bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane defects of the tolerant B cell. IV. Failure to accelerate antigen receptor loss.
Authors: Meucci V , Ashman R F
Published: December 2022

Mechanisms of immunologic tolerance affecting antibody responses include conditions extrinsic to the B cell such as dominant suppression by T cells (1), regulation by anti-idiotype (2), and tolerance in T helper cell populations (3). But tolerance can also result from changes in the antigen-reactive B cells such as their deletion (4), or that mysterious process by which they become "intrinsically tolerant", i.e., refractory to stimulation (5). One approach to learning more about the mechanism of intrinsic tolerance at the level of cell physiology is to determine which of the activation events that normally follow antigen contact occur or fail to occur in such cells. An established model of intrinsic B cell tolerance previously exploited in such studies in the trinitrophenyl (TNP)-self-induced tolerance model of Fidler and Golub (6). Having established that BDF1 mice injected with 2,4,6-trinitrobenzene sulfonic acid (TNBS) become tolerant to TNP, they showed by appropriate transfer experiments that the tolerance could be not induce antibody to TNP in such mice (8). cells (7). They also showed that lipopolysaccharide could not induce antibody to TNP in such mice (8). Together, these data indicated that in this example, tolerance is intrinsic to the B cells. B cells with receptors for TNP remain in these mice (9), providing an opportunity to study activation events in intrinsically tolerant B cells. This paper is part of an ongoing series of studies of activation events in TNP-antibody-binding cells (ABC)2 using this tolerance model (9-11). It shows that a TNP-antigen that normally induces rapid loss of antigen receptors on TNP-ABC cannot do so in mice rendered tolerant to TNP.
Production and characterization of a monoclonal antibody (A1-3) that binds selectively to activated monocytes and inhibits monocyte procoagulant activity.
Authors: Ewan V A , Cieplinski W , Hancock W W , Goldschneider I , Boyd A W , Rickles F R
Published: December 2022

We describe the generation and characterization of a new monoclonal antibody, A1-3, which possesses two unique properties. First, A1-3 binds selectively to stimulated human monocytes. Secondly, A1-3 inhibits the procoagulant activity expressed by stimulated monocytes and by human brain tissue factor. Unstimulated human peripheral blood cells (granulocytes, lymphocytes, monocytes, red blood cells, and platelets), prepared in the absence of detectable endotoxin, express no procoagulant activity and fail to bind A1-3. Stimulation of peripheral blood monocytes. alveolar macrophages, or the monocyte-like cell line U937, however, results in the expression of procoagulant activity and the binding of A1-3. The surface antigen recognized by A1-3 was recovered from endotoxin-stimulated human monocyte vesicles by immune precipitation and demonstrated an apparent m.w. of approximately 52,000. It is proposed that the monoclonal antibody A1-3 detects a differentiation antigen on human monocytes that is expressed in response to stimuli for monocyte activation.
Immunohistological studies with A1-3, a monoclonal antibody to activated human monocytes and macrophages.
Authors: Hancock W W , Rickles F R , Ewan V A , Atkins R C
Published: December 2022

A wide variety of monoclonal antibodies (mAb) have now been produced which recognize cell surface antigens on human peripheral blood monocytes. However, few of these mAb demonstrate specificity for monocytes, and fewer still recognize antigens exclusively on monocytes activated by one or more stimuli and/or block specific monocyte functions. The mAb A1-3 binds to lipopolysaccharide (LPS)-stimulated monocytes but not to resting blood monocytes, and inhibits the procoagulant activity of these LPS-activated cells. By using this mAb, we examined the reactivity of monocytes/macrophages (MO) in a broad range of normal and inflammatory tissues by means of a sensitive, four-layer immunoperoxidase technique. Cells of the MO system, in addition to lymphocytes and dendritic cells resident in lymphoid tissues, liver, lung, and other organs, were nonreactive with the A1-3 mAb. In contrast, intense staining of inflammatory MO was found in biopsies from patients with renal allograft rejection, acute glomerulonephritis, or granulomatous diseases. This apparent restriction of A1-3 binding to inflammatory, "activated" MO suggests that A1-3 mAb will be useful for the analysis of MO "activation" in many pathologic processes.
Autoimmune effector cells. VIII. Cellular requirements for the induction of autoreactive T cells of experimental allergic encephalomyelitis in nonimmune rats.
Authors: Silberg D G , Swanborg R H
Published: December 2022

We utilized a system of sequential in vitro cell culture and adoptive transfer to investigate the sequence of events which lead to the activation of effector cells responsible for the induction of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. This procedure involves only naive (nonimmune) rats, and eliminates the requirement for adjuvants. Spleen cells (SpC) from naive donors were sensitized in vitro to myelin basic protein (BP), then transferred to intermediate (primary) hosts. Although these recipients did not develop EAE, they were primed for disease because they exhibited accelerated onset of active EAE when challenged with BP in adjuvant. Moreover, SpC from nonchallenged primary recipients transferred EAE to secondary recipients subsequent to in vitro exposure to antigen. The cells from the naive cultures which primed the intermediate recipients were radioresistant (1500 R); other studies have indicated that these are macrophages. In contrast, the cells which transferred EAE to the secondary recipients were radiation-sensitive T lymphoblasts. The finding that these cells also elicit disease in lethally irradiated (850 R) secondary recipients suggests that the transferred cells either are the actual effector cells of EAE or induce disease in collaboration only with radioresistant host cells.
Interleukin 1 is a radioprotector.
Authors: Neta R , Douches S , Oppenheim J J
Published: December 2022

