IgG subclasses of islet cell surface antibodies and their cytotoxic activity against pancreatic islet cells

IgG subclasses of islet cell surface antibodies (ICSA) and their cytotoxic activities against pancreatic islet cells in the presence of complements were simultaneously investigated in ICSA-positive patients with insulin-dependent diabetes mellitus (n = 15). ICSA (IgG class) and ICSA-IgG subclasses were determined by flow cytometry using a fluorescence-activated cell sorter (FACS). Complement-dependent antibody-mediated cytotoxicity (CAMC) was measured by release of 51Cr from target cells. For these assays, rat insulinoma (RINr) cells were used as antigenic or target cells. Sera from 11 out of 15 patients who were positive for ICSA possessed at least one positive ICSA-IgG subclass, though these sera did not always exert positive CAMC activities. When the relationship between ICSA-IgG subclasses and CAMC was tested by chi-square analysis, a significant relationship (P less than 0.01) was observed between ICSA-IgG3 and CAMC. In sera from the other four patients, not any positive ICSA-IgG subclass or CAMC activity was found. The data suggest that (1) ICSA (IgG class) found in diabetics are not always cytotoxic to pancreatic islet cells, (2) the IgG subclass of ICSA varies with the patients, and (3) ICSA-IgG3 have a significantly higher association with CAMC to pancreatic islet cells. Thus, ICSA (IgG class) might not always be responsible for the impairment of pancreatic islet cells, at least in part, because of the heterogenous ICSA-IgG subclass.     

Allergologic-immunochemical study of tree and bush pollen. III--Cross reactions of human IgE antibodies with various tree pollen allergens

Partial identity between the major allergens of birch, beech, alder, hazel and oak pollen extract could be identified by means of RAST-, ELISA- and CRIE-inhibition as well as further types of crossed immunoelectrophoresis. It seems that spring time pollinosis in our region of Central Europe is caused principally by the major allergen of birch pollen. Cross reactivity between grass and tree pollen could not be found. Patients with symptoms in spring and summer time are double sensitized.     

Prevalence of anti-group B streptococcal type III capsular IgG antibodies in the United Kingdom and an analysis of their specific IgG subclasses

Neonatal infection due to group B streptococcus (GBS) has a higher incidence in the USA than in the United Kingdom. A British population was investigated to ascertain the proportion of women who have protective anti-GBS type III IgG levels. Thirty-one (34%) of 90 pregnant women, 10 (43%) of 23 nonpregnant women, and 5 (50%) of 10 mothers of healthy colonized infants had anti-type III IgG greater than or equal to 2 micrograms/ml. Of 19 mothers who had infants infected with GBS type III, 17 (89%) had low specific IgG levels; of the other 2, the infants themselves had low IgG levels. The proportion of women in the UK with protective antibody levels is higher than in the USA. Sera (12) were assayed for anti-type III IgG isotypes; all contained IgG2, 6 had detectable IgG1, and 1 had IgG4.     

Determination of circulating IgG subclasses against lipoarabinomannan in the leprosy spectrum and reactions

IgG subclasses against lipoarabinomannan of mycobacteria were analyzed in the sera of leprosy patients. Patients with active leprosy [tuberculoid and lepromatous, patients undergoing erythema nodosum leprosum (ENL) and reversal reactions] and inactive cases (tuberculoid and lepromatous who were cured after chemotherapy) were included in this study. Active lepromatous patients had higher levels of IgG subclasses, except IgG4, compared to active tuberculoid patients. Some of the inactive cases (lepromatous patients cured after chemotherapy) were positive for the IgG1, IgG2 and IgG3 subclasses. However, their levels are lower than active lepromatous cases. On the other hand, no difference in the subclass levels between the active and inactive tuberculoid groups could be observed. While a significant fall in the level of IgG3 in ENL was observed as compared to lepromatous leprosy without ENL, higher levels of IgG1 and IgG2 were found in patients with reversal reactions compared to their active counterparts without reactions.     

