bluuebunny/crossref_metadata_2025 huggingface dataset:
Fc‐Dependent IgG‐Mediated Suppression of the Antibody Response: Fact or Artefact?
Authors: HEYMAN B.
Published: June 2006

IgG antibodies have been shown to suppress the antibody response to all epitopes of their specific antigen as well as those the IgG do not bind to, so‐called ‘non‐epitope‐specific suppression‘. The present study was undertaken to clarify whether there is a true IgG‐mediated Fc‐dependent suppression of Ihe antibody response. This question is of fundamental importance to the understanding of the mechanism behind this phenomenon. It is demonstrated that F(ab')2 fragments of a monoclonal TNP (trinitrophenyl)‐specific IgG2a antibody are unable to suppress the murine in vitro non‐epitope‐specific plaque‐forming cell response against SRBC (sheep erythrocytes) when SRBC‐TNP is used as antigen. The same monoclonal IgG aniibody. when administered in intact form, is able lo induce up to 98% suppression of the SRBC‐specific antibody response. The lack of suppression is not due to mitogenic effects of pepsin in the F(ab')2 fractions or increased breakdown of F(ab'); fragments, as compared with intact antibody, in the cultures. These data clearly demonstrate that there is indeed a highly efficient, Fc‐dependent, nonepitope‐specific suppressive mechanism mediated by IgG aniibodies and support a hypothesis involving binding of the anligcn‐anlibody complexes lo Fc receptors as a step in the effector mechanism.
Alteration of Idiotypic Connectivity in Prenatally Tolerized Neonatal Mice*
Authors: ZÖLLER M.
Published: June 2006

Prenatal tolerization with trinitrobenzenesulphonic acid (TNBS) leads lo expansion of trinitrophenyl (TNP)‐specific B cells, the majority of which become refractory to stimulation during postnatal development [60]. One possible explanation could be that they belong to the repertoire of naturally activated B cells which are limited in expansion after antigenic stimulation due to a high degree of idiotypic connectivity [42]. To evaluate this hypothesis, 59 thymus‐ and 490 spleen‐derived B‐cell hybribomas from 6‐day‐old prenatally untreated and prenatally TNBS‐treated mice were tested for reactivity against 33 arbitrarily chosen clones derived from the same fusions, 17 being derived from control and 16 from tolerized litters. Two major points could be deduced:

Idiotypic connectivity, including connectivity of TNP‐ and anti‐TNP‐reactive monoclonal antibodies (MoAb), was maintained after prenatal tolerization. This accounted for thymus‐ and spleen‐derived MoAb.

Only TNP‐ and anli‐TNP‐reaclive MoAb derived from prenalally untreated and prenatally tolerized mice displayed significantly distinct idiotypic profiles. Differences were pronounced, especially with thymus‐derivcd MoAb.

Thus, TNP‐specilic B cells in prenatally tolerized newborns do not behave like B cells of adult mice stimulated by external antigen, but rather like a part of the naturally activated, ldiotypically connected B‐cell repertoire of the newborn. This could explain B‐ccI! unresponsiveness at older age as a consequence—at least partly—of their high idiotypic connectivity.
A Cell‐to‐Cell Mediated Interaction Involving Monocytes and Non‐T/CD16+ Natural Killer (NK) Cells is Required for Histamine H2‐Receptor‐Mediated NK‐Cell Activation
Authors: HELLSTRAND K. , HERMODSSON S.
Published: June 2006

Histamine (10‐1 to 10‐7 M) augmcnled natural killer cell cytotoxicity(NKCC)of human CD16+, non‐Tlymphocytes in vitro against the NK‐sensitive target cells K562erythroleukaemic, Molt‐4 lymphoma, Chang liver cells and against Epstein—Barr virus (EBV)‐transformed, NK‐insensitive Daudi B‐lymphohlastoid target ceils by a mechanism of action involving a prostaglandin‐ and interleukin 1 (IL‐l)‐independent accessory function of monoeyles. No evidence for the production of intermediary. NK‐enhancing cytokines by hisiamine was obtained, indicating a cell‐to‐cell mediated interaction between monoeytes and NK cells as a plausible mechanism of action for the NK‐augmenting effeci. Monocytes recovered by countercurrent centrifugal elutriation (CCE), but not monocyles recovered by adherence, reconstituted the effect of histamine when added to non‐adherent NK cells. The development of NKCC in response to histamine was time‐dependent with (i) an induction phase, dependent on the presence of accessory monocytes and ongoing hislamine H2‐receptor activation (hulf‐maximal response required approximately 30 min treatment of large granular lymphocyte (LGL)‐enriched lymphocytes and monoeytes with histamine), and (ii) an effector phase, independent of the presence of monocytes or hislamine receptor activation. Hislamine‐activated mononuclear cells (MNC) continued to exert augmented cytotoxicity for at least 8 h after removal of histamine and monocytes. In several experiments, histamine‐activated NK‐effector cells killed > 90% of the target cells at low baseline NKCC. We suggest that histatamine may have a role in non‐specific tumour defence by regulating an earlier unrecognized interplay between monocytes and NK cells.
Cellular and Molecular Characteristics of Transformed T Cells from an Antigen‐Specific T‐Cell Line
Authors: WEGENER A. M. K. , HOLM B. , GEISLER C. , RUBIN B.
Published: June 2006

An anligen‐specific T‐cell line which transforms into T‐lymphoma cells in vitro but apparently not in vivo is described. Membrane markers, tumorigenicity and T‐cell receptor(TcR) Vα and Vβ‐ gene usage of the in vitro transformed T‐cell line were analysed to investigate whether the transformation event was poly‐, oligo‐, or monoclonal. The results indicate that the Tlymphoma has no chromosome abnormalities, contains no tumour‐inducing virus, can induee clone‐specific immunity, and is oligodonal wilh respect to TcR Vα and Vβ expression. The nature of the transformation event and clinical application of vaccination against Tlymphomas is diseussed. In addition, the expressed TcR Vα and Vβ repertoire of Con A T blasts was apparently not affected by the Igh‐I or the MHC haplotype, as investigated in lgh‐1 and MHC congeneic C57BI mice.
Quantification of Non‐Activated (Native) Complement Component C9 Synthesized by Alveolar Macrophages from Patients with Sarcoidosis
Authors: PETTERSEN H. B. , JOHNSON E. , GARRED P. , HETLAND G. , OSEN S. S. , MOLLNES T. E.
Published: June 2006