Pretreatment with recombinant interleukin 1 (IL 1) protects mice in a dose-dependent manner from lethal effects of ionizing radiation. Two thousand units of IL 1, given i.p. 20 hr before irradiation, protect 88% of C57B1/6 mice from an LD100/17 radiation dose (dose of radiation that kills 100% mice in 17 days), and 1000 U of IL 1 protect 100% of DBA/1 mice from an LD50/30 dose. This finding provides the first evidence that a cytokine, IL 1, which acts as a differentiation- and maturation-inducing agent for a variety of cells, also can serve as a signal that initiates radioprotective events in vivo. Because many of the exogenous immunomodulators that have been shown to be radioprotective also induce endogenous IL 1 production, our observation suggests that IL 1 may mediate their radioprotective effects.
Recombinant human interleukin 1 alpha: purification and biological characterization.
Authors: Gubler U , Chua A O , Stern A S , Hellmann C P , Vitek M P , DeChiara T M , Benjamin W R , Collier K J , Dukovich M , Familletti P C
Published: December 2022

Interleukin 1 (IL 1) is a polypeptide hormone produced by activated macrophages that affects many different cell types involved in immune and inflammatory responses. The cloning and expression of a murine IL 1 cDNA in Escherichia coli encoding a polypeptide precursor of 270 amino acids has been reported, and expression of the carboxy-terminal 156 amino acids of this precursor in E. coli yields biologically active IL 1. By using the murine IL 1 cDNA as a probe, we have isolated its human homolog from cDNA generated to lipopolysaccharide-stimulated human leukocyte mRNA. Nucleotide sequence analysis of this cDNA predicts a protein of analysis of this cDNA predicts a protein of 271 amino acids (termed IL 1 alpha) which shows congruent to 61% homology to its murine counterpart but only 27% homology to a recently characterized human IL 1 precursor (IL 1 beta). We have expressed the carboxy-terminal 154 amino acids of IL 1 alpha in E. coli, purified this protein to homogeneity, and have compared it with pure recombinant murine IL 1 in several different IL 1 assays based on murine and human cells. Recombinant IL 1 is capable of stimulating T cell and fibroblast proliferation and inducing fibroblast collagenase and prostaglandin production, thus proving that a single molecule has many of the activities previously ascribed to only partially purified IL 1 preparations. Our results indicate that there exists a family of at least two human IL 1 genes (alpha and beta) whose dissimilar protein products have similar biological activities.
Molecular mapping of a histocompatibility-restricted immunodominant T cell epitope with synthetic and natural peptides: implications for T cell antigenic structure.
Authors: Berkower I , Buckenmeyer G K , Berzofsky J A
Published: December 2022

We have prepared synthetic and natural peptides that have allowed delineation of a major antigenic site of myoglobin recognized by histocompatibility (I-Ed)-restricted T cell clones. The smallest peptide capable of stimulating T cell proliferation consisted of residues 136-146. Residues Glu 136, Lys 140, and Lys 145 were essential for antigenicity, whereas Lys 133 and Tyr 146 added potency but were not required for antigenicity. The periodicity of these residues suggests that folding the peptide into its native alpha-helical structure may be essential for antigenicity either by forming a hydrophilic binding site for the T cell receptor or by participating in antigen presentation. The same folding could also produce a hydrophobic site on the opposite side of the alpha-helix that could participate in hydrophobic interactions. The extrapolation of these findings to other known peptide antigens suggests that this tendency to form an amphipathic alpha-helix may be a general property of antigenic sites recognized by T cells, perhaps due to a different functional role of each type of site in eliciting T cell responses.
Molecular mapping of idiotopes of anti-arsonate antibodies.
Authors: Jeske D , Milner E C , Leo O , Moser M , Marvel J , Urbain J , Capra J D
Published: December 2022

As part of understanding molecular function in structural terms, we have been attempting to map the idiotypic topography of specific anti-arsonate (Ars) antibodies. A panel of anti-Ars hybridomas of which the complete primary sequences are known were used. These molecules show a varied reactivity profile with a panel of monoclonal anti-idiotypic antibodies. By judicious chain recombination experiments and chemical modifications that altered this reactivity profile, we were able to identify particular amino acid residues or discreet regions of anti-Ars antibodies as having crucial roles in the expression of idiotypic determinants. Idiotopes were mapped to the heavy chain second hypervariable region and D segment, and to the light chain first and third hypervariable regions.
Human lung macrophage-derived histamine-releasing activity is due to IgE-dependent factors.
Authors: Liu M C , Proud D , Lichtenstein L M , MacGlashan D W , Schleimer R P , Adkinson N F , Kagey-Sobotka A , Schulman E S , Plaut M
Published: December 2022

