The binding sites of monoclonal antibodies to the non‐reducing end of Francisella tularensis O‐antigen accommodate mainly the terminal saccharide

We have previously described two types of protective B‐cell epitopes in the O‐antigen (OAg) of the Gram‐negative bacterium Francisella tularensis: repeating internal epitopes targeted by the vast majority of anti‐OAg monoclonal antibodies (mAbs), and a non‐overlapping epitope at the non‐reducing end targeted by the previously unique IgG2a mAb FB11. We have now generated and characterized three mAbs specific for the non‐reducing end of F. tularensis OAg, partially encoded by the same variable region germline genes, indicating that they target the same epitope. Like FB11, the new mAbs, Ab63 (IgG3), N213 (IgG3) and N62 (IgG2b), had higher antigen‐binding bivalent avidity than internally binding anti‐OAg mAbs, and an oligosaccharide containing a single OAg repeat was sufficient for optimal inhibition of their antigen‐binding. The X‐ray crystal structure of N62 Fab showed that the antigen‐binding site is lined mainly by aromatic amino acids that form a small cavity, which can accommodate no more than one and a third sugar residues, indicating that N62 binds mainly to the terminal Qui4NFm residue at the nonreducing end of OAg. In efficacy studies with mice infected intranasally with the highly virulent F. tularensis strain SchuS4, N62, N213 and Ab63 prolonged survival and reduced blood bacterial burden. These results yield insights into how antibodies to non‐reducing ends of microbial polysaccharides can contribute to immune protection despite the smaller size of their target epitopes compared with antibodies to internal polysaccharide regions.     

Associations of B cell‐activating factor (BAFF) and anti‐BAFF autoantibodies with disease activity in multi‐ethnic Asian systemic lupus erythematosus patients in Singapore

To measure the levels of B cell‐activating factor (BAFF) and endogenous anti‐BAFF autoantibodies in a cohort of multi‐ethnic Asian systemic lupus erythematosus (SLE) patients in Singapore, to determine their correlation with disease activity. Serum samples from 121 SLE patients and 24 age‐ and sex‐matched healthy controls were assayed for BAFF and anti‐BAFF immunoglobulin (Ig)G antibody levels by enzyme‐linked immunosorbent assay (ELISA). The lowest reliable detection limit for anti‐BAFF‐IgG antibody levels was defined as 2 standard deviations (s.d.) from blank. Correlation of serum BAFF and anti‐BAFF IgG levels with disease activity [scored by SLE Activity Measure revised (SLAM‐R)], and disease manifestations were determined in these 121 patients. SLE patients had elevated BAFF levels compared to controls; mean 820 ± 40 pg/ml and 152 pg ± 45/ml, respectively [mean ± standard error of the mean (s.e.m.), P < 0·01], which were correlated positively with anti‐dsDNA antibody levels (r = 0·253, P < 0·03), and SLAM‐R scores (r = 0·627, P < 0·01). In addition, SLE patients had significantly higher levels of anti‐BAFF IgG, which were correlated negatively with disease activity (r = –0·436, P < 0·01), levels of anti‐dsDNA antibody (r = –0·347, P < 0·02) and BAFF (r = –0·459, P < 0·01). The majority of patients in this multi‐ethnic Asian SLE cohort had elevated levels of BAFF and anti‐BAFF antibodies. Anti‐BAFF autoantibody levels correlated negatively with clinical disease activity, anti‐dsDNA and BAFF levels, suggesting that they may be disease‐modifying. Our results provide further information about the complexity of BAFF pathophysiology in different SLE disease populations and phenotypes, and suggest that studies of the influence of anti‐cytokine antibodies in different SLE populations will be required when selecting patients for trials using targeted anti‐cytokine therapies.     