Alveolar macrophages (AM) from sarcoidosis patients synthesize the functional alternative and terminal pathways of complement, and increased complement production may be one of multiple factors in the pathogenesis of sarcoidosis. We thus examined whether AM from sarcoidosis patients produced quantitatively more C9 in vitro than AM from healthy controls. AM from 16 patients with active sarcoidosis and seven healthy controls were cultured under serum‐free conditions for 6, 12, 24, 48, or 72 h. A quantitative production of C9 was found in the harvested medium in 10 of 16 sarcoidosis patients. There were no detectable levels of C9 in the seven controls. Activated C9 was found in all patients and in the majority of the controls. C9 was quantified by an enzyme immunoassay based on a monoclonal antibody (Ml) to non‐activated C9. Our results indicate greater production of C9 by sarcoidosis AM than by their healthy counterparts.
The Early Expression of Some Human Autoantibody‐Associated Heavy Chain Variable Region Genes is Controlled by Specific Regulatory Elements
Authors: CHEN P. P. , SOTO‐GIL R. W. , CARSON D. A.
Published: June 2006

Recent molecular cloning studies have revealed that some autoantibodies may be encoded directly by germline Ig variable (V) genes without any somatic mutation, suggesting strongly that such autoantibodies are physiologically important. Independent analyses of Ig gene expression in a human fetal liver showed that only nine heavy chain V (Vh) genes were used, out of a potential germline Vh gene repertoire of 100–200. We have observed that four of these nine Vh genes encode sequences identical or almost identical to human autoantibody heavy chains. This unexpected overlap implies that some autoantibodies are expressed preferentially during early development. Recent structural analyses of two Vh3 genes expressed in fetal liver revealed many more enhancer‐like sequences in the fianking regions than expected for a typical Vh gene. It is hypothesized that these autoantibody‐related Vh genes may contain various combinations of cis regulatory elements which infiuence their specific expression during early ontogenic development. Furthermore, these observations are consistent with network hypotheses, which suggest that early B‐cell development is driven by reactivity with self. The cis regulatory elements in the autoantibody genes may act in concert with the positional effects that have been shown to facilitate Vh gene engagement.
Oestrogen Receptors in Macrophages
Authors: GULSHAN S. , McCRUDEN A. B. , STIMSON W. H.
Published: June 2006

The presence of receptors for oestradiol‐17β and 5α‐dihydrotestosterone(5α‐DHT) in the human monocytic leukaemia cell line JIII and rat peritoneal macrophages was investigated using whole‐cell assays. For both cell types. high‐affinity binding species for oestrogen were detected, whereas no indication of specific binding was observed for 5α‐DHT. Analysis of the data according to Scatchard showed curved lines, indicating the presence of two different oestrogen‐binding species. The dissociation constant (Kd) values for the receptors of the rat peritoneal maorophages were calculated to be 1.4 × 10‐10M and 3.3 × 10‐9M, while for the JIII cells, the Kd values were 8.7 × 10‐11M and 2.5 × 10‐9M. Sucrose‐gradient ultracentrifugation identified one oestrogenbinding species or 7.IS. The receptors had a relatively high affinity for diethylstilboestrol (DES) but did not bind to a monoelonal antibody specific for the classical oestrogen receptor, suggesting that oestrogen receptors in macrophages could be of a different type.
IgG Subclass Antibody Responses to Pneumococcal Polysaccharide Vaccine in Splenectomized, Otherwise Normal, Individuals
Authors: AABERGE I. S. , MICHAELSEN T. E. , HEIER H. E.
Published: June 2006

Subclasses of IgG antibodies to pneumococcal polysaccharide serotypc antigens 4, 6A. and 23F were measured before and 4 weeks after vaccination with pneumoeoccal vaccine in young individuals splencetomized because of trautna and in a control group. An ELISA technique was applied. IgG2 anti‐pneuniococcal antibodies predominated before vaccination, especially against serotypes 4 anti 6A. The youngest individuals in the splenectomy group tended to have lower IgG2 antl‐pneumococcal antibody levels than the older ones. Vaccination induced antibodies of the IgGl and IgG2 subclasses, and in sotne individuals also of the IgG4 subclass. Splencetomy does not seem to inffuence the IgG subcllass paltern of antipneuniococcal antibodies.
Altered Generation of Interleukin 1 in Chronic Human Schistosomiasis Mansoni
Authors: ZWINGENBERGER K. , RICHTER J. , TAUPITZ S. , SIQUEIRA J. G. VERGETTI , DACAL A. R. CORREIA
Published: June 2006

