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Type I interferons (IFNs) play an essential role in antiviral immunity, correlate with severity of systemic autoimmune disease, and are likely to represent a key component of mRNA vaccine-adjuvanticity. Relevant to all, type I IFNs can enhance germinal center (GC) B cell responses but underlying signaling pathways are incompletely understood due to pleiotropic effects in multiple cell types. Here, we demonstrate that a succinct type I IFN response promotes GC formation and associated IgG subclass distribution primarily through signaling in cDCs and B cells. Type I IFN signaling in cDCs, distinct from cDC1, stimulates development of separable Tfh and Th1 cell subsets. However, Th cell-derived IFN-γ induces T-bet expression and IgG2c isotype switching prior to this bifurcation and has no evident effects once GCs andbona fideTfh cells developed. This pathway acts in synergy with early B cell-intrinsic type I IFN signaling, which reinforces T-bet expression in B cells and leads to a selective amplification of the IgG2c+GC B cell response. Despite the strong Th1 polarizing effect of type I IFNs, the Tfh cell subset develops into IL-4 producing cells that control the overall magnitude of the GCs and promote generation of IgG1+GC B cells. Thus, type I IFNs act on B cells and cDCs to drive GC formation and to coordinate IgG subclass distribution through parallel Th1 and Tfh cell-dependent pathways.

Introduction Duration of protection against pertussis is shorter in adolescents who have been immunized with acellular pertussis (aP) in infancy compared with adolescents who received whole-cell pertussis (wP) vaccines in infancy, which is related to immune responses elicited by these priming vaccines. To better understand differences in vaccine induced immunity, we determined pertussis, diphtheria, and tetanus (DTaP) vaccine antigen-specific IgG subclass responses in wP- and aP-primed children before and after two successive DTaP booster vaccinations. Methods Blood samples were collected in a cross-sectional study from wP- or aP-primed children before and 1 month after the pre-school DTaP booster vaccination at age 4 years. Blood samples were collected from two different wP- and aP-primed groups of children before, 1 month and 1 year after an additional pre-adolescent Tdap booster at age 9 years. IgG subclass levels against the antigens included in the DTaP vaccine have been determined with fluorescent-bead-based multiplex immunoassays. Results At 4 years of age, the IgG4 proportion and concentration for pertussis, diphtheria and tetanus vaccine antigens were significantly higher in aP-primed children compared with wP-primed children. IgG4 concentrations further increased upon the two successive booster vaccinations at 4 and 9 years of age in both wP- and aP-primed children, but remained significantly higher in aP-primed children. Conclusions The pertussis vaccinations administered in the primary series at infancy determine the vaccine antigen-specific IgG subclass profiles, not only against the pertussis vaccine antigens, but also against the co-administered diphtheria and tetanus vaccine antigens. These profiles did not change after DTaP booster vaccinations later in childhood. The different immune response with high proportions of specific IgG4 in some aP-primed children may contribute to a reduced protection against pertussis. ISRCTN65428640; ISRCTN64117538; NTR4089.

Background : A majority of patients with cystic fibrosis (CF) become colonised with Aspergillus fumigatus ( Af .), but only a minority develops allergic bronchopulmonary aspergillosis (ABPA). ABPA is associated with increased levels of specific immunoglobulin G (IgG) anti- Af . antibodies with a characteristic IgG subclass distribution. We examined whether this characteristic immune response was under the influence of GM and KM allotypes, which are genetic markers (antigenic determinants) on gamma- and kappa-light chains, respectively. Methods : Sera from 233 CF patients were typed for seven GM determinants and two KM determinants. The types were correlated to IgG subclass anti- Af . antibody levels and to the presence or absence of Af . colonisation as well as ABPA. Results : The IgG2 antibody level was significantly higher in heterozygous GM (1,2,17 23 5,21 and 1,3,17 23 5,21) compared to homozygous GM allotypes ( p =0.02). Patients with the same allotypes tended to have higher IgG1 ( p =0.051). In patients with ABPA, being heterozygous for G1M and G3M was linked to higher IgG4 and lower IgG3 as compared to the other genotypes. The KM markers did not influence the antibody levels. The allotype GM(3 23 5), associated with atopic bronchial asthma, tended to make a relatively larger group in ABPA patients compared to non-ABPA and patients not colonised with Af . ( p =0.09). Conclusions : An influence of the GM allotypes on the immune response to Af . and on the development of ABPA in patients with CF is suggested.

