bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of Paf-acether (platelet-activating factor). VII. Precursors of Paf-acether and acetyl-transferase activity in human leukocytes.
Authors: Jouvin-Marche E , Ninio E , Beaurain G , Tence M , Niaudet P , Benveniste J 
Published: December 2022

Abstract
Human polymorphonuclear neutrophils, monocytes, and lymphocytes were studied for their ability to synthesize Paf-acether when stimulated with the ionophore A 23187 (Io) or with specific secretagogues. When stimulated with Io, neutrophils produced 100 +/- 8.5 pmol Paf-acether 1 X 10(6) cells (mean +/- 1 SD, n = 5); monocytes were less efficient (44 +/- 3.3 pmol Paf-acether/1 X 10(6) cells), whereas lymphocytes were practically unable to form this mediator (1.0 +/- 0.4 pmol Paf-acether/1 X 10(6) cells). Neutrophils and monocytes released in the extracellular medium 49 and 37% of Paf-acether that they formed, respectively. We attempted to correlate the amount of Paf-acether produced by the various cell types with that of its precursors, 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine and 1-O-alkyl-sn-glycero-3-phosphocholine (2-lyso Paf-acether). In the three cell types, the amount of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine was sufficient to ensure the formation of 2-lyso Paf-acether and consequently that of Paf-acether. The quantity of 2-lyso Paf-acether formed appeared to be the limiting factor only in the case of the neutrophils. These cells increased their synthesis of Paf-acether in the presence of exogenous 2-lyso Paf-acether. To investigate the failure of lymphocytes to produce the mediator, the acetylating step of Paf-acether formation was studied, and we found a very weak activity (0.5 +/- 0.1 nmol Paf-acether/10 min/mg protein) in this cell type as opposed to monocytes (4.0 +/- 2.3 nmol Paf-acether/10 min/mg protein) and neutrophils (17.8 +/- 5.3 nmol Paf-acether/10 min/mg protein). These activities were doubled in Io-stimulated cells. Thus, the modulation of acetyl-transferase activity appears to be a key step in the regulation of Paf-acether biosynthesis. Also, the availability of 2-lyso Paf-acether could regulate Paf-acether synthesis in human neutrophils.
Evidence implicating I region-restricted antigen presentation in alloantigen and nominal antigen recognition by a dual-reactive helper T lymphocyte clone.
Authors: Ma D I , Wilde D B , Gajewski T , Dunn D E , Fitch F W 
Published: December 2022

Abstract
A helper T lymphocyte clone, designated A10, was generated from spleen cells of a B10.A mouse and demonstrated reactivity to both the nominal protein antigen hen egg ovalbumin (OVA) presented by I-Ak-bearing antigen-presenting cells (APC) and irradiated I-As-bearing spleen cells in the absence of OVA. A stimulatory signal was delivered to the cloned cells by syngeneic spleen cells that were exposed to OVA and then fixed with paraformaldehyde. However, paraformaldehyde-fixed allogeneic spleen cells that bear the I-As determinant recognized by a monoclonal antibody (mAb) were unable, by themselves, to stimulate the A10 cells. The inability of fixed allogeneic spleen cells to stimulate was rectified by the addition of irradiated I-Ak-positive spleen cells, suggesting that at least in this situation, alloantigen must be presented to the alloreactive A10 cells. Further evidence supporting this proposal for class II-restricted presentation of alloantigen included the observations that 1) irradiated I-Ak-negative spleen cells were unable to present the fixed H-2s spleen cells, 2) the anti-I-As mAb blocked the stimulatory signals delivered by irradiated H-2s spleen cells and by fixed H-2s spleen cells plus irradiated syngeneic spleen cells, 3) some anti-I-Ak mAb preparations were able to inhibit stimulation by OVA and by fixed H-2s spleen cells plus irradiated syngeneic spleen cells, and 4) an anti-L3T4a mAb effectively blocked all three stimulatory signals. These data suggested that alloreactivity can be mediated by an antigen-presentation process similar to that proposed for nominal peptide antigen presentation, and that alloantigen in the form of paraformaldehyde-fixed allogeneic spleen cells is recognized in the context of self-determinants before a stimulatory signal can be delivered.
Differentiation of thymocytes in fetal organ culture: analysis of phenotypic changes accompanying the appearance of cytolytic and interleukin 2-producing cells.
Authors: Kisielow P , Leiserson W , Von Boehmer H 
Published: December 2022

