract
Activation of sodium/proton (Na+/H+) antiport activity has been shown to occur as an early event in mitogenesis. Because amiloride inhibits Na+/H+ antiport activity, it is hypothesized that mitogenesis may be inhibited by amiloride. In this work, we examined the effect of amiloride on DNA synthesis as measured by [3H]thymidine uptake and immunoglobulin (Ig) production as measured by an ELISA system in human peripheral blood mononuclear cells (PBM). Amiloride at 100 microM concentration inhibited irradiated Raji cell (*R)-activated and phytohemagglutinin-P (PHA-P)-stimulated DNA synthesis by 50 +/- 11% and 72 +/- 12%, respectively. IgG production was inhibited by 71% at 100 microM amiloride concentration in *R-activated PBM. This concentration of amiloride inhibited Na+/H+ antiport activity by 92%. Because amiloride is known to inhibit other pre-replicative cellular functions such as protein synthesis, we used an amiloride analogue, dimethylamiloride, which inhibited Na+/H+ antiport activity by 90% at a concentration of 1 microM without inhibition of PBM Ig or DNA synthesis. Furthermore, neither PHA-P nor *R-stimulated PBM demonstrated an intracellular alkalinization even after 6 hr of stimulation. Similarly, T cell-enriched or B cell-enriched populations did not show intracellular alkalinization after PHA-P or *R activation. Thus, it appears that Na+/H+ antiport activation is not an early event in PBM mitogenesis. The inhibition of mitogenesis by amiloride may be due to abrogation of premitotic events such as protein synthesis.
The mechanism of action of lymphokines. IX. The enzymatic basis of hydrogen peroxide production by lymphokine-activated macrophages.
Authors: Freund M , Pick E 
Published: December 2022

Abstract
The purpose of this study was to elucidate the biochemical basis of the enhanced hydrogen peroxide (H2O2) production by guinea pig peritoneal macrophages (MP) cultured in lymphokine (LK)-containing medium. The markedly augmented H2O2 generation by these cells, demonstrable by the horseradish peroxidase (HRP)-catalyzed oxidation of phenol red, is distinguished by its lack of dependence on a second stimulus. We demonstrate that H2O2 production is truly spontaneous and is not caused by a stimulant present among the H2O2 assay reagents. The principal candidate for such a role was HRP type II (a mixture of five isoenzymes) that was reported to be capable of eliciting an oxidative burst in MP. Four distinct HRP isoenzymes that were found incapable of provoking an oxidative response were nevertheless adequate for demonstrating H2O2 production by LK-activated MP. Blocking the MP receptor for mannose by the addition of mannan to the assay system resulted in enhanced detection of H2O2 by low concentrations of HRP type II and by three out of four HRP isoenzymes. Treatment of MP with LK-containing medium for 72 hr did not result in a significant change in the activity of cellular superoxide dismutase (SOD) compared with MP cultured for the same length of time in control medium. By using the specific inhibitor of copper, zinc-containing SOD, sodium diethyldithiocarbamate (DDC), and the universal SOD inhibitor, sodium nitroprusside, we found that the predominant enzyme in guinea pig peritoneal MP is probably manganese-containing SOD. Incubation of LK-activated MP with nitroprusside resulted in almost total inhibition of H2O2 production and a simultaneous switch to superoxide (O2-) liberation. Similar exposure to DDC had no effect. These data indicate that H2O2 produced by LK-activated MP is derived exclusively by enzymatic dismutation of O2- mediated by a manganese-containing SOD. The increase in spontaneous H2O2 production induced by LK is therefore secondary to augmented O2- production that occurs at a cellular location where O2- is accessible to SOD. The enzymatic basis of the enhanced oxygen radical production was investigated by determining the kinetic parameters of the O2- -forming NADPH oxidase of resting LK-treated MP in a cellfree system in which O-2 production was induced by sodium dodecyl sulfate. The Km for NADPH and the Vmax of the enzyme of LK-treated MP were not different from those of the enzyme of MP incubated in control medium. We conclude that LK treatment of MP does not modulate the NADPH oxidase itself but, most likely, a process related to activation of the enzyme.
Bone marrow-derived macrophage expression of endogenous and transfected class II MHC genes during differentiation in vitro.
Authors: Pullen J K , Schook L B 
Published: December 2022

