bluuebunny/crossref_metadata_2025 huggingface dataset:
Agonistic Effects of Anti‐CD2 and Anti‐CD16 Antibodies on Human Natural Killer Killing
Authors: UGGLA C. K. , GEISBERG M. , JONDAL M. , KNOWLES R. W.
Published: June 2006

Two monoclonal antibodies (MoAb), 9–1 (anti‐CD2) and 3G8 (Anti‐CD16), were previously shown to enhance the cytotoxic activity of human natural killer (NK) cells. The present study examined the effect of 9–1 and 3g8 with different effector and target cell to determine whether they activate NK cells through a common mechanism. Analysis of purified lymphocyte subpopulations demonstrated that the CD3+ CD16+ CD3‐ NK effector cell population is enhanced by both antibodies, while purified CD2+ CD16‐ CD3+ T Cells are not activated by either antibody. Although both antibodies enhance killing of K‐562 and Daudi, killing of T‐cell lines is enhanced by 9–1 and enhanced by.3G8. In constrast, killing of the promyelocytic cell line, U‐937 is inhibited by 4–1 and enhanced by 3G8. On NK‐susceptible cells the pattern of enhancement with 3G8, an IgG1 MoAb, is consistent with the pattern of target cell expression of an Fc receptor, FcR II, known to bind IgG1 antibodies. This suggests that 3G8 may cross‐link effector and target cells through CD16 on the effectors and FcR II on these targets. This could activate NK killing by a mechanism similar in antibody‐dependent cellular cytotoxicity reactions (ADCC) with the MoAb in the reverse orientation. The failure of JG8 F(ab′)2 fragments to enhance NK killing, further supports the reverse ADCC mechanism of enhancement by.3G8. The pattern of enhancement mediated by 9–1, an IgG3 MoAb, is not correlated with any target cell Fc‐receptor known 10 bind IgG3 MoAb. The effect of 9–1 may result, instead, from its binding to the unique 9–1 epitope on the CD2 molecule involved in CD2‐medialed T‐cell activation, as previously described. Alternative mechanisms, including activation of NK killing by 9–1 mediated cross‐linking of CD2 and CD16 on the effector cells, have also been discussed.
Lymphocyte Extracellular Matrix Interactions
Authors: OFOSU‐APPIAH W. , WARRINGTON R. J. , MORGAN K. , WILKINS J. A.
Published: June 2006

Limiting dilution analysis was performed in the presence of interleukin 2 (IL‐2) on lymphocytes isolated from the synovial fluid (SF) and peripheral blood (PB) of patients with rheumatoid arthritis (RA) and PB of normal donors. Clones of theses ‘spontaneously’ IL‐2‐responsive cells from PB and SF were compared for their reactivity with component of the extracellular matrix (i.e. native or denatured type I or type II Collagen and proteoglycan). It was determined that all clones from both PB and SF were activated to produce interferon (IFN) in the presence of any of the connective tissue components (CTC) Clones derived from normal PH behaved in a similar fashion hut produced lower IFN‐γ levels There was a synergy between the CTC and serum or plasma fibronectin, which was more apparent when soluble CTC were used as the stimuli rather than immobilized CTC. The fibronectin alone was unable to induce 1FN‐γ production under any of the conditions tested (i.e. soluble or immobilized). These results demonstrate that clones of IL‐2‐responsivc T cells can be activated by interactions with connective tissue components lo produce IFN
Ability of Pure Resting CD8+ Human T Cells to Respond to Alloantigen
Authors: LEIVESTAD T. , HALVORSEN R. , GAUDERNACK G. , THORSBY E.
Published: June 2006

The ability of highly purified resting human CD8 cells to respond to alloantigens in vitro was examined. Necessary conditions for Induction of interleukin 2 receptors (IL‐2R), IL‐2 production, proliferative responses, and various effector functions were determined. Allogeneic non‐T cells induced IL‐2R expression in a high proportion of resting CD4 and CD8 cells, but only CD4 cells produced detectable amounts of IL‐2. CD8 cells also became IL‐2 responsive upon stimulation with purified resting allogeneic CD4 or CD8 cells, indicating that HLA class I+, II‐ cells alone may initiate activation of resting CD8 cells. The activated CD8 cells needed the presence of simultaneously activated CD4 cells or exogenous IL‐2 to be able to synthesize DNA. Effector functions like cytotoxicity, mixed lymphocyte culture (MLC) suppression, or gamma interferon (IFN‐γ) production were also only detectable when the CD8 cells were activated in the presence of IL‐2.
Primary and Secondary Responses to (NANP) Peptides by Plasmodium falciparum Sporozoites in Various Strains of Mice
Authors: DEL GIUDICE G. , CHENG Q. , MAZIER D. , MEUWISSEN J. H. E. T. , GRAU G. E. , CORRADIN G. , PESSI A. , VERDINI A. S. , LAMBERT P.‐H.
Published: June 2006

The repetitive epitope (Asn‐Ala‐Asn‐Pro=NANP) of the Plasmodium falciparum circumsporozoite protein is considered as the basis for the development of a recombinant or synthetic subunit vaccine against malaria. Vaccines consisting of (NANP)n molecules coupled to carrier proteins have already been tested in trials in human volunteers with partial success. In this paper we show that C57BL/6 mice, genetically responsive to carrier‐free (NANP)n molecules, exhibit a secondary antibody response to (NANP) if they are primed with carrier‐free (NANP)40 synthetic peptide, and then challenged with P. falciparum sporozoites However, such a sporozoite‐mediated boosting effect is not observed if C57BL/6 and BALB/c mice were previously primed with (NANP)40 peptide conjugated to carrier proteins the genetic restriction of the murine antibody response to (NANP)n is overcome when mice bearing seven different H‐2 haplotypes are immunized with entire P. falciparum sporozoites. These results may have implications for the understanding of natural or induced anti‐sporozoite immunity, and show that the use of T‐cell epitopes from the plasmodial antigenic repertoire would be very likely to represent an efficient approach for the development of a subunit malaria vaccine.
T‐Cell Phenotypes after Stimulation of Human Mononuclear Cells by Pokeweed Mitogen or Pokeweed Mitogen Bound to Erythrocytes
Authors: UITERDIJK H. G. , VAN DER KEUR M. , BREEDVELD F. C.
Published: June 2006

