bluuebunny/crossref_metadata_2025_split huggingface dataset:
Site of binding of IgG2b and IgG2a by mouse macrophage Fc receptors by using cyanogen bromide fragments.
Authors: Diamond B , Boccumini L , Birshtein B K 
Published: December 2022

Abstract
Cyanogen bromide fragments of murine IgG2b and IgG2a immunoglobulins were used to localize the sequences that are bound by specific IgG2b and IgG2a Fc receptors on murine macrophages. One fragment from the CH2 domain of IgG2b bound to the gamma 2b Fc receptor. Two fragments from IgG2a--one one from the CH2 domain, differing by only four amino acids from the homologous IgG2b fragment, and the other from the CH3 domain--specifically bound to the gamma 2a Fc receptor. In both a rosetting assay and a radioactive binding assay, these two fragments from IgG2a competed with intact IgG2a: however, they did not compete with each other. Rather, binding of the fragment from the CH3 domain of IgG2a augmented the binding of the fragment from the CH2 domain of IgG2a but not that of the homologous fragment from IgG2b. The binding of both IgG2a fragments was abolished by trypsin treatment of macrophages. These data suggest that 1) a sequence in the CH2 domain of IgG2b is sufficient for binding to the gamma 2b Fc receptor, 2) sequences from both the CH2 and CH3 domains of IgG2a bind to the gamma 2a Fc receptor, and 3) the binding of sequences from the CH3 domain of IgG2a may induce a conformational change in the gamma 2a Fc receptor that leads to enhanced binding of sequences from the CH2 domain.
Activation of the 5-lipoxygenase pathway in E-mast cells by peanut agglutinin.
Authors: Razin E 
Published: December 2022

Abstract
Mouse E-mast cells were differentiated and grown by culturing bone marrow cells in medium containing WEHI-3-conditioned medium. These cells possess surface receptors to the following agglutinins: peanut (PNA), concanavalin A (Con A), and soybean (Sb). One to 200 micrograms of PNA/10(6) E-mast cells selectively stimulated the generation of leukotriene C4 (LTC4) in the absence of beta-hexosaminidase release. Exposure of 10(6) E-mast cells to 1 to 200 micrograms Con A or Sb had no effect either on preformed mediator release or on the generation of leukotrienes. LTC4 was quantitated by integrated UV absorbance after resolution by reverse phase high pressure liquid chromatography. The optimum release of LTC4 (13.2 ng/10(6) cells) was achieved by 50 micrograms of PNA/10(6) cells. The response is characterized by the inhibition by excess amounts of PNA. The amount of LTC4 generated during optimal PNA stimulation is lower than the amount produced after stimulation by IgE-antigen or by calcium ionophore A23187 (19.8 ng and 148 ng, respectively). The release of LTC4 began within 5 min after PNA stimulation, and reached a plateau within 45 to 60 min at 37 degrees C. This kinetic pattern is similar to that observed after calcium ionophore A23187 stimulation of these cells. The results suggest that PNA is capable of selectively activating the 5-lipoxygenation of arachidonic acid without affecting beta-hexosaminidase secretion. Apparently, separate biochemical events may serve to mobilize each class of mediators.
The association of various D elements with a single-immunoglobulin VH gene segment: influence on the expression of a major cross-reactive idiotype.
Authors: Gridley T , Margolies M N , Gefter M L 
Published: December 2022

Abstract
A large fraction of the anti-p-azophenylarsonate antibodies of strain A/J mice share a major cross-reactive idiotype (IdCR). Structural analysis of monoclonal antibodies expressing this idiotype (IdCR+) indicates that a particular combination of variable region gene segments (Vk, Jk, VH, D, and JH) encodes the variable regions of the light and heavy chains of these IdCR+ antibodies. With the use of serologic methods, hybridoma cell lines have been isolated that produce monoclonal antibodies lacking IdCR determinants (IdCR-), but that are derived from most of the same combination of variable region gene segments that encode IdCR+ monoclonal antibodies. Structural analysis of these IdCR- monoclonal antibodies demonstrates that they are very homologous to each other and to IdCR+ monoclonal antibodies with respect to VH and VL sequences, but are markedly different from IdCR+ monoclonal antibodies in their utilization of D region segments. Comparisons of antigen avidity of these IdCR+ and IdCR- antibodies indicates that conservation of D region structure is not crucial for effective antigen binding. These results indicate the importance of the D region in idiotypy in the IdCR system and demonstrate the variation permitted in D region structure while maintaining antigen recognition.
Analysis of the rat major histocompatibility system by Southern blot hybridization.
Authors: Günther E , Wurst W , Wonigeit K , Epplen J T 
Published: December 2022