Abstract
C57BL/6 (H-2b) mice fail to express I-E molecules on the surface of their cells and thus are unable to respond to I-E-restricted antigens such as GL phi and cytochrome c. Previous experiments in our laboratory have involved developing a system for studying differentiation of bone marrow cells into mature macrophage to gain a better understanding of class II MHC gene expression and function. In this study, we have used this system to transfect the E alpha d gene (cosmid 17.2) into C57BL/6 bone marrow cells and subsequently observed I-E expression on bone marrow-derived macrophages (BMDM) after differentiation in vitro. By using a modified calcium phosphate protocol, we found that the optimal period for transfection of the bone marrow cells was after 2 days of culture in vitro. By using the anti-I-E monoclonal antibody (Ia.7) derived from hybridoma 14-4-4, we detected the I-E molecule on the surface of transfected macrophages by a radiobinding assay and immunoprecipitation. BMDM expressed the I-E product maximally at 5 days of differentiation, and expression then declined. Furthermore, we have found that the expression of the I-E molecule on transfected macrophage was dependent upon exposure to interferon-gamma. Expression of I-E molecules was also detected by the generation of an allogeneic response. Transfected BMDM were compared with (CB6)F1 BMDM for their ability to stimulate C57BL/6 T cells and they were found to be equally effective. By using these initial findings, we hope to further optimize the conditions for insertion and expression of class II MHC genes in bone marrow cells.
Conversion of specific to nonspecific cytotoxic T lymphocytes.
Authors: Havele C , Bleackley R C , Paetkau V 
Published: December 2022

Abstract
The type of cytotoxic T lymphocyte (CTL) generated during a mixed leukocyte culture has been shown to depend on the purity of interleukin 2 (IL 2) used to stimulate growth. Antigen-specific CTL requiring both antigen and IL 2 to proliferate or express cytotoxicity (designated Type I in this work) are generated and maintained with highly purified IL 2. In the presence of IL 2 alone, they persist in a quiescent, noncytotoxic state, and on its removal they rapidly die. A second type of CTL (Type II), of nonspecific cytotoxicity, and dependent only on IL 2 for growth, is generated by exposure to an impure lymphokine preparation containing IL 2. Type I cells are T lymphocytes which are nongranular and nonadherent, whereas Type II cells are larger, adhere to plastic, and contain many granules. Cloned Type I cells are converted to Type II under three conditions: by low levels of IL 2 in the presence of a crude lymphokine preparation; by high levels of IL 2 in the presence of antigen; or by high levels of IL 2 in the presence of the phorbol diester PMA. Conversion results from an effect of the growth conditions on individual cells, and not from selection of a minor population.
Identification and characterization of a suppressor T cell hybridoma specifically inducible by L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT).
Authors: Sorensen C M , Pierce C W 
Published: December 2022

Abstract
In vitro activation of naive spleen cells from C57BL/10 mice with GAT and the monoclonal GAT-TsF1, 372B3.5, followed by fusion with BW5147 resulted in generation of a hybridoma that fails to produce GAT-TsF constitutively, but upon reexposure to GAT and 372B3.5 is induced to secrete GAT-TsF2. The induction is GAT specific and requires de novo RNA, protein synthesis, and DNA synthesis. Although both GAT and 372B3.5 are required for induction, they may be added sequentially, provided the GAT is added first. The GAT-TsF produced by the induced cell is antigen specific and composed of two polypeptide chains: one capable of binding antigen, the other bearing determinants encoded by the I-J region of the MHC. The utility of this inducible GAT-TsF2 cell line for molecular biology and other studies is discussed.
Suppressive effect of human natural killer cells on Epstein-Barr virus-induced immunoglobulin synthesis.
Authors: Kuwano K , Arai S , Munakata T , Tomita Y , Yoshitake Y , Kumagai K 
Published: December 2022

