bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical, parasitological and immunological features of canal cleaners hyper-exposed to Schistosoma mansoni in the Sudan
Authors: Satti M Z , Sulaiman S M , Homeida M M A , Younis S A , Ghalib H W
Published: November 2003

The present work was a longitudinal study on Schistosoma mansoni infection in occupationally hyperexposed canal cleaners in the Sudan and the influence of therapy on the parasitological and humoral immune parameters. Chronically infected canal cleaners (n=28) were more resistant to reinfection (Fisher’s exact test, P<0.05) than newly recruited canal cleaners (n=17). Chronically infected canal cleaners had a significantly higher degree of Symmers' fibrosis (χ2=19.1, P<0.0001), significantly larger portal vein diameter (P<0.05) and enlarged spleen (χ2=4.2, P<0.05) than recently infected, newly recruited canal cleaners. ELISA was used to detect IgG, IgA and IgM in response to whole worm homogenate (WWH) and cercarial homogenate (CH). Chronically infected canal cleaners had significantly higher IgG to WWH antigen than newly recruited canal cleaners and normally exposed individuals (P<0.05), while both chronically infected and newly recruited canal cleaners had higher IgG levels to CH antigen than normally exposed individuals (P<0.05). The newly recruited canal cleaners had a significantly higher IgM level to CH antigen than chronically infected canal cleaners (P<0.05). The IgG level to WWH antigen increased significantly after treatment in newly recruited canal cleaners and normally exposed individuals (P<0.05). The IgA level to CH antigen increased significantly after treatment in the chronically infected group (P<0.05). Comparison of the serological parameters between the different study groups with regards to infection and treatment is discussed.
Differential spontaneous expression of mRNA for IL-4, IL-10, IL-13, IL-2 and interferon-gamma (IFN-γ) in peripheral blood mononuclear cells (PBMC) from atopic patients
Authors: Esnault S , Benbernou N , Lavaud F , Shin H C , Potron G , Guenounou M
Published: November 2003

Distinct cytokine-producing T cell subsets are well known to play a major role in IgE production and to be differentially regulated in allergic patients, although the characterization of the type 1/type 2 cytokine pattern in PBMC during allergic responses remains to be clearly defined. The aim of this study was to determine whether different cytokine profiles are observed directly in PBMC of atopic donors. We attempted to study several cytokines (IL-2, IFN-γ, IL-4, IL-10 and IL-13) using not only ELISA but also polymerase chain reaction (PCR) techniques, because the frequency of cytokine-producing cells in peripheral blood is very low. All the patients were selected during their acute symptomatologic phase. Data showed a significantly higher production of IL-4 (P=0.05) and IL-10 (P<0.005) as determined by ELISA in phytohaemagglutinin (PHA)/phorbol myristate acetate (PMA)-stimulated mononuclear cells of atopic donors compared with controls, although spontaneous IL-4 production without stimulation was never detected within either atopic or control groups. The reverse-transcriptase (RT)-PCR technique appeared to be advantageous in that it allowed the detection of the spontaneous expression of cytokine mRNA in cells without stimulation. We found a clear expression of IL-4 mRNA spontaneously in all atopic patients, whereas normal donors in most cases did not show specific signals (P<0.0001). Less differences between atopic subjects and controls were found in IL-10 mRNA expression. Although the technique of RT-PCR amplification used in this study is semiquantitative, a reproducible and significant (P<0.001) enhancement of IL-10 mRNA expression was observed in atopic donors. A heterogeneous expression of IL-13 mRNA was observed in individuals from the two groups studied, although mean levels in atopic donors were slightly enhanced compared with controls (P=0.02). Furthermore, we did not observe any alteration in the expression of the type 1-derived cytokines such as IFN-γ and IL-2. In addition, we showed a lack of correlation between the expression of serum IgE (total or specific) and spontaneous IL-4 mRNA expression. This study showed a tendency of PBMC from atopic donors to express a type 2-like cytokine pattern, with IL-4 as the most discriminatory cytokine. Additionally, as the level of serum IgE has a low predictive value in allergic disease, and as the elevated expression of IL-4 that we found was not correlated with serum IgE, we could strongly suggest that the measurement of IL-4 in blood mononuclear cells may be of great value in the analysis of allergic responses in atopic donors.
Transforming growth factor-beta 1 (TGF-β1) down-regulates IgA Fc-receptor (CD89) expression on human monocytes
Authors: Reterink T J F , Levarht E W N , Klar-Mohamad N , Van Es L A , Daha M R
Published: November 2003

IgA is the predominant immunoglobulin in human secretions and the second most important immunoglobulin in the circulation on a quantitative basis. The clearance of IgA is dependent on the function of at least three types of receptors. One of these receptors recognizes the Fc portion of the IgA molecule, FcαR, which has been cloned recently. FcαR, also designated CD89, is found on a number of cells, including human glomerular mesangial cells, and monocytes. In this study we analysed the effect of TGF-β1, a cytokine with strong immunosuppressive function, on the expression of CD89 on freshly isolated monocytes. We found that TGF-β1 down-regulates CD89 expression on human peripheral blood monocytes in a dose-dependent fashion. Optimal down-regulation occurred at a concentration of 5 ng/ml. The down-regulation of CD89 by TGF-β1 is linear in time, with a mean down-regulation of 34 ± 13% after 24 h. Also at the mRNA level, CD89 expression was down-regulated by TGF-β1, suggesting regulation of CD89 at the transcriptional level. Monocytes pre-treated with TGF-β1 displayed a reduced response to IgA, as measured by IL-6 production by monocytes, in contrast to monocytes pre-treated with medium alone. These results suggest an important role for TGF-β1 in the regulation of CD89. This down-regulation may have direct consequences for the handling of IgA by human monocytes.
Effects of in vitro hyperthermia on proliferative responses and lymphocyte activity
Authors: Huang Y H , Haegerstrand A , Frostegård J
Published: November 2003

