bluuebunny/crossref_metadata_2025 huggingface dataset:
Further Characterization of the Alternative Protein‐A Interaction of Immunoglobulins: Demonstration of an Fc‐binding Fragment of Protein A Expressing the Alternative Reactivity
Authors: INGANÄS M. , JOHANSSON S. G. O. , SJÖQUIST J.
Published: June 2006

Intact IgG and fragments F(ab')2γ, Fabγ and Fcγ from a rabbit anti‐protein‐A serum (RapA) and corresponding preparations from normal rabbit IgG (NRG) were tested for their inhibitory effect on the binding of protein‐A‐reactive 125I‐IgE and 125I‐Fcγ, respectively, to protein‐A–Sepharose. Intact IgG, F(ab')2γ and Fabγ of RapA inhibited the binding of protein‐A‐reactive 125I‐IgE, whereas only intact IgG and Fcγ fragments from both RapA and NRG inhibited the binding of 125Fcγ to protein A‐Sepharose. Further, the functional relationship between RapA and human polyclonal IgG was studied in a nephelometric test system. Intat IgG or fragments of IgG from human polyclonal IgG and rabbit anti‐protein‐A were found to affect the precipitation between human IgG and protein A in a similar way. Thus F(ab')2γ fragments and intact IgG enhanced the precipitation, whereas Fabγ and Fcγ fragments inhibited the precipitation. Protein A and an Fc‐binding fragment of protein A (fragment B) were tested for their abilities to link different radiolabelled immunoglobulin preparations expressing the alternative and the classical protein‐A reactivity to immobilized Fc fragments. All proteins expressing the alternative reactivity were efficiently bound both by fragment B and by protein A, indicating that fragment B, in addition to its classical Fc‐binding activity, also expresses the alternative protein‐A reactivity.
Quantitation of Specific IgG Antibodies in Rabbits by a Solid‐phase Radioimmunoassay with 125I‐Protein A from Staphylococcus aureus
Authors: LINDMARK R. , BIRIELL C. , SJÖQUIST J.
Published: June 2006

Radioiodinated protein a (SpA) from Staphylococcus aureus was used to quantitate specific‐antibodies of the IgG class at the nanogram level in rabbit serum by a standardized radioimmunoassay with the antigen covalently bound to paper discs. Quantitation of IgG in micrograms of IgG per millilitre of serum was done by using a standard carve with purified anti‐bovine serum albumin (BSA) IgG or by mean of the calculated molar SpA to rabbit IgG ratio of 1:1, thus converting counts per minute of 125I‐SpA to nanograms of IgG. The molar ratio for SpA to human IgG was also 1:1. The unspecific binding of IgG to the paper discs was studied and could be depressed by hen serum or by absorption of the serum sample to cellulose before the assay. The affinity constants of the extracellular SpA and human, rabbit and guinea‐pig IgG, respectively, were determined and found to be close to the values previously calculated for cell‐wall‐bound SpA. The applicability of the assay was demonstrated by quantitation of the specific IgG response on different days after immunization of rabbits with BSA and 3,5‐dinitrobenzene (DNP)‐BSA.
Induction of Antigen‐Specific Immunological Unresponsiveness by Inhibitors of Human Lymphocyte‐Activating Factor
Authors: BENDTZEN K.
Published: June 2006

Antigen‐stimulated blood mononuclear cells preincubated in vitro with Cd2+ phenanthroline, a Zn2+‐chelator, did not respond normally on restimulation with antigen, as judged by their ability to elaborate leucocyte migration inhibitory factor (LIF). Other divalent metal ions, including Zn2+, were ineffective. The effect was immunologically specific, since challenge of similarly pretreated cells with an unrelated antigen, to which the cells were also sensitized, resulted in normal LIF production. The lack of responsiveness could not be ascribed to cell death, carry‐over of the inhibitors, or exhaustive release of LIF during the inductive phase. Phenanthroline and Cd2+ are known to inhibit the activity of the macrophage‐derived lymphocyte‐activating factor (LAF), whose effect is exerted non‐specifically on antigen‐stimulated lymphocytes in G1. Seen in the context of a two‐signal model of lymphocyte activation, it is hypothesized that immediate tolerance induction is triggered by delivery of the antigenic stimulus (signal 1) without addition of the nonspecific signal 2 (LAF).
MHC Specified Lymphocyte Activating and Suppressor Activating Determinants in Human Mixed Lymphocyte Reactions
Authors: FAINBOIM L. , JARAQUEMADA D. , FESTENSTEIN H. , SACHS J. A.
Published: June 2006

We have shown (1) the presence of HLA‐linked Sad/s on a homozygous typing cell (HTC), FPA (8W321). When we used it to type the P family, which included an HLA‐B/DR recombinant sibling, its genes mapped towards the HLA‐B‐A end of the HLA haplotype separate from HLA‐D/DR and was found to be associated with HLA‐Bw35 homozygosity; (2) this same recombinant maps the C4 complement genes on the HLA‐D/DR end of the chromosome away from HLA‐B; (3) that the suppressor T cell subpopulations which was activated by the Sad of this consanguineous HTC FPA was left behind after separating the OKT4 positive cells with a monomorphic monoclonal anti‐T‐cell antibody (OKT4). These OKT4 positive cells reacted normally in MLC to the FPA Lad Fes 6; (4) that at least part of the genetic control of suppressor recognition is outside the HLA complex.
Relative Immunogenicity and Tolerogenicity of Individual Regions or Segments of the MHC
Authors: HAŠEK M. , HOLÁŇ V.
Published: June 2006