Abstract
The suppressive effect of human natural killer (NK) cells on Epstein-Barr virus (EBV)-induced immunoglobulin (Ig) synthesis by autologous B cells was investigated. By Percoll discontinuous density gradient centrifugation, low-density fractions enriched for NK cells were isolated from human peripheral blood lymphocytes. These NK-enriched fractions were added to purified autologous B cells in the presence of EBV, were cultivated for 8 days, and were examined for their suppressive effect on Ig synthesis by an enzyme-linked immunosorbent assay. The fractions markedly suppressed both IgM and IgG synthesis induced by EBV. It was possible to reduce the suppressive effect of NK-enriched cells by complement-dependent lysis of NK cells and Leu-11, but not by OKT3 monoclonal antibody, indicating that NK cells may be responsible for the suppression of Ig synthesis. Upon close examination of interferon (IFN) activity, it was revealed that the co-cultures of NK-enriched cells and EBV-infected B cells generated production of IFN-alpha, which might be produced by NK cells in response to EBV-stimulated B cells. Addition of anti-IFN-alpha but not anti-IFN-gamma serum almost completely abrogated the suppressive effect of NK-enriched cells on Ig synthesis, indicating that IFN-alpha produced are required for the NK cell-mediated suppression of Ig synthesis. However, addition of IFN-alpha into purified B cells showed no direct suppressive effect on EBV-induced Ig synthesis by B cells in the absence of NK cells. Nevertheless, NK cells when previously incubated with IFN-alpha and added to B cells showed a suppressor activity on Ig synthesis to a level higher than that of untreated NK controls. These results strongly suggest the possibility that NK cells display an interaction with EBV-infected B cells and produce IFN-alpha, which in turn activates NK cells. These activated NK cells suppress the Ig synthesis by B cells, which undergo transformation induced by EBV.
Structure-function relationships for the IL 2-receptor system. II. Localization of an IL 2 binding site on high and low affinity receptors.
Authors: Kuo L M , Rusk C M , Robb R J 
Published: December 2022

Abstract
The ligand-binding component of high and low affinity IL 2 receptors is a 55,000 m.w. glycoprotein termed Tac. Correlating the structure and function of this molecule should provide insight into the mechanism of IL 2-initiated signal transduction and the structural basis for high and low affinity receptor forms. As a first step in this process, various approaches were used to localize the IL 2 binding region of the Tac molecule. Antibodies prepared to synthetic fragments of Tac were tested for their ability to interfere with IL 2 binding and bioactivity. The results delineated segments in the C-terminal portion of the molecule which appeared to be distal to the ligand binding site. In a more direct approach, radioiodinated IL 2 was cross-linked to high and low affinity receptors, and the resulting complexes were subjected to mild tryptic digestion. Consistent with the antibody data, the IL 2 remained covalently associated with an N-terminal tryptic fragment which apparently consisted of residues 1-83 of the Tac protein. These results suggest that the N-terminal region of the Tac molecule contains important contact sites for ligand-receptor interaction.
Characterization of the human trophoblast-leukocyte antigenic molecules defined by a monoclonal antibody.
Authors: Stern P L , Beresford N , Thompson S , Johnson P M , Webb P D , Hole N 
Published: December 2022

Abstract
The murine monoclonal antibody H316 recognizes cell surface glycoproteins shared in expression by human trophoblast and peripheral blood leukocytes. It is also strongly expressed by many human tumor cell types, including choriocarcinoma and teratocarcinoma. The H316 antigenic determinant from these different cell types is carried on two wheat germ agglutinin-reactive glycoproteins of approximately 65,000 and 55,000 m.w. The antigenicity is not dependent on N-linked glycosylation. Biochemical fractionation procedures suggest that the molecules are related to each other, are not associated through intermolecular disulfide bonds, but do exhibit intramolecular disulfide interactions. These glycoproteins demonstrate m.w. heterogeneity between different cell lines and individual trophoblast membrane preparations. Such properties suggest that H316 molecules may be representative of TLX antigens (trophoblast-leukocyte common antigens), which have been suggested to influence maternofetal immunogenetic interactions.