Stimulation of human peripheral blood mononuclear cells (PBMC) by pokeweed mitogen bound to erythrocytes (E‐PWM) has been found to an increased blast cell formation, lymphocyte proliferation, and enhanced immunoglobulin production, compared to stimulation of PBMC by PWM. Using flow cytometric analysis we compared the T helper/inducer (CD4+) to T suppressor/cytotoxic (CD8+) cell ratios of PBMC after stimulation by PWM and by E‐PWM. E‐PWM mi found to induce significantly lower CD4+ CD8+ ratios on days 6 and 9 of the culture than PWM did This effect was due predominantly to a relative increase in CD8+ T cells after stimulation of PBMC by E‐PWM, compared with stimulation by PWM. However, the increase in T suppressor/cytotoxic cells on days 6 and 9 after E‐PWM stimulation was accompanied by a simultaneous relative decrease in CD4+/2H4+ T cells (T independent‐inducer cells) and by a relative decrease in CD8+/Leu‐15+ T cells (CDA+/2H4+ independent T suppressor cells) on day 9, compared with stimulation by PWM. These results suggest that the greater immunoglobulin production after stimulation of PBMC by E‐PWM than by PWM may be the result of a relative lack of suppression on fully differentiated B cells.
The Interaction of Ethanol with Human Monocyte IgG‐Fc Receptors, Characterized by Monoclonal Antibodies Raised against Two Distinct Receptor Subpopulations
Authors: MØRLAND B. , MØRLAND H.
Published: June 2006

Human blood monocytes (Mo) in medium containing 10% autologous serum were exposed to ethanol (160 mm) at 37°C for 15 min. After being washed, the cells were incubated with murine monoclonal antibodies (MoAb), one binding to the 40 kDa Fc receptor (FcR) (MoAb IV3) and the other to the 72 kDa FcR (MoAb 32). The incubation was performed with and without excess of human or rabbit IgG. The amount of receptor‐bound MoAb was evaluated by fluorescein isothiocyanate (FITC)‐labelled anti‐mouse IgG. Most control Mo bound MoAb IV3 (90 ± 8% stained cells) while only 52 ± 2% Mo were positively stained by MoAb 32. The staining increased in the presence of human IgG in the assay mixtures. Pre‐incubation with 160 mm ethanol reduced the MoAb IV3 binding (61 ± 2% stained cells), but had no significant effect on the binding of MoAb 32. Wash‐out experiments indicated normalization of receptor function (MoAb IV3 binding) after 4 h. Treatment of medium or serum with ethanol before incubation of the Mo had no effect. It was concluded that a brief exposure of human Mo to ethanol leads to changes in a subpopulation of IgG FcR. Since these changes appeared when MoAb were used against the receptors, they probably represent a decrease in functional receptors and not changes in affinity.
Recognition of Idiotypic Structures in the Thymus
Authors: ZÖLLER M.
Published: June 2006

During the passage through the thymus. T cells are selected which recognize sell major histocompatibility complex (MHC) antigens with Sow avidity. Whether the T‐cell repertoire for recognition of altered self is also built up intrathymically or in the periphery, and whether it is determined exclusively by external antigens or is shaped by the internal environment is still a matter of debate. This question was addressed by analysing the responsiveness of thymocytes during post‐natal development towards a nominal antigen [trinitrophenyl (TNP)] and an anti‐TNP monoclonal antibody (Sp6), which carries a recurrent idiotype. During the first weeks of life, in vitro cultures of thymocytes proliferated strongly in the absence of nominal antigen. Proliferation rates were not increased by the addition of nominal antigen [TNP ovalbumin (OA)], but a significant increase was noted in the presence of Sp6, thymocytes recognizing the processed immunoglobulin. After in vivo stimulation with TNP conjugates, ‘antigen‐specific’ clones could also he detected in the thymus, the frequency of clones proliferating in response to Sp6 being further augmented. With increasing age, the proliferative capacity of thymocytes from unstimulated and antigenically stimulated mice decreased significantly. Responsiveness of spleen cells (SC) differed in some respects. The response towards Sp6 decreased with age, while antigen‐Specific clones were detected at increasing frequencies during post‐natal development. Furthermore, after antigenic stimulation, the frequency solely of antigen‐specific, but not of Sp6‐specinc clones was increased. Thus, it appears that the T‐cell repertoire is shaped already during the intrathymic passage, being influenced primarily by the B‐cell repertoire and modulated further by external antigen.
Induction of Interleukin 1α (IL‐1α) and IL‐1β mRNA Expression and Cellular IL‐1 Production by Anti‐HLA‐DR Antibodies in Human Monocytes
Authors: PALAKAMA T. , SIHVOLA M. , HURME M.
Published: June 2006

We studied the role of HLA class II antigens in the regulation of interleukin 1 (IL‐1) production in human monocytes. Monocytes were cultured with monoclonal anti‐HLA‐DR antibodies for 24 h after which cellular (i.e. intracellular and membrane‐associated) IL‐1 production, IL‐1 secretion, and the expression of IL‐1α and IL‐1β mRNA were determined. One of the anti‐HLA‐DR antibodies tested (anti‐HLA‐DR, Becton Dickinson) clearly induced IL‐1α and IL‐1β mRNA expression and cellular IL‐1 production. The other anti‐HLA‐DR antibody tested (OKIa1, Ortho) had no effect on IL‐1 production. The stimulatory effect of anti‐HLA‐DR was enhanced by IFN‐γ in both fresh and aged monocytes. A synergistic effect by anti‐HLA‐DR and suboptimal doses of LPS (1 ng/ml) on both cellular IL‐1 production and secretion was also demonstrated. The possibility of contaminating LPS causing the IL‐1‐inducing effect of anti‐HLA‐DR was excluded by the inability of polymyxin B to abolish the anti‐HLA‐DR‐induced IL‐1 production.
Specific Depletion of Mature T Lymphocytes from Human Bone Marrow
Authors: GEISLER C. , MØLLER J. , PLESNER T. , DICKMEISS R. , PALLESEN G. , LARSEN J. K. , JACOBSEN N. , SVEJGAARD A.
Published: June 2006