Development of immunoglobulin G subclass antibodies to ovalbumin, birch and cat during the first eight years of life in atopic and non-atopic children.

In order to measure the serum levels of IgG and IgG subclass antibodies against Japanese cedar pollen, an ELISA procedure was developed with commercially available antigen-coated wells for measuring IgE antibodies. The specificity, sensitivity and reproducibility of this ELISA system were all highly reliable in our experiments. The results of this study suggest the clinical usefulness of this method for following the responses of serum IgG and IgG subclass antibodies during immunotherapy for Japanese cedar pollinosis.

One of the methods for calibration of antigen specific antibodies in a serum involves parallel titration of known concentrations of purified normal immunoglobulins (Igs) and a specific antiserum. We evaluated the effect of three methods for capturing known concentrations of purified normal mouse Igs (IgG, IgG subclasses and IgM) on the anti-tetanus toxoid antibody concentrations assigned to a reference mouse serum: (1) direct coating, (2) capture by pre-coated anti-mouse IgG (Fc) specific antibodies, and (3) capture by pre-coated anti-mouse IgG (Fab) specific antibodies. Direct coating of purified Igs onto plastic was the least efficient and would greatly overestimate antigen specific antibody concentrations. Equivalent concentrations of purified IgG subclasses and IgM produced higher absorbances when captured by anti-Fab antibodies pre-coated on plates than by anti-Fc antibodies. As a consequence, the anti-Fc capture method resulted in the assignment of IgG1, IgG2a and IgG2b tetanus specific antibody concentrations which exceeded the total IgG1, IgG2a and IgG2b concentrations. Additionally, the sum of tetanus specific IgG subclass antibodies exceeded the tetanus specific IgG antibody concentration by > 2-fold. In contrast, the anti-Fab capture method resulted in 2-9-fold lower assigned tetanus antibody concentrations which did not exceed the total Ig concentrations. We conclude that when using enzyme-linked immunosorbent assays, parallel titration of purified normal Ig standards captured by anti-Fab antibodies is superior to anti-Fc capture or direct coating for calibrating antigen specific antibodies in a reference serum.

抗Porphyromonas gingivalis抗体の機能と, 本菌の歯周感染における主要抗原を調べる目的で, 初診時歯周炎患者および健常者の血清について, IgGサブクラス特異的モノクローナル抗体を用いて, 固相免疫測定法ELISA) による抗P. gingivalis抗体価の測定と, イムノブロット法による各IgGサブクラス抗体の対応抗原 の (解析を行った。凍結乾燥全菌体を抗原としたELISAの結果, 患者群では全てのサブクラスにおいて抗体価の有意な上昇が認められ, 大部分の患者では特定のサブクラスの抗体価が選択的に上昇していた。IgG2抗体価と各種臨床指数との問には有意な正の相関が認められた。しかし, IgG1, IgG3, IgG4および総IgG抗体価については, 各種臨床指数との間に, 相関は認められなかった。本菌の超音波破砕上清を使用したイムノブロット法による解析においては, IgG2サブクラスの抗体が患者に特徴的な染色像を最も頻繁に示し, IgG1サブクラスの抗体はすべての患者および健常者において反応が認められ, IgG3, IgG4のサブクラスに反応が認められた者は, 患者においても健常者においてもまれであった。P. gingivalis特異的IgG抗体の中でもIgG2サブクラスにおいて顕著な特徴が認められた事から, 本菌の糖抗原は歯周炎の免疫応答において重要な役割を演じているものと考えられる。

