bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression of human NK cell cytotoxicity by an MLC-Generated cell population.
Authors: D'Amore P J , Golub S H 
Published: December 2022

Abstract
A suppressor cell generated in late MLC was capable of inhibiting the cytotoxic activity of fresh NK cells and MLC-generated NK-like cells. Maximum suppression was obtained by using the cells from a 12-day MLC and resulted in a 47% inhibition in fresh NK activity as measured by 51Cr release. The inhibition was also apparent in the single-cell cytotoxicity assay, where suppression was manifested at the level of target recognition. This was reflected in the number of target-binding conjugates (TBC), with a decreased number of TBC consistently found when day 12 MLC cells were added to fresh NK cells or MLC-generated NK-like cells. A soluble suppressive factor generated in MLC did not appear to be the mechanism underlying the suppression, because the addition of the supernatant from a 12-day MLC had no effect on the target binding or cytotoxic activity of fresh NK cells. An adherent cell population was not involved, as the removal of G-10 adherent cells from the day 12 MLC did not alter suppression of NK cytotoxicity. The phenotype of the regulatory cell in the day 12 MLC was Fcmu+ and HNK-1+ (Leu-7). These suppressor cells do not bear antigens detected by monoclonal antibodies to T cells (Leu-4), suppressor T cells (Leu-2a), HLA-DR, or the Fc gamma receptor on NK cells (B73.1). The manner in which the HNK-1+, Fcmu+ suppressor cells exerted their inhibitory effect was by binding directly to Fc gamma +, HNK-1+ fresh NK cells. In turn, the Fc gamma +, HNK-1+ NK cells were rendered incapable of binding to target cells. These results suggest that NK cells themselves can function as immunoregulators, controlling their own cytotoxic activity.
Stimulation of in vitro immunoglobulin production by interferon-alpha.
Authors: Neubauer R H , Goldstein L , Rabin H , Stebbing N 
Published: December 2022

Abstract
The effect of various natural and recombinant DNA-derived human interferon-alpha (IFN-alpha) on immunoglobulin (Ig) production by human B cells was investigated. The cell populations examined included peripheral blood mononuclear cells (PBMC) and highly purified B cell and helper T cell populations obtained by negative selection by using monoclonal antibodies and a fluorescence-activated cell sorter. In the presence of all forms of IFN-alpha tested, IgG and IgM production by PBMC increased twofold to fourfold. This increase was noted in the absence of pokeweed mitogen (PWM), was not affected by depletion of monocytes, required that IFN-alpha was present early in the culture period, and reached maximal levels around 500 U/ml IFN-alpha. Both IgG and IgM production were affected, but the magnitude of the IgM response was greater. The augmentation of Ig production was noted with the recombinant DNA-derived subtype, IFN-alpha F, two analogs, IFN-alpha Con1 and IFN-alpha Con2, as well as with buffy-coat-derived (leukocyte) IFN-alpha. The recombinant DNA-derived forms of IFN-alpha appeared to differ in their ability to augment Ig production. In the presence of PWM, IFN-alpha Con1 failed to increase Ig production by PBMC. In contrast to these results with PBMC, IFN-alpha Con1 increased the Ig production of purified B cells 10- to 20-fold in the presence of PWM. This increase reached maximal levels around 500 U/ml IFN-alpha Con1. Although purified B cells responded to IFN-alpha and PWM, maximal responses occurred in the presence of low numbers of helper T cells. Cell dilution experiments suggested that the effect observed with purified B cells was the result of the interaction of B cells with residual cells, e.g., helper T cells, remaining in the preparations.
Suppressor T lymphocyte induction by a factor released from cultured blastocysts.
Authors: Mayumi T , Bitoh S , Anan S , Hama T , Fujimoto S , Yamamoto H 
Published: December 2022