An effective method for specific depletion of mature T lymphocytes from human bone marrow mononuclear cells (BMMC) with preservation of prethymic T cells and natural killer (NK) cells is presented. The BMMC were incubated with F101.01, a monoclonal antibody recognizing an epitope of the T‐cell receptor CD3 complex, and subsequently with immunomagnetic beads. Flow cytometric analysis demonstrated that mature T cells were efficiently depleted and that NK cells and prethymic T cells were preserved in the BMMC. Furthermore, T cell‐mediated immune reaction as measured by thymidine incorporation after stimulation with phytohaemagglutinin was abolished, whereas NK activity as measured by 51Cr release using K562 as target cells was preserved. Recovery of colony‐forming units of granulocyte macrophages was 60–70%.
Expression of Activation Markers on CD4+ and CD8+ Cells from Synovial Fluid, Synovial Tissue, and Peripheral Blood of Patients with Inflammatory Arthritides
Authors: HOVDENES J. , GAUDERNACK G. , KVIEN T. K. , EGELAND T.
Published: June 2006

We studied the expression of the Tac antigen, the transferrin receptor (Tfr‐R), HLA class II antigens (DR, DQ, DP), CD30, and Act 1 on purified CD4+ and CD8+ cells isolated from synovial fluid (SF), synovial tissue (ST), and peripheral blood (PB) of patients with rheumatoid arthritis (RA) and with non‐RA inflammatory arthritides (not ST). Subfractionated T cells of PB from healthy individuals served as controls. SF CD4+ cells from RA and non‐RA arthritides expressed the Tac antigen much more frequently than corresponding CD8+ cells (54 and 58% versus 16 and 17%). In contrast, SF CD8+ cells of both patient groups expressed the HLA class II antigens rather more frequently than the corresponding CD4+ cells (88 and 68% versus 72 and 40%), Tfr‐R expression was low on CD4+ and CD8+ SF T cells from both patient groups SF T cells did not express CD30, and their expression of Act 1 did not differ from that of normal PB T cells. The RA ST findings were similar to those of RA SF. The overall expression of activation markers on PBT cells of patients was slightly higher than on those of normal controls, and the RA group was slightly higher than the non‐RA group. The results show that intra‐articular T cells in arthritis are activated and that CD4+ and CD8+ subsets differ in their expression of Tac antigen and HLA class II antigens. There were also similar patterns of activation markers on both CD4+ and CD8+ SF cells from RA and non‐RA arthritis patients, suggesting that several types of arthritis display a similar immunopathogenesis in the joints.
Sideways Killing: The Cytolysis of Fc Receptor‐Bearing Cells through Bridging to Cytolytic T Lymphocytes by Antibodies Specific for the T‐Cell Receptor‐T3 Complex
Authors: ITO M. , USUBA O. , UNKELESS J. C. , SCHREIBER R. , CELADA F. , BONA C. A. , MORAN T. M.
Published: June 2006

Cytolylic T lymphocytes (CTL) cause cytolysis of foreign or virus‐infected syngeneic cells when recognition of the target plus major histocompatibility complex (MHC) occurs via the T‐cell receptor (TCR). The recognition event leads to intimate contact between the two cells and activation of the cytolytic effector. Activation and target cell lysis can also occur in the presence of antibodies to the TCR. This is accomplished by bridging the effector cell TCR to the target cell FcR by an anti‐TCR monoclonal antibody (MoAb). Recent findings have placed the role of the FcR in this event in a questionable light. We confirm the importance of FcγR by demonstrating that: (a) melanoma cells are killed by CTL clones in the presence of anti‐TCR CD3 antibodies only when the melanoma cells express the FcγR on their surface; (b) native Ig, heat‐aggregated Ig, or an Fc fragment from an antibody expressing the same isotype as the anti‐TCR antibody can block the killing of high avidity FcγRI‐bearing cells mediated by anti‐TCR antibody (F23.1); and (c) anti‐FcγR MoAb (2.4G2)and a truncated soluble FcγRII molecule inhibit the killing of low‐avidity FcγRII‐bearing cells mediated by anti‐CD3 MoAb (145–2C11). Thus, we show that both high‐avidity FcγRI and low‐avidity FcγRII can mediate sideways killing depending upon the isotype of the anti‐TCR antibody and the type of FcR present on the target cell surface.
The Effect of Gamma Interferon on Interleukin 1 Release of Human Monocytes
Authors: SIHVOLA M. , HURME M.
Published: June 2006

The effect of gamma interferon (IFN‐γ)on interleukin 1 (IL‐1) production by human monocytes induced either by bacterial lipopolysaccharide (LPS) or silica dust was examined. Release of biologically active IL‐1 from LPS‐activated monocytes was enhanced in a dose‐dependent manner with IFN‐γ. The augmenting effect of IFN‐γ was most marked in monocytes stimulated with a sub‐optimal dose of LPS (1 ng/ml). IFN‐γ delivered the augmenting effect only if present at the beginning of the IL‐1 induction. The IL‐1 released in the presence of IFN‐γ was characterized by gel filtration on fast protein liquid chromatography (FPLC) and by isoelectric focusing; the augmented form of IL‐1 was a 17 kDa molecule, with pI 7, i.e. IL‐1β. In contrast to these data, IFN‐γ had a decreasing effect on IL‐1 release by monocytes stimulated with silica dust, in monocyte cultures stimulated with a sub‐optimal dose of silica (100 μg/ml), only minute amounts of biologically active IL‐1 were released in the presence of IFN‐γ. With higher silica concentrations the decreasing effect was less strong. The effects of IFN‐γ on the levels of IL‐1β mRNA were also analysed. IFN‐γ did not alter the accumulation of IL‐1β mRNA in LPS‐stimulated monocytes. In contrast in silica‐stimulated monocytes IFN‐γ reduced the steady‐state levels of IL‐1bT mRNA. Thus, these data indicate that, depending on the stimulating agent, IFN‐γ either down‐ or up‐regulates IL‐1 production: the former takes place mainly al the level of transcription, while the latter occurs with post‐transcriptional mechanisms.
Differential Sensitivities of Purified Human Eosinophils and Neutrophils to Defined Chemotaxins
Authors: MORITA E. , SCHRÖDER J.‐M. , CHRISTOPHERS E.
Published: June 2006