Fever is induced by both exogenous products like endotoxin, and endogenous cytokines, most notably IL-1 and IL-6, and tumour necrosis factor (TNF). These mediators are believed to interact with the hypothalamus, to induce enhanced body temperature. However, little is known about the biological effects of fever on the function of the immune system. We here report that a 90-min pulse of mild hyperthermia (40°C) induces enhanced proliferation of peripheral blood mononuclear cells (PBMC). This proliferative response was completely inhibited by antibodies to MHC class II, which had no effect on mitogen-induced proliferation of PBMC. The enzyme-linked immunospot (ELISPOT) assay is a sensitive method for detection of single cells secreting antibodies or cytokines. A 90-min pulse of mild hyperthermia (40°C) induced a significantly enhanced immunoglobulin production in PBMC, as determined by ELISPOT, indicating B cell activation. The T cell cytokine pattern both with and without stimulation with hyperthermia differed between individuals. Enhanced interferon-gamma (IFN-γ) secretion was noted at 39–41°C. This IFN-γ response was inhibited by antibodies to MHC class II and thus was MHC class II-restricted and dependent on antigen-presenting cells. None of the individuals tested showed IL-4 response after stimulation with hyperthermia. These findings favour the notion that fever may play an important role in immune responses, and it is possible that fever may act as a physiological adjuvant, with effects on the immune system both in infection and inflammation of other origins.
Epitope mapping of anti-glomerular basement membrane (GBM) antibodies with synthetic peptides
Authors: Hellmark T , Brunmark C , Trojnar J , Wieslander J
Published: November 2003

Autoantibodies to the non-collagenous (NC1) domain of the α3(IV)-chain of type IV collagen are found in sera from patients with anti-GBM nephritis. These antibodies have been shown to be pathogenic. In this study the antibody specificity has been investigated in patients with Goodpasture’s syndrome and from a patient with atypical anti-GBM antibodies, recognizing the α1(IV)-chain only. Overlapping synthetic peptides, covering the complete NC1 domains of the α1(IV)- and α3(IV)-chains were used in sandwich ELISA and competitive ELISA. None of the Goodpasture sera showed reactivity to the synthetic peptides. However, antibodies from the patient with atypical anti-GBM antibodies recognized a 20 amino acid peptide from the α1(IV)-chain. The reactive peptide was further narrowed down with glycine substitution of the different amino acids. We have localized the epitope to the four last C-terminal amino acids of the α1(IV)-chain, with the sequence 1754-MRRT. The two arginine residues were found to be essential for antibody binding. Threonine is important, while methionine is of less importance. These four amino acids are also determined to be the smallest peptide that could inhibit the binding of the autoantibodies to the native α1(IV)-chain. This study shows that overlapping peptides can be used to map linear epitopes. However, for conformational epitopes such as the Goodpasture epitope, other methods must be used. It would be prognostically important to know the fine specificity of anti-GBM antibodies, since the patient with anti-α1(IV) antibodies had a mild disease, while the Goodpasture patients with anti-α3(IV) antibodies had a rapidly progressive disease.
Elevation of plasma-soluble tumour necrosis factor receptors (TNF-R) in sarcoidosis
Authors: Nakayama T , Hashimoto S , Amemiya E , Horie T
Published: November 2003

Two types of receptor for tumour necrosis factor-alpha (TNF-R), the 55-kD receptor (TNF-RI) and the 75-kD receptor (TNF-RII), have been identified. Soluble TNF-RI (sTNF-RI) and soluble TNF-RII (sTNF-RII) can be measured in culture supernatants and biological fluids, and the role of sTNF-R has been suggested. In the present study, we measured plasma sTNF-RI and sTNF-RII levels in 19 patients with active sarcoidosis by ELISA in order to assess the state of both types of receptors in this disease. Both plasma sTNF-RI and sTNF-RII levels in patients with active sarcoidosis were significantly higher than those in normal control subjects. A longitudinal evaluation of plasma sTNF-RI and sTNF-RII levels showed that the magnitude of changes in sTNF-RII was closely related with the clinical course of sarcoidosis. These results suggest that plasma sTNF-RII levels may be useful parameters for monitoring the clinical course of sarcoidosis as well as markers for identifying disease activity.
IL-12 protects mice against pulmonary and disseminated infection caused by Cryptococcus neoformans
Authors: Kawakami K , Tohyama M , Xie Q , Saito A
Published: November 2003

We examined the role of IL-12 in host resistance to Cryptococcus neoformans using a murine model of pulmonary and disseminated infection. In this model, mice were infected intratracheally with viable yeast cells. Mice untreated with IL-12 allowed an uncontrolled multiplication of yeast cells in the lung with infiltrations of few inflammatory cells, and a cryptococcal dissemination to the brain and meningitis by 3 weeks, resulting in death of all animals within 4–6 weeks. IL-12, when administered from the day of tracheal infection for 7 days, induced a marked infiltration of inflammatory cells, consisting mostly of mononuclear cells, and significantly reduced the number of viable yeast cells in the lung. The treatment suppressed brain dissemination, as shown by a marked reduction of yeast cells in the brain and prevention of meningitis. These effects resulted in a significant increase in the survival rate of infected mice. In contrast, late administration of IL-12 commencing on day 7 after instillation of yeast cells failed to protect the mice against infection with C. neoformans. In further experiments, early administration of IL-12 markedly induced interferon-gamma (IFN-γ) mRNA in the lungs of infected mice, while no IFN-γ mRNA was detected without this treatment. Our results indicate that IL-12 is effective when administered in the early period of pulmonary cryptococcal infection.
Detection of nucleosome–IgG immune complexes in ascites from mice transplanted with anti-DNA antibody-secreting hybridomas and in plasmas from MRL-lpr/lpr mice
Authors: Fournié G J
Published: November 2003