Human lung macrophages obtained from surgical specimens spontaneously secreted a factor(s) (which we term macrophage factor) during 24-hr culture that induced calcium-dependent histamine release from human basophils and lung mast cells. Macrophage factor induced noncytotoxic histamine release from purified (85%) basophils. The kinetics of release were relatively slow and similar to that of anti-IgE. We performed a series of experiments to test the IgE dependence of macrophage factor-induced release. Preincubation of basophils with anti-IgE in calcium-free medium resulted in complete desensitization to macrophage factor-induced histamine release (i.e., when calcium and macrophage factor were added to the basophils, no histamine release occurred), and preincubation with macrophage factor in calcium-free medium resulted in partial desensitization to anti-IgE-induced histamine release. Pretreatment of basophils with pH 3.9 lactic acid buffer, which dissociates basophil IgE from its receptors, markedly reduced the capacity of basophils to release histamine in response to macrophage factor. Basophils that were incubated with IgE myeloma (but not with IgG) after lactic acid treatment partially or completely regained their capacity to release histamine in response to macrophage factor. Fluid-phase IgE myeloma (15 micrograms/ml) (but not IgG) inhibited basophil histamine release induced by two macrophage-derived supernatants, whereas IgE myeloma (200 micrograms/ml) did not inhibit release due to other supernatants. IgE-affinity columns removed the histamine-releasing activity of five macrophage-derived supernatants, and IgG-affinity columns had similar effects. However, neither affinity column removed the histamine-releasing activity of three other macrophage-derived supernatants. On Sephadex G-75 chromatography, nearly all of the histamine-releasing activity migrated as single peak with an apparent m.w. of 18,000. These results suggest that, although macrophage factor are heterogeneous, they are related, as they are a IgE-dependent factors that induce histamine release by interacting with cell surface IgE. These macrophage factors may be responsible for stimulation of basophil/mast cell mediator release in chronic allergic reactions.
Secretory IgA specific for Toxoplasma gondii.
Authors: McLeod R , Mack D G
Published: December 2022

Secretory IgA specific for Toxoplasma gondii was identified in intestinal secretions of mice infected perorally with bradyzoites (encysted in brain) of the Me49 strain of T. gondii by using immunofluorescence microscopy and an ELISA. This activity was absorbed with tachyzoites of T. gondii but not mouse brain. To determine whether increased total amount of intestinal IgA might cause a nonspecific reaction in the ELISA for T. gondii-specific IgA, mice were immunized perorally with cholera toxin. This immunization produced intestinal IgA antibody to cholera toxin and increased the total amount of intestinal IgA, but there was no reactivity of intestinal secretions in the ELISA for T. gondii-specific IgA. Experiments in which ELISA were performed with monoclonal IgA, IgG, or IgM and antisera to IgA, IgG, or IgM demonstrated that the ELISA was specific for each Ig class. In addition, monoclonal IgA competed with the anti-Toxoplasma IgA activity of intestinal secretions obtained from mice infected with T. gondii.
L3T4+, B2A2+ thymocytes from infant mice produce IL 2 after interaction with accessory cells expressing self class II antigens.
Authors: Lattime E C , Stutman O
Published: December 2022

The presence of a thymocyte population in infant (3 to 10 day old), but not adult mice, that produces IL 2 after self class II MHC antigen stimulation is described. The responding thymocyte expresses the antigenic phenotype: Thy-1+, Ly-1+, Ly-2-, L3T4+, B2A2+. Cell-cell mixing experiments and limiting dilution analysis were consistent with a loss of the self-Ia-reactive IL 2-producing thymocyte in the adult, with no evidence for active suppression found. Although thymocytes from adult animals failed to generate IL 2 after self class II stimulation, a similar frequency of IL 2-producing cells was demonstrated in both infant and adult after allo stimulation. These findings, taken with the recent demonstration of IL 2 receptors on neonatal thymocyte subpopulations, demonstrate a mechanism for IL 2 production in the thymus that may play a role in intrathymic differentiation of T cells.
Inhibition of DNA repair by deoxyadenosine in resting human lymphocytes.
Authors: Seto S , Carrera C J , Wasson D B , Carson D A
Published: December 2022

Profound lymphopenia is characteristic of immunodeficient children who lack adenosine deaminase (ADA). When ADA is inactive, deoxyadenosine (dAdo) is phosphorylated by immature T lymphoblasts and inhibits cell division. However, dAdo also causes the slow accumulation of DNA strand breaks in nondividing, mature human peripheral blood lymphocytes. To explore the basis for this phenomenon, we have assessed the effects of dAdo and other deoxynucleosides on the repair of gamma-radiation induced DNA strand breaks in resting normal lymphocyte cultures. As measured by a sensitive DNA unwinding assay, most DNA strand breaks were rejoined within 2 hr after exposure of lymphocytes to 500 rad. In medium supplemented with deoxycoformycin, a tight binding ADA inhibitor, dAdo retarded DNA rejoining in a dose and time dependent manner. The inhibition required dAdo phosphorylation. Over an 8-hr period, 10 microM dAdo gradually rendered peripheral blood lymphocytes incompetent for DNA repair. Among several other compounds tested, 2-chlorodeoxyadenosine, an ADA resistant dAdo congener with anti-leukemic and immunosuppressive activity, was the most powerful inhibitor of DNA repair, exerting significant activity at concentrations as low as 100 nM. Both dAdo and 2-chlorodeoxyadenosine blocked unscheduled DNA synthesis in irradiated resting lymphocytes, as measured by [3H]thymidine uptake. On the basis of this and other data, we suggest that quiescent peripheral blood lymphocytes break and rejoin DNA at a slow and balanced rate. The accumulation of dATP progressively retards the DNA repair process and thereby fosters the time-dependent accretion of DNA strand breaks. By inhibiting DNA repair, dAdo, 2-chlorodeoxyadenosine and related compounds may substantially potentiate the toxicity of DNA damaging agents to normal and malignant lymphocytes.
Suppression of natural killer cell activity by human seminal plasma in vitro: identification of 19-OH-PGE as the suppressor factor.
Authors: Tarter T H , Cunningham-Rundles S , Koide S S
Published: December 2022