Functions of eosinophils and neutrophils isolated from normal human blood were determined by measuring chemotactic migration and release of β‐glucuronidase. Four well‐Characterized chemotaxins, the complement fragment C5a, formyl‐methionyl‐leucyl‐phenylalanine (FMLP), platelet‐activating factor (PAF), and leukotriene B4 (LTB4) were used as stimuli. Neutrophils showed remarkable chemotactic responses to all four chemotaxins. In contrast, eosinophils showed a significant chemotactic response to C5a and PAF, but only weak responses to FMLP and LTB4. Using these chemotaxins we found the following order of chemotactic potency (maximal number of migrated cells): C5a=LTB4>FMLP>PAF for neutrophils and PAF=C5a>LTB4=FMLP for eosinophils. Neutrophils elicited a significant β‐glucuronidase release when stimulated by C5a and FMLP, whereas only small amounts were released with PAF and LTB4. On the other hand, an amount of β‐glucuronidase released from eosinophils comparable to that from neutrophils was elicited only with C5a. FMLP, LTB4, and PAF caused the release of small percentages of β‐glucuronidase. The important cellular functions of eosinophils and neutrophils, chemotaxis and enzyme release, are thought to be controlled by differential responsiveness to stimuli.
Regulation of Intercellular Adhesion Molecule‐1 Expression on Endothelial Cells with Correlation to Lymphocyte‐Endothelial Binding
Authors: RENKONEN R
Published: June 2006

Intercellular adhesion molecule‐1 (ICAM‐1) expression on cultured human umbilical cord vein endothelial cells (EC) and its correlation to the leucocyte adherence to EC was investigated. Gamma interferon (IFN‐γ) increases the ICAM‐1 expression on EC and concomitantly also increases the binding of leucocytes to EC in vitro. Methylprednisolone down‐regulates the IFN‐γ‐induced binding, but does not alter the ICAM‐I expression. Leukotriene B4 (LTB4) rapidly increases the binding of lymphocytes to EC, but does not induce ICAM‐1 expression on the EC. The dissociation between ICAM‐1 expression and leucocyte binding to EC clearly indicates that ICAM‐1 is not the only ligand.
Increased Thymic Size and Thymocyte Interleukin 2 Production in Androgen‐Resistant Mice
Authors: OLSEN N. J. , KOVACS W. J.
Published: June 2006

The functional significance of androgen receptors in thymocytes is unknown. To investigate whether such receptors might mediate androgen‐induced effects on thymocyte proliferation or differentiation we examined mice bearing a known defect in the gene coding for the androgen receptor. This mutation, termed testicular feminization (Tfm/Y), renders these mice resistant to the action of androgenic hormones. Testicular feminization mice were found to have large thymuses that were an average of 2.8 times as heavy as those of their unaffected male litter mates, and contained up to 36 times as many thymocytes. Similar findings were observed when Tfm mice were compared with C57B1/6 control mice. Thymocytes from androgen‐resistant mice produced several limes more interleukin 2 in culture than did thymocytes from control mice. A small but significant reduction in the population of cells bearing neither CD4 nor CDS surface markers (‘double negatives') was observed in the androgen‐resistant mice. These data indicate that androgen resistance is associated in the Tfm/Y mouse with alterations in thymocyte number, phenotype, and function that may be attributable to lack of androgen action during thymic development.
Target Cell Lysis by Natural Killer Cells is Influenced by β2‐Microglobulin Expression
Authors: MÜLLBACHER A. , KING N. J. C.
Published: June 2006

Natural killer (NK) cells form part of the vertebrate defence against viruses and tumours, but show only limited specificity. The molecule(s) recognized by NK cells on target cells are at present unknown. Major histocompatibility complex (MHC) class I antigen concentration on target cells is inversely correlated with NK cell lysis. Here we show that MHC class I‐unassociated β2‐microglobulin (β2‐m) expression is involved in NK cell‐target cell interaction. Two human MHC class I negative cell lines. Daudi and K562, are differentially susceptible to NK cell lysis. Daudi cells are β2‐m‐negative and resistant to NK lysis, K562 are β2‐m‐positive and highly susceptible to lysis by NK cells. Interferon (IFN) treatment augments β2‐m expression and NK lysis of K562, but not in Daudi cells. NK cell lysis of K562, but not YAC‐1 cells, can be inhibited by monoclonal anti‐human β2‐m antibody. Furthermore, susceptibility of mouse embryo fibroblasts (MEF) to NK lysis can be increased by infection with recombinant vaccinia virus expressing the human β2‐m gene.
T‐Cell Response to Anti‐CD2 Monoclonal Antibodies in Down's Syndrome
Authors: BERTOTTO A. , CRUPI S. , ARCANGELI C. , GERLI R. , MARINELLI I. , VELARDI A. , VACCARO R.
Published: June 2006