Mixed lymphocyte culture (MIX) reactivity, induction of cytotoxicity in vitro, survival of skin allografts, and induction of neonatal transplantation tolerance were compared in mice of the strain combinations differing in the entire H‐2 complex or in individual segments of it. The results showed that antigenic products of the K end of the H‐2 complex were more immunogenic and also more resistant to tolerance induction than the products of the D end of H‐2. I‐region products that elicited transplantation reactions of variable strength, depending on the detection system, were relatively easier to overcome in tolerance induction and could, at least in some combinations, contribute to tolerance induction across the barrier represented by the products of the K region of the H‐2 complex.
Purification and Characterization of a Nuclear SS‐B Antigen
Authors: TEPPO A.‐M. , GRIPENBERG M. , KURKI P. , BAKLIEN K. , HELVE T. , WEGELIUS O.
Published: June 2006

A nuelear SS‐B antigen was isolated from a saline extract of acetone powder of rabbit thymus by precipitation with ammonium sulphate, affinity chromatography with Blue Sepharose CL‐6B, and preparative agarose gel electrophoresis. The mol. wt of the antigen was 68,000. Its electrophoretic mobilily was similar to that of pro‐albumin, and the iso‐electric point was around pH 4.0. The main amino acids of the antigen were gluiamie acid, leucine, lysine and alanine. Both histidine and tyrosine were also found. The purified antigen precipitated with anti‐SS‐H sera but not with any other reference antisera. It resembled La and Ha antigens in susceptibility to proteolytic and nucleolytic enzymes and to heat. The purified SS‐B antigen, however, had a higher molecular weight than did the Ha and La antigens. The molecule eould not be split inlo subunits with mercaptoethanol or acid. Counter‐electrophoresis showed antibodies to the SS‐B antigen in sera from patients wilh rheumatic diseases, including rheumatoid arthritis, systemic lupus erythematosus and Sjögren's sjndrome, but not in any of the control sera.
Role of Zn2+ and Other Divalent Metal Ions in Human Lymphokine Production in Vitro
Authors: BENDTZEN K. , MAYLAND L.
Published: June 2006

The effects of phenanthroline and of various metal ions on human leucocyte migration inhibitory factor (LIF) production were studied. Previously reported preliminary data showed that phenanthroline, a divalent metal ion chelator, reduced the elaboration of LIF in a dose‐dependent manner by specifically but not by non‐specifically stimulated lymphocytes. This paper shows that the suppression of LIF production caused by phenanthroline could be entirely reversed by Zn2+, Ni2+ and, most effectively, by Co2+. When a battery of divalent cations were tested for direct inhibitory effects on LIF production, Cd2+ and, to a lesser extent, Cu2+ were found to be effective. Again, only specifically stimulated cells were susceptible. This profile of responses resembles greatly that seen in experiments with carboxypeptidases, indicating that a carboxypeptidase‐like, probably Zn2+‐dependent enzyme is active during antigen‐induced lymphokine production. This metalloenzyme may be derived from activated monocytes/macrophages and, like the lymphocyte‐activating factor, exerts its activity in the G1 phase of the cell cycle.
The Lipid Nature of a Tumour‐Associated Autoantigen from a Chemically Induced Rat Hepatoma
Authors: LANDO P. , BERZINS K. , PERLMANN P.
Published: June 2006

The target antigens for the complement‐dependent cytotoxic antibodies in D23 tumour‐hearer serum from rats carrying the chemically induced D23 hepatoma were exlraciable from extranuclear membranes of tumours with chloroform methanol. The antigenic activity, measured by inhibition of D2J TBS cytotoxidly against D23 cells, was recovered in the phospholipid‐containing fraction after silica gel chromalography. Preparative thinlayer chromatography (in chloroform/methanol/0.25%., CaCl2) revealed that the anligenie activity migrated similarly to phosphalidylethanolamine and cardiolipin, although these phospholipids did not cause the inhibition seen with the anligenic fractions, Phospholipase A2 digestion of the phospholipid fraction did not affect the antigenic activity nor did it alter the mobility of the antigen when analysed with thin‐layer chromalography. From these results it was concluded that the antigen extracted from D23 hepatoma may he of phospholipid nature, although its molecular identity remains to be established.
Decreased Syngeneic Mixed Lymphocyte Reaction in Autoimmune Susceptible Mice
Authors: HOM J. T. , TALAL N.
Published: June 2006

The syngeneic mixed lymphocyte reaction (SMLR) is a proliferative response mediated by murine splenic thymus‐derived (T) lymphocytes after stimulation by syngeneic non‐T cells. Several murine strains genetically susceptible to autoimmune diseases have decreased SMLR compared with normal strains. This diminished SMLR occurs before the onset of clinical disease and is most pronounced in those autoimmune mice that express a severe form of the disease. For example, in NZB/NZW F1 hybrid (B/W) mice, the SMLR is lower at 7 than at 2 months of age. The SMLR is lower in BXSB males, which develop more accelerated autoimmune disease, than in BXSB females. The defect in these autoimmune strains resides within the responding Lyt 1+, 2, 3− T‐cell population. These results suggest the presence of a common T‐cell defect in several murine strains that spontaneously develop autoimmunity.
Soluble Cytostatic Factor(s) Released from Human Monocytes
Authors: HAMMERSTRØM J.
Published: June 2006

Human monocytes activated with lymphokines after 3–7 days of in vitro maturation released stable cytostalic factor(s) (CF), as determined by reduction of [methyl‐3H]thymidine incorporation and cell counts in (arget cell cultures, Lipopolysaccharide from Escherichia coli slightly enhanced the release of CF. The CF release was greatest at an intermediate stage of the in vitro monocyte maturation to large, macrophage‐like cells. Three transformed human cell lines (NHIK 3025, K‐562, and U‐20S) and normal skin fibroblasts were consistently inhibited by CF. Normal human mesothelial cells were variably affected, while normal human lymphocytes proliferating in response to allogeneic cells in mixed lymphocyte culture were not inhibited. Further analysis of CF may disclose one of the mechanisms whereby human monocytes and macrophages inhibit growth of human tumour cells.
Interference by Rheumatoid Factor and Clq in the Detection of IgG Complexes: Studies of Model Systems by ELIS A
Authors: WAGER O. , LINDSTRÖM P.
Published: June 2006