Autoantibodies directed against chromatin components characterize lupus diseases. Immune complexes made of these autoantibodies bound to nucleosomes released from dead cells could play some pathogenic role. The aims of this study were to investigate if nucleosome–IgG complexes could contaminate IgG anti-DNA MoAb preparations, and if such complexes circulate in lupus diseases. A new method was set up using preformed nucleosome–IgG complexes. Complexes were adsorbed onto microplate through Fc binding and nucleosomal DNA was detected by internal incorporation of labelled nucleotide. Using this method, high amounts of complexes were found in ascites from mice transplanted with anti-DNA antibody-secreting hybridomas. In some ascites, nucleosome was found to be strongly associated with the MoAb, confirming that nucleosome–IgG complexes could contaminate monoclonal autoantibody preparations. In MRL-lpr/lpr mice, nucleosome–IgG complexes were detected at 16–24 weeks of age at a time when kidney lesions are rapidly worsening, raising the question of their pathogenic significance.
FcγRIIa polymorphism in systemic lupus erythematosus (SLE): no association with disease
Authors: Botto M , Theodoridis E , Thompson E M , Beynon H L C , Briggs D , Isenberg D A , Walport M J , Davies K A
Published: November 2003

An allotypic variant of FcγRIIa, FcγRIIa-HR (FcγRIIa-R131), has been shown in vitro to reduce the capacity of phagocytic cells to bind and internalize IgG-containing immune complexes. Our aim was to determine whether this allotypic variant was associated with susceptibility to SLE and the development of lupus nephritis, as previous studies have suggested. FcγRIIA genotype analysis was performed by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in 215 Caucasoid, 70 Afro-Caribbean, and 46 Chinese patients with SLE, and in 259, 77, and 49 ethnically matched controls, respectively. Distribution of FcγRIIa genotypes between the patients and ethnically matched controls was not significantly different in the three populations studied. No association between the FcγRIIa-HR allotype and nephritis was found. Our results suggest that the FcγRIIa-HR allotype is not a major factor predisposing to the development of SLE, or to lupus nephritis.
Production of nitrite by dengue virus-induced cytotoxic factor
Authors: Misra A , Mukerjee RUMA , Chaturvedi U C
Published: November 2003

Dengue type 2 virus (DV) infection induces production of a cytokine, the cytotoxic factor (CF) in the spleen of mice. The present study was undertaken to investigate the production of nitrite (NO−2) by the spleen cells of mice in vitro and in vivo following inoculation of DV or CF. Maximum NO−2 production occurred at 45 min after inoculation of 5 μg CF, both in vitro and in vivo. The NO−2 was produced by macrophages and T cells and not by B cells. Pretreatment of CF with anti-CF antisera inhibited production of NO−2. DV-stimulated spleen cell culture supernatants showed peak production of CF and NO−2 at 72 h. In DV-infected mouse spleen, maximum NO−2 production occurred at 8–11 days post-infection, which correlated with peak cytotoxic activity in the spleen. Pretreatment of spleen cells with NG-monomethyl l-arginine (NMMA) inhibited NO−2 production. NO−2 production was abrogated in a dose-dependent manner by treatment of spleen cells with Ca2+ channel blocking drug, Nifedipine. The findings demonstrate that DV-induced CF induces production of NO−2 in spleen cells, probably in a Ca2+-dependent manner, and may be a mechanism of target cell killing.
Characterization of a soluble form of CD58 in synovial fluid of patients with rheumatoid arthritis (RA)
Authors: Hoffmann J C , Bayer B , Zeidler H
Published: November 2003

Reduced levels of a soluble form of the adhesion receptor and CD2 ligand CD58 (sCD58) were previously described in RA patients. In order to understand the biological significance of this finding we biochemically characterized sCD58 in RA and asked how well sCD58 binds to CD2. sCD58 concentrations were measured in serum and synovial fluid (SF) samples of RA patients by two ELISAs, one detecting domain 1 of CD58 (CD58-D1), and the other one the complete molecule (CD58-D1 + D2). Small amounts of split sCD58-D1 were found in most RA sera, but not SF. In addition, split sCD58-D2 was detected in SF by affinity chromatography, SDS–PAGE, and Western blotting. Gel filtration gave similar peaks at 95–125 kD for RA sera, SF, and normal serum. Binding of SF-sCD58 to the CD2+ Jurkat variant JBB1 or recombinant CD2 was stronger than urinary sCD58 and reached binding of oligomeric recombinant CD58 at low concentrations. In conclusion, sCD58-split products were found in RA sera and SF. At concentrations as they occur in vivo, SF-sCD58 binds to CD2 much more strongly than urinary sCD58. It is conceivable that locally released sCD58 blocks the CD2/CD58 interaction under physiological conditions. Insufficient release of sCD58, e.g. in synovitis, might result in T cell accumulation and perpetuation of inflammation.
VH gene-family representation in peripheral activated B cells from systemic lupus erythematosus (SLE) patients
Authors: Demaison C , David D , Fautrel B , Theze J
Published: November 2003