Human seminal plasma (SP) was found to contain a potent suppressor of human natural killer (NK) cell cytotoxic activity against the K562 erythroleukemia target in vitro. Pooled and filter-sterilized SP reduced the NK cell activity of normal blood donors in a concentration-dependent manner; strong reduction of target cell lysis was observed at a final dilution of 1/400. Possible toxic effects of SP on NK cells were ruled out, because donor leukocytes incubated in a final SP dilution of 1/100 remained greater than 99 percent viable as determined by trypan blue exclusion. SP did not affect the lysability of the tumor targets, but suppressed the cytotoxic activity of the effector leukocytes, an effect that was reversed after washing the leukocytes free of the SP. The suppressive action of SP was retained after heating to 95 degrees C for 10 min, but was removed after adsorption with activated charcoal (Norit-A). Lipids extracted from SP were tested for suppression of NK cell cytotoxic activity, and the active principle was identified with the acidic lipid fraction. Components of the acidic lipid fraction of a single freshly obtained SP sample were separated by high pressure liquid chromatography, and suppression of NK cell cytotoxic activity was found to be associated with the predominant prostaglandins (PG) in this fraction, 19-OH-PGE1 and 19-OH-PGE2. Suppression of cellular immune functions by SP has been described; however, the identity of the suppressor factor (or factors) is unknown. The 19-OH-PGE are present in high concentration in primate semen, and may minimize immunologic sensitization to sperm in females after insemination. In addition, these compounds may suppress NK cell antitumor and antiviral activities in the vagina, as well as in their tissues of origin.
Murine IgA binding factors (IgA-BF) suppressing IgA production: characterization and target specificity of IgA-BF.
Authors: Noro N , Adachi M , Yasuda K , Masuda T , Yodoi J
Published: December 2022

Chemical and functional properties of IgA binding factor(s) (IgA-BF) from both murine Con A-activated spleen cells and Fc gamma R+, Fc alpha R+ T hybridoma cells (T2D4) were studied. IgA-BF produced from the cells after preculture with IgA were purified with IgA-Sepharose. Purified IgA-BF inhibited the binding of IgA to Fc alpha R+ L5178Y T lymphoma cells, and class-specifically suppressed in vitro IgA synthesis of the pokeweed mitogen (PWM)-stimulated murine spleen cells. Both IgA-specific suppressive activity and IgA binding activity of the factor(s) were co-fractionated between BSA and OVA in gel filtration analysis. SDS-PAGE analysis of IgA-BF biosynthetically labeled with [35S]methionine showed a specific band on 56,000. Suppressive activity of IgA-BF was absorbed with lentil-lectin-Sepharose and was eluted with 0.2 M alpha-methyl-D-mannoside. The suppressive activity obtained from T2D4 cells (H-2k) and BALB/c Con A blasts (H-2d) was absorbed with the corresponding anti-H-2 and anti-I-A column and recovered in the acid-eluate. The activity was not absorbed with the unrelated anti-H-2 column. Despite the presence of MHC products, IgA-BF from both cell sources equally suppressed IgA-specific responses of BALB/c (H-2d), C3H/He (H-2k), and C57BL/10 (H-2b) spleen cells. They also suppressed IgA production as well as IgA synthesis of PWM-stimulated culture of human peripheral blood lymphocytes without affecting IgM and IgG responses. Suppression of murine and human IgA responses both in mouse and human were mediated by the molecules having the same Ia products, suggesting that there is no MHC, as well as species restriction, for the interaction between IgA-BF and their target cells. IgA-specific suppressive activity was absorbed with human B blastoid cells bearing surface IgA (Dakiki) but not with those bearing surface IgG (CESS) or murine and human T cell line cells (BW5147, L5178Y, HPB-ALL, and MOLT4), indicating that IgA-BF interact with B cells bearing IgA to suppress their differentiation.
The class I MHC antigens of erythrocytes: a serologic and biochemical study.
Authors: Spack E , Edidin M
Published: December 2022

We have measured the binding of anti-H-2K monoclonal antibodies to purified erythrocytes of a number of mouse strains. The purified erythrocytes specifically bound between 500 and 2000 molecules of labeled anti-H-2K antibodies per cell, whereas lymphocytes bound approximately 10(5) molecules of antibody per cell. Not all of the antibodies that bound to lymphocytes bound to erythrocytes. Antibodies to both public and private specificities that reacted with H-2k lymphocytes failed to react with H-2k erythrocytes. A similar pattern was found when comparing H-2b erythrocytes with lymphocytes. Failure to bind erythrocytes is not a function of antibody isotype or avidity. Isolated H-2K antigens of erythrocytes are integral membrane proteins identical in apparent m.w. and very similar in charge heterogeneity to the H-2K antigens of lymphocytes. Limited peptide maps of exogenously labeled antigens are also nearly identical. We also find that antibodies against epitopes of all three external domains of H-2K may react with erythrocyte H-2K. The altered reactivity of erythrocyte H-2K antigens is unlikely to be due to domain deletion, or to differences in membrane environments in erythrocytes and lymphocytes. The difference in reactivity could be due to subtle post-transcriptional modifications, or to expression of other class I genes in erythroid precursors.
Size and charge heterogeneity of murine IgG-binding factors (IgG-BF).
Authors: Blank U , Fridman W H , Daëron M , Galinha A , Moncuit J , Néauport-Sautès C
Published: December 2022