Interference by purified IgM rheumaloid factors (RFs) and Clq in the detection of model complexes was studied by enzyme‐linked immunosorbent assay (ELISA). Soluble monoclonal and polycloral cryoglobulin IgM RFs und human or porcine Clq inhibited dosedepcndently the binding of human IgG complexes to solid‐phase IgM RF, Clq, and bovine conglutinin (Kg). The inhibition patterns of the Kg binding were dependent on the order of confrontation between the reactants. To achieve inhibition, Clq or RF had to he offered lo the complexes before treatment with fresh normal human serum (NHS); complexes pretreated with fresh NHS (alexinated complexes) were resistant to inhibition. Heating at 56 °C or 63 °C, which destroyed the alexinating capacity of NHS, did not affect the Kg binding of alexinated complexes. On the basis of present and previous findings it is concluded that intrinsic Clq and RFs are likely to interfere with detection of circulating immune complexes (CICs) in Clq‐ or RF‐binding assays; they are less likely to interfere with detection of CICs in Kg‐binding assays. The problems associated with selective removal of intrinsic Clq and RFs are discussed.
Modulation of Human B‐Lymphocyte Receptors for IgG Does Not Affect HLA‐DR Antigens
Authors: COLOMBATTI M. , SÉKALY P. R.
Published: June 2006

Receptors for the Fc portion of immunoglobulin G (FcγR) on the surface of human peripheral T cells can be modulated on contact with antigen‐antibody immune complexes (IgG‐IC). Our results demonstrate that the FcγR present on the surface of human B cells are also modulated on exposure to IgG‐TC. Furthermore, the expression of HLA‐DR molecules is not affected by the TgG‐IC‐induced disappearance of FcγR. In fact, the percentage of HLA‐DR‐positive cells and the relative amount of HLA‐DR molecules on individual B cells analysed by flow microfluorometry was shown not to be influenced by FcγR modulation. Moreover, pretreatment of cells with monoclonal antibodies directed against non‐polymorphic determinants of HLA‐DR antigens did not prevent the binding of IgG‐coated ox erythrocytes. These results argue against a structural relationship between FcγR and HLA‐DR molecules on the surface of the B‐cell populations investigated here.
Role of IgM in Human Monocyte‐Mediated Target Cell Destruction in Vitro
Authors: ÖHLANDER C. , PERLMANN P.
Published: June 2006

The presence on human monocytes of surface receptors binding IgM molecules (Fcμ receptors) and the role of IgM antibodies in monocylic effector functions were investigated. IgM antibodies were first purified by one passage through anti‐Feγ immunosorbent. Rosette techniques in which either the indicator crythrocyles or the monocytes had been pretreatcd with IgM antibodies did not reveal the presence of Fcμ receptors on monocytes. Phagocytosis and cytolysis of bovine erythrocytcs were, however, regularly observed in the presence of high concentrations of one IgM preparation. Inhibition experiments with human IgG or IgM indicated lhat the phagocytic and cytolytic effects obtained with this IgM preparation were due to contaminating IgG antibodies. This was confirmed by further immunosorbent purification of the IgM antibody preparation. Lymphocytes carrying Fcμ receptors did not transmit any effector cell activity to co‐cultivated autologous monocytes as a result of interaction with IgM. It was concluded that IgM does not mediate antibody‐dependent target cell destruction by human monocytes that seem to lack Fcμ receptors.
An Analysis of the Lymphocytotoxic Activity Found in Sera from Patients with Hypogammaglobulinaemia
Authors: MACDONALD S. , WEBSTER A. D. B. , PLATTS‐MILLS T. A. E.
Published: June 2006

Sera from 59 patients with hypogammaglobulinaemia (hypogamma) were assessed for lymphocytotoxic activity. The activity was compared wilh that found in sera from patients with systemic lupus erythematosus (SLE) in titre, class of antibody, target cell, and complement requirements. Sera from patients with hypogamma showed cytotoxic activity when compared with sera from normal donors; however, the activity was far less than that in sera from SLE patients. The cytotoxic titre of both hypogamma and SLR sera was greater against T cells than non‐T cells. Sera showing activity could be used to sensitize lymphocytes and render them susceptible to subsequent lysis, but IgM was not detectable on the surface of the sensitized cells. Following sucrose density gradient fractionalion of the sera the lymphocytotoxic activity was recovered in those fractions that contained IgM. Lymphocy‐lotoxic activity was dependent on classical complement pathway activity. In all the experiments the hypogamma sera showed the same pattern of activity as the SLE sera, but the activity was always far weaker than that found in SLE sera. The evidence does not suggest that lymphocytotoxicity is likefy to be important in the pathogenesis of hypogamma.
Regulation of IgG‐IgM Interplay by Antibody Specificity in Human K‐Cell‐Mediated Cytotoxicity
Authors: ÖHLANDER C. , PERLMANN H. , PERLMANN P.
Published: June 2006

IgM antibodies, by themselves unable to induce human K‐cell‐mediated cytotoxicity, enhanced the lysis of TNP‐coated bovine erythrocytes (TNP‐Eh) induced by suboptimal concentrations of IgG antibodies. The antibodies used were directed against either TNP or intrinsic Eb antigens. The best enhancement of antibody‐dependent ceal‐mediated cytotoxicily (ADCC) was obtained when IgG and IgM antibodies had different specificities. IgM antibodies with specificity similar to that of the IgG antibodies often inhibited rather than enhanced cytolysis. By using 125I‐labelled anti‐DNP IgG. the number of IgG/TNP‐Eb was determined. Under the present conditions, at least 9000 IgG molecules/TNP‐Eb were required for K‐cell‐mediated lysis in the absence of IgM. In the presence of IgM antibody concentrations optimal for enhancement of ADCC, the minimal number of IgG molecules required for induction of ADCC was 30–100 times lower. No enhancement of cytotoxicity was seen with more than the optimal concentration of IgM even when IgG binding to the target cells was not reduced by IgM. This suggested that induction of ADCC was dependent on contiguous IgG‐Fc receptor interactions, which were inhibited owing to steric hindrance by excessive amounts of IgM in the critical contact areas between effector cells and target cells.
Mitogenic Responses to Lipopolysaccharide by B Lymphocytes from Patients with Systemic Lupus Erythematosus
Authors: ABE T. , TOGUCHI T. , TAKEUCHI T. , KIYOTAKI M. , HOMMA M.
Published: June 2006