A semiquantitative polymerase chain reaction (PCR) assay described in this study has been used to analyse the VH1, VH3 and VH4 repertoire expressed by total IgM+ and IgG+ B cells from normal individuals and lupus patients. This approach consists of a combination of B cell selection, utilization of the anchored PCR technique to avoid technical bias in the amplification of different VH gene family cDNA templates, and screening of the amplified IgM or IgG cDNA rearrangements by family-specific oligonucleotide probes. In four lupus patients, VH family representation in IgM+ and IgG+in vivo activated B cells, selected by anti-CD71 antibody, and in total CD19+ B cells were compared. In all patients, VH4 gene family segments were preferentially underrepresented in IgM+ activated B cells. In IgG+ B cells the results suggest that VH4 expression is variable, depending on the phase of the disease. Polyclonal B cell activation, which is usually considered as being the first event in autoantibody production in SLE, cannot explain our results. The data evoke the possible involvement of a VH4-specific B cell superantigen in the onset or development of SLE. This hypothesis is also supported by the sequence conservation of the fourth β loop—a putative superantigen binding site—of functional VH4 gene segments which are preferentially used by anti-dsDNA lupus antibodies of established clones and hybridomas.
Function of C3 in a humoral response: iC3b/C3dg bound to an immune complex generated with natural antibody and a primary antigen promotes antigen uptake and the expression of co-stimulatory molecules by all B cells, but only stimulates immunoglobulin synthesis by antigen-specific B cells
Authors: Thornton B P , Větvička V , Ross G D
Published: November 2003

Previous studies have shown that an optimal humoral response to a primary protein antigen requires C3 and CR2 (CD21). Sera from non-immunized donors contain natural IgM and IgG antibodies to the primary antigen keyhole limpet haemocyanin (KLH), and these have been previously shown to form immune complexes (IC) that activate the classical pathway of C, fixing iC3b/C3dg onto the KLH antigen. Such KLH IC bind to CR2 on KLH-non-specific B lymphocytes, resulting in antigen processing and MHC class II-dependent presentation to KLH-specific helper T cells. KLH IC also induce B lymphocytes to express the CD80 co-stimulatory molecule via simultaneous CR2 ligation with C3 and FcγRII (CD32) stimulation by IgG natural antibody. The current study demonstrated that KLH IC ligation to either CR2 or FcγRII resulted in activation of a second co-stimulatory molecule, LFA-1 (CD11a, CD18). The possibility of polyclonal B cell stimulation by the presentation of KLH-iC3b/C3dg by antigen-non-specific B cells was excluded by demonstration that in vitro cultivation of peripheral blood mononuclear cells (PBMC) with KLH-iC3b/C3dg elicited only anti-KLH, and did not stimulate synthesis of antibodies to hepatitis C virus (HCV) or tetanus toxoid (TT). Of greatest significance, a specific anti-KLH response was only detectable in cultures stimulated with KLH-iC3b/C3dg and not in cultures stimulated with KLH alone or KLH-IgG. Thus, iC3b/C3dg that was bound to a primary protein antigen enhanced recognition and specific immunoglobulin synthesis by antigen-specific B cells, even though the antigen was taken up and processed via CR2 by both antigen-specific and non-specific B cells.
Dietary β-carotene and ultraviolet-induced immunosuppression
Authors: Noonan F P , Webber L J , de Fabo E C , Hoffman H A , Bendich A , Mathews-Roth M
Published: November 2003

Ultraviolet (UV)-induced immunosuppression is a critical step in UV carcinogenesis, permitting tumour outgrowth. We investigated the effect of dietary β-carotene on UV suppression of contact hypersensitivity (CHS) to trinitrochlorobenzene (TNCB) in BALB/c mice. Mice were fed for 10–16 weeks chow alone or supplemented with 1% β-carotene or placebo as beadlets. Serum β-carotene was detectable by high performance liquid chromatography (HPLC) analysis only in β-carotene-fed mice (2.06 ± 0.15 μg/ml). Serum retinol was 0.22–0.27 μg/ml in all three groups. Mice (n = 41/dietary group) were irradiated with 0, 4.5, 9 or 18 kJ/m2 of UVB and the CHS response was measured. Decreased CHS responses were observed in all UV-irradiated groups compared with unirradiated controls. UV dose–responses for suppression of CHS derived by first-order regression analyses of plots of percentage suppression of CHS as a function of log10UV dose showed significant slopes (P < 0.02) for all three dietary groups and similar residual variances between groups, P > 0.05. The UV dose for 50% suppression of CHS was 6.3 kJ/m2 for control, 6.4 kJ/m2 for placebo, and 5.5 kJ/m2 for β-carotene-fed mice. No significant differences in slopes or elevations between UV dose–responses were observed, P > 0.05. Skin levels of the initiator of UV-induced immunosuppression, cis urocanic acid, were determined by HPLC in mice given 0 or 9 kJ/m2 of UV (n = 28/dietary group). No significant differences were observed between dietary groups (range 35.2–41.1 ng/mg skin, P > 0.15) We conclude feeding β-carotene to BALB/c mice does not alter susceptibility to UV immune suppression, in contrast to human studies.
Generalized immune activation in pulmonary tuberculosis: co-activation with HIV infection
Authors: Vanham G , Edmonds K , Qing L , Hom D , Toossi Z , Jones B , Daley C L , Huebner R , Kestens L , Gigase P , Ellner J J
Published: November 2003