Size and charge of murine IgG-binding factors (IgG-BF) were determined. Four different sources were used to produce the factors: a) cells of a T cell hybrid (T2D4) constitutively secreting IgG-BF upon incubation in serum-free medium, b) T2D4 cells incubated with mouse monoclonal IgG1 antibody in order to induce in vitro the production of isotype-specific IgG1-BF, c) T2D4 cells induced in vivo by passage as ascites in nude mice and incubated in serum-free medium, and d) in vivo alloantigen-activated T cells (ATC) incubated in serum-free medium. IgG-BF were affinity purified on Sepharose beads coated with rabbit or mouse IgG and identified by their biologic activities, i.e., inhibition of in vitro secondary IgG antibody production to SRBC and inhibition of rosette formation between Fc gamma receptor-positive spleen cells and rabbit IgG-sensitized erythrocytes. IgG-BF produced by either of these cell sources was found to be heterogeneous in both size and charge. In each case, IgG-BF activities were recovered in three fractions of apparent Mr-74,000 to 78,000, 35,000 to 40,000, and 19,000 to 23,000-and in four fractions of pI-4.7 (or 5.3, depending on experimental conditions), 6.5, 7.7, and 8.4. Moreover, IgG-BF translated in vitro from T2D4 poly A RNA by using rabbit reticulocyte lysate exhibited the same heterogeneity. Thus, IgG-BF contain different proteins exerting similar biologic activities.
Influence of avidity and idiotope recognition on the modulation of surface immunoglobulin on malignant human B cells by rat monoclonal anti-idiotype antibodies.
Authors: Campbell M , Bieber M , Levy R , Teng N N
Published: December 2022

Immunoglobulin (Ig) was obtained from the tumor cells of patients with B cell malignancies by somatic cell hybridization to mouse-human heteromyeloma cells. The human Ig secreted by one of these hybridomas was used as an immunogen for the production of rat monoclonal antibodies (mAb). A panel of mAb specific for the idiotype (Id) was produced and characterized. Competitive binding studies that made use of [Se]-labeled anti-Id mAb (MAID) demonstrated several distinct yet topographically related Id on the Id-bearing Ig. These antibodies were shown to have avidities ranging from 0.38 to 45.3 X 10(8) l/mol. Additional studies demonstrated varying degrees of antigenic modulation of surface Id in vitro by MAID. The degree of modulation correlates with antibody avidity.
Cytolytic T lymphocyte effector function requires plasma membrane chloride flux.
Authors: Gray L S , Russell J H
Published: December 2022

Treatment of cytotoxic murine T lymphocytes (CTL) with certain stilbene disulfonate derivatives results in a dose-related loss of lytic capacity. This effect is reversible and apparently not a function of drug toxicity. Additionally, CTL function is inhibited by isosmotic replacement of extracellular chloride with several relatively membrane-impermeable chloride analogues. Both inhibitory manipulations act on the effector rather than the target cell and are effective only during delivery of the lethal hit. These results suggest that delivery of the lethal hit may involve CTL exocytosis.
Antibody mediated suppression of secondary IgM response in nude mice against vesicular stomatitis virus.
Authors: Charan S , Zinkernagel R M
Published: December 2022

Nude mice immunized with either of the two serotypes of vesicular stomatitis virus (VSV), VSV Indiana (VSV-Ind) or VSV-New Jersey (VSV-NJ), showed an early T cell independent immunoglobulin (Ig) M antibody response comparable with normal euthymic mice. Unlike euthymic mice, however, nude mice reinjected with the homologous serotype were unable to mount a second measurable serum neutralizing (SN) antibody response; a second injection with the heterologous serotype induced a normal primary type of SN antibody response. The serotype-specific refractoriness to a second challenge recovered at about 10 wk after primary infection. When antibody responses were assayed by enzyme-linked immunoabsorbent assay (ELISA), suppressive effects by previous immunization could be observed even after challenge with the heterologous serotypes; this finding probably reflects the known existence of common nonneutralizing determinants shared between the two serotypes. A weak 2-mercaptoethanol (2-ME)-resistant anti-VSV IgG SN antibody response was noticed during the primary response in nude mice and was also found in ELISA; after second infections, this 2-ME-resistant response did not develop. Serum transfer studies in nude and +/+ mice confirmed that the serotype-specific transitory refractoriness of a second response in nude mice was mediated through the anti-VSV-specific IgM antibodies.
Class-switching from mu to gamma 3 or gamma 2b production at pre-B cell stage.
Authors: Sugiyama H , Maeda T , Akira S , Kishimoto S
Published: December 2022

An Abelson virus-transformed murine pre-B cell line class-switched from mu to gamma 3 or gamma 2b at the pre-B stage during culture. A class-switch was mediated by the deletion mechanism of the intervening CH genes on the active chromosome. This study showed for the first time that class-switching at the pre-B cell stage was not always confined to gamma 2b production.
Interferon sensitive and insensitive MHC variants of a murine thymoma differentially resistant to methotrexate-containing antibody-directed liposomes and immunotoxin.
Authors: Machy P , Arnold B , Aliño S , Leserman L D
Published: December 2022