Analysis of specific IgE and IgG subclass antibodies for diagnosis of Echinococcus granulosus

The potential roles of specific antibodies of different immunoglobulin G (IgG) subclasses and IgE in serological diagnosis of cystic echinococcosis (CE) were investigated by an enzyme linked immunosorbent assay (ELISA) based on Antigen 5 (Ag5). Presence of IgG1 was demonstrated in all sera from 58 patients with CE. The most discriminatory and specific antibodies found in this study belonged to IgG4 and IgE. Only one false-positive reaction was observed with IgG4 and no IgE cross-reactivity occurred with 40 sera from healthy controls. In 36 sera from patients infected with parasites other than CE two false-positive reactions with IgG4 were observed but none occurred with IgE. In immunoblotting, it was shown that IgG1 subclass was responsible for cross-reactivity of human antibodies that reacted with a 38 kDa subunit of Ag5. IgG4 and IgE antibodies could not recognize the 38 kDa subunit and under non-reducing conditions reacted with the 57 kDa subunit without any cross-reactivity to other parasites. The results demonstrated that IgG4 and IgE are the most important antibodies for serological diagnosis of hydatid cyst in an Ag5 based immunoassay system.     

Activity of specific IgG, IgM and IgE antibodies in human trichinellosis.

The activity of IgG, IgM and IgE antibodies to somatic antigen of Trichinella spiralis in the sera of patients with trichinellosis at various intervals after infection was examined by means of ELISA. Mathematical analysis of the dose-response curves was used. Elevated level of IgG and IgM antibodies of relatively high avidity and of rather low IgE avidity was documented. Amount or avidity of IgG antibodies was found to be most useful for the diagnosis of trichinellosis (85% positive results in patients' sera). The isotype of IgM avidity constitutes a better diagnostic value than the amount of it (60% and 35% of positive results, respectively).     

IgE and IgG antibodies to beta-propiolactone and human serum albumin associated with urticarial reactions to rabies vaccine

We examined the antibody response to a rabies vaccine doubly inactivated with 0.025% beta-propiolactone and 0.1% tri(n)butyl phosphate and stabilized with 2.5% human serum albumin. Antibodies were measured by using the following four antigen preparations: complete doubly inactivated rabies vaccine, rabies vaccine inactivated only with tri(n)butyl phosphate, beta-propiolactone and human serum albumin, and human serum albumin alone. The fluid phase of the preparation of beta-propiolactone and human serum albumin completely inhibited IgE binding to solid-phase vaccine. Of 21 subjects with urticarial reactions to a booster, 19 had IgE to doubly inactivated vaccine and to beta-propiolactone and human serum albumin. None of 27 immunized subjects without urticaria had detectable IgE. In paired pre- and postimmunization sera, IgE appeared in six of seven of the subjects with urticaria and in one of seven nonreactors. These sera did not contain a significant level of IgE to singly inactivated vaccine or to human serum albumin alone.     

Maternal antibodies against fetal blood group antigens A or B: lytic activity of IgG subclasses in monocyte-driven cytotoxicity and correlation with ABO haemolytic disease of the newborn

IgG antibodies against blood group antigens A or B (anti-A/B) are able to sensitize erythrocytes for destruction in an antibody-dependent cell-mediated (ADCC) assay with monocytes as effector cells. The activity of maternal IgG anti-A/B in this test was compared with clinical signs of haemolytic disease of the newborn (HDN). When the ADCC was negative (less than 10% of the sensitized cells lysed), signs of increased red-cell destruction in the children were never observed. In three cases with a strongly positive ADCC (greater than 45% lysis), the children were severely affected and needed more than one exchange transfusion. In the cases with greater than 10% but less than 45% lysis in the ADCC, there was no clear correlation between the result of the ADCC and the degree of lysis in the newborn infants. In these cases, the degree of lysis of the red cells of the infant was shown to be strongly influenced by the number of A/B antigens per red cell. There was a direct correlation between the degree of lysis in the ADCC and the titre of IgG3 anti-A/B in the sera. There was comparable activity of maternal IgG anti-A/B in the ADCC test in the 32nd week of pregnancy and at the moment of delivery.     

Food allergies associated with birch pollen: comparison of Allergodip and Pharmacia CAP for detection of specific IgE antibodies to birch pollen related foods.