Peripheral blood mononuclear cells from 10 subjects with cytogenetically documented Down's syndrome (DS) and from 10 age‐ and sex‐matched healthy controls were assayed for their ability to proliferate in response to phytohaemagglutinin, anti‐CD3 (OKT3), or anti‐CD2 (T112 plus T113) monoclonal antibodies. Interleukin 2 (IL‐2) receptor expression and IL‐2 production in mitogen‐pulsed lymphocyte cultures was also investigated in parallel. DS cells responded poorly to all the blastogenic stimuli used in this study. Under certain experimental conditions (anti‐CD3 or anti‐CD2 antibody stimulation), the patients' lymphocytes expressed low levels of IL‐2 surface receptors and failed to produce normal amounts of this lymphokine. Studies are currently in progress in our laboratories to determine whether these defects are due to an impairment of the early signalling events surrounding the complexing of CD3, CD2, or lectin receptors to their respective ligands.
Deficiency of the Eighth Component of Complement. Evidence for Linkage of C8α‐γ Pattern with C8β Deficiency in Sera of Twelve Patients
Authors: NÜRNBERGER W. , PIETSCH H. , WILLERS R. , BUFON T. , HÄNSCH G. M. , SEGER R. , RODRIGUEZ‐VALVERDE V. , SCHROTEN H. , HERSHKO C. , TEDESCO F. , WAHN V.
Published: June 2006

The C8α‐γ subunit of the eighth component of complement was analysed by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis and immunoblotting in sera from 68 normal individuals, 12C8β‐deficient patients (from seven unrelated families), and 10 of the parents of the latter. Three different forms of the C8α‐γ subunit were observed: 34/68 normal individuals were found to have a C8α‐γ triple band (termed C8α‐γ1, C8α‐γ2, C8α‐γ3 variants), 23/68 the C8α‐γ2 and C8α‐γ3 variants, and 11/68 the CSα‐γ1 and C8α‐γ3 variants. In contrast, all C8β‐deficient patients had detectable C8α‐γ2 and C8α‐γ3 variants but lacked the C8α‐γ1 variant in addition to the C80 subunit. Three out often parents of the C8β‐deficient patients were found to have the C8α‐γ triple band, whereas 7/10, like their children, had the C8α‐γ2 and C8α‐γ3 variants only. We conclude that there is a linkage between the C8α‐γ pattern and C8β deficiency. These data may support earlier findings that in humans the genes encoding for C8α‐γ and C8β are closely linked on chromosome 1.
Binding Properties of Human Anti‐DNA Antibodies to Cloned Human DNA Fragments
Authors: SANO H. , TAKAI O. , HARATA N. , YOSHINAGA K. , KODAMA‐KAMADA I. , SASAKI T.
Published: June 2006

The DNA–anti‐DNA antibody immune complexes were isolated from plasma of systemic lupus crythematosus (SLE) patients and DNA fragments separated from immune complexes were subjected to molecular cloning. The resulting recombinant DNA clones showed a molecular size of 37–79 base pairs, a high guanine and cytosine content, high frequencies of CpG dinucleotides, and palindromic sequences, and also clusters of G+C‐ and A+T‐rich segments. These clones hybridized randomly to total human DNA. The reactivity of dsDNA antibodies, both monoclonal and polyclonal, from SLE was examined with a cloned SLE antigen DNA. A competitive inhibition assay showed that human monoclonal antibodies had at least one magnitude higher affinity to the cloned DNA than to the native DNA fragments. In order to characterize the factors that were recognized by antibodies, human G+C‐rich and also A+T‐rich 100 bp DNA fragments were cloned, and their base sequences determined. The antibody showed a higher affinity to the G+C‐rich DNA fragment (71% G+C) than to the A+T‐rich DNA fragment (46% G+C). When cytosines in CpG doublets in G+C‐rich fragments were methylated (mCpG), the reactivity increased up to 100‐fold. The native anti‐DNA antibodies from SLE patients also showed preferential binding to G+C‐rich fragments. These observations suggested that human anti‐dsDNA antibodies may recognize some unique structures around the G+C regions or G+C clusters of DNA.
Modulation of Both Interleukin 2 Receptor Expression and Interleukin 2 Production during Experimental Murine Trypanosoma cruzi Infection
Authors: ROTTENBERG M. , LINDQVIST C. , KOMAN A , SEGURA E. L. , ÖRN A.
Published: June 2006

A massive activation of T cells takes place during the early stages of a Trypanosoma cruzi infection in mice. We present data indicating that substantial amounts of Interleukin 2 (IL‐2) are secreted and IL‐2 receptors are expressed during the period of increased proliferation (4–7 days post infection). Both concanavalin A‐induced proliferation and IL‐2 production are markedly decreased later in the acute infection (around 3 weeks post infection). This proliferation cannot be restored by externally added IL‐2 Simultaneously, there is a drastic reduction in the number of both high‐and low‐affinity IL‐2 receptors. The reduction is not attributable to the elimination of a particular T‐cell population. In vivo administration of recombinant IL‐2 failed to improve resistance to T. cruzi parasites as measured by parasitaemia and mortality.
Plasticity of T‐Cell Function
Authors: MELCHERS I. , RODEWALD H.‐R. , RZEPKA R.
Published: June 2006

EL‐4 lymphoma cells are able to suppress the primary humoral immune response of spleen cells to sheep erythrocytes or 4‐hydroxy‐3‐iodo‐5‐nitrophenylac‐keyhole limpet haemocyanin (NIP‐KLH (in vitro. Typically, the cells suppress very efficiently in small numbers, but lose this capacity as the numbers increase. Three clones were analysed and this fluctuation in function was paralleled by a fluctuation in the expression of CD8 (Ly‐2). Clones were incubated for 2 days, starting from different seeding concentrations, and analysed with cytofluorography. Neither Thy‐I nor CDS (Ly‐1). H‐2 K, H‐2 D, LFA‐1 (all positive) nor CD4 (L3T4) or MEL‐14 (both negative) were influenced by this treatment. In contrast, cells were CD8‐ at high seeding concentrations, and CD8‐ at low seeding concentrations. When cell cultures grew to higher densities, the cells again lost the capacity to express CD8. Experiments testing the suppressive capacity of individual EL‐4 clones after preculture at different densities or in the practice of antibodies against CD8 suggest that the efficiency of suppression may well be correlated to the amount ofCD8 expressed.
Regulation of the Immune Response to Hepatitis B Virus and Human Serum Albumin
Authors: HELLSTRÖM U. B. , SYLVAN S. P. E.
Published: June 2006