We evaluated the ability of methotrexate-containing liposomes or a ricin alpha-chain immunotoxin, both associated with monoclonal antibodies specific for the major histocompatibility complex-encoded class I molecule H-2Kk, to kill cells of the murine k haplotype thymoma RDM4. Cells were incubated with liposomes or immunotoxin in the presence or absence of interferon-gamma, which is known to augment the expression of the target class I molecules. The great majority of cells were killed by either of these reagents. Two types of mutant cells were obtained: type 1 cells, selected by methotrexate-containing liposomes, failed to express sufficient target H-2k molecules to be killed by liposomes in the absence of interferon-gamma. In the presence of interferon-gamma, these cells increased expression of all H-2 class I molecules and could be killed by targeted liposomes. Type 2 cells were immunoselected from cloned type 1 cells by liposomes in the presence of interferon. These cells failed to respond to interferon with expression of the H-2Kk molecule, but continued to augment H-2Dk expression in response to interferon. A third variant (type 3) selected from the wild type population by an H-2Kk specific immunotoxin in the absence of interferon phenotypically resembled type 1 cells. Type 1 but not type 2 cells respond to interferon by augmented synthesis of H-2Kk specific mRNA. The results suggest that for interferon-sensitive cell surface molecules of tumor cells, use of interferon improves the efficacy of targeted chemotherapy, but does not prevent development of mutants lacking the target molecule.
Expression of three cross-reactive idiotypes on rheumatoid factor autoantibodies from patients with autoimmune diseases and seropositive adults.
Authors: Fong S , Chen P P , Gilbertson T A , Weber J R , Fox R I , Carson D A
Published: December 2022

Approximately one-half of human monoclonal IgM anti-IgG autoantibodies (rheumatoid factors (RF] from unrelated individuals with cryoglobulinemia coordinately express three cross-reactive idiotypic antigens (CRI). The CRI are detected with: 1) monoclonal antibody 17.109, which recognizes a conformation-dependent CRI on K-light chains; and 2) two rabbit anti-peptide antibodies that react with primary sequence-dependent CRI (PSL2 and PSL3) corresponding to the conserved second and third K-chain complementarity-determining regions, respectively. In the present experiments, the structural features of polyclonal RF autoantibodies from diverse patients with rheumatoid arthritis and from those with primary Sjögren's syndrome, and from seropositive elderly subjects without overt autoimmune diseases, were investigated with these three defined anti-CRI reagents. The pattern of expression of the CRI differed among patient groups. Only the RF autoantibodies from Sjögren's syndrome patients frequently displayed all three CRI. However, the RF from nearly every subject tested, including patients with rheumatoid arthritis, were enriched in the primary sequence-dependent PSL2-CRI as compared to RF-depleted Ig from the same subjects. Amino acid sequence analysis of monoclonal IgM-RF indicates that PSL2-CRI-positive light chains probably represent the products of a single Vk gene. Therefore, a proportion of the polyclonal RF from different autoimmune states may represent somatic variants of this germ-line RF Vk gene which retain the PSL2 sequence as a common element.
Phenotypic changes induced by interferon in resting T cells: major enhancement of Ly-6 antigen expression.
Authors: Dumont F J , Palfree R G , Coker L Z
Published: December 2022

The murine Ly-6 locus controls multiple cell surface antigenic specificities with distinct cellular and tissue distributions. Although the functions of Ly-6 antigens are unknown, several of these antigens represent interesting markers of T cell differentiation and activation. In this work we used a panel of monoclonal antibodies (MAb) in conjunction with flow cytofluorometry (FCF) analysis to investigate the effect of interferon (IFN) on the surface representation of T cell-associated Ly-6 antigens. It was found that in vitro treatment of purified T cells from both C57Bl/6 (Ly-6.2) and BALB/c (Ly-6.1) mice with 10 to 10(4) U IFN-alpha/beta/ml results in a dose-dependent enhancement of Ly-6 antigen expression. This effect was already detectable after 12 to 18 hr and culminated after 48 hr of incubation. Both frequencies and brightness of Ly-6 bearing cells were increased. The most dramatic shifts were observed for the Ly-6A, D, and E antigens, which were augmented by eightfold to 20-fold upon exposure to 10(4) U IFN alpha/beta/ml. Expression of Ly-6C antigens was enhanced by fourfold to sixfold under the same conditions. Immunochemical analyses and use of metabolic inhibitors additionally demonstrated that such IFN-alpha/beta-induced phenotypic alterations of T cells reflect augmented de novo biosynthesis of Ly-6 molecules. Comparison of purified IFN-alpha and IFN-beta revealed that both are equally active in influencing Ly-6. IFN-gamma also enhanced Ly-6 expression but less efficiently than IFN-alpha/beta. Additional experiments were carried out to determine the selectivity of IFN-alpha/beta action on T cell phenotype. These studies demonstrated that IFN-induced Ly-6 enhancement occurs without emergence of interleukin 2 or transferrin receptors. Expression of H-2 and beta 2m antigens, previously known to be sensitive to IFN, was increased but to a much lesser extent than Ly-6. Most other cell surface antigens examined were minimally affected by IFN-alpha/beta with the exception of Ly-11 and Ly-23. Augmentation of these latter markers was lower than for Ly-6 antigens, however. Therefore the Ly-6 locus appears to be preferentially activated by IFN-alpha/beta in resting T cells. Additional exploration of this phenomenon should provide insight into both the biological significance of Ly-6 antigens and the mechanism(s) by which IFN affect T cell functions.
Mouse L cells express a molecular complex carrying the human epitopes recognized by monoclonal antibodies 44D7 and 44H7 after DNA-mediated gene transfer.
Authors: Quackenbush E J , Linsley P , Letarte M
Published: December 2022