Measurement of serum IgG antibodies against Helicobacter pylori seems to be useful in the diagnosis of H. pylori infections. IgG subclass antibodies against H. pylori have, however, not been investigated thoroughly. In this study IgG1, IgG2, IgG3 and IgG4 antibody levels against H. pylori were measured using an ELISA technique in 187 normal adult persons and in 174 patients with dyspeptic symptoms, of whom 99 patients were H. pylori positive. None of the IgG subclass antibody levels were better than the total IgG level for the diagnosis of H. pylori infection. The discrimination between H. pylori-positive and H. pylori-negative patients was better with IgG1, IgG2 and IgG4 antibody levels than with IgG3 antibody level. IgG2 was the IgG subclass antibody that mainly contributed to the age-dependent increase in the IgG antibody level. This sustains the suspicion that cross-reactions between lipopolysaccharide (LPS) from H. pylori and LPS from other Gram-negative bacteria may occur.

This research was planned to detect IgG and IgG subclasses in sera of patients with active cutaneous leishmaniasis (CL). Sera from 30 patients with active CL aged between 10 and 50 years and from 30 healthy controls aged between 8 and 50 years were included in the study. Levels of IgG and its subclasses were measured by a nephelometer. Levels of IgG, IgG1 and IgG3 in the CL patients were higher than in the controls. In addition, IgG and IgG1, and IgG and IgG3 levels showed a significant positive correlation. These results showed that IgG subclasses could possibly be used as a helpful diagnostic marker in CL.

House dust mites have been known as the most important allergen in respiratory allergic diseases. Among several mite allergens, group I and group II antigens were recognized as major allergens. We measured specific IgE and IgG subclass antibodies against whole body antigen (WBA) and two major allergens of Dermatophagoides farinae (Der fI and Der fII) in sera from 66 adults with asthma (asthma group) and 34 normal subjects (healthy group) by ELISA. The mean O.D. values of WBA-specific IgE and IgG subclass antibodies in 100 studied sera were significantly higher than those of the two major allergens (p < 0.001) and the level of Der fII- IgG1, IgG4 and IgE were higher than those of Der fI but IgG2 of Der fI was higher than that of Der fII (p < 0.001). The level of IgG4 of WBA were significantly higher in the atopic group than in the nonatopic group (1.280 +/- 0.634 v.s. 0.8290 +/- 0.388, p < 0.001), but the WBA- IgG1, IgG2, IgG3 were not different between the two groups. Among IgG subclass antibodies of Der fI, IgG2 was significantly higher in the nonatopic group than in the atopic group (1.7770 +/- 0.255 v.s. 1.636 +/- 0.390, p < 0.05) but there were no differences in IgG1, IgG3, and IgG4. Among IgG subclass antibodies of Der fII, IgG2 (1.534 +/- 0.380 v.s. 1.3010 +/- .431, p < 0.05) and IgG4 (1.09650 +/- .567 v.s. 0.708 +/- 0.146, p < 0.001) were significantly higher in the atopic group than in the nonatopic group. IgE antibodies to WBA, Der fI and Der fII were significantly higher in the atopic group (p < 0.001). There were significant correlationships between the levels of IgE and IgG4 of WBA (r = 0.60), Der fI (r = 0.33) and Der fII (r = 0.72). Even though there were no differences in the levels of allergen specific IgE and IgG subclass antibodies between nonatopic healthy and nonatopic asthmatic groups, the number of sera with prominent level of IgG2 of WBA were more common in the nonatopic asthmatic group (69% in nonatopic asthma group v.s. 28% in nonatopic healthy group, X2-test, p < 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Based on a 3-year prospective study of 20 pollen-allergic patients, where a detailed analysis of the IgE, IgG, and IgG4 immune response was performed, we propose that a common regulatory mechanism exists between the IgE and IgG1 synthesis and between IgE and IgG4 synthesis during immunotherapy. It was found that the IgE immune response to a number of antigens was quantitatively diminished during the period of immunotherapy when IgG1 was present early (week 12), and for other antigens there was a rise in IgE without an early IgG1 antibody response. Additionally, it was found that for some antigens a rise in IgE antibodies was contrasted by a fall in the IgG4 antibody response and for other antigens the opposite was true, indicating a regulatory mechanism between the IgE and the IgG4 synthesis. A statistical analysis showed that these findings were statistically significant at the 0.01 % level for the IgE/IgG1 relationship and at the 0.05% level for the IgE/IgG4 relationship. These findings could have implications for future immunotherapy regimens.