Abstract
The organization of the rat major histocompatibility complex, RT1, was studied at the DNA level by Southern blot hybridization. Genomic DNA from eight different RT1 congenic rat strains was digested by various restriction enzymes and was hybridized under stringent conditions with probes of mouse class I and class II H-2 genes. Few cross-hybridizing DNA fragments, showing no polymorphism, were seen with class II A alpha and A beta probes. The class I probes allowed for the distinction of about 8 to 19 cross-hybridizing bands, which exhibited extensive polymorphism. With the use of five RT1 recombinants, about 20% of the DNA fragments could be mapped to the RT1.A region, which codes for the ubiquitously expressed class I antigens, and about 80% to the RT1.C region-determining class I-like antigens, which are different from RT1.A antigens with respect to tissue distribution, restriction function in immune responses, and allograft rejection. The number of class I genes present in the rat genome and the possible relationship of RT1.C to H-2Qa, Tla of the mouse are discussed.
Phenotypic variation in clonal Abelson virus lymphoma cells.
Authors: Green P L , Lamph W W , Dudley J , Arfsten A , Risser R , Lanier L L , Warner N L , Tung J S , Scheid M P 
Published: December 2022

Abstract
Two clonal A-MuLV lymphoma cell lines have the capacity to generate phenotypic variants when grown in vivo as ascites tumors. Variant lines differed from parental lymphoma cells in their expression of enzymatic or cell surface differentiation markers. Parental lines expressed the B220 and Lyb-2 glycoproteins characteristic of pre-B cells and bound B220-specific monoclonal antibodies such as 14.8. The parental cells expressed low levels of TdT activity but did not synthesize detectable mu-heavy chain, a cellular phenotype that may correspond to lymphoid progenitor cells. Three classes of phenotypic variants were recovered from the Thy-1- parental lines: 1) 14.8+, Lyt-1+, Thy-1- cells; 2) 14.8 +/-, Lyt-1+, Thy-1+ cells, and 3) 14.8-, Lyt-1+, Thy-1+ cells. Cell cloning experiments indicated that Thy-1+ variant cells can be recovered within 14 days of in vivo inoculation as a minor proportion (1/10(6] of the tumor cell population and subsequently become the predominant tumor cell population. These clonal tumor lines provide a model for the study of cellular and molecular alterations that occur during neoplastic differentiation and progression in the lymphoid system.
Prethymic T cell precursors express receptors for antigen.
Authors: Chervenak R , Moorhead J W , Cohen J J 
Published: December 2022

Abstract
An anti-idiotype serum raised in BALB/c mice against syngeneic lymph node T cells from 2,4-dinitrofluorobenzene (DNFB)-sensitized mice was used to study the early expression of antigen receptors on developing T cells. Normal BALB/c bone marrow cells were treated with either anti-Thy-1.2 plus complement or anti-Thy-1.2 and anti-idiotype plus complement before use in the reconstitution of lethally irradiated syngeneic mice. Five weeks after reconstitution, recipient mice were assayed for both contact sensitivity (CS) and in vitro proliferative responses to DNFB. Mice reconstituted with bone marrow cells treated with both anti-Thy and anti-idiotype sera showed a significant decrease in reactivity to DNFB in both assay systems when compared with mice reconstituted with marrow treated with anti-Thy only. CS response to the noncross-reacting hapten oxazolone was identical in both recipient groups. Bone marrow mixing experiments showed no evidence of anti-idiotype-induced suppressor cells in these experiments. These data provide strong evidence that at least some T cell precursors express receptors for antigen prethymically.
Strain difference in the radiosensitivity of immunocompetent cells and its influence on the residual host-vs-graft reaction in lethally irradiated mice grafted with semiallogeneic bone marrow.
Authors: Sado T , Kamisaku H , Kubo E 
Published: December 2022