Peripheral B and T cells sensitized to human serum albumin (USA) were found in a cohort of patients chronically infected with hepatitis B virus (HBV). Throughout this study, two groups of symptomatic chronic hepatitis B surface antigen (HBsAg) earners could be distinguished, characterized by divergent T‐cell regulation of the spontaneous IgG anti‐HSA secretion. Patients in a quiescent phase of the disease [patients with chronic persistent hepatitis B (CPH), anti‐HBe reactivity and absence of viral replication, group A] bad circulatory in vivo HBsAg‐HSA preactivated B cells with the capacity to secrete spontaneously IgG antibodies with specificity for HSA when isolated and cultured. The addition of autologous T lymphocytes at a T/B‐cell ratio of 8,0 suppressed the spontaneous anti‐HSA secretion. In contrast, patients in an active stage of the disease exhibited in vivo preactivated T cell sensitized helper cell functions on the spontaneous IgG anti‐USA secretion Memory T cells, sensitized to low concentrations of HbsAg‐HSA with disparate regulatory functions, were also detectable in the two groups of patients.
The Primary Structure of Equine Serum Amyloid A (SAA) Protein
Authors: SLETTEN K. , HUSEBEKK A. , HUSBY G.
Published: June 2006

The complete amino acid sequence of equine serum amyloid A (SAA) was elucidated. The protein consists of 110 amino acid residues and contains an 8‐amino acid residue insertion tentatively located between positions 69 and 70, as compared with human SAA. Microheterogeneities were detected at positions 16,44, and 59, compatible with the existence of more than one SAA gene in the horse. This corresponds to the situation in man and mouse. Pronounced homology with SAA from man and several animal species was observed, thus confirming the conserved structure of this acute phase reactant and apoprotein of high‐density lipoprotein (HDL).
T Lymphocytes in Human Gut Epithelium Preferentially Express the α/β Antigen Receptor and are often CD45/UCHL1‐Positive
Authors: BRANDTZAEG P. , BOSNES V. , HALSTENSEN T. S. , SCOTT H. , SOLLID L. M. , VALNES K. N.
Published: June 2006

A revived interest in intraepithelial lymphocytes (IEL) has been elicited by several recent reports suggesting that murine and avian intestinal epithelium contains mainly CD3+CD8+ cells expressing the γ/δ T‐cell receptor (TcR) for antigen; this contrasts with systemically distributed T cells which preferentially employ the TcRα/β. An anatomical dichotomy in the distribution of these two T‐cell lineages has hence been proposed. Here we report that this concept does not hold true in man. In situ studies with monoclonal TcR‐framework antibodies showed that most (70–90%) human intestinal IEL (which are mainly CD3+CD8+) expressed TcRα/β. Moreover, almost half of the intraepithelial CD3+ cells were positive for the smallest (180 kDa) CD45 molecule (UCHL1); this probably reflected that they are antigen‐primed and thus represent traditional CD3+CD8+α/β+ memory T cells.
Induction of Non‐Specific Immunosuppression in Mice by Mycobacterial Infections and Its Relationship to Macrophage Activation
Authors: APPELBERG R. , SOARES R. , FERREIRA P. , SILVA M. T.
Published: June 2006

The development of non‐specific immunosuppression during the infection of different strains of mice with three mycobacterial species was evaluated by studying the immune response to a heterologous antigen (sheep red blood cells) and comparing it with the induction of non‐specific resistance to a Listeria monocytogenes challenge. It was shown that early (at 15 days) immunosuppression developed in Mycobacterium avium‐susceptible mouse strains infected with a high inoculum dose [2.5 ± 106 colony forming units (CFU)] of virulent M. avium but not in resistant mice infected with a similar inoculum nor in susceptible mice infected by a smaller inoculum dose (2.5 ± 106 CFU). In the latter case it developed only during the second month of infection and was of smaller magnitude. An inoculum of M. avium of attenuated virulence did not induce immunosuppression. M. lepraemurium induced a late immunosuppression, which occurred when extensive bacterial proliferation had already taken place. The non‐pathogenic M. bovis BCG induced immunosuppression in C57BL/6 mice. The results do not establish a correlation between the development of generalized immunosuppression and susceptibility to infection. It could be seen that the early immunosuppression was observed in those situations where there was extensive macrophage activation as shown by the development of non‐specific resistance to a listeria challenge. The late immunosuppression was observed when bacterial proliferation was extensive.
Complement‐Fixing Properties of Human IgA Antibodies Alternative Pathway Complement Activation by Plastic‐Bound, But Not Specific Antigen‐Bound, IgA
Authors: RUSSELL M. W. , MANSA B.
Published: June 2006

The complement‐fixing properties of human IgA antibodies bound lo specific antigen, or coated directly on plastic surfaces, were examined in comparison with those of IgG antibodies. Use was made of antigen‐binding (anti‐staphylococcal α‐toxin) IgA and IgG monoclonal antibodies and normal polyclonal IgA and IgG, purified >99.9% by avoidance of denaturing processes. Complement‐fixation ELISA was used, with a high density of biotin‐conjugated staphylococcal α‐toxin bound to avidin‐coated plates for the efficient capture of antibodies, and conditions were adjusted for the assessment of classical and alternative pathways of complement activation. Although IgA coated directly on plastic surfaces activated the alternative complement pathway in a dose‐dependent manner, IgA antibodies bound to antigen failed to fix complement by either classical or alternative pathways. In contrast, IgG antibodies, either bound to antigen or coated directly on plastic, activated complement mainly by the classical pathway. It was concluded that the complexation of IgA antibodies with antigen is insufficient to elicit complement actuation: rather a degree of denaturation seems to play a part in the expression of alternative complement pathway‐activating properties by IgA.
NcoI Restriction Fragment Length Polymorphism (RFLP) of the Tumour Necrosis Factor (TNFα) Region in Primary Biliary Cirrhosis and in Healthy Danes
Authors: FUGGER L. , MORLING N. , RYDER L. P. , PLATZ P. , GEORGSEN J. , JAKOBSEN B. K. , SVEJGAARD A. , DALHOFF K. , RANEK L.
Published: June 2006