Chronic schistosomiasis mansoni is associated with impaired cell‐mediated immune responsiveness (CMI). To assess co‐stimulatory factors essential in the induction phase of CMI, interleukin 1 (IL‐1) concentration was determined in the sera and cell culture supernatants of Schistosoma mansoni‐infected patients, and circulating monocytes were phenotyped, labelling membrane IL‐1 and HLA‐DP. In addition, adherent cell oxidative‐burst capacity was investigated. Since involvement of IL‐1β in the pathogenesis of severe granulomatous lesions could not be ruled out, 17 patients with intestinal schistosomiasis and 17 patients with hepatosplenic schistosomiasis were matched for intensity of infection and monitored 3–6 months after praziquantel therapy. Seventeen age‐ and sex‐matched uninfected residents ofthe study area in Alagoas, Brazil, acted as controls. Whereas schistosomiasis patients and controls did not differ in the expression of monoeyte surface antigens and the capacity of adherent cells to generate H2O2, IL‐1β release by monocytes in vitro was significantly reduced in both intestinal and hepatosplenic patients. Low concentrations of circulating IL‐1β were detected in comparable frequencies in untreated patients and controls. Three months after therapy, IL‐Iβ was detectable in serum in an increased proportion of intestinal schistosomiasis patients. IL‐1 release in vitro gradually increased in all patients and reached control values 6 months after therapy.
Rapid Adhesive Responses of Endothelial Cells and of Neutrophils Induced by Leukotriene B4 are Mediated by Leucocytic Adhesion Protein CD18
Authors: LINDSTRÖM P. , LERNER R. , PALMBLAD J. , PATARROYO M.
Published: June 2006

Controversy has existed as to the ability of leukotriene B4(LTB4) to enhance adhesive properties of human neutrophils (PMN) and endothelial cells. We found that LTB4 induced a rapid but transient adhesion of PMN to an albumin‐coated plastic surface and to cultured human umbilical vein endothelial cells (HUVEC). Although the adhesive response of PMN to the chemotactic peptide N‐formyl‐methionyl‐leucyl‐phenylalaninc (fMLP) was longer lasting, peak hyperadherence was of similar magnitude as to LTB4 and was less susceptible to assay conditions. Adherence induced by either LTB4 or fMLP could be abrogated by the monoclonal antibody 60.3, indicating similar dependence on the leucocyte adhesion protein CD18. Lipoxin A did not induce PMN hyperadherenee. Treating HUVEC with LTB4, but not with its omega‐oxidized metabolites 20‐OH‐ and 20‐COOH‐LTB4, lipoxin A, or with IMLP conferred a rapid, dose‐related, enhanced adhesion of PMN. This effect was dependent on CD18 and on divalent cations. It disappeared with prolonged exposure to LTB4, required a metabolically active HUVEC, and was not due to passive binding of LTB4 lo HUVEC. Thus, LTB4 induces a transient expression of hyperadhesiveness in HUVEC as well as in neutrophils, and both effects are dependent on expression of CD18.
Regulation of Isotype Immunoglobulin Production by Adjuvants in Vivo
Authors: KARAGOUNI E. E. , HADJIPETROU‐KOUROUNAKIS L.
Published: June 2006

Mice were immunized against fiuorescein isothiocyanate (FITC)‐labelled human gamma globulin (HGG) or dexlran sulphate (DXS) in the absenee or presence of different adjuvants. The immune response was assayed as the total Ig‐secreting cells and FITC‐speeilic plaque‐forming cells (PFC) found in various lymphoid organs. The adjuvants inliueneed the isolype of antibodies produced to the same antigenic determinant. The PFC of different IgG subclasses were favoured by different adjuvants. The IgG3 isotype was produecd mainly alter immunization with either anligen and lipopolysaccharide(LPS)or Li sail asadjusani; IgGI was produced with incomplete Feund's adjuvant (IFA), complete Freund's adjuvani (CFA), alum, poly I:C. Quil A, Be salt, and poly A:U. Some of the above adjuvanis (Be salt and poly A:U) favoured the production of lgG2b, and others (CFA, alum. Quil A, and poly I:C) favoured ihe IgG2a isotype besides the main isotype. Attempts were made to correlate the activation by the various adjuvants of certain TH subtypes with the isotypes produced.
Expression of Heterozygous lpr Gene in MRL Mice
Authors: CARLSTEN H. , TARKOWSKI A. , JONSSON R. , NILSSON L.‐Å.
Published: June 2006

Recently we showed that not only homozygous MRL lpr/lpr mice but also heterozygous MRL +/lpr mice display defective antigen‐ and mitogen‐driven T‐cell responses as well as polyclonal B‐cell activation compared with congeneic MRL +/+ mice. In this study we examined die impact of the heterozygous lpr gene on organ pathology in kidneys, joints, and salivary glands, as well as serum levels of immunoglobulins and autoantibodies in young and old MRL mice. Only 1 out of 17 heterozygous lpr‐bearing MRL mice developed clinically overt renal disease with significant proteinuria and haematuria during the first year of life. However, examination of Ig and C3 deposits in glomeruli of kidneys from these mice revealed that the expression of the heterozygous lpr gene in MRL mice accelerates glomerulonephritis in addition, histological examination of the submandibular salivary glands showed an increased focus score in heterozygous MRL mice at 4–5 months of age compared with that of matched congeneic +/+ mice. In contrast, no signs of arthropathy were registered in the heterozygous lpr‐bearing MRL mice. Heterozygous MRL mice displayed an expanding lymphoid system as evaluated by significantly increased spleen and lymph node weights com pared with those of matched MRL +/+ mice. Further evidence for immunomodulatory properties of the heterozygous lpr gene was obtained when analysing serum levels of IgG, IgM, and autoantibodies. Thus, heterozygous MRL +/lpr mice produced significantly higher levels of both Ig and autoantibodies than matched MRL +/+ mice. We conclude that the expression of the heterozygous lpr gene in MRL mice results in acceleration of the autoimmune process, giving rise to precocious clinical disease.
Mitogenic Effect of α1‐Microglobulin on Mouse Lymphocytes
Authors: BABIKER‐MOHAMED H , ÅKERSTRÖM B. , LÖGDBERG L.
Published: June 2006