Abstract
For the analysis of immunologic escape mechanisms of embryos during the implantation period in mice, the effects of culture supernatant of blastocysts on in vitro responsiveness to alloantigen of mice was investigated. Blastocyst-cultured conditioned medium was prepared by culturing late blastocysts of outbred ICR mice for 5 days. The addition of culture supernatant containing four or eight blastocysts to allogeneic mixed lymphocyte culture inhibited both the MLR responses and the generation of cytotoxic T lymphocytes (CTL). Preincubation of the culture supernatant with lymphocytes syngeneic to the responder cells of MLR induced potent suppressor cell activity in the MLR. The supernatant did not inhibit the activity of CTL at the effector phase, but preinduced suppressor cells obtained by incubation of splenocytes with the supernatant showed almost complete suppression of CTL activity at the effector phase. Both of the suppressor cells, active on MLR and at the generation phase of CTL as well as active at the effector phase, had a surface phenotype of Thy-1+ and Ig-. The suppressive material could be extracted from the eight-cell stage of fertilized ova or blastocysts but not from unfertilized ova, indicating that the production of the factor(s) is dependent on the stages of early embryogenesis. These results suggest that the active induction of suppressor T lymphocytes by the factor(s) released from implanted embryos is one of the protective mechanisms from maternal immunologic attack.
Interaction of monoclonal antibodies with MHC class I antigens on mouse spleen cells. II. Levels of expression of H-2K, H-2D, and H-2L in different mouse strains.
Authors: Dower S K , Segal D M 
Published: December 2022

Abstract
The numbers of MHC class I molecules expressed by spleen cells from various mouse strains were determined by using MHC-specific monoclonal antibodies and a radioactive binding assay. Although small differences were found to exist in some cases, our general conclusion is that different mice of the same strain, congenic mice of different haplotypes, and syngeneic mice of varying background all express similar numbers of class I antigens. B10.A mice (8 to 10 wk old), for example, express 5.3 X 10(4) Kk molecules/cell, 5.4 X 10(4) Dd molecules/cell, and 2.2 X 10(4) Ld molecules/cell. Some of the differences observed in class I antigen expression included: 1) the level of Kk expression increased to a small but significant extent with age in B10.A mice; 2) female B10.A mice expressed slightly higher amounts of Kk than male mice; and 3) B10.A(2R) and B10.A(4R) recombinant strains expressed elevated levels of K-end antigens and slightly decreased levels of D-end antigens when compared with the unrecombinant B10.A strain. In several strains, F1 mice express approximately 50% as many copies of each parental antigen as do the homozygous parents. B10 mice, which are negative for the L antigen, nevertheless express the same total number of D-end molecules as do B10.A mice. The data suggest that the levels of expression of MHC class I molecules are controlled by at least two factors: gene dosage and another factor(s) that gives rise to the small variations in class I antigen expression seen with age, sex, and strain, and to the low expression of Ld relative to Dd and Kk.
Characterization of a polyvalent antibody directed against the IgG Fc receptor of human mononuclear phagocytes.
Authors: Anderson C L , Spence J M , Edwards T S , Nusbacher J 
Published: December 2022

Abstract
We have raised an antibody to the IgG Fc receptor (FcR) of human mononuclear phagocytes by immunizing a goat with FcR purified by ligand affinity from a human monocyte line (U937). This antiserum, which inhibited the binding of IgG ligand to the receptors on U937, precipitated from detergent lysates of surface-radioiodinated U937 cells a 72 Kd sialoglycoprotein (p72) identified as the FcR by several previously published criteria. Two other bands seen in autoradiograms of SDS gels were precipitated by this antiserum: a 40 to 43 Kd band that co-purified with p72 and a 170 Kd protein that was not present in the immunogen. Fractionation of the IgG of this antiserum into two subclasses yielded one subclass (IgG1) in which anti-p72 activity was considerably enriched relative to antibody activities against other molecules. This antiserum precipitated p72 not only from U937 but from HL60 cells and from human peripheral blood monocytes as well, indicating common antigens on the p72 molecules from these three cells. However, p72 was not recovered from lysates of surface-iodinated human polymorphonuclear leukocytes or murine macrophage lines. Anti-p72 activity was not completely removed by adsorption with intact U937, suggesting that the antiserum recognizes portions of p72 that are not exteriorly disposed, perhaps noncarbohydrate portions of the molecule. We expect this antiserum to be useful for a number of studies of receptor structure and function.
A linkage between the hemostatic and immune systems embodied in the fibrinolytic release of lymphocyte suppressive peptides.
Authors: Edgington T S , Curtiss L K , Plow E F 
Published: December 2022