Peripheral blood lymphocytes from 43 patients with systemic lupus erythcmatosus (SLE) and from age‐ and sex‐matched normal controls were cultured with lipopolysaccharide (LPS) to examine the response to the polyclonal B‐cell activator. Lymphocytes from active SLE patients incorporated 4840±471 (mean ± SE) cpm in response to LPS, whereas lymphocytes from inactive SLE patients incorporated 6906 ± 897 cpm. In contrast, lymphocytes from normal individuals incorporated 7452 ± 1126 cpm. Ig synthesis of lymphocytes from active SLE in response to LPS stimulation was also less than that of normal individuals. The helper T‐cell function of active SLE, as examined by co‐culturing irradiated SLE lymphocytes with unirradiated normal lymphocytes, was normal. These results thus suggested that a defect of B lymphocytes exists in active SLE patients. This B‐cell defect and T suppressor cells apparently play an important role in the pathogenous of SLE.
The Effect of Anti‐Ia Antibody on Immunoglobulin‐secreting Cells from Healthy Individuals and Myeloma Patients
Authors: NAGAI K. , NAGAI T. , TAKATSUKI K. , UCHINO H.
Published: June 2006

Immunoglobulin‐secreting cells (ISC) in the peripheral blood of healthy individuals and in the bone marrow, peripheral blood, or plasmacytomas of patients with multiple myeloma were enumerated by a protein‐A plaque‐forming cell assay after treatment with anti‐Ia antibody and complement. Rabbit anti‐human B‐cell antisera and monoclonal anti‐Ia antibody (OKIal) were used. By this treatment, the number of ISC in the peripheral blood of healthy individuals decreased to half, and that of M‐protein‐secreting cells from some patients with multiple myeloma also decreased markedly. In one patient, the number of M‐protein‐secreting cells in the bone marrow were markedly reduced by this treatment, but this was not the case after 6 months of chemotherapy, suggesting that the chemo therapy reduced chiefly the Ia‐positive myeloma cells rather than Ia‐negative myeloma cells.
Islet Transplantation in Mice Differing in the I and S Subregions of the H‐2 Complex
Authors: SCOTT J. , STEFFES M. W. , LERNMARK A.
Published: June 2006

Pancreatic islets from A.TH mice were transplanted into the spleen or streptozotocin (SZ)‐diabetic A.TL mice. The two strains of mice are congenic inbred strains, differing only in the I and S subregions of the H‐2 complex. The allogeneic islet grafts decreased blood glucose temporarily, but the islets were rejected after 21 ± 7 days (mean ± SD). The effect of skin presensitization was tested by giving both allogeneic and syngeneic skin grafts to each of a second set of A.TL mice before streptozotocin treatment and islet transplantation. The time course of rejection of the allogeneic islets in animals that received initial skin grafts was decreased to 8 ± 3 days. In both skin‐presensitized and non‐presensitized mice syngeneic islet grafts were able to restore normoglycaemia, even in animals that had previously rejected an islet allograft. These observations demonstrate that transplantation of pancreatic islet allografts across the I and S subregions of the H‐2 complex is sufficient to induce rejection of the islets. The islet rejection was markedly accelerated by prior sensitization with allogeneic skin grafting. It is suggested that elements in allogeneic skin grafts serve as inducers of cytotoxic T‐cell responses directed against gene products of the I and/or S subregions present on cells in the allogeneic islets.
Thymic Influences on Autoimmunity in MRL‐1pr Mice
Authors: WOFSY D. , LEDBETTER J. A. , ROUBINIAN J. R. , SEAMAN W. E. , TALAL N.
Published: June 2006

We have examined the role of the thymus in the development of autoimmunity in MRL/Mp‐lpr/lpr (MRL‐lpr) mice. MRL‐lpr mice develop a lymphoproliferative disorder characterized by features of systemic lupus erythematosus and by massive proliferation of a subpopulation of Lyt‐1+23‐ T cells. Using fluorescein‐conjugated monoclonal antibodies and the fluorescence‐activated cell sorter, we have found an abnormal pattern of differentiation within the MRL‐lpr thymus characterized by a loss of Lyt‐123+ thymocytes and an increased frequency of Lyt‐1+23‐ thymocytes. Neonatal thymectomy retarded lymphoproliferation, reduced autoantibody concentrations, improved renal function, and prolonged life. Furthermore, neonatal thymectomy resulted in a relatively specific elimination of the subset of T cells involved in the lymphoproliferative process. These findings suggest that thymic maturation of T cells with alloantigenic characteristics of a helper subpopulation may contribute to the marked lymphoproliferation and severe autoimmunity of MRL‐lpr mice. Neonatal thymectomy may protect against autoimmunity by preventing the maturation of this helper subpopulation.
Degradation of Soluble Immunoglobulin Aggregates in Vitro by Monocytes from Normal Subjects and from Patients with Systemic Lupus Erythematosus
Authors: DAHA M. R. , VAN ES L. A. , HAZEVOET H. M. , KIJLSTRA A.
Published: June 2006