Human α1‐m microglobulin (α1‐m), a low molecular weight plasma protein, was found to exert mitogenic effects on mouse lymphocytes from lymph nodes and spleen. The stimulatory effects appeared lo be strain‐restricted: α1‐m induced a varying degree of proliferation of lymphocytes from three strains, whereas one strain responded poorly. Experiments with lymphocyte subpopulations showed only weak stimulatory effects of α1‐m on purified T and B lymphocytes cultivated alone. The addition of mitomycin‐treated cells of the other subpopulation could not restore the proliferative responses in either T or B lymphocytes. Strong stimulations were recorded only when both T and B lymphocytes were present, indicating that the T and B lymphocytes cooperate to achieve the proliferation However, FACS studies on cultured splenocytes indicated (hat the proliferating cells are predominantly B lymphocytes. These data extend our earlier findings of a mitogenic effect of α1‐m on guinea pig lymphocytes. Furthermore. results were obtained indicating the presence of a receptor on mononuclear cells. Iodine‐labelled α1‐m was bound lo mononuclear cells prepared from spleens, and the binding could be blocked by an excess of non‐labelled α1‐m. Scatchard plotting of the data gave an equilibrium constant of 0.7 × 105/M for the binding between α 1‐m and the receptor. Together with the documented inhibitory activity of α1‐m on antigen‐driven proliferation of lymphocytes, these results suggest an immunoregulatory role for α1‐m.
Interleukin 1β Increases the Cytosolic Free Sodium Concentration in Isolated Rat Islets of Langerhans
Authors: HELQVIST S. , BOUCHELOUCHE P. N. , JOHANNESEN J. , NERUP J.
Published: June 2006

Interleukin l (1L‐I) exerts both stimulatory and inhibitor) (cytotoxic) effects on insulin producing βcells in isolated pancreatic islets. Since alteration in ion fluxes is crucial for endocrine cell activation and is a denominator of cell death, and since IL‐1 was recently shown to increase the total sodium content in a murine pre‐B‐lymphocyte cell line, we investigated the effect of recombinant human IL‐lβ (rhIL‐1β) on the cytosolic tree sodium concentration (Na +) in rat islets, furthermore, long‐term rhIL‐1βeffects on islet cell function were studied during exposure of islets to amiloride. a blocker of the plasma membrane Na+/H+ exchange. One hour of islet exposure to 60 U/ml of rhIL‐lβ caused a threefold increase in I Na + . in islet cells, and this effect was abolished by deplelion of extracellular sodium. Blockade of Na+/H+ exchange with amiloride abolished the inhibitory effect of rhIL‐1β Son insulin release. In conclusion. rhIL‐lβwas found to increase sodium influx in pancreatic islet cells. This might underlie the widespread effects of rhIL‐lβ on β‐cell function and morphology, possibly related to IL‐l‐mediated toxic free radical formation.
Terminally Differentiated Human Intestinal B Cells
Authors: BJERKE K. , BRANDTZAEG P.
Published: June 2006

The relative distribution of IgA and IgG subclass‐producing immunocytes was examined by two‐colour immunohistochemistry in normal human distal ileum including Rover's patches (PP). regional mesenteric lymph nodes (MLN). and peripheral lymph nodes. IgA2 cells predominated slightly over IgA1 cells in the PP dome area. There was a decreasing median proportion of IgA2 cells in the order of PP (52%), distant ileal lamina propria (40%), MLN (32%), and peripheral lymph nodes (11%). The reverse was (rue for IgA1 cells in independent enumerations. These results support the notion that PP‐derived B cells after stimulation are seeded mainly to the lamina propria of the distal gut, but that there is a substantial retention and terminal differentiation of this migrating population in regional MLN. The median subclass proportions of IgG‐producing cells in the PP dome area were in independent determinations 68% IgG1.23%. IgG2, 8% IgG3, and 9% IgG4. This distribution was fairly similar to that seen in other tissue categories, except for a trend towards increased IgG1 and reduced IgG2 proportions in peripheral lymph nodes and reduced IgG1 along with increased IgG3 in normal palatine tonsils. The data suggested an association between the expression of IgG2 (and possibly IgG4) and IgA2 in intestinal mucosal immune responses.
Stimulation of Macrophages by Endotoxin Results in the Reactivation of a Persistent Herpes Simplex Virus Infection
Authors: DOMKE‐OPITZ I. , KIRCHNER H
Published: June 2006

Previous work has shown that splenic macrophages derived from herpes simplex virus (HSV)‐resistant C57BL/6 mice undergo a persistent HSV infection which is characterized by the continuous release of infectious virus particles from a small subpopulation of infected cells. Treatment of persistently infected macrophages for 2 weeks with lipopolysaccharide (LPS) resulted in an increase of HSV yield and in virus‐induced cytopathic effects. HSV was also reactivated by treatment of macrophage cultures with lipid A or tumour necrosis factor (TNF). Like macrophages of C57 BL/6 origin, cells from LPS‐hyporesponsive C3H/HeJ mice could be persistently infected with HSV. These cells were resistant to LPS‐induced virus reactivation. The results show that macrophages derived from C57BL6 mice are rendered susceptible to lytic HSV infection by treatment with LPS or TNF. Thus, these substances may interfere with persistent HSV infection which can he established due to genetically controlled properties of the host.
Identity of HML‐1 Antigen on Intestinal Intraepithelial T Cells and of B‐ly7 Antigen on Hairy Cell Leukaemia
Authors: MOLDENHAUER G. , MIELKE B. , DÖRKEN B. , SCHWARTZ‐ALBIEZ R. , MÖLLER P.
Published: June 2006

Immunoprecipitation of radioiodinated hairy cell leukaemia (HCL) cell lysates with monoclonal antibody (MoAb) HML‐1. originally reported to recognize intraepithelial T cells, and with MoAb B‐ly7, originally reported to react with HCL. led to identical biochemical characteristics. In SDS PAGE under reducing conditions, a major band of 143 kDa. a broad band ranging from 112 to 122 kDa. and two additional faint bands of 175 and 100 kDa could be determined. Deglycosylation of N‐linked sugar moieties by treatment of immunoprecipitates with endoglycosidases indicated that the two main protein cores of the antigen are predominantly if not exclusively glycosylated by complex and hybrid types of oligosaccharide chains. Competitive binding inhibition demonstrated that both MoAb are directed against different epitopes. Immunohistochemically. the staining patterns obtained with both MoAb in normal tissues, in T‐and B‐cell lymphomas, and in HCL were identical except for a single case of HCL which was HML‐1−/B‐ly‐7+, We conclude that MoAb HML‐1 and B‐1y7 recognize the same antigen.
Immunomorphology of Graft‐Versus‐Host Disease after Small Bowel Transplantation in the Rat
Authors: WALLANDER J. , SCHEYNIUS A. , LÄCKGREN G. , TUFVESON G.
Published: June 2006