Abstract
Some cellular immune responses initiate the coagulation protease cascade and promote the formation of fibrin. Local fibrin deposition is requisite for the induration associated with delayed hypersensitivity reactions. The deposited fibrin also is catabolized. In the present study we demonstrate that plasmic cleavage of fibrinogen results in the generation of immunosuppressive activity in vitro that is not expressed by the intact molecule. This property is associated with small dialyzable peptides recovered from advanced plasmic digests of fibrinogen. The peptides inhibit phytohemagglutinin-, pokeweed mitogen-, and allogeneic cell-stimulated blastogenesis as well as proliferation in a dose-dependent fashion. The suppression of lymphocyte responses does not result from loss of cells or their viability. Suppression requires the presence of the peptides at the time of, or immediately after, the exposure of cells to the appropriate stimulus, and is manifest as both a delay and an absolute inhibition of [3H]thymidine uptake. Human peptides inhibit the response of murine spleen cells to mitogens, and B and T lymphocyte classes appear to be equally sensitive to suppression. Thymidine uptake by two continuous lymphoblastoid cell lines also is inhibited by the peptides, indicating a direct effect of the fibrinogen-derived peptides on lymphocytes. In contrast, the peptides stimulate thymidine uptake by a diploid fibroblast line, suggesting selectivity in the biologic effects of the peptides. These observations indicate that in addition to its primary role in hemostasis, the participation of fibrinogen and its derivative fibrin in inflammatory lesions includes the release of lymphocyte-suppressive peptides. This may play a role in regulation of the evolution of immunologic lesions in vivo.
Binding and activation of hemolytic complement by IgG antibodies: cooperativity between antibodies of different hapten specificity.
Authors: Borsos T , Circolo A 
Published: December 2022

Abstract
The ability of IgG antibodies with different hapten specificities to fix C1 and activate C as a function of hapten density on a red cell surface was investigated. Rabbit anti-methotrexate and anti-folinic acid IgG antibodies in a mixture were highly efficient in fixing C1 and activating C when cells carried simultaneously high levels of both haptens. We wished to find out whether in a C-activating IgG complex both IgG molecules had to be in a form that could activate C1. By reducing hapten density of one of the haptens on a double labeled cell, complexes were generated where only one in a pair of IgG molecules was in the activating form; such a pair had the same activating efficiency as a pair in which both IgG molecules were in the activating form. It was concluded that cooperative activation of C in C1-binding IgG complexes required only one IgG in the complex to be in the activating form.
A large subpopulation of lymphocytes with T helper phenotype (Leu-3/T4+) exhibits the property of binding to NK cell targets and granular lymphocyte morphology.
Authors: Velardi A , Grossi C E , Cooper M D 
Published: December 2022

Abstract
A discrete subpopulation of lymphocytes sharing several phenotypic characteristics with natural killer (NK) cells was identified within the circulating pool of human lymphocytes that bear the T helper marker Leu-3. This Leu-3+ subpopulation of cells formed cell conjugates with the NK target cell lines K562 and MOLT-4, but did not bind to mouse myeloma and hybridoma cell lines that are insensitive to NK cells. The Leu-3+ lymphocytes binding to NK cell targets contained cytoplasmic granules similar in ultrastructure and cytochemistry to those previously defined in granular lymphocytes with NK function, except that the granules in Leu-3+ cells were smaller and fewer in number. Unlike classical NK cells, however, the granular Leu-3+ cells did not kill the target cells to which they bound, even after treatment with interferon. The proportion of granular Leu-3+ cells with the capacity to bind to NK cell targets was approximately 7% at birth and increased to approximately 21% of the Leu-3+ cells in adults. These observations suggest the possibility of a lineal relationship between the granular Leu-3+ cells and granular Leu-3- cells with NK capability.
Recognition of influenza virus hemagglutinin by subtype-specific and cross-reactive proliferative T cells: contribution of HA1 and HA2 polypeptide chains.
Authors: Katz J M , Laver W G , White D O , Anders E M 
Published: December 2022

Abstract
The recognition of influenza virus hemagglutinin (HA) by T lymphocytes was examined by assaying the T cell proliferative response of influenza virus-primed T cells to purified HA of different influenza A subtypes or to isolated heavy (HA1) or light (HA2) polypeptide chains of the HA molecule. The proliferative response to HA was dependent on the activation of an Ly-1+2- subset of T cells and required the presence of nylon wool-adherent, radiation-resistant accessory cells. T cells from mice primed by infection with one strain of type A influenza virus cross-reacted with other purified HA not only of the same subtype as the priming virus but also of serologically distinct subtypes of influenza A (but not B) virus. The response of virus-primed T cells to the homologous HA or to HA of the same subtype was shown to involve recognition of determinants on both the HA1 and the HA2 chains. The recognition of HA of different subtype by cross-reactive T cells appeared to be directed predominantly to determinants on HA2. Because the antibody response to influenza virus HA is not cross-reactive between subtypes and is directed predominantly to determinants on HA1, the present results indicate that at least some of the determinants on HA recognized by T cells are different from those recognized by B cells and that the HA2 chain may be involved primarily in stimulation of T cell rather than B cell immunity.
Stimulated rat T cell-derived inhibitory factor for cellular DNA synthesis (STIF). I. Isolation and characterization.
Authors: Chiba K , Nishimura T , Hashimoto Y 
Published: December 2022