Abstract
A striking difference in radiosensitivity was noted between C3H/He (H-2k) and C57BL/6J (H-2b) strain mice when assessed by primary anti-SRBC PFC response of intact animals and primary cell-mediated lympholysis (CML) response of spleen cells to allogeneic cells in vitro, the C3H strain being more radioresistant. On the other hand, when C3H and B6 mice were exposed to 6.62 to 10.40 grays (Gy) of x-rays and then were transplanted with 2 X 10(6) bone marrow cells from B6C3F1 (H-2b/k) donor mice within 3 hr or at 24 hr after radiation exposure, the early mortality caused by residual host-vs-graft (HVG) reaction was much higher when C3H mice were used as recipients. Furthermore, the proportion of surviving animals manifesting host-type lymphohemopoiesis, i.e., host-type revertants, was much higher in B6C3F1 to C3H than in B6C3F1 to B6 combination. Spleen cells from such host-type revertants manifested strong anti-donor reactivity when assessed by mixed lymphocyte reaction (MLR) and/or CML in vitro. Increase of radiation doses to the recipients to 10.40 Gy resulted in 100% survival and 100% donor-type lymphohemopoiesis in both groups of chimeras. These results indicate strongly that a genetic difference in radiosensitivity of immune system of the recipients can greatly influence the magnitude of residual HVG reactions observed in hybrid to parental strain bone marrow transplantation in mice.
High frequency of natural autoantibodies in normal newborn mice.
Authors: Dighiero G , Lymberi P , Holmberg D , Lundquist I , Coutinho A , Avrameas S 
Published: December 2022

Abstract
Spleen cells from 6-day-old nonimmunized BALB/c and BALB.B10 mice were fused with the nonsecreting hybridoma cell line Sp2/0. Three hundred and eighty-four immunoglobulin-secreting hybrids were screened for antibody activity against mouse actin, tubulin, and myosin, and against TNP, peroxidase, renin, DNA, and neurofilaments. At least 24 hybridomas in the collection (6.25%) exhibited antibody activity against this panel of antigens. Ten of these hybrids were cloned, were propagated, and the corresponding monoclonal IgM protein was isolated from ascitic fluids and was further characterized. At least four groups of antibody specificities were identified: 1) one clone reacting with TNP only; 2) one clone reacting with both actin and tubulin; 3) two clones which bound to both TNP and actin; and 4) a fourth group, comprising the six other clones, which all exhibited widespread reactivity and bound to actin, tubulin, myosin, and TNP. These results indicate: 1) B cell clones directed against self antigens are activated in the internal environment and are recovered consequently by somatic cell hybridization; 2) the widespread antibody specificities found for these newborn mouse antibodies are very similar to those previously characterized with human natural antibodies and human monoclonal Ig; and 3) the frequency of B cells binding to cytoskeletal proteins and TNP is very high (at least 6.25%).
Modulation of autoimmunity in NZB mice by cyclophosphamide-induced, nonspecific suppressor cells.
Authors: Greeley E H , Segre M , Segre D 
Published: December 2022

Abstract
A group of NZB mice received six biweekly injections of cyclophosphamide-induced nonspecific suppressor cells, with treatment commencing at 2 mo of age. Mice were evaluated for Coombs and natural thymocytotoxic antibody at 6-wk intervals thereafter, and for anti-DNA autoantibodies, total IgM and IgG levels, and renal histology at selected time points. The administration of suppressor cells resulted in marked and prolonged suppression of both Coombs and natural thymocytotoxic antibody reactivity in the majority of animals while not measurably affecting the levels of anti-DNA autoantibodies, the total IgM and IgG levels, or the life span of the mice.
The four biochemically distinct species of human interleukin 1 all exhibit similar biologic activities.
Authors: Wood D D , Bayne E K , Goldring M B , Gowen M , Hamerman D , Humes J L , Ihrie E J , Lipsky P E , Staruch M J 
Published: December 2022