Relationship between natural and infection‐induced antibodies in systemic autoimmune diseases (SAD): SLE,SSc and RA

Infection or vaccine‐induced T cell‐dependent immune response and the subsequent high‐affinity neutralizing antibody production have been extensively studied, while the connection between natural autoantibodies (nAAbs) and disease‐specific antibodies has not been thoroughly investigated. Our goal was to find the relationship between immunoglobulin (Ig)M and IgG isotype nAAbs and infection or vaccine‐induced and disease‐related autoantibody levels in systemic autoimmune diseases (SAD). A previously described indirect enzyme‐linked immunosorbent assay (ELISA) test was used for detection of IgM/IgG nAAbs against citrate synthase (anti‐CS) and F4 fragment (anti‐F4) of DNA topoisomerase I in 374 SAD samples, with a special focus on systemic lupus erythematosus (SLE) (n = 92), rheumatoid arthritis (n = 73) and systemic sclerosis (n = 157) disease groups. Anti‐measles IgG and anti‐dsDNA IgG/IgM autoantibodies were measured using commercial and in‐house indirect ELISA tests. In all SAD groups the anti‐measles IgG‐seropositive cases showed significantly higher anti‐CS IgG titers (P = 0·011). In anti‐dsDNA IgG‐positive SLE patients, we detected significantly higher levels of anti‐CS and anti‐F4 IgG nAAbs (P = 0·001 and < 0·001, respectively). Additionally, we found increased levels of IgM isotypes of anti‐CS and anti‐F4 nAAbs in anti‐dsDNA IgM‐positive SLE patients (P = 0·002 and 0·016, respectively). The association between IgG isotypes of pathogen‐ or autoimmune disease‐related antibodies and the IgG nAAbs may underscore the immune response‐inducible nature of the diseases investigated. The relationship between protective anti‐dsDNA IgM and the IgM isotype of anti‐F4 and anti‐CS may provide immunoserological evidence for the beneficial roles of nAAbs in SLE patients.     

Immunogenicity of a Glycoconjugate from Hydrazine‐Detoxified Lipopolysaccharide of Vibrio cholerae O139

A glycoconjugate (dLPS‐CBSA) from hydrazine‐detoxified lipopolysaccharide (LPS) of Vibrio cholerae O139 and BSA was used for immunization of BALB/c mice. The immunogenicity (concentration of induced IgG antibodies) of the conjugate was determined by enzyme‐linked immunosorbent assay. The highest level of LPS‐specific IgGs was found in sera collected 2 weeks after the third immunization. Both IgM and IgG antibodies present in the anti‐V. cholerae O139‐specific sera showed long‐lasting vibriocidal activity. The glycoconjugate also stimulated production of IL‐4, IL‐6, IFNγ, TNFα and IL‐10. Immunization with the conjugate induced significant production of both Th1 and Th2 cytokine sets, indicating balanced Th1/Th2 immune response polarization. The quantitative analysis of total and LPS‐specific IgM and IgG antibodies production by B lymphocytes (from both the spleen and the bone marrow) was performed by ELISPOT assay. From the analysis of antibodies produced directly by B lymphocytes in the bone marrow (of dLPS‐CBSA immunized mice), we were able to identify the IgM‐IgG switch in the antibodies produced.     

Fine specificity of anti‐citrullinated peptide antibodies discloses a heterogeneous antibody population in rheumatoid arthritis

Anti‐citrullinated peptide antibodies (ACPA) are highly specific for rheumatoid arthritis (RA). However, the predominant B cell epitopes have not yet been defined. The aim of this study was to examine the reactivity of ACPA against different peptides derived from citrullinated proteins and to investigate whether or not these antibodies constitute a homogeneous population. For this purpose, sera from patients with RA (n = 141), systemic lupus erythematosus (SLE) (n = 60), Sjögren's syndrome (SS) (n = 54) and healthy controls (n = 100) were tested for their reactivity against six citrullinated peptides derived from peptidyl arginine deiminase (PAD), vimentin (vim), alpha‐enolase (enol), fibrin, type II collagen (col‐II) and filaggrin, respectively. A non‐citrullinated control peptide derived from PAD was used as control (ctrlPAD^621–40). Antibody reactivity against each individual peptide was evaluated by enzyme‐linked immunosorbent assay (ELISA). Specificity and cross‐reactivity of ACPA were tested by using two prototype sera with homologous and cross‐inhibition assays. Specificity of ACPA from two prototype sera was confirmed by purification of anti‐peptide antibodies and homologous‐inhibition experiments. We found that sera from patients with RA reacted diversely with the six citrullinated peptides. More specifically, PAD^211–30 displayed 29·08% sensitivity, vim^60–75 29·08%, enol^5–21 37·59%, fibrin^617–31 31·21%, col‐II^358–75 29·97% and filaggrin^306–24 28·37%, while control ctrlPAD^621–40 showed no reactivity. All reactive peptides were found to be highly specific for RA. A notable cross‐reaction (>70%) was found mainly between filaggrin and the majority of anti‐citrullinated peptide antibodies. We concluded that ACPA in RA constitute a heterogeneous population with limited cross‐reactivity and without a predominant epitope.     