Abstract
A lymphokine inhibitory for cellular DNA synthesis (termed STIF) was isolated from the culture supernatants of concanavalin A (Con A)-stimulated SD rat spleen cells. STIF inhibited the DNA synthesis of mouse bone marrow cells as well as mouse leukemia cells. STIF has an apparent m.w. of 45,000 to 50,000 and is separable from IL 2, m.w. 20,000 to 25,000, by Sephacryl S-200 gel filtration, but not from immune interferon (IFN) having the same m.w. as STIF. Con A-Sepharose chromatography of the fraction containing STIF and IFN could separate these lymphokines into Con A-unbound and Con A-bound fractions, respectively. Further fractionation of the STIF fraction by DEAE-Sephadex A-50 or Mono Q-FPLC anion exchange chromatography indicated that the STIF fraction contained two components of STIF activity, both showing the same pI value (5.1 to 5.6) on flat-bed isoelectric focusing. STIF was characterized as a sugar-free lymphokine of trypsin-sensitive protein nature.
Natural killer (NK) cell activating factor released from murine thymocytes stimulated with an anti-tumor streptococcal preparation, OK-432.
Authors: Shitara K , Ichimura O , Mitsuno T , Osawa T 
Published: December 2022

Abstract
Natural killer (NK) activity of mouse splenocytes was significantly augmented when the splenocytes were incubated for 3 to 4 hr with culture supernatants of mouse thymocytes stimulated by OK-432, an antitumor preparation from the Streptococcus pyogenes SU-strain. Antiviral activity was also detected in the culture supernatants, but IL 2 activity was not. When the culture supernatants of thymocytes stimulated by OK-432 were fractionated on a column of Blue Sepharose CL-6B, NK enhancing activity and antiviral activity were observed in partly overlapping fractions that bound to the column. However, the antiviral activity in the Blue Sepharose-bound fraction was neutralized completely by treatment with anti-IFN (alpha, beta) antiserum, whereas significant NK cell enhancing activity was still observed after treatment with anti-IFN (alpha, beta) antiserum. When the Blue Sepharose-bound fraction was subjected to gel filtration, the NK cell enhancing activity was detected in the 25,000 to 35,000 and 40,000 to 67,000 m.w. regions, but antiviral activity was observed in the over 67,000 m.w. region. These results indicate that a new kind of lymphokine, called natural killer cell activating factor (NKAF), distinct from IFN and IL 2, was found. The NKAF was found to have the following properties: its pI value is between pH 5.5 and 6.5, it binds to concanavalin A- and lentil agglutinin-Sepharose, and it is stable with pH 2-24 hr treatment. In addition, NKAF-producing cells were peanut agglutinin (PNA)-thymocytes when thymocytes were fractionated by the agglutination-sedimentation method with the use of PNA.
Serologic and topographic characterization of idiotopes on murine monoclonal anti-streptococcal group A carbohydrate antibodies.
Authors: Greenspan N S , Davie J M 
Published: December 2022

Abstract
We have employed five spectrotypically distinct monoclonal anti-variable region antibodies in the definition and characterization of a set of idiotopes expressed on murine monoclonal antibodies specific for streptococcal group A carbohydrate (GAC). By evaluating which of a panel of monoclonal anti-GAC antibodies were bound by the various anti-idiotopes, we observed four distinct reactivity profiles for the five anti-idiotopes ranging from highly restricted (binding of the homologous anti-GAC monoclonal antibody only) to broadly cross-reactive (binding of 18 of the 38 IgG3 anti-GAC antibodies). With N-acetyl-D-glucosamine and soluble GAC used as haptens, this spectrum of reactivity profiles was paralleled by a gradient of susceptibility to hapten inhibition of anti-idiotope binding to idiotope. The degree of cross-reactivity exhibited by a given anti-idiotope was found to be inversely related to its susceptibility to hapten inhibition. The topographic relationships among the idiotopes, defined by the results of competitive binding assays, were suggestive of a linear idiotope map spanning the variable region from the antigen-binding site to the vicinity of the constant region. Additional data from competitive inhibition assays with isolated and recombined H and L chains from a prototype monoclonal anti-GAC antibody (HGAC 39), and from isoelectric focusing of whole or reduced and alkylated HGAC 39, suggested that one of the idiotopes was located, at least primarily, on the VL domain.
Species specificity of recognition by the alternative pathway of complement.
Authors: Horstmann R D , Pangburn M K , Müller-Eberhard H J 
Published: December 2022