In a previous study, we isolated from the non-T, non-B acute lymphoblastic leukemia cell line, HOON, a molecular complex comprised of a minimum of two polypeptide chains linked by disulfide bonds and expressing two distinct epitopes, 44D7 and 44H7. The DNA from the HOON cell lines has been co-transfected with the herpes simplex thymidine kinase gene into mouse L cells. By using a flow cytometer, a stable thymidine kinase-positive cell population expressing both 44H7 and 44D7 antigens of the human leukemic cells has been generated by repeated sorting of cells reactive with monoclonal antibody 44H7. After three sequential sorting experiments, cloned cell lines were established, and a subclone designated 3D5 has been additionally characterized. Greater than 90% of the 3D5 cells stained positively with monoclonal antibodies 44H7 and 44D7 and with 4F2, which reacts with an epitope identical or spatially related to that seen by 44D7. The ratio of antigenic density 4F2:44D7 calculated from the relative fluorescence indices was similar on the HOON leukemic cells and on the 3D5 transfectant cells. However, 3D5, which was selected with antibody 44H7, expressed a higher ratio of 44H7:44D7 than did the HOON cells. The molecular complex carrying these epitopes was isolated from a 3D5 cell extract on a column of 44D7-IgG-Sepharose and was additionally purified by immunoprecipitation. Although several polypeptide chains were present in the immunoprecipitates, the major polypeptide band had an apparent m.w. of 127,000 under nonreducing conditions. After reduction, three bands of apparent m.w. 91,000, 38,000, and 33,000 appeared. The presence of the 91,000 and 38,000 subunits linked by disulfide bonds was also observed for the 44D7 antigen isolated from HOON cells, whereas the polypeptide of apparent m.w. 33,000 was only seen in immunoprecipitates of the transfectant cell extracts. Because the antigen expressed in the transfectants is associated with a multimeric complex containing disulfide-linked subunits, it is possible that only the gene encoding one of the polypeptide chains, namely that carrying the epitopes, was in fact transfected. This HOON gene product could be one subunit associating with murine subunits encoded by genes of the L cell. Alternatively, the antigenic complex may be the product of closely linked genes transfected together, or of a single human gene that is modified post-translationally to create a disulfide-linked complex.
Protective effect of the membrane skeleton on the immunologic reactivity of the human red cell Rho(D) antigen.
Authors: Paradis G , Bazin R , Lemieux R
Published: December 2022

It has recently been shown that the 30,000 m.w. Rho(D) protein is associated with the membrane skeleton of the human red cell. We have studied the effects of the membrane skeleton on the immunoreactivity of the Rho(D) antigen present in Rho(D)+ membranes. Solubilization of the membranes with the Triton X-100 detergent and centrifugation of the extracts showed that more than 90% of the immunoreactive Rho(D) antigen sedimented with the membrane skeleton structures. The skeleton-bound Rho(D) antigen could be solubilized by disruption of the skeleton in low ionic strength medium. The removal of the membrane skeleton structure before the solubilization of the membranes with detergent resulted in the inactivation of the majority of the Rho(D) antigen. The effect of the membrane skeleton on the stability of the Rho(D) antigen was additionally studied in detergent extracts prepared from native and skeleton-free membranes. The assay of the Rho(D) antigen activity in the extracts showed that the Rho(D) antigen was 100 times more sensitive to the detergent inactivation in skeleton-free membranes than in native membranes. These results indicate that the membrane skeleton is important for stabilizing the immunoreactive form of the Rho(D) protein on the red cell membrane.
Elimination of terminal complement complexes in the plasma membrane of nucleated cells: influence of extracellular Ca2+ and association with cellular Ca2+.
Authors: Carney D F , Hammer C H , Shin M L
Published: December 2022

Nucleated cells, unlike erythrocytes, are able to survive limited complement attack by eliminating potentially cytolytic complement channels from the plasma membrane (PM) by processes that involve, plasma membrane (PM) by processes that involve, but may not be limited to, endocytosis. The observation that C5b-9 channels, as well as C5b-8 and C5b-7 intermediates, are rapidly eliminated from the cell surface of nucleated cells has prompted us to examine whether terminal complement complexes stimulate membrane events that lead to accelerated elimination of these complexes. We have suggested previously that ion flux through terminal complement complexes might influence the rate of elimination on the basis of our finding that terminal complement complexes with larger functional channel sizes are more rapidly eliminated. In this study, we examined the role of Ca2+ on the elimination rate of terminal complement complexes in the PM of Ehrlich cells, because changes in Ca2+ flux across the PM are known to influence many metabolic activities including endocytosis. To determine the elimination rate for terminal complement complexes by functional analysis, cells bearing C5b-7 or C5b-8 complexes with or without a sublytic dose of C9 were incubated at 37 degrees C for various time intervals before converting the remaining complexes to lytic C5b-9 channels. The initial elimination rates for the terminal complement complexes were compared in the presence of 0.015, 0.15, and 1.5 mM CaCl2 in the medium. Sufficient lowering of the extracellular Ca2+ concentration, (Ca2+)o, resulted in prolonging the elimination of each of the terminal complement complexes to a different extent. The effect of (Ca2+)o on the elimination rate was most pronounced for C5b-8 in the presence of a sublytic number of C5b-9, with less of an effect on C5b-8 alone, and the least effect with C5b-7. The elimination rates for terminal complement complexes were also determined by measuring the persistence of C5b antigen on the cell surface at 37 degrees C in the presence of various (Ca2+)o by using fluorescence-activated cell sorter analysis and were comparable with that obtained by functional analysis. Examination of the effect of terminal complement complexes on the cellular Ca2+ concentration, (Ca2+)i, revealed that these complexes increased the (Ca2+)i in proportion with the known functional pore size of the terminal complement complex in the PM. In addition, Quin 2, which can buffer internal Ca2+ transients, was found to increase the susceptibility of Ehrlich cells to lysis by C5b-9, further suggesting a relationship between the (Ca2+)i and the elimination process.(ABSTRACT TRUNCATED AT 400 WORDS)
Antigen-specific, interleukin 2-propagated T lymphocytes confer resistance to a murine malarial parasite, Plasmodium chabaudi adami.
Authors: Brake D A , Weidanz W P , Long C A
Published: December 2022