Antigenic cross‐reactivity between Schistosoma mansoni and peanut: a role for cross‐reactive carbohydrate determinants (CCDs) and implications for the hygiene hypothesis

The antigenic reactivity of constituents of Schistosoma mansoni and peanut (Arachis hypogaea) was investigated to determine whether identical antigenic epitopes possessed by both organisms provided a possible explanation for the negative correlation between chronic schistosome infection and atopy to allergens. Aqueous extracts of peanuts were probed in Western immunoblots with rabbit IgG antibodies raised against the egg, cercarial and adult worm stages of S. mansoni. Several molecules in the peanut extract were antigenically reactive with antibodies from the various rabbit anti‐schistosome sera. A pair of cross‐reactive peanut molecules at ~30 000–33 000 molecular weight was purified and both proteins were identified by mass spectrometric analysis as the peanut allergen Ara h 1. Anti‐S. mansoni soluble egg antigen antibodies that were eluted off the peanut molecules reacted with two S. mansoni egg antigens identified by mass spectrometry as IPSE/α‐1 and κ‐5. Alignments of the amino acid sequences of Ara h 1 and either IPSE/α‐1 or κ‐5 revealed a low level of peptide sequence identity. Incubation of nitrocellulose paper carrying electrophoresed peanut molecules, six constituents of other allergic plants and S. mansoni egg antigens in a mild solution of sodium metaperiodate before probing with antibodies, inhibited most of the cross‐reactivities. The results are consistent with the antigenic cross‐reactive epitopes of S. mansoni egg antigens, peanut and other allergic plants being cross‐reactive carbohydrate determinants (CCDs). These findings are novel and an explanation based on ‘blocking antibodies’ could provide an insight for the inverse relationship observed between schistosome infection and allergies.     

High Frequency of Anti‐Protein Z IgM and IgG Autoantibodies in Women with Idiopathic Recurrent Spontaneous Miscarriage

Citation Sater MS, Finan RR, Al‐Hammad SA, Mohammed FA, Issa AA, Almawi WY. High frequency of anti‐protein Z IgM and IgG autoantibodies in women with idiopathic recurrent spontaneous miscarriage. Am J Reprod Immunol 2011; 65: 526–531 Problem Protein Z (PZ) system is an anticoagulant pathway involved in the physiologic regulation of coagulation, and PZ deficiency reportedly enhances prothrombophilic mechanisms, including those implicated with idiopathic recurrent miscarriage (RSM). We investigate plasma anti‐PZ IgM and IgG levels in RSM women and in multiparous control women. Methods Anti‐PZ IgM and IgG levels were measured in 265 RSM women and 283 age‐matched control women by ELISA. Results Elevated anti‐PZ IgG (P < 0.001) and IgM (P < 0.001) titers were seen in patients. The areas under the curves for ROC curve for anti‐PZ IgM (0.898 ± 0.044) and IgG (0.898 ± 0.042) demonstrated no variation in diagnostic capacity. Multivariate analysis confirmed the association of elevated anti‐PZ IgM [adjusted odds ratio, aOR (95% CI) = 6.46 (2.44–17.11)] and IgG [aOR (95% CI) = 7.44 (2.54–21.79)] as independent predictors of RSM after adjusting for confounding covariates and demonstrated a clear gradation of increasing RSM risk associated with increased antibody titers. Conclusion The presence of anti‐PZ IgM and IgG antibodies are risk factors for RSM.     