We have estimated by ELISA the levels of IgG subclass antibodies against P. gingivalis strain W83 whole cells in 35 cases of adult periodontitis and 35 age, sex, ethnic origin and plaque index-matched healthy controls. The mean levels of IgG1 (p < 0.0003) and IgG2 (p < 0.0416) were significantly elevated in the cases. Many sera had no detectable IgG4 antibodies but by categorising IgG4 responses into high, low and absent, this subclass was more often present (p < 0.002) in the cases. Analysis of the paired differences between cases and controls showed that only IgG1 (p < 0.0005) and IgG4 (p < 0.003) levels were significantly greater in the cases. The data support the role of P. gingivalis as a key pathogen in adult periodontitis and high levels of IgG4 antibodies might possibly provide a marker of patients with active disease.

The differential diagnostic potential of serum gliadin-specific IgG subclass antibodies was assessed by comparing the antigliadin IgG1, 2, 3, 4 profile at different stages of coeliac disease with that of gastro-intestinal infection and also conditions associated with increased intestinal permeability. The IgG subclass profile of untreated coeliac disease was found to be the same as in healthy controls (IgG1 approximately IgG2 > IgG3 > IgG4), with only the magnitude of the individual subclass responses being increased in coeliac patients. Coeliac adults and children on gluten-free diets had different antigliadin IgG subclass profiles with IgG2 being elevated. Increased intestinal permeability or recent gastro-intestinal infection did not alter the antigliadin subclass profile from that observed in healthy individuals. Assessment of the diagnostic potential of antigliadin IgA1 and IgG1-4 measurements in screening for coeliac disease demonstrated that measurement of subclasses of gliadin-specific IgA and IgG was less sensitive and specific compared with the combined use of total antigliadin IgA and IgG. Therefore it is suggested that IgG subclasses should not be used for routine screening for coeliac disease.

天疱瘡, 類天疱瘡および妊娠性疱疹の患者血清およびそれらより分離したIgG 3画分とIgG 1. 2. 4. 画分を補体成分とともに培養液中に加えて健常人皮膚を器官培養した。その器官培養皮膚の経時的形態変化と免疫組織学的所見(蛍光抗体法)を検討した。天疱瘡の場合患者血清, IgG 1. 2. 4. 画分と反応させると, 表皮細胞間にIgGの沈着と棘融解様変化が認められた。IgG 3画分と反応させると棘融解様変化は認められたが, 表皮細胞間にIgGの沈着は認められなかつた(3/3例)。類天疱瘡の場合, 患者血清と反応させると基底膜部へのIgGの沈着とdermo-epidermal separation(以下DESと略す)が認められた。IgG 1. 2. 4. 画分と反応させると基底膜部へのIgGの沈着は認められたが, DESは認められなかつた。IgG 3画分と反応させると基底膜部へのIgGの沈着も, DESも認められなかつた(3/3例)。妊娠性疱疹の場合, 患者血清と反応させると基底膜への補体(C3)の沈着とDESが認められた(3/3例)。IgG 3画分と反応させるとDESは認められたが, 基底膜部へのC3の沈着は認められなかつた。IgG 1. 2. 4. 画分と反応させると基底膜部へのC3の沈着もDESも認められなかつた(2/2例)。したがつて天疱瘡, 類天疱瘡, 妊娠性疱疹ではIgG subclass抗体の水疱形成への関与機構が多少異なることが示唆される。

Several mouse monoclonal antibodies specific for human IgG1, IgG2, IgG3, and IgG4 were evaluated by enzyme-linked immunosorbent assay to detect human IgG subclass antibodies to herpes simplex virus (HSV) antigens. The variable results with different monoclonal antibodies point to the need for well-characterized reagents in the study of antibody responses to infectious agents. The 204 sera tested were obtained from 157 patients with various forms of clinically manifest HSV infections and from several controls. IgG1 antibodies were demonstrated in almost all HSV-infected subjects and were the first antibodies to appear in primary genital infections. IgG2, IgG3, and IgG4 antibodies were detected in acute-phase sera, most often in patients with recurrent genital herpes but in none of those with primary infections. IgG4 antibodies occurred significantly more frequently in sera from men than in those from women with recurrent genital infections.