Abstract
At the 14th day of gestation, embryonic thymocytes+ are large, functionally incompetent cells with H-2K+ Thy-1+ B14- Ly-2- L3T4- phenotype, some of which express TL antigen. Differentiation of these cells in organ culture is characterized by: 1) appearance of cells expressing Ly-2 and L3T4 molecules, first among the population of large cells, after 2 days of culture; 2) appearance of small H-2K- Thy-1+TL+B14+Ly-2+L3T4+ and H-2K-Thy-1+TL+B14-Ly-2+ L3T4+ cells between days 2 and 4; 3) accumulation of small H-2K- Thy-1+ TL+ B14- Ly-2+ L3T4+ (but not H-2K- Thy-1+ TL+ B14+ Ly-2+ L3T4+) cells until day 5 of culture, and their subsequent gradual disappearance which is paralleled by an increase of the proportion of medium-sized H-2K+ Thy-1+ TL- B14- cells with various Ly-2 L3T4 phenotypes; 4) appearance and subsequent accumulation of cytolytic and IL 2-producing cells between days 4 and 6. Comparison of these results with the data from similar in vivo studies shows that differentiation of organ-cultured thymocytes rather closely follows the in vivo development only during the first week of culture and shows significant deviations thereafter. Precursors of cytolytic cells and cytolytic effector cells as well as IL 2-producing cells are found among both Ly-2+ and Ly-2- populations of thymocytes, indicating that there is no clear association between Ly-2 phenotype and the ability to kill or to secrete IL 2.
Activation of acceptor-suppressor hybridoma with antigen-specific suppressor T cell factor of two-chain type: requirement of the antigen- and the I-J-restricting specificity.
Authors: Sumida T , Takei I , Taniguchi M 
Published: December 2022

Abstract
The molecular mechanisms of activation of immunoregulatory T cells were characterized by using two complementary suppressor T cell hybridoma systems: the KLH-specific monoclonal suppressor factor (KLH-TsF), and the inducible acceptor-suppressor hybridoma line with anti-idiotypic receptor for KLH-TsF. It was demonstrated that the identity of the KLH specificity and genetic specificity was required for the TsF-acceptor interaction. These specificities were found to be mediated by the two polypeptide chains of TsF: KLH-binding, Ct-bearing heavy chain and I-J+ light chain. These two chains were essential for stimulation of the acceptor hybridoma. The results were also confirmed by the findings that the mixture of the 11S and 13S mRNA translation products reconstituted the active TsF to stimulate the acceptor hybridoma. Furthermore, the genetic restriction observed was found to be mediated by the I-J+ light chain and to be governed by the gene linked to the H-2 complex but not to the Igh genes. The gene controlling the restriction specificity was strongly suggested to be in the intra-H-2 complex, but not outside of the H-2 complex.
Characterization of anti-idiotypic suppressor T cells (Tsid) induced after antigen priming.
Authors: Sherr D H , Dorf M E 
Published: December 2022

Abstract
The induction and fine specificity of idiotype-specific suppressor T cells (Tsid) were studied. Spleen cells from C57BL/6 mice, immunized 4 wk previously with NP-KLH, failed to express NPb3 idiotype-bearing PFC when challenged in vitro with NP-Ficoll or NP-Brucella abortus. After treatment of NP-primed responder cultures with anti-Thy-1.2 anti-serum + C, NPb idiotype-bearing B cells could be detected. This B cell subset was preferentially suppressed by the addition of T cells from NP-primed mice. With this reconstitution protocol, it was determined that suppression of the NPb idiotype-bearing portion of the B cell response was mediated by a specifically induced T cell population (Tsid) that directly suppressed NPb-bearing B cells. As with a previously described suppressor population induced with hapten-modified syngeneic spleen cells (Ts2), the Tsid population bound and was lysed by NPb idiotype-bearing serum antibodies. However, the Tsid could be distinguished from the Ts2 population because it lacked I-J determinants and functioned as an effector T cell, not an intermediary suppressor cell. Furthermore, fine specificity studies with monoclonal NP-specific antibodies expressing various levels of serologically detectable NPb idiotypic determinants indicated that unlike the Ts2, the Tsid population reacts with conventional, serologically detected members of the NPb family. The combined idiotype binding studies for the Tsid and Ts2 populations demonstrate that the fine specificity of suppressor T cell populations reflects their independent mechanisms of regulation.
The allogeneic effect: the mechanism of allosuppression by Lyt-1, Ia- T cells.
Authors: Eastman A Y , Lawrence D A 
Published: December 2022