Immunoglobulin A anti‐phospholipid antibodies in Swedish cases of systemic lupus erythematosus: associations with disease phenotypes,vascular events and damage accrual

Immunoglobulin (Ig) G‐ and IgM‐class anti‐cardiolipin antibodies (aCL) and lupus anti‐coagulant (LA) are included in the 1997 update of the American College of Rheumatology (ACR‐97) systemic lupus erythematosus (SLE) criteria. Despite limited evidence, IgA‐aCL and IgA anti‐β₂‐glycoprotein‐I (anti‐β₂GPI) were included in the 2012 Systemic Lupus International Collaborating Clinics criteria. The present study aimed to evaluate IgG‐/IgA‐/IgM‐aCL and anti‐β₂GPI occurrence in relation to disease phenotype, smoking habits, pharmacotherapy, anti‐phospholipid syndrome (APS) and organ damage among 526 Swedish SLE patients meeting ACR‐97. Patients with rheumatoid arthritis (n = 100), primary Sjögren’s syndrome (n = 50) and blood donors (n = 507) served as controls. Anti‐phospholipid antibodies (aPL) were analysed by fluoroenzyme‐immunoassays detecting aCL/anti‐β₂GPI. Seventy‐six (14%) SLE cases fulfilled the Sydney APS‐criteria, and ≥ 1 aCL/anti‐β₂GPI isotype (IgG/IgA/IgM) occurred in 138 SLE patients (26%). Forty‐five (9%) of the SLE cases had IgA‐aCL, 20 of whom (4%) lacked IgG‐/IgM‐aCL. Seventy‐four (14%) tested positive for IgA anti‐β₂GPI, 34 (6%) being seronegative regarding IgG/IgM anti‐β₂GPI. Six (1%) had APS manifestations but were seropositive regarding IgA‐aCL and/or IgA anti‐β₂GPI in the absence of IgG/IgM‐aPL and LA. Positive LA and IgG‐aPL tests were associated with most APS‐related events and organ damage. Exclusive IgA anti‐β₂GPI occurrence associated inversely with Caucasian ethnicity [odds ratio (OR) = 0·21, 95% confidence interval (CI) = 0·06–0·72) and photosensitivity (OR = 0·19, 95% CI = 0·05–0·72). Nephritis, smoking, LA‐positivity and statin/corticosteroid‐medication associated strongly with organ damage, whereas hydroxychloroquine‐medication was protective. In conclusion, IgA‐aPL is not rare in SLE (16%) and IgA‐aPL analysis may have additional value among SLE cases with suspected APS testing negative for other isotypes of aPL and LA.     

Serum lipid profile as a predictor of dengue severity: A systematic review and meta‐analysis

Dengue virus is known to modulate host cell lipid metabolism in order to promote efficient viral replication. Recent studies have focused on circulating lipids as potential biomarkers of dengue severity; however, the results obtained so far lack the consistency to establish a definite relationship between the two. Therefore, in the present study, we investigated serum lipids as potential biomarkers of dengue severity by conducting a meta‐analysis of the currently available clinical data. Nine studies that evaluated 1,953 patients were included in the review, many of which were cross‐sectional (44.4%) and conducted in Asian countries (55.5%). These studies observed the presence of lipids in serum samples (77%) of patients in the acute phase of the disease (88.8%). Circulating total‐cholesterol (P = .001) and LDL (P = .001) levels, but not HDL (P = .07), VLDL (P = .9) and triglyceride (P = .57) levels, were inversely and significantly correlated with dengue severity. Total cholesterol (P ≤ .001) and LDL (P = .001) were also useful in determining the risk of hypovolemic shock in patients with severe dengue. Subgroup analysis showed that factors, such as design (cross‐sectional vs cohort), racial‐ethnic differences (Asian vs Latin Americans), and age range (children vs adult) influenced the correlation and also contributed to the high level of heterogeneity in the studies. Our meta‐analysis demonstrates that total‐cholesterol and LDL‐cholesterol levels should be explored as routine laboratory markers for dengue severity, as they will help in employing an appropriate patient therapy, and thus optimize the use of available resources.     