Abstract
The supernatants of human monocytes incubated with endotoxin are able to stimulate the proliferation of murine thymocytes in the presence of PHA. This is known as LAF (lymphocyte activating factor) activity and is a characteristic activity of interleukin 1 (IL 1). The LAF activity can be resolved into four major fractions: a 15,000 dalton (pI 7), a 15,000 (pI 5.5), a 35,000 (pI 7), and a 35,000 (pI 5.5) fraction. To determine whether these four fractions shared the other biologic activities ascribed to IL 1, they were compared in a series of bioassays. When standardized with respect to their LAF activities, the four fractions did not differ significantly as mitogens for murine thymocytes, inducers of IL 2, murine or human B cell activators, human chondrocyte or synoviocyte stimulants, or inducers of acute phase proteins in vivo. On the other hand, the samples differed markedly as stimulators of porcine synoviocytes, with the 15,000 dalton (pI 5.5) fraction being the only strongly active fraction. These results are consistent with the hypothesis that all four LAF could be products of a single gene, although the porcine receptor may be able to distinguish between them. If this is the case, all four fractions can properly be termed IL 1.
Activation of virus specific CTL clones: antigen-dependent regulation of interleukin 2 receptor expression.
Authors: Andrew M E , Churilla A M , Malek T R , Braciale V L , Braciale T J 
Published: December 2022

Abstract
Interleukin 2 (IL 2) is a lymphocyte-specific growth hormone, whose effect on lymphocyte proliferation is exerted through a cell surface receptor expressed on activated lymphocytes. In this report we have used monoclonal antibodies directed to the murine IL 2 receptor to examine the regulation of the IL 2 receptor expression on cloned populations of influenza virus-specific CTL. The CTL clones, which are dependent on both specific antigenic stimulation and exogenous IL 2 for continuous in vitro propagation, express high levels of the IL 2 receptor shortly after antigenic stimulation (day 2 or 3). Over the next 5 to 8 days of in vitro cultivation in IL 2-containing medium, these cloned CTL cells express decreasing levels of IL 2 receptor. Concomitant with this fall in IL 2 receptor expression, the cells become refractory to the IL 2 proliferative stimulus. The cloned cells remain refractory to IL 2 until specifically stimulated by antigen, which induces high levels of the IL 2 receptor on the cells and renders the cells sensitive to IL 2 once again. These results support the concept that IL 2 receptor expression on activated T lymphocytes is transitory and that receptor expression is endogenously regulated in the activated T lymphocytes. These results also suggest that antigen plays a primary role in regulating T lymphocyte proliferation by maintaining IL 2 receptor levels.
Interleukin 2-mediated events in gamma-interferon production are calcium dependent at more than one site.
Authors: Johnson H M , Vassallo T , Torres B A 
Published: December 2022

Abstract
Both leukotrienes and dibutyryl cyclic GMP can replace the interleukin 2 (IL 2) requirement for gamma-interferon (gamma-IFN) production. In this study, the Ca dependence of the IL 2 help was demonstrated by blockage of gamma-IFN production by the Ca blocker Mn, and the competitive reversal of this block by Ca. Neither leukotriene C4 nor dibutyryl cyclic GMP could reverse the Mn block, which suggests that arachidonic acid release from phospholipids is not the only Ca-dependent event in IL 2 help for gamma-IFN production. A role for calmodulin or protein kinase C in the IL 2-mediated events was suggested by the blockage of gamma-IFN production by chlorpromazine. Relatively high concentrations of Ca were able to replace the IL 2 helper effects. Consistent with this were Ca influx experiments that showed that IL 2 helper signals for gamma-IFN production involved activation of a Ca channel.
Helper effects required during in vivo priming for a cytolytic response to the H-Y antigen in nonresponder mice.
Authors: Juretić A , Malenica B , Juretić E , Klein J , Nagy Z A 
Published: December 2022

Abstract
Induction of H-Y-specific cytotoxic T lymphocyte (CTL) responses in nonresponder female mice was attempted by i.v. injection of allogeneic male cells, followed by in vitro restimulation of recipient spleen cells with syngeneic male cells. Responses were obtained only in two strain combinations in which the recipients, although phenotypically nonresponders, carried responder alleles at class I major histocompatibility complex (MHC) loci, and the immunizing cells differed from the recipients at class II MHC loci. The two positive strain combinations were B10.A(2R) anti-B10.A(4R), and B10.GD anti-B10.D2(R101). In the first combination, both recipient and donor are nonresponders to H-Y, and the CTL are induced via a bystander effect of another CTL response to a previously undetected minor histocompatibility (H) antigen. This "carrier" antigen can only induce CTL against H-Y and itself when the immunizing cells express class II MHC molecules. Furthermore, the presence of H-Y and the carrier antigen on the same cell is a prerequisite for the generation of H-Y-specific CTL. In the second combination, the recipient is a nonresponder, whereas the donor is a responder. The two strains differ at only E alpha and E beta class II MHC loci. For the induction of CTL, H-Y and the foreign E molecule must be expressed on the same cells. Thus, the B10.D2(R101) cells that express E molecules on their surface probably provide the E-nonexpressor B10.GD recipients with a stimulus for the generation of H-Y-specific T helper cells. The data are consistent with the notion that antigen-specific class II MHC-restricted T helper cells are involved in the initiation of CTL responses to minor H antigens.
Physiology of B cells in mice with X-linked immunodeficiency. I. Size, migratory properties, and turnover of the B cell pool.
Authors: Sprent J , Bruce J , Ron Y , Webb S R 
Published: December 2022