Abstract
The recognition function of the alternative complement pathway was studied with isolated human and rabbit components. Zymosan and homologous and heterologous erythrocytes were used as representative activators or nonactivators. The binding affinity of Factor B and Factor H for particle-bound C3b was measured. In both species, the average affinity of Factor H for bound C3b on homologous cells (nonactivators) was eight to 10 times higher than on zymosan particles (activators). The interaction between Factor H and C3b on rabbit erythrocytes was species-specific: rabbit Factor H bound strongly to rabbit C3b on rabbit erythrocytes and also on human erythrocytes, which are nonactivators for the rabbit alternative pathway. Human Factor H bound strongly to human C3b on human erythrocytes but seven times weaker on rabbit erythrocytes, which are activators of the human alternative pathway. No substantial differences were found in the binding of Factor B to bound C3b regardless of the nature of the particle to which C3b was bound. The results indicate that in the two species studied, the molecular mechanism of recognition is analogous and that recognition is species-specific.
Depletion of NK cells with the lysosomotropic agent L-leucine methyl ester and the in vitro generation of NK activity from NK precursor cells.
Authors: Shau H , Golub S H 
Published: December 2022

Abstract
Human natural killer (NK) cell activity in peripheral blood lymphocytes (PBL) is totally inhibited by pretreatment of the effector cells with a lysosomotropic agent, L-leucine methyl ester (LeuOMe). This treatment specifically eliminates cells expressing the NK cell markers HNK-1, OKM1, B73.1, or Leu-11b, but has minimal effect on viability of cells with T cell markers Leu-1, OKT3, Leu-2a, or Leu-3a. LeuOMe also drastically decreased the proportion of K562 target-binding lymphocytes among PBL. PBL pretreated with LeuOMe respond normally in thymidine uptake to stimulation by phytohemagglutinin or allogeneic lymphocytes as long as irradiated autologous accessory cells are provided, indicating that the treatment is not toxic to T cells. NK activity can be regenerated in the NK cell-depleted PBL population by incubation with IL 2 or by mixed lymphocyte cultures, but not by alpha-interferon. Cells responsible for regeneration of such NK activity are probably large agranular lymphocytes, because they are resistant to LeuOMe treatment but have the same low buoyant density as NK cells in Percoll density gradient separation. The in vitro-generated NK is still sensitive to LeuOMe inhibition, but a higher concentration of the reagent is required to achieve total inhibition of the activity.
Organization and polymorphism of rabbit immunoglobulin heavy chain genes.
Authors: Knight K L , Burnett R C , McNicholas J M 
Published: December 2022

Abstract
Germline genes encoding C mu, C gamma, C alpha, and C epsilon heavy chains of rabbit immunoglobulins have been isolated from recombinant phage and cosmid libraries. The JH, C mu, C gamma, and C epsilon are found in a 5'-JH-C mu-C gamma-C epsilon-3' orientation on a 90kb stretch of DNA. Four C alpha genes have been cloned and presumably reside 3' to the other CH genes. Southern blot analysis of rabbit sperm DNA indicates that the rabbit genome contains a single C gamma gene, one C mu gene, and as many as 10 C alpha genes. Restriction site polymorphism is found for C mu, C gamma, and C alpha genes of rabbits of various heavy chain haplotypes. The organization of the rabbit CH genes differs from that of mouse and human CH genes in that the rabbit has multiple C alpha genes, whereas mouse and human have one or two C alpha genes, respectively. In addition, mouse and human have four C gamma genes, whereas rabbit has only one C gamma gene. The presence of a single C gamma gene indicates that at least in the rabbits examined, no germline gene encoding latent or unexpected, C gamma allotypes is present. The genetic control of the expression of latent C gamma allotypes is discussed.