The restriction fragment length polymorphism of the human tumour necrosis factor (TNFα) region was investigated by means of 20 different restriction enzymes and a human TNFα cDNA probe. Only one of the enzymes, NcoI, revealed a polymorphic pattern consisting of fragments of 10.5 and 5.5 kb, which behaved as alleles. In a panel of 108 random, healthy, unrelated Danes, the phenotype frequencies of the 10.5 and 5.5 kb bands were 0.94 and 0.53 and the gene frequencies were 0.71 and 0.29, respectively. The test for Hardy‐Weinberg equilibrium showed no significant deviation from the expected values. The 5.5 kb band was strongly positively associated with HLA‐DR3, HLA‐B8, and HLA‐A1. In 22 patients with primary biliary cirrhosis a significantly (corrected P= 0.024) decreased frequency of the 10.5 kb fragment was found. Additional studies are in progress to substantiate this association.
Failure to Synthesize the Human T‐Cell CD3‐ζ Chain and Its Consequence for the T‐Cell Receptor‐CD3 Complex Expression
Authors: GEISLER C. , KUHLMANN J. , PLESNER T. , RUBIN B.
Published: June 2006

The T‐cell antigen receptor is composed of two variable chains (α and β, termed TcR) which confer ligand specificity, and four constant chains (γ, δ,ɛ, and ζ, collectively termed CD3) whose functions are not Cully understood. To explore the role of the individual CD3 components, the human T‐cell tumour line Jurkat was chemically mutagenized followed by negative selection with F101.01 (a monoclonal antibody against the TcR‐CD3 complex), and cloning. Growing clones were analysed for TcR‐CD3 expression by immunofluorescence. One clone, J79, was found to express greatly diminished levels of TcR‐CD3. This clone produced all the TcR‐CD3 components except the CD3‐ζ, as demonstrated by metabolic labelling and immunoprecipitation followed by one‐ and two‐dimensional sodium dodecyl sulphate‐polyacrylamide gel electrophoresis. These data indicate that the CD3‐ζ determines the normal intracellular fate of the TcR‐CD3 complex, and that the CD3‐ζ is necessary for the intracellular transport and expression at the cell surface of the TcR‐CD3 complex.
Inhibition of Human Natural Killer Cell and Lymphokine‐Activated Killer Cell Cytotoxicity and Differentiation by Vitamin D3
Authors: LEUNG K. H.
Published: June 2006

Recent data suggest that vitamin D3 may be capable of immunoregulation after it is converted to an active metabolite, 1,25‐dihydroxyvitamin D3 (1,25(OH)2D3). The effect of vitamin D3 and 1,25(OH)2D3 on human natural killer (NK) cells and their activation by interferon (IFN) and interleukin 2(IL‐2) was investigated. Vitamin D3 and 1,25(OH)2D3 inhibited NK cytotoxicity in a dose‐dependent manner. Pretreatment of non‐adherent (NA) cells at 37°C for 18 h with the vitamins also led to inhibition of NK activity. Both the inhibition of NK lysis and pretreatment of NA cells were dependent on the concentrations of fetal calf serum (FCS) in the medium. The inhibition of NK activity was less effective in the presence of 10% FCS than with 1% FCS. Vitamin D3 inhibited both IFN and IL‐2 activation of NK activity. However, increasing doses of IL‐2 were able in abrogate the inhibition caused by vitamin D3. Vitamin D3 was able to inhibit NK activity of phytohaemagglutinin and IL‐2‐activaled cells, and also inhibit the proliferation and lymphokine‐activated killer activity induced by IL‐2. NA cells pretreated with vitamin D3 did not respond well to IL‐2. NA cells pretreated with tow doses of IL‐2 were sensitive to inhibition by vitamin D3 while those pretreated with high doses of IL‐2 were not. The data presented suggest that vitamin D3 and 1,25(OH)2D3 inhibit NK activity and LAK cellular differentiation.
Auto‐Antibodies to Tumour Necrosis Factor a in Healthy Humans and Patients with Inflammatory Diseases and Gram‐Negative Bacterial Infections
Authors: FOMSGAARD A. , SVENSON M. , BENDTZEN K.
Published: June 2006

A semi‐quantitative immunoblotting method was developed to screen for scrum auto‐antibodies against tumour necrosis factor α (TNFα). Forty nitrocellulose strips containing identical amounts of human recombinant TNFα (rTNFα) were prepared for each set‐up, and the anti‐TNFα antibody immunoreactivities were scored according to the density of the resulting colour reaction. A significant number of sera from apparently healthy donors contained detectable auto‐antibodies to TNFα (40%), while the strongest reaction was observed in 8%. A higher prevalence of anti‐TNFα antibodies was found in ten from patients with Gram‐negative bacterial septicaemia (66%), cystic fibrosis with chronic Pseudomonas aeruginosa lung infection (72%), and various rheumatic diseases (61%). The antibodies in sera from these patients belonged primarily to the IgG and IgM classes, the latter exhibiting the strongest response. Longitudinally collected serum samples from patients in septic endotoxin shock revealed that the anti‐TNFα antibodies were induced initially during septicaemia, reaching maximum reactivities within the first week and returning to tow or undetectable levels on days 9‐20.
Monoclonal Antibodies against Measles Virus Haemagglutinin React with Synthetic Peptides
Authors: MÄKELÄ M. J. , SALMI A. A. , NORRBY E. , WILD T. F.
Published: June 2006