Parameters of immune activation/differentiation were studied in a group of newly diagnosed HIV− and HIV+ pulmonary tuberculosis (TB) patients. Compared with controls, HLA-DR expression on both CD4 and CD8 T cells from the HIV− TB patients was approximately doubled; HLA-DR on T cells from the HIV+ group was tripled. The monocytes from both groups of patients expressed abnormally high levels of the Fcγ receptors I and III. Serum levels of tumour necrosis factor-alpha (TNF-α), neopterin and β2-microglobulin were increased in HIV− and even more so in HIV+ TB patients. The expression of HLA-DR on T cell subsets and of FcγR on monocytes correlated with each other, but not with serum activation markers. This pattern of non-specific activation during TB infection may be associated with enhanced susceptibility to HIV infection.
Cross-reactive antibodies between HIV-gp120 and platelet gpIIIa (CD61) in HIV-related immune thrombocytopenic purpura
Authors: Bettaieb A , Oksenhendler E , Duedari N , Bierling P
Published: November 2003

We have previously demonstrated that immune platelet destruction observed in an AIDS-free HIV-infected patient was associated with the presence of a cross-reactive antibody recognizing both HIV-glycoprotein (gp)120 and platelet gpIIIa (CD61). We have now investigated the presence of such antibodies in other HIV-infected patients, together with the molecular structure of the cross-reactive epitope. Platelet gpIIb/IIIa antibodies were characterized in sera from HIV-infected patients with immune thrombocytopenic purpura by means of an ELISA and a radioimmunoprecipitation procedure (RIP). The platelet antibodies were purified and tested for their ability to recognize HIV-gp. We also tried to characterize the antibody target epitope on HIV-gp120 using recombinant gp and synthetic peptides. IgG with anti-gpIIb/IIIa activity were detected, by means of an ELISA with purified gpIIb/IIIa, in 101/138 (73%) sera from HIV-infected patients with immune thrombocytopenic purpura. The platelet antibodies were purified from 23 sera by absorption/elution on purified immobilized platelet gpIIb/IIIa, and recognition of gpIIIa was confirmed in eight cases with a RIP. Furthermore, the presence of a cross-reactive antibody between HIV-gp120 and platelet gpIIIa was demonstrated in 18/18 patients (including the eight with a confirmed gpIIIa antibody) by the ability of the serum HIV-gp160/120 antibodies to bind to purified gpIIb/IIIa. The cross-reactive epitope was shown to be independent of the carbohydrate moieties of gp120, since deglycosylation of two recombinant (r)-gp120s did not abolish antibody binding. However, the antibody did not recognize synthetic gp120 peptides spanning 355 of the 516 amino acids of gp120, particularly the four regions exhibiting sequences of four or five consecutive amino acids that are identical between r-gp120 and gpIIIa. Our results thus support the hypothesis that the cross-reactive antibody recognizes the conformational structure of gp120. These results strongly suggest that molecular mimicry between HIV-gp120 and platelet gpIIIa may be important in the pathogenesis of immune thrombocytopenia in AIDS-free HIV-infected patients.
Differential maturation of avidity of IgG antibodies to gp41, p24 and p17 following infection with HIV-1
Authors: Thomas H I J , Wilson S , O’Toole C M , Lister C M , Saeed A M , Watkins R P F , Morgan-Capner P
Published: November 2003

We have evaluated solid-phase ELISA IgG antibody avidity studies as a means of identifying cases of recent HIV-1 infection. Although separate studies on the avidity of anti-gp41 and anti-p24 antibodies in seroconvertors have been reported, a comparison of the ability of patients to simultaneously mature their immune response to more than one HIV antigen immediately following seroconversion appears to be lacking. We have demonstrated a maturation in anti-gp41 avidity which reflects the time since seroconversion in all cases. In contrast, however, only some patients produced high-avidity anti-p24 or anti-p17 antibodies during the same time span. While the avidity of anti-gp41 antibodies remained high in cases of non-recent HIV infection, even in the face of advanced disease, we have confirmed the findings of others that the avidity of anti-p24 falls before the onset of ARC or AIDS. Therefore, whilst the avidity of anti-gp41 antibodies could reliably be of value in identifying cases of recent HIV infection, the avidity of anti-p24 or anti-p17 antibodies could not, but may be of prognostic value, even at an early stage. The time taken to reach maximum anti-p17, anti-p24 and anti-gp41 titres was variable, but anti-gp41 titres, like anti-gp41 avidity, remained high. In contrast, anti-p24 titres fell, even during the early follow-up period in some seroconvertors. Anti-p24 antibody avidity, however, appeared to be a better predictor of disease progression in ‘remote’ cases than anti-p24 titre. The avidity and titres of these antibodies are presented in relation to the clinical details, p24 antigen status, CD4 and CD8 counts where these are known.
Virus-specific cytotoxic T cell responses are associated with immunity of the cottontop tamarin to Epstein–Barr virus (EBV)
Authors: Wilson A D , Shooshstari M , Finerty S , Watkins P , Morgan A J
Published: November 2003