Increased Antifungal Antibodies in Bronchoalveolar Lavage Fluid and Serum in Pulmonary Sarcoidosis

The recent studies suggest a role of fungi in development of sarcoidosis. Moreover, the immune response in sarcoidosis and fungal infection shows a striking similarity. We formulated a hypothesis of the possible increase in antifungal antibodies in bronchoalveolar lavage fluid (BALF) and serum in pulmonary sarcoidosis. BALF and serum levels of IgG‐, IgM‐ and IgA‐specific antibodies against the cell wall β‐D‐glucan and mannan of Candida albicans and Saccharomyces cerevisiae were tested in 47 patients (29 pulmonary sarcoidosis patients and 18 patients with other interstitial lung diseases (ILD – control group)) and 170 healthy controls. Our results proved: (1) an increase in IgG‐, IgM‐ and IgA‐specific antifungal antibodies in BALF in pulmonary sarcoidosis compared with the control group (C. albicans: IgG: P = 0.0329, IgM: P = 0.0076, IgA: P = 0.0156; S. cerevisiae: IgG: P = 0.0062, IgM: P = 0.0367, IgA: P = 0.0095) and (2) elevated levels of serum antifungal antibodies in pulmonary sarcoidosis compared with healthy controls (C. albicans: IgG: P = 0.0329, IgM: P = 0.0076, IgA: P = 0.0156; S. cerevisiae: IgG: P > 0.05, IgM: P < 0.05, IgA: P < 0.001). The study showed increased serum and BALF levels of antifungal antibodies in pulmonary sarcoidosis. The hypothesis that fungal infection is one of the possible aetiologic agents of sarcoidosis is interesting and deserves further attention.     

Putative risk alleles for LATE‐NC with hippocampal sclerosis in population‐representative autopsy cohorts

Limbic‐predominant age‐related TAR‐DNA‐binding protein‐43 (TDP‐43) encephalopathy with hippocampal sclerosis pathology (LATE‐NC + HS) is a neurodegenerative disorder characterized by severe hippocampal CA1 neuron loss and TDP‐43‐pathology, leading to cognitive dysfunction and dementia. Polymorphisms in GRN, TMEM106B and ABCC9 are proposed as LATE‐NC + HS risk factors in brain bank collections. To replicate these results in independent population‐representative cohorts, hippocampal sections from brains donated to three such studies (Cambridge City over 75‐Cohort [CC75C], Cognitive Function and Ageing Study [CFAS], and Vantaa 85+ Study) were stained with hematoxylin–eosin (n = 744) and anti‐pTDP‐43 (n = 713), and evaluated for LATE‐NC + HS and TDP‐43 pathology. Single nucleotide polymorphism genotypes in GRN rs5848, TMEM106B rs1990622 and ABCC9 rs704178 were determined. LATE‐NC + HS (n = 58) was significantly associated with the GRN rs5848 genotype (χ²(2) = 20.61, P < 0.001) and T‐allele (χ²(1) = 21.04, P < 0.001), and TMEM106B rs1990622 genotype (Fisher's exact test, P < 0.001) and A‐allele (χ²(1) = 25.75, P < 0.001). No differences in ABCC9 rs704178 genotype or allele frequency were found between LATE‐NC + HS and non‐LATE‐NC + HS neuropathology cases. Dentate gyrus TDP‐43 pathology associated with GRN and TMEM106B variations, but the association with TMEM106B nullified when LATE‐NC + HS cases were excluded. Our results indicate that GRN and TMEM106B are associated with severe loss of CA1 neurons in the aging brain, while ABCC9 was not confirmed as a genetic risk factor for LATE‐NC + HS. The association between TMEM106B and LATE‐NC + HS may be independent of dentate TDP‐43 pathology.     