The ability of 17 monoclonal antibodies (MoAb) antibodies measles virus haemagglutinin (MV‐H) to bind to 10 selected MV‐H‐specific synthetic peptides was tested in an enzyme immunoassay (EIA). Three peptides representing residues 126–135 (close to the NH2 terminus). 309–318 (middle), and 587–596 (C‐terminal) reacted with MoAb designated 48, 129, and 18, respectively. Binding of MoAb 129 to purified virus was abolished after pre‐incubation with the peptide 309–318. Similarly. MoAb 48 did not bind to the virus after absorption with the peptide 126–135. Longer peptides of 19 residues from the regions reacting with the MoAb were also synthesized and tested in EIA. None of the MoAb recognized these longer peptides when the latter were bound as free peptides on solid phase. However, MoAb 129 binding to purified virus was blocked equally well by peptides 304–322 and 309–318. In contrast, peptide 121–139 absorbed the reactivity of the MoAb 48 much more weakly than the shorter peptide 126–135, suggesting that the conformation of the longer peptide in solution is different. To analyse affinities in the antigen antibody reactions, the plates were washed with buffers of varying pH after absorption of the MoAb to MV or peptides. The MoAb 129 bound both to MV and peptide 309–318 with equal affinity, but MoAb 48 and 18 bound to the peptides 126–135 and 587–596 with lower affinity than to the virus. This study indicates that regions corresponding to amino acids 126–135, 309–318, and 587–596 define antigenic sites of the H protein.
Stimulation of Histamine Receptors of Human Monocytoid and Hepatoma‐Derived Cell Lines and Mouse Hepatocytes Modulates the Production of the Complement Components C3, C4, Factor B, and C2
Authors: FALUS A. , WALCZ E. , BROZIK M. , ROKITA H. , FUST G. , HAJNAL A. , MERETEY K.
Published: June 2006

The influence of histamine (and the related agonists and antagonists) alone or in the presence of recombinant human interleukin 1α (IL‐1α) and gamma interferon (IFN‐γ) was studied on the production of complement components C3, C2, factor B, and C4 in vitro with human monocytoid cell line U937, hepatoma‐derived cell line HepG2, and mouse hepatocytes. Both U937 and HepG2 cells responded to histamine through H1 and H2 histamine receptors. The effect of histamine on the biosynthesis and gene expression of complement proteins was predominantly enhancing via the H1 histamine receptors and inhibitory through the H2 receptors. The actual predominance of the histamine receptor involved (and the outcome of the ligand interaction) seemed to be greatly affected by the simultaneous activation of the cells by IL‐1 or IFN‐γ.
Requirements for Induction of Activation and Proliferation of Human B Cells Analysed with Anti‐Idiotype Monoclonal Antibodies
Authors: DE RIE M. A. , VAN LIER R. A. W. , IMHOLZ M. J. M. , SCHUMACHER T. N. M. , VAN SCHIJNDEL G. M. W. , MIEDEMA F.
Published: June 2006

We have produced five monoclonal antibodies (MoAb) directed against idiotypic determinants of surface immunoglobulins (sIg) expressed on malignant B cells from a patient suffering from prolymphatic leukaemia (B‐PLL). The anti‐idiotype MoAb were characterized by immunofluorescence‐binding studies, allotype reactivity, and immunoprecipitation studies and were found to recognize at least two distinct epitopes on the sIg of the neoplastic B cells. Differential effects of the soluble anti‐idiotype MoAb on phorbol myristate acetate (PMA)‐induced B‐PLL‐cell proliferation were found: three types of anti‐idiotype MoAb could be distinguished: (1) MoAb that enhanced the PMA‐induced B‐PLL‐cell proliferation, (2) MoAb without effect, and (3) MoAb that inhibited the PMA‐induced B‐PLL‐cell proliferation. Addition of the calcium ionophore A23187 could abolish the differential effects of the anti‐idiotype MoAb on PMA‐induced B‐PLL‐cell proliferation. The negative effect of the type 3 MoAb on PMA‐induced B‐PLL‐cell proliferation was associated with a more than 10‐fold stronger binding to sIg expressed on the B‐PLL cells, compared with the other anti‐idiotype MoAb. The differential effects of the types 1 and 2 MoAb cannot be explained solely by differences in the Fc portion of the MoAb and binding characteristics. Neither did differences in epitope specificity necessarily lead to differential effects on PMA‐induced B‐PLL‐cell proliferation. In contrast to the clear differences found in the proliferation induction experiments, all MoAb were equally able to induce an early rise in free intracellular Ca2+ concentration. Our data suggest that for B‐cell proliferation to occur, apart from early rises of intracellular Ca2+, more prolonged [Ca2+]i elevations or additional intracellular activation signals are required. The differences in proliferative responses of B‐PLL cells to anti‐idiotype MoAb may be relevant for immunotherapy of B‐cell tumours with anti‐idiotype MoAb.
Comparison of Interleukin 1 Release and Interleukin 1 mRNA Expression of Human Monocytes Activated by Bacterial Lipopolysaccharide or Synthetic Lipid A
Authors: HURME M. , SERKKOLA E.
Published: June 2006

Several of the biological effects of bacterial lipopolysaccharide (LPS)can be induced by the lipid A part of the molecule. Here we show that in human peripheral blood monocytes, synthetic E. coli lipid A is as effective as the whole LPS molecule in inducing the production of interleukin 1 (IL‐1) bioactivity which remains associated to the cells (i.e. IL‐1α). In contrast, LPS‐ but not lipid A‐stimulated cells released the bioactive IL‐1 produced into the culture supernatant (mainly IL‐1β). Northern blotting analysis demonstrated, however, that LPS and lipid A are equally effective in inducing the accumulation of IL‐1α and IL‐1β mRNA. These data support the hypothesis that induction of IL‐1 biosynthesis and activation of the secretory mechanism for IL‐1 are independent phenomena.