The cytotoxic responses of peripheral blood lymphocytes from cottontop tamarins to in vitro re-stimulation with autologous lymphoblastoid cell lines (LCL) were assayed. Lymphocytes from immune tamarins that had recovered from EBV challenge developed potent cytotoxicity for natural killer (NK) cell targets and for autologous LCL. The cytotoxicity for LCL targets was EBV-specific, as B cell blasts uninfected with EBV were not killed. The cell lines could be maintained by repeated stimulation with LCL and the addition of IL-2. Flow cytometry showed that they were T cell lines expressing CD2, CD3, CD4, CD8 and CD25. Dual-colour flow cytometry revealed two subpopulations, one CD4+ CD8+ population and the other CD4− CD8+. After separation by magnetic cell sorting both subpopulations were shown to be cytotoxic and the CD4+ CD8+ fraction was also shown to be MHC class II-restricted; the MHC restriction of the CD8+ subpopulation could not be determined. The unseparated T cells and both the subpopulations were able to inhibit LCL outgrowth in vitro. In contrast, PBL from naive tamarins stimulated by autologous LCL developed less NK cell cytotoxicity and little cytotoxicity for LCL. The cytotoxic response was enhanced at higher levels of LCL stimulation, but the cells were unable to inhibit LCL outgrowth in vitro. We conclude that cytotoxic responses capable of inhibiting LCL growth in vitro correlate with in vivo immunity in the tamarin model and provide a basis for understanding the mechanism of vaccine-induced immune protection.
Gluten activation of peripheral blood T cells induces a Th0-like cytokine pattern in both coeliac patients and controls
Authors: Nilsen E M , Gjertsen H A , Jensen K , Brandtzaeg P , Lundin K E A
Published: November 2003

Coeliac disease is apparently a T cell-mediated disease, precipitated in the proximal small intestine of susceptible individuals by gluten. Preferential presentation of gluten peptides most probably takes place in coeliac mucosa by the disease-associated HLA-DQ2 and -DQ8 molecules. In peripheral blood, however, both HLA-DR, -DQ and -DP-restricted T cell responses to gluten have been observed. We examined gluten-specific T cell clones (TCC) derived from peripheral blood for cytokine production to see if their profiles were related to the HLA restriction or the disease state of the donors. As previously found for mucosal TCC, the main product was interferon-gamma (IFN-γ), often with additional IL-4, IL-5, IL-6, IL-10, tumour necrosis factor, and transforming growth factor-beta. Regardless of restriction element or disease state, gluten-reactive TCC from peripheral blood therefore seem to secrete cytokines compatible with a Th0 profile.
IL-6-induced anaemia in rats: possible pathogenetic implications for anaemia observed in chronic inflammations
Authors: Jongen-Lavrencic M , Peeters H R M , Rozemuller H , Rombouts W J C , Martens A C M , Vreugdenhil G , Pillay M , Cox P H , Bijser M , Brutel G , Breedveld F C , Swaak A J G
Published: November 2003

Anaemia of chronic disease (ACD) is frequently found in rheumatoid arthritis (RA). In the pathogenesis of ACD both cytokines, such as tumour necrosis factor-alpha (TNF-α), IL-1 and Il-6 as well as a relative deficiency of erythroprotein (EPO), are thought to play a key role. In the present study the role of IL-6 in the pathogenesis of this anaemia was investigated. IL-6 was administered intraperitoneally to rats for 14 sequential days. It appeared that IL-6 was able to induce anaemia. No evidence for suppression of bone marrow erythropoiesis or enhanced sequestration of erythrocytes in the liver was found. However, decreased plasma and bone marrow iron contents were observed in anaemic rats. Blood loss in intestinal tissue was demonstrated using erythrocyte labelling with 99mtechnetium. Histologically this was associated with inflammatory cell infiltration, oedema and bleeding in the intestinal wall. In conclusion, IL-6 induced anaemia in rats. This anaemia was caused by intestinal blood loss.
T cell clones from a Sjögren’s syndrome salivary gland biopsy produce high levels of IL-10
Authors: Brookes S M , Cohen S B A , Price E J , Webb L M C , Feldmann M , Maini R N , Venables P J W
Published: November 2003

Sjögren’s syndrome (SS) is characterized by a focal periductal salivary gland infiltrate consisting mainly of T and B lymphocytes. Most of the T cells bear the memory of CD4+ Th-1-like phenotype and express high levels of class II, though CD8+ cells are also present. We have studied 17 labial salivary gland and 15 peripheral blood T cell clones from a patient with primary SS. The tissue clones were 71% CD8+ and 29% CD4+, and the peripheral blood-derived clones were 60% CD8+ and 40% CD4+. The CD4+ T cell clones from both the salivary gland and autologous peripheral blood were of the Th1 phenotype, in that they produced interferon-gamma (IFN-γ) and IL-2 but very little IL-4 after 24 h stimulation with phorbol myristate acetate and anti-CD3 antibody. The salivary gland-derived CD4+ clones produced 15 times more IL-10 (7.92 ng/ml) than peripheral blood-derived CD4+ clones (0.52 ng/ml, P≤0.02). The tissue CD8+ clones produced 1.2 times (P<0.04) more IFN-γ and CD4+ clones produced 3.5 times less IL-2 (P<0.02) than the respective PBM-derived clones. The accumulation of Th1-type cells producing high levels of IL-10 in the salivary gland suggests a specific immunoregulatory function at the site of inflammation in SS.
Impairment of the inhibitory effect of sodium on basophil histamine release in patients with systemic sclerosis
Authors: Tedeschi A , Palella M , Milazzo N , Mascagni B , Miadonna A
Published: November 2003