The capacity of human peripheral monocytes to degrade soluble immunoglobulin (IgG) aggregates (AIgG) was studied in vitro. Under serum‐free conditions peripheral monocytes from normal donors were able to degrade soluble AIgG in a linear and time‐dependent fashion. Addition of fresh human or fresh guinea‐pig serum to the incubation mixtures caused a marked increase in degradation of the amount of soluble AIgG available. The stimulatory effect of fresh serum was complement‐mediated, because it was abolished by heat treatment of the serum and was not seen when C4‐ or C3‐deficient sera were tested. Functional inactivation of C3 receptors on the phagocytes by trypsin also abolished the complement‐mediated stimulation, suggesting cooperation between Fc and C3 receptor in degradation of soluble AIgG. No significant differences were found between monocytes from normal donors and those from patients with systemic lupus erythematosus, as far as degradation is concerned in the presence of complement.
Autologous Mixed Lymphocyte Reactions in Patients with Rheumatoid Arthritis and Juvenile Rheumatoid Arthritis: Both Non‐T Cells and in‐Vivo‐Activated T Cells Can Act as Stimulator Cells
Authors: FØRRE Ø. , EGELAND T. , DOBLOUG J. H. , KVIEN T. K. , NATVIG J. B.
Published: June 2006

The lymphocyte responses in autologous mixed lymphocyte reactions (AMLR) between irradiated non‐T and T lymphocytes from the peripheral blood (PB) of rheumatoid arthritis (RA) and juvenile RA (JRA) patients were decreased compared with the AMLR responses of normal PB lymphocytes. Normal AMLR responses were seen in the synovial tissue and the synovial fluid lymphocytes from RA and JRA patients. The lymphocyte responses were also decreased in AMLR between irradiated non‐T cells from peripheral blood and T cells from synovial tissue (ST) in RA patients and between irradiated non‐T from PB and synovial fluid (SF) T cells in JRA patients. However, when irradiated non‐T cells from ST of RA patients or from SF of JRA patients were mixed with autologous PB T lymphocytes, increased lymphocyte responses were observed. SF T lymphocyters and ST T cells were also shown to stimulate autologous PB T lymphocytes.
Concanavalin A Inhibits the Effector Phase of Specific Cytotoxicity
Authors: BERETTA A. , PERSSON U. , RAMOS T. , MÖLLER G.
Published: June 2006

The effects of concanavalin A (Con A) on the effector phase of specific and nonspecific cytotoxicity were studied. The addition of the lectin to the cytotoxicity assay resulted in inhibition of specific cytotoxicity and induced the lysis of nonspecific targets only when the lectin was added after the target cells. Preincubation of the effector cells with the ligand strongly inhibited specific cytotoxicity and did not induce nonspecific cytotoxicity. However, preincubation of the target cells with Con A before addition to the assay had no effect on the specific lysis and strongly facilitated the lysis of nonspecific targets. The inhibitory effect was not due to the agglutinating property of the lectin, since another agglutinogenic and non‐mitogenic lectin (Helix pomatia) did not inhibit cytotoxicity. Induction of effector‐to‐effector killing seemed unlikely, since the addition of Con A to 51Cr‐labelled effector cells did not significantly enhance the release of isotope. The inhibitory effect could be reversed by a subsequent incubation of the Con‐A‐treated effectors with alpha‐methyln‐mannoside. We suggest that Con A inhibits specific alloreactive cytotoxicity by blocking the antigen‐binding receptors of T cells and induces nonspecific cytotoxocity by already activated cytotoxic T lymphocytes (CTLs) by binding to the major histocompatibility complex (MHC) antigens of the targets and creating structures mimicking allogeneic MHC products that will be recognized by CTLs via the antigen‐binding receptor.
Circular Dichroism of Immune Complexes, IgG and Faby with Unique Antigenic Determinants from Rheumatoid Serum
Authors: UESSON M. , HANSSON U.‐B.
Published: June 2006

IgG‐lgG and IgG‐IgM complexes were isolated from one rheumatoid arthritis (RA) serum by affinity chromatography to immobilized F(ab′)2γ of specific antibodies against unique determinants in the complexes. Both IgG und IgM, when isolated from these complexes, contained the unique determinants. The circular dichroism (CD) spectrum of IgG differed from that of normal IgG at neutral pH. At pH 3 both IgG and IgM displayed normal CD spectra, and only one third of the molecules now had affinity for the immobilized ligand. The molecules with affinity at pH 3 exhibited an abnormal CD spectrum at pH 3, and a normal CD spectrum was obtained only of those components that lacked affinity. Onethird of the Fabγ isolated from the IgG and IgG complexes with the unique determinants contained the unique determinants that were lacking in the rest of the Fabγ and in all of the Fcγ fragments. The CD of the two Fabγ preparations showed the same principal differences as the CD of the molecules with and without affinity to the ligand at acidic pH.
Increased Number of IgG Fc Receptors on Monocyte‐Enriched Peripheral Blood Leucocytes from Patients with Rheumatoid Arthritis
Authors: RASMUSSEN J. MØLLER , BRANDSLUND I. , RASMUSSEN G. G. , SVEHAG S.‐E.
Published: June 2006

The number of free Fc receptors (FcR) per cell and the association constant (Kass) for the binding of monomeric IgG were determined for monocyte‐enriched peripheral blood mononuclear cells, isolated from 16 patients with active classical rheumatoid arthritis (RA) and from 15 normal healthy donors. The assay system was based on binding under equili brium conditions of 125I‐labelled monomeric rabbit IgG to monocytes purified from peripheral blood on a continuous gradient of Petcoll. Monocytes from 14 untreated RA patients (6 seropositive, 8 seronegative) expressed on the average 4.8±1.3 × 104 FcR/cell. This number was significantly higher (P<0.01) than that found in the control group (3.46±0.7 × 104 FcR/cell). There was also a significant difference between the mean Kass of the RA group and the control group‐2.1±0.7 × 1031/mol and 2.6±1.0 × 103 1/mol, respectively (0.05 >P> 0.01). Two seropositive RA patients receiving systemic treatment with penicillamine expressed the same number of FcR/cell as the mean of the control group (3.6 ± 104). Levels of circulating immune complexes (CIC) and of the complement‐factor C3 split product C3d were also measured. No correlation was found between the number of FcR/cell and the concentration of C3d, but there was a weak correlation between the number of FcR/ccll and the level of CIC.
Ontogenic Development of the Suppressed Secondary Response to Native Dextran
Authors: WOOD C. , FERNANDEZ C. , MÖLLER G.
Published: June 2006