Abstract
The kinetics of allohelp mediated by diffusable factors revealed that help by nonirradiated T cells (TOR) peaked at 48 to 72 hr, followed by a sharp decline if the T cells remained in the cultures. The temporal decrease in help after 72 hr was not mediated by suppressor lymphokines because mixtures of early (24 to 48 hr) and late (120-hr) allogeneic supernatants enhanced help synergistically. Lyt-1, Ia- T cells mediated the temporal decline in help and suppressed allogeneic B cell activation in co-cultures, and this "down-regulatory" activity (allosuppression) was radiosensitive. Help by irradiated T cells (T1000R) increased gradually until it plateaued between 96 and 120 hr. The helper activities of the allogeneic supernatants were directly proportional to their T cell growth factor (TCGF) activities. In addition, their kinetics were identical, and the removal of TCGF from 48-hr allogeneic supernatants by adsorption with TCGF-dependent HT-2 cells depleted both helper and TCGF activities. Help was restored to depleted 48-hr and 120-hr allogeneic supernatants by preparations of TCGF obtained from concanavalin A (Con A)-stimulated FS6-14.13 hybridoma cells that were adsorbed with lipopolysaccharide (LPS)-activated B cells or normal spleen cells (NS), but not with HT-2 cells. These results indicate that allohelp is dependent on TCGF. Moreover, help was dependent on at least one factor in addition to TCGF, because a high level of synergy occurred between TCGF and the "help-deficient" 120-hr allogeneic supernatant. In conclusion, the mechanism whereby Lyt-1, Ia- T cells regulated B cell activation with positive and negative allogeneic effects was through the production and subsequent exhaustion of TCGF, respectively. The production of TCGF and help was radioresistant, but exhaustion of TCGF and suppression was radiosensitive.
Involvement of the transferrin receptor in the production and NK-induced suppression of human antibody synthesis.
Authors: Brieva J A , Stevens R H 
Published: December 2022

Abstract
Earlier studies have shown that the antibody-secreting lymphoblastoid (LB) B cells which arise in the circulation after immunization can be down-regulated by NK cells and an unusual T suppressor cell. Because the LB B cells require division in vitro before maximal antibody secretion, and as such may express the transferrin receptor, we wished to determine if this receptor is recognized by the NK and/or T suppressor cells. The addition of the antitransferrin receptor antibody B3/25 to cultures of LB cells resulted in a partial inhibition of antibody secretion. This inhibition was not seen with the addition of monoclonal anti-Dr or OKT-8 antisera, and indicated that the LB cells expressed the transferrin receptor and that its activity was required for antibody secretion. The addition of free Fe ions to the culture medium, however, allowed the secretion of antibody by the LB cells even in the presence of B3/25 antibody. Under these conditions, the inhibition of antibody secretion mediated by interferon-activated NK cells was no longer observed. The inhibition induced by pokeweed mitogen-stimulated T suppressor cells was not affected by the antibody treatment, suggesting that these two inhibitory cells recognize different target structures. These results indicate that LB B cells expressed the transferrin receptor at a stage of the in vitro culture, and that this structure is involved in the NK- but not the T cell-mediated inhibition of antibody synthesis.
Alterations in Fc receptor function of macrophages from streptozotocin-induced diabetic rats.
Authors: Abrass C K , Hori M 
Published: December 2022

Abstract
The presence of elevated levels of circulating immune complexes in diabetic humans and animals suggests impaired phagocyte function. To evaluate FcR-mediated phagocytosis, resident peritoneal macrophages were harvested from control, streptozotocin-induced diabetic, and insulin-treated diabetic rats. FcR number and avidity were determined from Scatchard analysis of binding of 125I-labeled aggregated rat IgG (ARG) to macrophages. The total and fractional catabolic capacity were determined by quantitating the digestion of ARG as a percent of the total ARG added and as a percent of ARG bound. Insulin-deficient diabetic rats had an increase in the number of FcR per cell (26.8 +/- 3.5 X 10(4)) as compared with control animals (13.1 +/- 1.2 X 10(4)) (p less than 0.01). In contrast, insulin-treated diabetic animals had a reduction in the number of FcR per cell (9.8 +/- 1.4 X 10(4)) (p less than 0.01). FcR of macrophages from insulin-deficient diabetic rats had a lower avidity (Kd = 6.9 +/- 1.8 X 10(-10)M) when compared with control (3.7 +/- 0.6 X 10(-10)M) and insulin-treated diabetic rats (3.6 +/- 0.9 X 10(-10)M) (p less than 0.01). Total catabolism of ARG by macrophages from both insulin-deficient and insulin-treated diabetic rats was reduced (31.0% +/- 3.4 and 17.5% +/- 3, respectively) when compared with controls (49.6% +/- 5.2) (p less than 0.01). Fractional catabolism by macrophages from insulin-deficient diabetic rats was significantly reduced (21% +/- 1.9 and 4.6% +/- 0.9/10(4) FcR) when compared with results from control rats (26% +/- 1.3 and 6.7% +/- 0.7/10(4) FcR) (p less than 0.01), whereas the results from insulin-treated diabetic rats (32% +/- 2.4 and 10.8% +/- 1.0/10(4) FcR) (p less than 0.01) were greater than those from controls. These studies demonstrate that FcR-mediated phagocytosis of soluble, "model" immune complexes is impaired in macrophages from both insulin-deficient and insulin-treated diabetic rats; however, different mechanisms account for this impairment in phagocytosis. Despite an increase in FcR number of macrophages from insulin-deficient diabetic rats, the depression of post-receptor-mediated catabolism results in a net depression in phagocytic activity. In contrast, macrophages from insulin-treated diabetic rats display augmented post-receptor-mediated catabolism; however, this does not overcome the low initial binding of ARG to the cell that results from the depression of FcR number.
Genetic studies in NZB mice. VI. Association of autoimmune traits in recombinant inbred lines.
Authors: Miller M L , Raveche E S , Laskin C A , Klinman D M , Steinberg A D 
Published: December 2022