Evaluation of membrane‐bound and soluble forms of human leucocyte antigen‐G in systemic sclerosis

Systemic sclerosis (SSc) is a complex disease characterized by immune dysregulation, extensive vascular damage and widespread fibrosis. Human leucocyte antigen‐G (HLA‐G) is a non‐classic class I major histocompatibility complex (MHC) molecule characterized by complex immunomodulating properties. HLA‐G is expressed on the membrane of different cell lineages in both physiological and pathological conditions. HLA‐G is also detectable in soluble form (sHLA‐G) deriving from the shedding of surface isoforms (sHLA‐G1) or the secretion of soluble isoforms (HLA‐G5). Several immunosuppressive functions have been attributed to both membrane‐bound and soluble HLA‐G molecules. The plasma levels of sHLA‐G were higher in SSc patients (444·27 ± 304·84 U/ml) compared to controls (16·74 ± 20·58 U/ml) (P < 0·0001). The plasma levels of transforming growth factor (TGF)‐β were higher in SSc patients (18 937 ± 15 217 pg/ml) compared to controls (11 099 ± 6081 pg/ml; P = 0·003), and a significant correlation was found between TGF‐β and the plasma levels of total sHLA‐G (r = 0·65; P < 0·01), sHLA‐G1 (r = 0·60; P = 0·003) and HLA‐G5 (r = 0·47; P = 0·02). The percentage of HLA‐G‐positive monocytes (0·98 ± 1·72), CD4⁺ (0·37 ± 0·68), CD8⁺ (2·05 ± 3·74) and CD4⁺CD8⁺ double‐positive cells (14·53 ± 16·88) was higher in SSc patients than in controls (0·11 ± 0·08, 0·01 ± 0·01, 0·01 ± 0·01 and 0·39 ± 0·40, respectively) (P < 0·0001). These data indicate that in SSc the secretion and/or shedding of soluble HLA‐G molecules and the membrane expression of HLA‐G by peripheral blood mononuclear cells (PBMC) is clearly elevated, suggesting an involvement of HLA‐G molecules in the immune dysregulation of SSc.     

Correlation of natural autoantibodies and cardiovascular disease‐related anti‐bacterial antibodies in pericardial fluid of cardiac surgery patients

Our previous studies showed that anti‐citrate synthase (anti‐CS) immunoglobulin (Ig)M natural autoantibodies are present in healthy individuals without previous antigen stimulation, but no studies have investigated their presence in the pericardial fluid (PF). Therefore, we detected the natural anti‐CS IgG/M autoantibody levels in plasma and PF of cardiac surgery patients and investigated their relationship with cardiovascular disease‐associated bacterial pathogens. PF and blood samples of 22 coronary artery bypass graft (CABG) and 10 aortic valve replacement (AVR) patients were tested for total Ig levels, natural autoantibodies and infection‐related antibodies using enzyme‐linked immunosorbent assay (ELISA) and Luminex methods. The B cell subsets were measured by flow cytometry. The total Ig subclass levels were four to eight times lower in PF than in plasma, but the natural anti‐CS IgM autoantibodies showed a relative increase in PF. The frequency of CD19⁺ B lymphocytes was significantly lower in PF than in blood (P = 0·01), with a significant relative increase of B1 cells (P = 0·005). Mycoplasma pneumoniae antibody‐positive patients had significantly higher anti‐CS IgM levels. In CABG patients we found a correlation between anti‐CS IgG levels and M. pneumoniae, Chlamydia pneumoniae and Borrelia burgdorferi antibody titres. Our results provide the first evidence that natural autoantibodies are present in the PF, and they show a significant correlation with certain anti‐bacterial antibody titres in a disease‐specific manner.     