The ontogenic development of the plaque‐forming cell (PFC) response to the thymus‐independent (TI) antigen alpha 1–6 native dextran B512 was studied to determine when the first minimal amounts of anti‐dextran antibodies are formed. Substantial antibody responses to certain other TI polysaccharide antigens arise during the first month of life, whereas the development of the response to native dextran has been found to be conspicuously delayed in high‐responder mice. Results indicated that CBA mice began to produce minimal amounts of anti‐dextran antibodies between 15 and 21 days of age, and the development continued progressively until peak levels were reached at 90 days of age. The alpha 1–6 native dextran system is also one of the few murine models in which endogenous anti‐idiotypic antibodies are formed subsequent to anti‐dextran production. It has been shown that the anti‐idiotypic antibodies are responsible for specific inhibition of secondary PFC responses to dextran. Suppression of the secondary response was used here to ascertain whether the initial low level of anti‐dextran antibodies elicited in 15‐day‐old animals was sufficient to lead to inhibition of the secondary response. The approach confirmed the initiation of anti‐dextran production at 15–21 days of age and indicated that the small amount of anti‐dextran antibodies produced at this age was sufficient to induce the mechanism leading to suppression of the secondary response.
Induction of Cell‐Mediated Cytotoxic Self Responses by Epidermal Cells Modified with a Haptenic Sulphydryl Reagent
Authors: PEHAMBERGER H. , LEVY R. B. , HENKART P. , KATZ S. I.
Published: June 2006

Murine epidermal cells (EC) act as stimulator cells in the generation of ullogeneic cyto‐toxic T lymphocytes (CTL) in cell‐mediated lympholysis (CML) and are suitable targets for allogeneic and hapten‐self CTL. To analyse the role of EC in the generation of and recognition by ami‐self CTL, syngeneic hapten‐modified murine EC were used as in vivo and in vitro stimulating populations and as target cells in a hapten‐self CML system. Epidermal cells were modified with the sulphydryl‐reactive haptenic reagent N‐iodoacetyl‐N′‐(5‐sulphonic‐l‐naphthyl)ethylenediamine (I‐AED). C3H.SW (H‐2b) AED‐self CTL responses were generated by stimulation with syngeneic AED‐modified EC and were readily demonstrated when tested on syngeneic hapten‐modified EC. These CML responses were hapten‐specific and H‐2‐restricted. No substantial difference was detected in the ability of AED‐modified EC and spleen cells (SC) to stimulate the generation of secondary AED‐self CTL. Cold target inhibition experiments with hapten‐modified EC and SC blockers did not reveal tissue‐specific recognition of hapten‐modified EC or SC targets by AED‐self CTL. These findings demonstrate that hapten‐modified EC, when used for priming in vivo and subsequently for in vitro sensitization, can induce hapten‐specific self CTL that are reactive against syngeneic hapten‐modified EC.
Influence of Complement Components on the Size and the Opsonization of DNA‐Anti‐DNA Complexes
Authors: LAMERS M. C. , DE GROOT E. R. , DAHA M. R. , ROOS D.
Published: June 2006

We studied the influence of complement components on the size and the phagocytosis of DNA‐anti‐DNA complexes. Large precipitating complexes, prepared with either IgG or IgM anti‐DNA, were readily solubilized by fresh normal serum. This process can proceed via the alternative pathway of complement activation and is probably C3‐dependent. When IgG anti‐DNA‐DNA complexes were prepared in the presence of fresh normal serum, two phenomena were observed. Low concentrations of fresh serum (up to 2.5 % v/v) led to an increase in the size of small IgG anti‐DNA‐DNA complexes. This increase in size was due to the interaction of Clq with the complexes. Higher concentrations of fresh serum prevented the formation of large complexes; this process consumes components of the classical pathway of complement activation and is most likely C3‐dependent. The interaction both with Clq and with C3 needs the Fc parts of the IgG molecules. Phagocytosis of IgG anti‐DNA‐DNA complexes by monocytes and neutrophils from peripheral human blood was dependent on the size of the complexes rather than on fixation of C3. Fresh serum enhanced the phagocytosis of large complexes that were suboptimally opson‐ized with IgG anti‐DNA. In contrast with the findings with IgG anti‐DNA‐DNA complexes, fresh normal serum did not detectably increase the size of IgM anti‐DNA‐DNA complexes; only prevention of the formation of large complexes was observed. Phagocytosis of IgM anti‐DNA‐DNA complexes was negligible in the absence of fresh serum. However, in the presence of fresh serum, phagocytosis by monocytes but not by neutrophils was observed. This process utilized the C3b receptor on the monocytes.
Tissue Distribution of Intravenously Injected Dinitrophenylated Human Serum Albumin
Authors: SKOGH T.
Published: June 2006

After intravenous injection into mice, human serum albumin (HSA) substituted with 35 dinitrophenyl (DNP) groups per molecule rapidly became deposited on and endocytosed by non‐parenchymal liver cells. Much was also found outside the reticuloendothelial system, e.g. in heart and skeletal muscle. The relative amount of circulating DNP35HSA taken up diminished with increasing amounts injected. The capacity of DNP35HSA clearancecould not be saturated, however. Injection of small amounts (0.14 mg) of DNP35HSA did not result in glomerular deposition, whereas injectionof slightly larger amounts (0.7 mg) did. Rabbit IgG anti‐DNP increased the entrapment of DNP35HSA in the liver, whereas mouse IgA anti‐DNP hadless pronounced effects. DNP‐HSA conjugates with lesser degree of DNP substitution, which are cleared from the blood at slower rates, became located to the liver to a lesser extent than was DNP35HSA. Rabbit IgG anti‐DNP increased the amount taken up by the non‐parenchymal liver cells. MouseIgA anti‐DNP did not alter the antigen distribution within the liver; that is, immune complexes formed between IgA anti‐DNP and DNP‐HSA became locatedvirtually exclusively to the non‐parenchymal liver cells.
Degradation of Amyloid Proteins with Protease I from Aspergillus oryzae
Authors: SKOGEN B. , AMUNDSEN E.
Published: June 2006