It has been demonstrated that Na+ down-regulates IgE-dependent and IgE-independent histamine release from basophils of normal subjects. The aim of this study was to evaluate whether Na+ exerts its inhibitory effect on basophil histamine release in patients with systemic sclerosis (SSc). Peripheral blood leucocytes were stimulated with anti-IgE, n-formyl-methionyl-leucyl-phenylalanine (fMLP) and IL-3 in the presence of high and low Na+ concentrations, and histamine release was measured by a fluorometric method. The dose–response curves of histamine release induced by the above stimuli were similar in SSc patients (n = 15) and in normal subjects (n = 39). Na+ removal from the extracellular medium and its isosmotic replacement with choline chloride led to a significant increase of anti-IgE-and fMLP-induced histamine release in normal subjects, but not in SSc patients. In the former population, histamine release induced by an optimal dose of anti-IgE (1/5000) was 26.4 ± 3.1% in high Na+ and 59.3 ± 3.5% in low Na+ (mean ± s.e.m., P < 0.0001), whereas in the latter population mean histamine release was 20.4 ± 5.1% in high Na+ and 15.8 ± 2.9% in low Na+ (P NS). A similar trend was observed when basophils were stimulated with fMLP. Na+ exerted a dose-dependent inhibitory effect on anti-IgE- and fMLP-induced histamine release in normal subjects, but not in SSc patients. IL-3-induced histamine release from basophils of SSc patients was increased in a low-Na+ solution, but to a lesser extent when compared with normal controls. Therefore basophils from normal subjects and SSc patients behave in a different way when stimulated in a low-Na+ medium. The inhibitory effect of Na+ on basophil histamine release is impaired in SSc patients, and this abnormality could contribute to basophil dysfunction.
Role of glycosaminoglycans (GAGs) in regulation of the immunogenicity of human vascular endothelial cells
Authors: Rix D A , Douglas M S , Talbot D , Dark J H , Kirby J A
Published: November 2003

Heparan sulphate is a common glycosaminoglycan component of proteoglycans present on the luminal surface of vascular endothelium. It has been proposed that an important function of these molecules is the sequestration of a range of proinflammatory and proadhesive cytokines. Such cytokines play a vital role during lymphocyte recruitment from the blood at sites of inflammation. In this study it is shown that the effects of interferon-gamma (IFN-γ), but not of tumour necrosis factor-alpha (TNF-α), are inhibited by treatment with soluble heparin. Specifically, heparin was shown to inhibit the induction of class II MHC antigens and the up-regulation of intercellular adhesion molecule-1 (ICAM-1) produced by treatment of cultured human endothelial cells with IFN-γ. Furthermore, it was shown that heparin blocked the enhanced adhesion of T lymphocytes to IFN-γ-treated endothelial cells. Investigation of the inhibitory effects of other GAG molecules demonstrated a requirement for heparin-like structural domains as chondroitin sulphate was unable to inhibit the function of IFN-γ. These results may explain reported immunosuppressive properties of heparin, and are consistent with the model that heparin may compete with cell surface GAGs to bind IFN-γ, thereby reducing effective biological activity.
The effects of the immunosuppressant rapamycin on the growth of rheumatoid arthritis (RA) synovial fibroblast
Authors: Migita K , Eguchi K , Aoyagi T , Tsukada T , Tsuboi M , Kawabe Y , Nagataki S
Published: November 2003

RA is a chronic inflammatory disease characterized by mononuclear cell infiltration and the overgrowth of synovial fibroblast. This invasive growth of synovial tissues corresponds with the progressive destruction of articular carilage and bone. Several immunosuppresive agents, such as cyclophosphamide, cyclosporin A and mizoribine, have been clinically used to control disease progresssion, though relatively little is known of their effects on rheumatoid synovium. Rapamycin exhibits a strong immunosuppressive activity by acting on T cell signalling pathways. In the present study we examined the effects of rapamycin on the growth of synovial fibroblast isolated from RA patients. Platelet-derived growth factor (PDGF) is a potent growth factor in synovial fibroblasts isolated from RA patients. PDGF and serum stimulation resulted in a rapid phosphorylation of tyrosine and activation of mitogen-activated protein kinase (MAP kinase), 70-kD-S6 kinase (P70S6K) and 90-kD-S6 kinase (P90rsk). Rapamycin, a macrolide immunosuppressant, inhibited completely growth factor-induced synovial fibroblast proliferation and P70S6K activation. In contrast, tyrosine phosphorylation and activation of MAP kinases and P90rsk were not influenced by rapamycin treatment. Our data demonstrate that growth factor-mediated P70S6K activation is closely related to the growth of synovial fibroblast, and suggest the efficacy of rapamycin for controlling synovial hyperplasia in RA.
The frequent mutation Gly/Asp in CDR1H may determine a cross-reactive idiotope in anti-I cold agglutinins
Authors: Abatangelo C , Plotkin L , Mathov I , Squiquera L , Leoni J
Published: November 2003

Variable domains (VH) of all known anti i/I cold agglutinin (CA) heavy chains are codified by the VH4–21 gene. While anti-i CAs are the expression of gene rearrangement without mutations represented by amino acid changes, anti-I CAs present, among others, a frequent somatic mutation of Gly by Asp at position 31. The hydropathy profile calculated for the CDR1H (position 30 to position 35), as well as some adjacent positions of the heavy chain belonging to anti-i and anti-I antibodies, showed the conformational changes accompanying the replacement of Gly by Asp. A MoAb (LP91), which had been obtained in BALB/c mice immunized with a Fabμ fragment from a monoclonal IgMκIIIb anti-I CA (protein KAU), proved capable of inhibiting human adult erythrocyte cryoagglutination by anti-I CAs but not that of fetal erythrocytes by anti-i CAs. Western blot analysis disclosed that such MoAbs recognized a sequential epitope located in the Fd fragment of all anti-I CAs employed in this study. With the purpose of checking whether Asp31 was involved in the epitope recognized by the MoAb, two peptides, D and G, were synthesized which mimicked the CDR1H structure of anti-I and anti-i, respectively; the MoAb only reacted with peptide D by ELISA. Subsequent experimental results indicate that the Gly/Asp mutation could be associated with the diverse specificity presented by these autoantibodies, a change determining a characteristic epitope/idiotope, recognized by LP91 in the CDR1H.
Mice that carry the resistance allele of the Bcg gene (Bcgr) develop a superior capacity to stabilize bacille Calmette–Guérin (BCG) infection in their lungs and spleen over a protracted period in the absence of specific immunity
Authors: Medina E , North R J
Published: November 2003