Combined cytotoxic activity of an infectious,but non‐replicative herpes simplex virus type 1 and plasmacytoid dendritic cells against tumour cells

Malignant melanoma is an aggressive tumour of the skin with increasing incidence, frequent metastasis and poor prognosis. At the same time, it is an immunogenic type of cancer with spontaneous regressions. Most recently, the tumoricidal effect of plasmacytoid dendritic cells (pDC) and their capacity to overcome the immunosuppressive tumour microenvironment are being investigated. In this respect, we studied the effect of the infectious, but replication‐deficient, herpes simplex virus 1 (HSV‐1) d106S vaccine strain, which lacks essential immediate early genes, in pDC co‐cultures with 11 melanoma cell lines. We observed a strong cytotoxic activity, inducing apoptotic and necrotic cell death in most melanoma cell lines. The cytotoxic activity of HSV‐1 d106S plus pDC was comparable to the levels of cytotoxicity induced by natural killer cells, but required only a fraction of cells with effector : target ratios of 1 : 20 (P < 0·05). The suppressive activity of cell‐free supernatants derived from virus‐stimulated pDC was significantly neutralized using antibodies against the interferon‐α receptor (P < 0·05). In addition to type I interferons, TRAIL and granzyme B contributed to the inhibitory effect of HSV‐1 d106S plus pDC to a minor extent. UV‐irradiated viral stocks were significantly less active than infectious particles, both in the absence and presence of pDC (P < 0·05), indicating that residual activity of HSV‐1 d106S is a major component and sensitizes the tumour cells to interferon‐producing pDC. Three leukaemic cell lines were also susceptible to this treatment, suggesting a general anti‐tumour effect. In conclusion, the potential of HSV‐1 d106S for therapeutic vaccination should be further evaluated in patients suffering from different malignancies.     

Anti‐C1q autoantibodies are linked to autoimmune thyroid disorders in pregnant women

Anti‐C1q antibodies (anti‐C1q) have been implicated in the pathogenesis of autoimmune diseases, including autoimmune thyroid disorders (AITD). The aim of this study was to evaluate the association between anti‐C1q and thyroid function in pregnancy‐associated AITD. In 96 pregnant women screened positive for AITD (thyroid dysfunction and/or antibodies against thyroperoxidase – TPOAb), anti‐C1q were measured during the 9‐11th gestational week and after delivery (median 16 months after delivery), and compared to the corresponding serum levels of thyroid hormones. As controls, 80 healthy pregnant women, 72 non‐pregnant AITD patients and 72 blood donors were included. In the non‐pregnant AITD group, two serum samples ≥ 6 months apart were analysed. Compared to blood donors, anti‐C1q levels were substantially higher in all pregnant women analysed. In pregnancy, anti‐C1q levels were higher in the TPOAb‐positive women than in controls (37 versus 17·5%, P < 0·0001). Anti‐C1q‐positive pregnant women screened positive for AITD had higher thyroid‐stimulating hormone (TSH) levels than anti‐C1q‐negative women (2·41 versus 1·94 mU/l, P = 0·01), and TSH correlated positively with anti‐C1q (r = 0·226, P = 0·045) in the TPOAb‐positive women. After delivery, serum levels of anti‐C1q decreased in the positively screened TPOAb‐negative women (8·8 versus 5·9 U/l, P = 0·002), but not in the TPOAb‐positive ones, and they no longer correlated with TSH. Anti‐C1q antibody levels increase during pregnancy in general and even more in the context of AITD, where they correlate with thyroid stimulating hormone levels.     

Characteristics of Schistosoma japonicum infection induced IFN‐γ and IL‐4 co‐expressing plasticity Th cells