Abstract
Because recombinant inbred lines, which are homozygous at most loci, can have any combination of parental genes, the numbers and the association of genes responsible for traits can be suggested by examining phenotypic distribution in these lines. Such studies, reported herein, uncovered two major families of nonlinked genetic loci whose interactions underlie autoimmune abnormalities in NZB mice. One family of genes leads to antibodies to murine leukemia virus, ssDNA, and erythrocytes, as well as to defective tolerance to bovine gamma-globulin. The other group of genes leads to polyclonal B cell activation, stem cell abnormalities, endogenous murine leukemia virus expression, and NTA. These studies help explain previously observed dissociations between the traits associated with these two groups of genes. Such genetic analyses provide the basis for future molecular biologic studies of the genes and gene products that underlie autoimmune disease.
Growth of a cloned helper T cell line induced by a monoclonal antibody specific for the antigen receptor: interleukin 1 is required for the expression of receptors for interleukin 2.
Authors: Kaye J , Gillis S , Mizel S B , Shevach E M , Malek T R , Dinarello C A , Lachman L B , Janeway C A 
Published: December 2022

Abstract
By using as an experimental system the induction of growth of a cloned, antigen:Ia-reactive helper T cell line by an antigen receptor-specific monoclonal antibody, we demonstrated that growth requires two essential co-factors, exogenously produced IL 1 and endogenously produced IL 2. The primary role of the IL 1 is in the expression of receptors on the T cell surface for IL 2, rather than for promoting the synthesis of IL 2. The use of a clone-specific activating monoclonal antibody at nanogram amounts to activate a cloned helper T cell should allow a detailed characterization of T cell activation via antigen receptor cross-linking.
Characterization of an antigen-specific suppressive factor derived from a cloned suppressor effector T cell line.
Authors: Kitamura K , Nakauchi H , Koyasu S , Yahara I , Okumura K , Tada T 
Published: December 2022

Abstract
A cloned effector-type suppressor T cell line, 3D10, which is known to suppress the antibody response against dinitrophenylated keyhole limpet hemocyanin (KLH), produced a soluble KLH-specific factor (TsF) that can replace the function of parental T cell clones. High activity of TsF was released spontaneously into the culture supernatant when cultured in interleukin 2 (IL 2)-containing medium, requiring no antigenic stimulation. The culture supernatant of 3D10 was also capable of inhibiting the KLH-induced proliferative response of primed T cells in an antigen-specific manner. The direct target of TsF was found to be Lyt-1+2- T cells undergoing an early stage of antigen-specific proliferation. TsF was antigen binding but lacked any other serologic markers such as I-J and immunoglobulin heavy chain-linked allotypic determinants on T cells. No genetic restriction was found in its action on allogeneic T cells. The production of IL 2 in proliferative T cells by antigenic stimulation was not inhibited by TsF. These results indicate that the TsF described here is the legitimate mediator produced by the effector-type suppressor T cell that suppresses the antigen-specific responses of Lyt-1+2- T cells. The m.w. of TsF was approximately 75,000.
Oxidized N-formylmethionyl-leucyl-phenylalanine: effect on the activation of human monocyte and neutrophil chemotaxis and superoxide production.
Authors: Harvath L , Aksamit R R 
Published: December 2022