In mice, natural resistance to infection with BCG is under the influence of an autosomal gene designated Bcg. It is shown here in agreement with others that mice that possess the dominant resistant allele of the gene (Bcgr ) are more capable than mice that possess the susceptible recessive allele (Bcgs ) at restricting the growth of BCG in their lungs, as well as in their spleens, during the first 20 days of infection. It is shown, in addition, that in the absence of specific immunity the resistance difference between Bcgr and Bcgs mice became much more pronounced as infection progressed beyond day 20. Whereas T cell-depleted Bcgr mice developed a capacity after day 20 to cause infection in their lungs and spleens to stabilize and plateau for a least 40 days, T cell-depleted Bcgs mice were unable to prevent infection from progressing in these organs. On the other hand, both types of T cell-depleted mice were capable of causing infection to plateau in their livers and kidneys. Moreover, this T cell-independent mechanism of resistance was essentially abolished in all organs in which it was expressed by treating the mice with hydrocortisone. In the lungs of immunocompetent Bcgs mice, failure to stabilize infection was associated with heavily infected macrophages and failure to contain BCG at original sites of infection.
Anti-DNA antibody derived from a systemic lupus erythematosus (SLE) patient forms histone–DNA–anti-DNA complexes that bind to rat glomeruli in vivo
Authors: Morioka T , Fujigaki Y , Batsford S R , Woitas R , Oite T , Shimizu F , Vogt A
Published: November 2003

Histone can mediate the binding of both free DNA and DNA complexed to anti-DNA antibody to the glomerular capillary wall. We tested whether preformed histone–DNA–anti-DNA immune complexes (IC) could bind to the glomerular capillary wall. The immune complex, generated with anti-DNA antibody derived from an SLE patient and excess of 125I-DNA followed by digestion with DNase, was mixed with histones. The complex containing 4 μg DNA was injected via the aorta into the left kidney of rats. At 15 min, 1.3% of the histone–DNA–anti-DNA antibody complex bound (measured as 125I-DNA), when histone was omitted less than 0.1% of the DNA–anti-DNA antibody complex bound. By immunofluorescence human immunoglobulins and histones, representing the IC, could be observed in a capillary pattern; but no complement deposition was detected. Electron microscopy revealed discrete, electron dense deposits in a subendothelial, subepithelial and mesangial localization at 15 min. These results provide direct evidence that antibodies from serum of SLE patients can form soluble histone–DNA–anti-DNA immune complexes that bind to the glomerular capillary wall in vivo
Inhibition of the transendothelial migration of human lymphocytes but not monocytes by phosphodiesterase inhibitors
Authors: Lidington E , Nöhammer C , Dominguez M , Ferry B , Rose M L
Published: November 2003

This study describes an in vitro model of peripheral blood mononuclear cell (PBMC) migration through human endothelial cells, held on polycarbonate inserts, which allows automatic differential counting of migrated cells as lymphocytes and monocytes. Using this system it was found that treatment of PBMC with the phosphodiesterase (PDE) inhibitors theophylline (at 1 and 10 μg/ml) and RO-20-1724 (at 1 μm) inhibited the migration of the lymphocyte component to 64.2 ± 16.4%, 48.9 ± 3.0% and 47.5 ± 5.8% of the control values, respectively, while the migration of the monocytes component was largely unaffected. The PDE inhibitors needed to be present during the assay to inhibit migration, whereas pre-treatment of either the endothelium or the PBMC did not consistently effect lymphocyte migration. The drugs also inhibited the migration of lymphocytes through control inserts, either uncoated or coated with fibronectin, suggesting that some of the inhibition is an effect on lymphocyte motility rather than lymphocyte–endothelial interactions. Lymphocyte migration through fibronectin-coated filters was significantly enhanced compared with uncoated filters. Activation of the PBMC by anti-CD3 MoAb increased motility and migration by up to 300%. This migration appeared to be greatly inhibited by the PDE inhibitors, although the effect was complicated by problems of lymphocyte aggregation. This study provides a novel method of measuring mononuclear cell transendothelial migration, and suggests a possible role of PDE inhibitors in reducing this process.
IL-6 acts on endothelial cells to preferentially increase their adherence for lymphocytes
Authors: Watson C , Whittaker S , Smith N , Vora A J , Dumonde D C , Brown K A
Published: November 2003

Using a quantitative monolayer adhesion assay, the current report shows that treatment of human umbilical vein endothelial cells (HUVEC) with IL-6 increases their adhesiveness for blood lymphocytes, particularly CD4+ cells, but not for polymorphonuclear cells and monocytes. This effect, which was most pronounced when using low concentrations of the cytokine (0.1–1.0 U/ml) and a short incubation period (4 h), was also apparent with microvascular endothelial cells and a hybrid endothelial cell line. Skin lesions from patients with mycosis fungoides contain high levels of IL-6, and blood lymphocytes from patients with this disorder also exhibited an enhanced adhesion to IL-6-treated HUVEC. The cytokine enhanced intercellular adhesion molecule-1 (ICAM-1) expression and induced the expression of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin on endothelial cells. Antibody blocking studies demonstrated that the vascular adhesion molecules ICAM-1, VCAM-1 and E-selectin and the leucocyte integrin LFA-1 all contributed to lymphocyte binding to endothelium activated by IL-6. It is proposed that IL-6 may be involved in the recruitment of lymphocytes into non-lymphoid tissue.