The process of graft‐versus‐host disease (GVHD) elicited by small bowel semi‐syngeneic gratis in Lewis rats was studied by an immunohistochemical staining technique for analysis of MHC (major histocompatibility complex) class II antigen expression and of T‐cell subpopulations in different organs. Specimens from the graft, native bowel, brain, testis, liver, kidney, and skin were taken on days 5,10, and 15. All the investigated organs displayed strong class II antigen induction during the course of GVHD. In the native bowel of semi‐syngcneically transplanted animals, only discrete morphological changes were noted, whereas the graft displayed a generalized serosal reaction with large infiltrates of rounded and polygonal cells expressing class II antigens. This was not observed in the graft of syngeneically transplanted animals. In the lamina propria of the semisyngeneic graft,‘free’lymphocyte‐like cells were depleted and, at the same time, localized aggregates of these cells were observed. Crypt cell class II expression in the native bowel, and to some extent in the graft, was increased during GVHD. However, pronounced intraindividual variations in MHC class II antigen expression were noted, and class II expression was therefore not considered to be a good marker for GVHD.
Immunoglobulin V Regions of a Bactericidal Anti‐Neisseria meningitidis Outer Membrane Protein Monoclonal Antibody
Authors: LARRICK J. W. , COLOMA M. J. , VALLE J. DEL , FERNANDEZ M. E. , FRY K. E. , GAVILONDO‐COWLEY J. V.
Published: June 2006

C6 is a potentially therapeutic murine monoclonal antibody that recognizes the class 1 outer membrane protein of Neisseria meningitidis. C6 specifically immunoblots this antigen and augments in vitro killing of N. meningitidis bacteria. We describe a general method of obtaining the heavy and light chain variable‐region sequence from immunoglobulin‐secreting cells, The method uses mixed polymerase chain reaction (PCR) primers designed from the 5 end of the framework 1 (FR1) sequences of the heavy and light chains, and 3‐end primers for constant‐region conserved sequences. The method has been applied to the cloning and sequencing of the variable region of C6 to construct a humanized monoclonal antibody. Rapid amplification and sequencing of variable regions by this general method have multiple applications in the study of the immune response to infectious diseases.
Participation of CD11a–c/CD18 and RGD‐Recognizing Adhesion Molecules in the Binding of LGL to Fibroblasts
Authors: HEISKALA M. K. , PATARROYO M , TIMONEN T. T.
Published: June 2006

We have previously shown [10] that large granular lymphocytes (LGL) are inactivated by contact with natural killer (NK) resistant monolayer target cells. In this work we have analysed which adhesion molecules are involved in the binding of LGL to such targets, as exemplified by fibroblasts, and in the subsequent inhibition of their NK activity. The result‐, indicate that antibodies against CD54 (intercellular adhesion molecule 1. ICAM‐1). CD11a (leucocyte function antigen I, LFA‐l, α chain), and CD18 (common β chain of the β2 ‐integrin family) significantly (by 50%) reduce the binding of LGL onto inhibitory target cells. The matrix protein‐based synthetic peptide RGD (arginine‐glycine aspartic acid. Ref. 19) and attli‐CD29 (the common β chain of the β1 integrin family) antibodies also diminish the binding (by 35%). The effects of the antiadhesion molecule antibodies and the peptide are additive, the combination of both leading to an almost complete block of adhesion. It may be hypothesized that sonic of the binding‐relevant adhesion molecules of the RGD‐binding domain on LGL (CD29) may be involved in the delivery of the inactivating signal to the effector cell. Indeed, incubation of LGL with anti‐CD11a antibodies, but neither with antibodies against other binding‐relevant epitopes nor with RGD. significantly reduced their NK. activity. The mechanism of the inactivation was similar to that induced by intact NK‐resistant target cells [7]. On the basis of the present results we suggest that the CD11a molecule is involved in the down‐regulation of the NK activity of peripheral blood lymphocytes.
Quantitation of Immunoglobulins Produced by Donor Lymphocytes in Transplant Patients and the Possible Identification of Donor Cell‐Produced Antiviral Antibodies by Imprint Immunofixation
Authors: FLESLAND Ø. , SOLHEIM B. G. , MELLBYE O. J. , VANDVIK B. , ALBRECHTSEN D. A.
Published: June 2006

In the present study two patients were studied in detail to estimate the quantity of IgG of donor lymphocyte origin. Using IgG subclass quantitation and Gm haemagglutination inhibition titre, we estimated that up to 3% of IgG found after transplantation may be of donor lymphocyte origin. Analysis of viral antibody patterns by imprint immunofixation suggested polyclonal production of donor‐derived antibodies.
Major Autoantigenic Sites of the (U1) Small Nuclear Ribonucleoprotein‐Specific 68‐kDa Protein
Authors: NETTER H. J , GULDNER H. H. , SZOSTECKJ C. , WILL H
Published: June 2006