A comparative study was made of the neutralizing activities of IgG subclasses IgG1 and IgG2, fractionated from guinea pig antisera against Sendai virus. The yields of IgG2 from the antisera were about 16 times as much as those of IgG1. The neutralizing activity of IgG2 per unit weight was four times as high as that of IgG1. This neutralizing activity of both IgG subclasses was enhanced about 10 times by addition of antibodies to the L-chain of guinea pig immunoglobulin. It is suggested that, in the complement-dependent neutralization of the virus, IgG1 and IgG2 activate the complement through the alternative and the classical pathway, respectively.

The sera of patients with pigeon breeders' disease usually contain precipitating serum factors as well as human complement consuming factors as shown by incubation of the serum with pigeon dropping antigens. Although a single serum factor, possibly an IgG antibody, might account for both phenomena, affinity chromatography experiments revealed that the sera of patients with pigeon breeders' disease contain non-precipitating, human complement consuming, serum factors besides precipitating serum factors which are also capable of complement consumption. The non-precipitating serum factors most likely belong to the IgG3 immunoglobulin subclass, whereas the precipitating antibodies belong to the subclasses IgG 1 and IgG 2 .

The data obtained so far indicate that house dust mite immunotherapy stimulates an IgG antibody response that is predominantly of IgG4 subclass. Early in the course, however, a rise in IgG1 antibodies can be detected, but as treatment goes on IgG4 becomes more prominent. The association between the development of IgG4 antibodies and objectively measured clinical improvements resulting from immunotherapy, strongly suggests that IgG4 antibodies might exert a blocking effect on IgE-mediated immediate hypersensitivity.

Enzyme linked immunosorbent assays (ELISA) were developed for the determination of human IgG subclass antibodies to dietary antigens (ovalbumin (OA), beta-lactoglobulin (BLG), casein and gliadin). Quantification was approached by determining the parallel binding of myeloma subclass protein to F(ab')2 anti-light chain antibody in the microplate. The dominating subclasses in healthy individuals were IgG1 and IgG4 for anti-OA and anti-BLG antibodies, whereas anti-casein antibodies were more evenly distributed between the subclasses. The complement binding of IgG subclass antibodies to OA, BLG and casein was investigated by measuring (ELISA) the binding of complement factor C4b to purified antibodies of subclasses IgG1 and IgG4, respectively. Preliminary results indicated binding of C4b at varying levels to both IgG1 and IgG4 antibody preparations

The data obtained so far indicate that 1) presence of high titer of IgE antibodies was related with symptoms of egg hypersensitivity, 2) it seems unlikely that increased IgG4 antibody levels against egg white is a cause of egg hypersensitivity, and one should pay much attention to IgG1 antibodies, instead, 3) it is possible that increased IgG4 may reduce the effect of complement-fixing antibodies like IgG1 and/or interfere the action of IgE antibodies.

We studied the IgG subclass antibody response in allergic patients immunized with complex allergen mixtures (grass pollen (GP), birch pollen (BP), house dust mite (HDM), the mould Cladosporium (CS), and yellow jacket venom (YJV)). IgG subclass antibodies were quantitated by means of different types of immunoradiometric assays. We found the IgG antibody response to be restricted to the IgG1 and IgG4 subclasses during immunotherapy with GP, BP, and YJV. Whereas these subclasses also were predominant in the response to HDM and CS, some patients produced large amounts of IgG2 and IgG3 antibodies to CS. In patients immunized with GP or CS, a statistically significant association between low initial IgG4 antibody response and good clinical outcome was observed. Possible immunobiological mechanisms underlying this finding are discussed