Schistosoma japonicum infection can induce granulomatous inflammation and cause tissue damage in the mouse liver. The cytokine secretion profile of T helper (Th) cells depends on both the nature of the activating stimulus and the local microenvironment (e.g. cytokines and other soluble factors). In the present study, we found an accumulation of large numbers of IFN‐γ⁺ IL‐4⁺ CD4⁺ T cells in mouse livers. This IFN‐γ⁺ IL‐4⁺ cell population increased from 0·68 ± 0·57% in uninfected mice to 7·05 ± 3·0% by week 4 following infection and to 9·6 ± 5·28% by week 6, before decreasing to 6·3 ± 5·9% by week 8 in CD4 T cells. Moreover, IFN‐γ⁺ IL‐4⁺ Th cells were also found in mouse spleen and mesenteric lymph nodes 6 weeks after infection. The majority of the IFN‐γ⁺ IL‐4⁺ Th cells were thought to be related to a state of immune activation, and some were memory T cells. Moreover, we found that these S. japonicum infection‐induced IFN‐γ⁺ IL‐4⁺ cells could express interleukin‐2 (IL‐2), IL‐9, IL‐17 and high IL‐10 levels at 6 weeks after S. japonicum infection. Taken together, our data suggest the existence of a population of IFN‐γ⁺ IL‐4⁺ plasticity effector/memory Th cells following S. japonicum infection in C57BL/6 mice.     

Effect of Branched α‐Oligomannoside Structures on Induction of Anti‐Candida Humoral Immune Response

Several studies have established the potential efficacy of humoral immunity, primarily mannan‐specific antibodies, in host protection against major fungal pathogen Candida albicans. In this study, we analysed humoral immune response induced by immunization with BSA‐based conjugates bearing synthetic α‐1,6‐branched oligomannosides (pentamannosides (M5) or hexamannosides (M6)) mimicking antigenic sequences of Candida cell wall mannan. We analysed the ability of antibodies prepared by immunization to recognize relevant antigenic determinants in mannan polysaccharide structure and in C. albicans yeast and hyphal morphoforms. M6‐BSA conjugate induced markedly higher levels of mannan‐specific IgG compared with M5‐BSA conjugate. In contrast to M5‐BSA conjugate, M6‐BSA conjugate induced immunoglobulin isotype class switch from IgM to IgG, as revealed also from ELISPOT analysis. Immunization‐induced antibodies showed higher reactivity with hyphal form of C. albicans cells. The reduced immunogenicity of M5‐BSA conjugate seems to be related to branching point location at terminal non‐reducing end in comparison with M6‐BSA oligomannoside with branching point at non‐terminal location. Candidacidal activity assay revealed different capacity of sera prepared by immunization with M5‐BSA and M6‐BSA conjugates to improve candidacidal activity of polymorphonuclear leucocytes. Limited capacity of α‐1,6‐branched oligomannoside – BSA conjugates to induce antibodies significantly enhancing candidacidal activity of polymorphonuclear leucocytes – was presumably related to absence of antibodies with strong reactivity to corresponding antigenic determinants in natural cell wall mannan and with reduced ability to activate complement. The study documented markedly structure‐dependent immunogenicity and limited capacity of branched α‐mannooligosides conjugates to induce production of potentially protective antibodies.     

Porphyromonas gingivalis‐induced inflammatory responses in THP1 cells are altered by native and modified low‐density lipoproteins in a strain‐dependent manner

Strong epidemiological evidence supports an association between cardiovascular and periodontal disease and furthermore, the periodontopathogen Porphyromonas gingivalis has been identified in blood and from atheromatous plaques. Blood exposed to P. gingivalis shows an increased protein modification of low‐density lipoprotein (LDL). In this study, we investigate the inflammatory responses of THP1 cells incubated with P. gingivalis and the effects of native or modified LDL on these responses. Reactive oxygen species (ROS) and IL‐1β were observed in THP1 cells following infection with P. gingivalis ATCC33277 and W50. Caspase 1 activity was quantified in THP1 cells and correlated with IL‐1β accumulation. Oxidized LDL (oxLDL) induced IL‐1β release and CD36 expression on THP1 cells. Modified LDL co‐stimulated with ATCC33277 exhibited regulatory effects on caspase 1 activity, IL‐1β release and CD36 expression in THP1 cells, whereas W50 induced more modest responses in THP1 cells. In summary, we show that P. gingivalis is capable of inducing pro‐inflammatory responses in THP1 cells, and native and modified LDL could alter these responses in a dose‐ and strain‐dependent manner. Strain‐dependent differences in THP1 cell responses could be due to the effect of P. gingivalis proteases, presence or absence of capsule and proteolytic transformation of native and modified LDL.