A 68‐kDa protein associated with (U1)snRNP is a major target for human autoantibodies to small ribonucleoprotein particles (snRNP) prevalent in a variety of Inflammatory rheumatic diseases. The epitopes recognized by these antibodies were mapped by expression of subfragments of p68 cDNA in Escherichia coli and testing of the corresponding recombinant proteins for immunoreactivity with sera of patients with autoimmune diseases. Three of four antigenic regions were analysed in detail. The immunodominant autoantigenic region was found lo coincide with the RNA‐binding domain of the p68 protein and was shown to contain a nested set of overlapping discontinuous epitopes. Two additional non‐overlapping major antigenic domains were localized in the carboxy‐terminal half of the p68 protein. Each of these two carboxy‐terminal domains was shown to contain more than one conformation‐dependent epitope. Taking into account previous mapping studies, the data demonstrate that p68 contains at least four antigenic regions, each of which harbours multiple epitopes which are recognized in a patient‐specific manner.
The Presence of Infectious Virus but not Conventional Antigen can Exacerbate Graft‐Versus‐Host Reactions
Authors: CRAY C. , LEVY R. B.
Published: June 2006

Previous reports have demonstrated that the introduction of virus (MCMV, HSV‐1) concurrent with a graft‐versus‐host reaction (GvHR) limited to a class I MHC disparity can result in the enhancement of GvHR‐associated phenotypic (changes in CD4/CD8 ratio) and functional (inability to produce secondary antibody responses) alterations including the augmentation of in situ natural killer (NK) and donor anti‐host cytotoxic T‐cell activity. In the present study, we investigated whether immunogens other than infectious virus may be capable of enhancing GvHR. Mice receiving donor cells and the T‐dependent antigen dinitrophenyl‐bovine serum albumin (DNP–BSA) did not display exacerbated GvHR as evidenced by the absence of phenotypic alterations and the absence of elevated NK activity and the lack of donor anti‐host cytotoxic activity. Furthermore, these recipients produced normal levels of IgM and IgG anti‐DNP antibody. In addition, mice which received ultraviolet light (UV)‐inactivated virus (even at 100 × dosage) together with donor cells also did not exhibit exacerbated GvHR. In total, these findings illustrate a novel ability of infectious virus to exacerbate GvH reactions and are consistent with the hypothesis that viral‐induced immune responses may be important in the ability of a pathogen to induce the development of severe GvHR.
Monocyte‐Mediated Suppression of IL‐2‐Induced NK‐Cell Activation
Authors: HELLSTRAND K. , HERMODSSON S.
Published: June 2006

In the present study, the effects of serotonin on human natural killer (NK)‐cell responsiveness to interleukin 2 (IL‐2) was investigated. Concomitant treatment of human lymphocytes, enriched for NK effector cells by Percoll density‐gradient centrifugation, with serotonin and/or IL‐2 yielded a synergistic activation of NK‐cell cytotoxicity (NKCC) in the presence but not in the absence of monocytes. The monocyte‐dependent. regulatory effects of serotonin and/or IL‐2 were prosta‐glandin‐independent and could be reconstituted when monocytes, recovered by countercurrent centrifugal elutriation (CCE), were added to purified NK effector cells. The effects of serotonin on baseline and IL‐2‐activalcd NK cells were mimicked by the 5‐HT1A receptor‐specific agonists 8‐OH‐DPAT and (+)‐ALK. Our data suggest that serotonin regulates NK‐cell responsiveness to IL‐2 via 5‐HT1a receptors.
Antigen‐Presenting Activity of Non‐Langerhans Epidermal Cells in Contact Hypersensitivity Reactions
Authors: BAADSGAARD O. , LISBY S. , AVNSTORP C. , CLEMMENSEN O. , LANGE‐VEJLSGAARD G.
Published: June 2006

Despite the critical role of the Langerhans cells in the induction of contact hypersensitivity reactions, non‐Langerhans antigen‐presenting cells in already sensitized individuals may play a role in the elicitation phase of a contact hypersensitivity reaction, following epicutaneous challenge with antigens, the number of CD1+ DR+ epidermal Langerhans cells increased in a time‐dependent way and. concomitantly. CD1−OKM5+ DR+ epidermal non‐Langerhans cells appeared. In parallel with this, the capacity of epidermal cells to present both alloantigens and auto, nominal antigens increased, and 4 days after initiation of the contact hypersensitivity reactions 33–53% of the epidermal antigen‐presenting capacity was due to CD1− non‐Langerhans antigen‐presenting cells. Thus, contact hypersensitivity skin reactions are accompanied by the appearance of non‐Langerhans antigen‐presenting cells capable of presenting both alloantigens and auto/nominal antigens.
Influence of Sulphate Ions on the Structure of AA Amyloid Fibrils
Authors: WONG S. , KISILEVSKY R.
Published: June 2006

To explore the possible interaction of sulphated GAG with AA amyloid peptides, human AA amyloid fibrils were exposed to buffers containing various salts, and the accessibility of free amino groups on the peptides to reductive methylation was examined. Sodium chloride had little effect except at concentrations of 1 m, where it reduced the accessibility of AA peptides to labelling. In contrast 70 min Na2SO4 led to a significant increase in peptide accessibility to labelling. The results suggest that, at least in part, GAG interact with AA peptides through their sulphate moieties.
Neutrophil Beta‐2 Microglobulin: an Inflammatory Mediator
Authors: BJERRUM O. W. , NISSEN M. H. , BORREGAARD N.
Published: June 2006

Beta‐2 microglobulin (β2m) constitutes the light invariant chain of HLA class I antigen, and is a constituent of mobilizable compartments of neutrophils. Two forms of β2 m exist: native β2m and proteolytically modified β2m (Des‐Lys58‐β2m). which shows α mobility in crossed radioimmuno‐electrophoresis. The modification of native β2m can be executed by membrane‐associated activity of mononuclear cells, and Des‐Lys5B‐β2m augments the production of interleukin 2. In this study we present evidence that human neutrophils contain native β2:m in specific granules, secretory vesicles, and plasma membrane, β2m was released in the native form from neutrophils in response to stimulation with chemotactic stimuli and phorbol ester. The results of experiments designed to study the modification of native β2m by neutrophils indicated that neutrophils do not participate in the proteolysis of β2m. However, we demonstrated that native β2m following degranulation may he transformed to Des‐Lys58‐β2m by lymphocytes. We suggest that neutrophil β2m following exocytosis may be transformed to Des‐Lys58‐β2m. acting as an extracellular messenger between granulocytes and lymphocytes in the inflammatory focus.
Phenotypical and Functional Differentiation of CD4+ CD45RA+ Human T Cells Following Polyclonal Activation
Authors: KRISTENSSON K. , DOHLSTEN M. , FISCHER H. , ERICSSON P. O , HEDLUND G. , SJÖGREN H.‐O. , CARLSSON R.
Published: June 2006