Abstract
F-met-leu-phe, a potent neutrophil and monocyte chemoattractant, can be oxidized to F-met-leu-phe sulfoxide by metabolically activated neutrophils. We investigated the interaction of human neutrophils and monocytes with chemically prepared oxidized derivatives of F-met-leu-phe: F-met-leu-phe sulfoxide and F-met-leu-phe sulfone. We compared the derivatives with nonoxidized parent F-met-leu-phe for specific binding to neutrophils and monocytes, and for effectiveness as chemoattractants and stimuli of superoxide production. We observed that neutrophils did not migrate to either derivative over the concentration range of 10(-9) to 10(-3) M. In marked contrast, monocytes migrated to both oxidized peptides, with optimal chemotaxis occurring at derivative concentrations 10- to 100-fold higher than the optimal parent F-met-leu-phe concentration. F-met-leu-phe sulfoxide and sulfone stimulated neutrophil and monocyte superoxide production and specifically bound to both neutrophils and monocytes at optimal concentrations that were 10- to 100-fold greater than the optimal parent F-met-leu-phe concentration. These results suggest that the higher concentrations of oxidized derivatives required for monocyte migration and for neutrophil and monocyte superoxide production are due to a reduced affinity of the oxidized derivatives for the F-met-leu-phe receptor. The finding that oxidized F-met-leu-phe binds to the neutrophil receptor without eliciting a chemotactic response suggests that the F-met-leu-phe receptor complex or chemotaxis transduction mechanism is different in human neutrophils and monocytes.
Characterization of murine lymphocyte IgE receptors by flow microfluorometry.
Authors: Katona I M , Urban J F , Titus J A , Stephany D A , Segal D M , Finkelman F D 
Published: December 2022

Abstract
A flow microfluorometric technique has been developed to analyze IgE receptors on splenic and mesenteric lymph node mononuclear cells from BALB/c mice. Our data show that 1) the binding of DIBADL cross-linked IgE dimers to IgE receptors is specific in that it is inhibited by monomeric rat and mouse IgE but not by mouse or rabbit IgG or by the monoclonal anti-Fc gamma R antibody 2.4G2, and conversely, the binding of DIBADL cross-linked IgG dimers is inhibited by monomeric IgG or 2.4G2 but not by rat or mouse IgE; 2) the binding of IgE dimers is saturable on cells from uninfected and Nippostrongylus brasiliensis (Nb)-infected mice; 3) IgE dimer binding is detectable on most splenic B lymphocytes from uninfected and Nb-infected mice, but not on T lymphocytes from uninfected mice, and on few, if any, T lymphocytes from Nb-infected mice; 4) Nb infection causes a parallel increase in the percentages of B lymphocytes and cells expressing IgE receptors and Fc gamma R; 5) Nb infection leads to a marked increase in B lymphocyte IgE receptor expression, has little if any effect on IgE receptor affinity, and causes only minor changes in Fc gamma R expression; and 6) in vivo activation of B lymphocytes by a goat antibody to mouse IgD decreases IgE receptor expression considerably, but has a minimal effect on Fc gamma R expression. Thus, there are separate receptors for IgE and IgG on murine B lymphocytes, and the effect of Nb infection or anti-IgD treatment on their expression is different.
Heterologous antibody responses in mice with chronic T. cruzi infection: depressed T helper function restored with supernatants containing interleukin 2.
Authors: Reed S G , Inverso J A , Roters S B 
Published: December 2022

Abstract
Antibody production to sheep erythrocytes (SRBC) or hapten-conjugated SRBC (TNP-SRBC) was studied in mice with chronic Trypanosoma cruzi infections. Studies in vivo demonstrated that both IgM and IgG anti-SRBC responses were suppressed during chronic infection. Secondary IgG responses were suppressed regardless of whether the primary immunization was given before or after infection. The ability of cells from infected mice to provide help for antibody production was examined in vitro. Anti-SRBC responses were restored to cultures of whole spleen cells from infected mice by the addition of interleukin 2 (IL 2)-rich supernatants, indicating that these cells were capable of antibody production when sufficient help was provided. T cells from SRBC-primed infected mice were unable to provide significant help to normal B cell/M phi cultures for in vitro anti-TNP or anti-SRBC responses. The percentages of Thy-1+, Lyt-1+, and Lyt-2+ spleen cells were not significantly different between normal and infected mice. Anti-TNP and anti-SRBC responses were restored to cultures that contained T cells from infected mice and normal B cell/M phi by the addition of IL 2-rich spleen cell supernatants. The suppression of in vitro antibody responses in mice with chronic T. cruzi infections was associated with a lack of T cell help, which was provided by exogenous spleen cell supernatant.