Abstract
In terms of certain immune functions and density of surface IgM, B cells from xid mice are often viewed as the equivalent of the immature (Lyb-5-) B cell subset of normal adult mice. In this paper we examine xid B cells with regard to certain physiologic functions, including homing to the lymphoid tissues, recirculation, and turnover. Xid mice were found to possess about one-third of the total number of B cells found in normal mice. This applied irrespective of whether one examined the spleen, lymph nodes, or outputs of B cells in thoracic duct lymph. In terms of migration to spleen, lymph nodes, and Peyer's patches, capacity to recirculate from blood to thoracic duct lymph, and turnover, xid B cells proved to be indistinguishable from normal spleen or thoracic duct B cells. Within these parameters, most xid B cells closely resemble the normal mature long-lived population of B cells residing in the recirculating pool of normal mice. Because xid B cells are functionally quite different from normal mature B cells, it seems reasonable to view xid B cells as an abnormal population not represented in normal mice.
Characterization of the opsonic and monocyte adherence functions of the specific fibronectin fragment that enhances phagocytosis of particulate activators.
Authors: Czop J K , Kadish J L , Zepf D M , Austen K F 
Published: December 2022

Abstract
The functional opsonic and monocyte adherence domains within the 180,000 m.w. opsonic fibronectin fragment (180K-opFnf) that selectively augments human monocyte phagocytosis of particulate activators of the alternative complement pathway were analyzed with Fab fragments of monoclonal anti-fibronectin antibodies BC7, CE9, BD4, AB3, and CPG1, and with fragments of intact human plasma fibronectin derived by cathepsin cleavage and isolated by affinity chromatography. Monoclonals AB3 and CPG1, which recognize epitopes within 40,000 daltons of the carboxy terminus of intact fibronectin, and the cathepsin D-derived, disulfide-linked fragments that contain these epitopes each inhibited the opsonic function of 180K-opFnf. Monoclonals AB3 and CPG1 inhibited monocyte ingestion of rabbit erythrocytes (Er) by 60 and 50%, respectively, when 180K-opFnf was pretreated with 20 micrograms of these monoclonals, but neither monoclonal affected the enhanced monocyte ingestion of Er pretreated with the fibronectin fragment. The pretreatment of Er with 5 micrograms and 40 micrograms of the disulfide-linked, cathepsin D derivatives isolated from high and low affinity heparin fractions, respectively, inhibited the proportion of ingesting monocytes by 60%, but these types of fragments had little effect when concurrently incubated with the opsonic fragment and Er. Monoclonals CE9 and BD4, which recognize epitopes located adjacent to or within the cell-adhesive domain of intact fibronectin, respectively, inhibited the monocyte adherence function of 180K-opFnf, as evidence by their comparable inhibitory effects when present before or after Er were opsonized with 180K-opFnf. When 20 micrograms of monoclonals CE9 and BD4 were each introduced before and after Er were opsonized with 180K-opFnf, monocyte ingestion was inhibited by 60 and 65% and by 51 and 60%, respectively. At 42 micrograms, cathepsin D-derived, non-gelatin-binding, low affinity heparin fragments that contained both BD4 and CE9 determinants or only the BD4 determinant inhibited monocyte ingestion by 53 and 74%, respectively, when concurrently incubated with 180K-opFnf and target Er, but were without effect when used to pretreat Er before the addition of 180K-opFnf. Thus, the inhibitory effects produced by monoclonals AB3 and CPG1 and by cathepsin D-derived, disulfide-linked fragments containing their corresponding epitopes demonstrated that the opsonic domain within 180K-opFnf is immunologically similar to regions within the carboxy terminus of intact plasma fibronectin.(ABSTRACT TRUNCATED AT 400 WORDS)