Human CD4+ T cells differ in their expression of the leucocyte common antigen. Antibodies detecting certain forms (CD45RA and CD45RO) of this antigen have been used to identify and isolate Subpopulations of the CD4+ T cells, These isolated subsets have been shown to have different abilities concerning lymphokine production and provision of help to B cells for Ig production. When these T‐cell subsets were activated in vitro with polyclonal activators, the CD45RA + cells lost this market and gained the expression of CD45RO. This was true for all mitogens used in this report, i.e. accessory cell‐dependent stimulation with SFA and accessory cell‐independent activation with PMA or PHA. A correlation between proliferation and differentiation was observed, but this was probably not causative as stimulation with PMA in the absence of DNA synthesis resulted in the acquistion of CD45RO and loss of the CD45RA antigen. Moreover, cells proliferating vigorously for long periods of lime expressed both markers at significant levels, which suggests that proliferation did not automatically result in complete loss of the CD45RA marker. The phenotypical differentiation was associated with a functional differentiation which induced the stimulated cells’ability to act as helper cells For Ig production and to produce gamma interferon (IFN‐γ). The results obtained in this study support the contention that the CD45RO + cells are precursors of the CD45RO + cells and that die two subsets represent different maturational stages of the same lineage.
The First Icelandic Family with X‐Linked Agammaglobulinemia: Studies of Genetic Markers and Immune Function
Authors: THORSTEINSSON L. , ÖGMUNDSDÓTTIR H. M. , SIGFÚSSON Á. , ÁRNASON A. , EYJÓLFSSON G. , JENSSON Ó.
Published: June 2006

This paper describes studies of genetic markers and immune functions in the first Icelandic family identified with X‐linked agammaglobulinaemia (X‐LA). including three affected brothers. The eldest brother was diagnosed at the age of 9 in 1963. He suffered repeated infections and died at the age of 23. The other two affected brothers, diagnosed at 6 years and 1 year age, are a live and well on immunoglobulin replacement therapy at the ages of 32 and 24, All were typed for HLA. complement, and various other markers. Pedigree analysis suggests an X‐linked segregation of the disease. Their serum IgG is maintained at normal levels on therapy. Several parameters of immune function were studied. The following results were obtained for the X‐LA brothers: B cells are absent in their peripheral blood samples. T‐cell numbers are normal, but monocytes are increased in numbers and activity. No immunoglobulin production could be elicited in vitro with PWM and no cells containing cytoplasmic Ig were detectable among PWM‐stimulated blasts. Nevertheless the proliferative response was particularly vigorous, but the responding cells were shown to be exclusively T cells. No blast transformation could be achieved with EB virus. NK‐cell activity was normal‐high normal. Other cell‐mediated immune functions were normal. In conclusion our data indicate that the differentiation of B cells is blocked in the two surviving X‐LA brothers. They have survived for a longer time and in better health than is generally reported. Early diagnosis and adequate replacement treatment with Ig is clearly crucial. Vigorous non‐specific immune mechanisms may help to compensate for the defective specific immunity.
Histological and Immunohistochemical Characterization of Joint Inflammation and Flare‐up Reactions Induced by Cloned MT4 +,Lyt‐2−T cells
Authors: KLASEN I. S. , LADESTEIN R. M. T. , GRANDIA A. A. , VAN DER KWAST TH. H. , BENNER R.
Published: June 2006

This report describes the histological and immunohistochemical characterization of joint inflammations and flare‐up reactions in mice induced by cloned MT4+, Lyt‐2− T cells. The T‐cell clone used was specific for the antigen methylated bonne serum albumin (mBSA) and was inoculated locally into a joint together with the antigen. The histological examination was performed in methylmethacrylate sections, and the various cell types were quantified m distinct regions of the knee joint. The infiltrates consisted predominantly or granulocytes admixed with small numbers of histiocytes. Few lymphocytes were present, while plasma cells were not found. Fibrosis was prominent in the later stages of the inflammation.

Immunohistochemical analysis of total unfixed, non‐decalcified sections using monoclonal antibodies revealed the presence of T cells which were predominantly of the helper phenotype. sporadic B cells, and a considerable number of la‐positive cells. Macrophages were scattered throughout the infiltrate. The synovial lining was shown to express Ia antigens and to contain cells that stained with macrophage markers Cell clusters were found including helper T (Th) cells, some B cells, and Ia‐positive cells.

These results are in line with immunohistological examinations in other arthritis models and resemble the early events in human rheumatoid arthritis. The data indicate that activated helper T cells are required and sufficient to give rise to the inflammatory infiltrates that are characteristic of the inflammations and exacerbations in human rheumatoid arthritis.
Gamma Interferon‐Induced Specific Binding of Tetanus Toxin on the GG2EE Macrophage Cell Line
Authors: BLASI E. , PITZURRA L. , FUAD A. M. BURHAN , MARCONI P. , BISTONI F.
Published: June 2006

We have recently demonstrated that tetanus toxin (TT) selectively inhibited gamma interferon‐(IFN‐γ)‐induced, but not basal, lysozyme activity in the GG2EE macrophage cell line. By an indirect immunofluorescence technique, we show that tetanus toxin, as well as the BIIb tetanus toxin‐derived fragment, selectively binds to IFN‐γ‐treated cells but fails to bind to control cells. Moreover, BIIb fragment and TT share the same binding sites, as demonstrated by competition/ displacement experiments. These data indicate that IFN‐γ pretreatment results in the acquisition of tetanus toxin binding sites on GG2EE cells by a mechanism(s) yet to be identified.
Immunological Tolerance to Many Self Epitopes may be Unnecessary
Authors: PREHN R. T.
Published: June 2006