To explore cell-mediated immune mechanisms in host defense against malaria, we utilized a murine model system in which antibody-independent mechanisms of immunity are known to play a major role. Splenic T lymphocytes obtained from Plasmodium chabaudi adami-immune mice were maintained in vitro by using IL 2-containing medium and frequent antigenic stimulation. These IL 2-propagated T lymphocytes were characterized for their antigen reactivity, surface phenotype, and ability to confer protection to P. chabaudi adami in reconstituted mice. IL 2-dependent T lymphocytes maintained their capacity to proliferate in vitro to solubilized parasite preparations of homologous but not heterologous antigens. Antigen-specific proliferation was H-2 restricted, requiring antigen-presenting cells of the correct haplotype. More importantly, these propagated T lymphocytes were effective in adoptively transferring protection to both athymic nude mice and sublethally irradiated recipients. The protective response was dose dependent and antigen specific, because recipients resisted challenge infection with P. chabaudi adami but not with the heterologous parasite Plasmodium yoelii 17X. Pretreatment of the IL 2-propagated cells with anti-Thy-1.2 and complement abrogated their ability to transfer protection. Collectively, these results suggest that T lymphocytes obtained from P. chabaudi adami-immune mice, propagated and expanded in vitro, retain antigen specificity and passive protective activity in vivo.
Immunogenicity of the repetitive and nonrepetitive peptide regions of the divergent CS protein of Plasmodium knowlesi.
Authors: Sharma S , Gwadz R W , Schlesinger D H , Godson G N
Published: December 2022

The circumsporozoite (CS) protein of the Nuri strain of the simian malarial parasite Plasmodium knowlesi was expressed as a fusion protein in E. coli. This fusion protein cross-reacted with the polyclonal monkey sera raised against irradiated sporozoites of another strain (H strain) of P. knowlesi. The antibody against the repeat units of the H strain CS protein was affinity purified from the polyclonal sera by using synthetic repeat peptides. The affinity-purified antibody did not cross-react with the Nuri CS fusion protein. The immunogenicity of different regions of the CS protein was additionally studied by using several synthetic peptides. All but the most COOH-terminal peptide showed cross-reactivity with the polyclonal sera. Because the repeat regions of the CS protein of the two strains are diverse, whereas the non-repetitive regions are immunogenic and conserved, the latter may be better suited for a potential vaccine.
Structure of a class I gene from Syrian hamster.
Authors: McGuire K L , Duncan W R , Tucker P W
Published: December 2022

Syrian hamsters possess a multigene class I family yet fail to perform several associative immunologic functions. In an attempt to determine whether representative hamster genes are structurally functional, we have cloned two closely linked class I-like genes and determined the complete sequence of the 5' member. Its exon organization is similar to that seen in mouse and man, although only two intracytoplasmic domains are encoded instead of the usual three. Comparison of the predicted amino acid sequence and the 3' untranslated region to mouse and human genes suggest along with the linkage data that the hamster gene may be related to either or both K and Qa region genes but probably not to D and L region genes.
Mononuclear phagocyte function in SLE. I. Bipartite Fc- and complement-dependent dysfunction.
Authors: Kimberly R P , Meryhew N L , Runquist O A
Published: December 2022

To determine the relative contributions of Fc- and complement-mediated immune clearance to the overall mononuclear phagocyte system (MPS) dysfunction in SLE, we performed a kinetic analysis of clearance rate data from 32 patients and 49 normal controls. Three rate constants regulating complement-mediated MPS clearance and one rate constant regulating Fc-mediated MPS clearance were evaluated. Mean values for rate constants regulating complement-mediated phagocytosis (k4) and Fc-mediated clearance (k3) were significantly lower for the patient population as a whole when compared with normal controls (p less than 0.01 and p less than 0.001, respectively). Further analysis by clinical subgroups revealed that mean k3 values were significantly low for all but the inactive nonrenal subset of patients, whereas mean k4 values were significantly low for both the active and inactive renal patients but not for nonrenal patients. Rate constant values for Fc-mediated clearance correlated significantly with disease activity scores for the entire SLE group (p less than 0.001) as well as for the subset of patients with active and inactive renal disease (p less than 0.001). Neither k3 nor k4 correlated significantly with anti-DNA antibody, titers, total hemolytic complement levels, or circulating immune complexes. These data indicate that both Fc- and complement-mediated clearance defects occur in SLE. Nonrenal patients have at least one clearance mechanism intact, whereas immune complex glomerulonephritis is associated with dysfunctions in both of these clearance mechanisms.