The effect of the thrombolytic enzyme protease I from Aspergillus oryzae (brinase) on the amyloid protein AA was investigated. The effect of the enzyme on purified, low molecular weight protein AA was very high. Protein AA in intact amyloid fibrils suspended in neutral buffer was also degraded by the enzyme, although at a much lower rate. Amyloid fibrils in tissue sections could also be attacked and removed, leaving the tissue structure fairly intact. The in vivo effect of brinase on protein SAA was demonstrated in rabbits by an increase in the clearance rate of SAA after enzyme infusion.
Evidence that Agarose Must Be Internalized to Stimulate Mouse Macrophages in Vitro
Authors: JOHNSON E. , BÖGWALD J. , SELJELID R.
Published: June 2006

Agarose stimulation of macrophages in vitro was studied. Under conditions where agarose was ingested, stimulation was detected during 24–48 h of incubation at a time when the agarose increasingly was concentrated in the perinuclear region. Removal of extracellular agarose after 24 h when endocytosis had reached a plateau did not reduce the stimulatory effect. Preincubation for 4 days with dextran sulphate in concentrations reported to inhibit phagosome‐lysosome fusion potentiated strongly the stimulatory effect. In all situations in which agarose was not internalized—in teflon tubes where the cells remain in suspension, on glass cover slips with inhibitors (2‐deoxy‐D‐glucose, cytochalasin B), or with large, noningestible Sepharose beads—no stimulation was recorded. The possibility is discussed that stimulation of macrophages by agarose may be related to complement activation in phagosomes.
Characterization of Effector Cells Mediating IgG and IgM Antibody‐Dependent Cellular Cytotoxicity
Authors: ZÖLLER M. , ANDRIGHETTO G. C. , HEYMAN B. , LAMON E. W. , WIGZELL H.
Published: June 2006

Spleen effector cells for IgG‐ and IgM‐induced antibody‐dependent cellular cytotoxicity (ADCC) were characterized with respect to density and cell surface markers by using sheep erythrocytes (SRBC) coated with hybridoma‐derived monoclonal anti‐SRBC IgG or anti‐SRBC IgM antibodies as targets. While basically the same effector celts are cytolytic for IgG and IgM antibody‐coated SRBC, they differ with respect to their relative killing capacity for IgG‐ versus IgM‐coated target cells. On the basis of physical and biochemical properties three populations with cytolytic capacity could be separated: (I) A light fraction of large cells had high cytolytic potential for both IgG‐ and IgM‐coated SRBC. The cells were negative for the Fc receptor for IgG (Fcy‐R−) and the C3‐receptor (C3‐R−), they carried the receptor for Helix pomatia A agglutinin (HP‐A+), and reactivity was strongly reduced after treatment with anti‐Thy‐1 and complement (C). (II) High activity was also observed with a medium‐dense fraction, preferably lysing IgG antibody‐coated cells. The cells were Fcy‐R+, partly C3‐R+, mostly HP‐A −, and only a minor portion of the cells were Thy‐1+. (Ill) A dense fraction, displaying on a percell basis low cytolytic potential, was more active in IgM than IgG ADCC. The cells were Fcy‐R+, HP‐A+ and Thy‐1+. All three effector cell populations were non‐adherent, non‐phagocytic, and surface immunoglobulin‐negative (s‐Ig−).
The Production of T‐Cell‐Inducing Factors in Mice Is Controlled by the Brain Neocortex
Authors: RENOUX G. , BIZIERE K. , RENOUX M. , GUILLAUMIN J. M.
Published: June 2006

The synthesis of factors that monitor the expression of the Thy‐l cell surface component by marker‐negative precursor cells requires an intact left cerebral cortex, whereas the activity of sodium diethyldithiocarbamate, an immunopotentiator that increases this synthesis, seems to require an intact right neocortex. These results suggest a role for the cerebral cortex in the coordinated interregulation of lymphocyte subclasses. The finding extends previous information suggesting relationships between the central nervous system and the T‐cell arm of the immune system.
IgM‐Induced Specific Antibody Responses: Direct Correlation between Responsiveness and Natural or Induced Recurrence of the Idiotype
Authors: IVARS F. , HOLMBERG D. , CAZENAVE P.‐A. , COUTINHO A.
Published: June 2006

The idiotype (Id) expressed on antibodies of the trinitrophenol (TNP)‐spccific BALB/c hybridoma TNP.11 is defined as a ‘nonrecurrent’ or private Id in BALB/c mice, whereas the analysis of splenic plaque‐forming cells (PFC) and circulating antibody in DBA/2 mice immunized with TNP antigens revealed that TNP.11 is a ‘recurrent’ Id in this strain. TNP.11 antibodies were characterized by their ability to induce an antigen‐independent anti‐TNP response in these two strains. Whereas this antibody was negative in BALB/c mice [18], a clearcut increase in splenic anti‐TNP PFC, preferentially expressing the TNP.11 Id, was observed in DBA/2 mice. This correlation between Id recurrency and ability to induce antigen‐independent responses was further probed in BALB/c mice repeatedly immunized with anti‐TNP.11 Id antibodies (Ab3). Such BALB/c mice express the TNP.11 Id in detactable amounts even without antigen challenge and respond with increased numbers of splenic anti‐TNP PFC to the injection of low amounts of TNP.11 antibody. These findings suggest that the ability of an antibody to induce antigen‐independent PFC responses is associated with the‘recurrency’, either natural or induced, of the antibody Id.
Epidermal Langerhans Cells as Accessory Cells in Con A Stimulation of T Lymphocytes in the Guinea‐Pig
Authors: SCHEYNIUS A. , GRÖNVIK K.‐O. , ANDERSSON J.
Published: June 2006