The demonstration of the existence of antigenic mimicry suggests that immunological tolerance to self antigens may be an insufficient basis for distinguishing self from non‐self. However, some data suggest that even in the absence of tolerance most self epitopes would not immunize the host and that tolerance to all self epitopes may, therefore, not be necessary for the prevention of autoimmune disease.
Tumour Necrosis Factor Alpha (TNF‐α) and Interleukin 6 in a Zymosan‐Induced Shock Model
Authors: VON ASMUTH E. J. U. , MAESSEN J. G. , VAN DER LINDEN C. J. , BUURMAN W. A.
Published: June 2006

TNF plays a central role in septic shock induced by endotoxin or Gram‐negative bacteria. Zymosan can elicit a septic shock‐like syndrome in rodents in the absence of endotoxin. TNF and IL‐6 release in mice treated with zymosan was investigated. One hour after intraperitoneal zymosan injection, maximal TNF levels were measured in serum, followed by IL‐6 peak levels 1 h later. Treatment with a monoclonal antibody against TNF lowered zymosan‐induced mortality from 63 to 11.6%, while maximal IL‐6 levels were lowered by about 40%.

Mechanisms triggering zymosan‐induced cytokine release in murine macrophages were analysed in vitro. Cytokine release was only slightly triggered by uncoated zymosan particles. Thirty‐nine per cent of TNF release by macrophages appeared to be triggered by zymosan‐bound activated complement. Maximal TNT release also required the presence of natural antibodies against zymosan and zymosan‐activated scrum. In contrast, maximal 11–6 release was reached upon stimulation with zymosan‐activated serum only, while the presence of zymosan particles lowered this response.

We conclude that TNF is a crucial mediator m zymosan‐induced shock. TNF release can be induced by different immunological pathways, without the need for the direct presence of endotoxins. Although IL‐6 release during septic shock is partly dependent on TNF. in vitro trigger mechanisms for IL‐6 and TNF differ remarkably.
Dynamics of Blood Components and Peritoneal Fluid during Treatment of Murine E. coli Sepsis with β‐1,3‐D‐polyglucose Derivatives
Authors: RASMUSSEN L.‐T. , FANDREM J. , SELJELID R.
Published: June 2006

The influences of pretreatmeni with β‐1.3‐D‐polyglucose derivatives on levels of cytokines and arachidonic acid metabolites in body fluids in experimental peritonitis in mice are reported. Peritonitis was induced by an intraperitoneal injection of 108 live Escherichia coli. Pretreated animals survived the infection, untreated animals died about 12 h after inoculation with E. coli.

Levels of IL‐l in plasma and peritoneal fluid, measured by cytotoxicity assay of the HT‐2 cell line, increased significantly during the first 48 h after intraperitoneal treatment with β‐1.3‐D‐polyglucose‐derivalized microbeads (GDM) or soluble, animated /β‐1,3‐D‐polyglucose (AG). After subsequent challenge with E. coli. the levels of IL‐1 were significantly lower than in untreated animals. There was no increase in levels of TNF after treatment with GDM or AG, measured by cytotoxicity assay of the WEHI clone 13 cell line. After challenge with E. coli. TNF in plasma and peritoneal fluid was significantly lower compared with untreated animals. Both PGE2; and LTB4. measured by radioimmunoassay kits, were increased in peritoneal fluid alter treatment with GDM and AG. After challenge with E coli. PGE2 and LTB4 in peritoneal fluid increased to about half the concentration of infected control animals. Intraperitoneal injection of indomethacin to pretreated animals resulted in increased levels of IL‐l and TNF‐ and decreased levels of PGE2; following challenge with E. coli. The levels of IL‐1 and TNF remained elevated until the animals died after about 12 h.

These studies demonstrate that the raised levels of arachidonic acid metabolites after pretreatment with GDM or AG seem to inhibit the otherwise lethal elevation of IL‐1 and TNF in body fluids which is seen in untreated animals.
Monoreactive and Polyreactive Rheumatoid Factors Produced by in Vitro Epstein‐Barr Virus‐Transformed Peripheral Blood and Synovial B Lymphocytes from Rheumatoid Arthritis Patients
Authors: BURASTERO S. E. , CUTOLO M. , DESSI V. , CELADA F.
Published: June 2006

The CD5 membrane molecule, initially identified as an exclusive T‐cell marker, also defines a phenotypically and functionally distinct B‐lymphocyte population. In normal individuals, CD5+ B cells are committed to secrete‘natural’polyreactive (auto)antibodies, that is antibodies, mainly IgM, endowed with multiple antigen‐binding capabilities, including rheumatoid factor (RF) activity. At variance with this, in rheumatoid arthritis (RA) as well as in other autoimmune conditions, monoreactive autoantibodies binding with high affinity and specificity to a given self antigen have been isolated and the cells from which they originate differently related to the CD5+ B‐lymphocyte subset.

Here, we studied the proportions of CD5+ B cells and the characteristics, in terms of polyreactivity and monoreactivity, of RF produced by B lymphocytes in RA patients with classified disease activity. Our results suggest that patients with a more severe disease activity have higher proportions of CD5+ B cells and higher frequencies of B lymphocytes committed to secrete RF, with the characteristics of polyreactive antibodies. On the other hand, we did not find a significant difference between the proportions of peripheral B cells producing monoreactive RF in patients with high‐ versus patients with low‐activity RA. However, in two highly active RA patients, we found that synovial fluid, compared with peripheral blood, was significantly enriched for (IgG and IgA) monoreactive RF‐producing B cells.