Stimulation of guinea‐pig T cells by concanavalin A (Con A) requires Ia‐anligen expressing accessory cells. Such functional accessory cells were identified among the normal epidermal cells and could be fractionated and enriched by centrifugal ion on discontinuous Percoll density gradients. Epidermal cells collecting at a density of 1.08 g/ml were the most effective in mediating Con A‐dependent T cell proliferation, induced the highest activity of T cell growth factors (TCGF) and were enriched fivefold for Ia antigen expressing cells. A monolayer immunosorbent technique yielded a 35‐fold enrichment of Ia antigen expressing epidermal cells. This cell fraction induced high levels of TCGF in the culture supernatants. Since the only cells in the normal epidermis expressing Ia antigens are the Langerhans cells, we conclude that the Langerhans cells may act as accessory cells for Con A stimulation of T cells.
Immune Responses during Human Schistosomiasis Mansoni
Authors: COLLEY D. G. , KATZ N. , ROCHA R. S. , ABRANTES W. , da SILVA A. L. , GAZZINELLI G.
Published: June 2006

T lymphocyte immunoregulatory subsets (T4+ and T8+ cells) have been analysed in eight cases of hepatosplenic schistosomiasis mansoni, and compared to parallel analyses of seven intestinal Schistosoma mansoni‐infected patients and four uninfected control subjects. The mean T4+:TK+ ratio in hepatosplenic cases was markedly less than observed in other groups (0.94 vs 1.86 vs 2.22. respectively). Proliferative responses stimulated by a soluble adult worm extract correlated directly with the observed T4:T8 ratios. Normal levels of E rosette‐positive and surface immunoglobulin‐bearing lymphoid cells were observed in intestinal patients, while hepatosplenic patients demonstrated normal B lymphocyte proportions but highly erratic E rosette‐positive percentages. Curiously, in hepatosplenic patients the percentage of E rosette‐positive cells often did not correlate with the proportion of T3+ cells.
Activation of Macrophages by in Vitro Allostimulated T Cells
Authors: WHITTEN H. D. , CRUSE J. M. , FUDENBERG H. H.
Published: June 2006

Murine peritoneal macrophages, parabiotically co‐cultured with combinations of in vitro H‐2 sensitized thymus‐derived lymphocytes obtained from drug‐pretreated mice, possessed an increased cytotoxicity against alloantibody‐coated target cells. This heightened activity appeared to be accentuated by and dependent on T‐cell synergy. After 5 days of in vitro allosensitization at 37°C, cortisone‐resistant thymocytes allosensitized in combination with cyclophosphamide‐pretreated splenic T cells released molecules that produced strong antibody‐dependent macrophage‐mediated cytotoxicity (ADCC). This enhanced ADCC correlated with increased macrophage resetting with IgG‐sensitized erythrocytes. These heightened activities resulted from soluble mediators released by the activated T cells which diffused across a 0.22‐μm Millipore filter and were not dependent on lymphocyte‐macro‐phage contact. Evidence that these molecules originated from the highly enriched T‐cell populations and were not synthesized de novo by macrophages was supported by results of pretreatment with protein and RNA synthesis inhibitors. Evidence that soluble Fc receptors released from the alloactivated T cells were responsible for the increased macrophage EA binding and ADCC was obtained in affinity chromatography experiments in which activity could be depleted by passage over a Sepharose‐Fc‐coupled column and recovered in the column eluate.
Spontaneous DNA Synthesis in Rheumatoid Arthritis: Evidence of Enhanced Circulating Non‐T‐Cell Proliferation
Authors: AL‐BALAGHI S. , STRÖM H. , MÖLLER E.
Published: June 2006

3H‐thymidine incorporation in cultures of peripheral blood mononuclear cells from patients with seropositive rheumatoid arthritis (RA) and healthy controls was measured in vitro in the absence of added stimulants. A significantly higher level of spontaneous DNA synthesis was found in cultures of mononuclear cells from patients with clinically active RA than from patients with inactive disease and normal controls. This activity was more apparent in 24–h cultures than in 72–h cultures. There was no correlation between DNA levels and IgM rheumatoid factor (RF) litres. When T‐ and non–T–cell populations were separated and cultured simultaneously with unfractionated cells, only non‐T cells maintained high levels of DNA synthesis, and enrichment of surface membrane Ig+ (SmIg) cells was generally associated with enhancement of 3H‐thymidine incorporation. Furthermore, no difference was found in spontaneous DNA synthesis between cultures either containing or depleted of phagocytic cells. Moreover, the addition of graded numbers of autologous monocytes to highly purified T– and non–T–cell populations did not alter the background DNA synthesis. Thus, endogenously activated cells in RA patients are neither T lymphocytes nor monocytes. A regulatory influence by monocytes could not be demonstrated. It is suggested that cells actively engaged in DNA synthesis in RA blood are non–T cells in origin, most probably B lymphocytes.
The Recirculation of T and B Lymphocytes in the Athymic, Nude Rat
Authors: POSSUM S. , SMITH M. E. , FORD W. L.
Published: June 2006

The recirculation of lymphocytes through the tissues and their return to the blood were compared in nude and euthymic rats. Three approaches were used: the organ distribution of 15Cr‐labelled lymphocytes from nude or euthymic donors at 24 h after injection: the compartmental distribution of B and T lymphocytes as assessed by autoradiography of the spleen, lymph nodes, and Peyer's patches; and the tempo of recirculation from blood to thoracic duct lymph as estimated by counting timed fractions of lymph from a recipient of labelled lymphocytes. The following conclusions were drawn: (1) The distribution of lymphocytes between organs and wilhin organs is very similar in nude and euthymic recipients. In particular, B lymphocytes proceed normally to the follicular areas in the absence of T cells. (2) The recircufation from blood to lymph is delayed in nude rats. (3) For equal numbers of B and T cells injected intravenously about half as many B cells as T cells enter mesenteric and cervical lymph nodes, but approximately equal numbers of B and T cells enter the spleen and Peyer's patches.