Sera from 42 patients sensitive to birch pollen were investigated in a pilot study with the new Allergodip screening dipstick for cross-reactive allergens (Allergopharma). The dipstick contained nine separate allergen pads with extracts from birch pollen, hazel pollen, alder pollen, apple, hazelnut, carrot, peach, mugwort pollen and celery root (celeriac), together with negative and positive controls. The results of the test were assessed visually and classified in Allergodip classes 0-4 and compared with the results from the Pharmacia CAP method and with the symptoms reported by the patients. The Allergodip method showed good reproducibility for color intensity and visual assessment. The correspondence between Pharmacia CAP and Allergodip was high for tree pollens (98-100%) and medium for mugwort pollen, celery, hazelnut and carrot (60-71%). Apple and peach showed only 24% and 42% concordance, respectively The sensitivity and specificity of Allergodip and Pharmacia CAP differed in regard to food symptoms. However, they were always within the range of earlier publications. As a consequence of this study, the manufacturer of Allergodip has improved the apple allergen extract by adopting a low temperature extraction procedure. Subsequent measurements with sera from 14 apple-allergic patients showed greatly improved concordance with both CAP measurements and symptoms (93% and 86%, respectively).     

Cross reaction of specific IgE antibodies directed against cow's milk and bovine hair (author's transl)]

Sera of 25 children living in town were examined by means of RAST on the presence of IgE antibody against milk and cow's hair antigens. 18 cases had IgE antibodies reacting with milk and 9 with cow's hair. There was correlation between the levels of these antibodies with the exception of two cases. The results give evidence that half of the asthmatic children allergic to milk will react with bronchospasm in the cases if they ar exposed to inhalation of cow's hair.     

严重急性呼吸综合征患者冠状病毒总抗体及N和S蛋白抗体的随访研究

目的了解SARS冠状病毒（SARS—CoV）感染者血清中特异性IgM、IgG抗体和两个结构蛋白抗体的持续时间及相互关系。方法对146例SARS临床确诊且血清抗-SARS—CoV阳性病例,随访采集发病当13至发病后660d期间的血液标本共362份。以ELISA法分别检测抗-SARS—CoVIgM和IgG抗体、SARS—CoVN蛋白和S蛋白IgG抗体。结果抗-SARS—CoV IgM阳性率在发病20d内为46．5％（20／43）,21—40d阳性率最高（80．6％,25／31）,尔后逐渐下降,至发病后500d左右仅为8．2％（6／73）。IgG总抗体在发病20d内阳性率（34．9％,15／43）低于IgM抗体,在发病21～40d迅速达到100％,至发病后600—660d,其阳性率仍高达98．6％（70／71）。N—IgG抗体在发病40d后阳性率（92．5％,37／40）高于S-IgG（67．5％,27／40）,在61～90d、450—510d和600—660d3个时间点检测阳性率均高于S-IgG抗体;但两种结构蛋白抗体阳性率随时间延长均逐渐下降,两者于不同时间点的阳性率均低于抗-SARS—CoV总IgG。结论临床与病原学确诊的SARS患者,SARS—CoV特异性抗体阳性率在21—40d达高峰,IgG抗体阳性率100％。IgM抗体91．8％在感染500d以内消失;感染后两年IgG总抗体阳性率仍高达98．6％,推测可持续阳性3—5年。N—IgG和S-IgG抗体持续时间可能较短。     

Human IgG1 and IgG4: the main antibodies against Triatoma infestans (Hemiptera: Reduviidae) salivary gland proteins

The Triatoma infestans salivary gland proteins (TSGP) can induce local and systemic hypersensitivity reactions in humans. IgG antibodies against TSGP were present in higher levels in sera of Chagas disease patients, and in individuals living in triatomine-infested areas than in controls living in triatomine-free areas. TSGP-specific IgG1 was found in sera of Chagas patients, and of individuals living in triatomine-infested rural areas, and uniquely specific IgG4 was present in sera of Chagas patients living in triatomine-infested areas, reactive against TSGP. Unique specificities were not detected in sera of individuals reacting against the ubiquitous mosquito Culex quinquifasciatus saliva proteins (CSGP). In conclusion, IgG1 reactive against TSGP is the main antibody present in individuals living in the triatomine-infested study areas. Also, IgG4 is found in the sera of insect-transmitted Chagas disease patients living in study areas.     

Enhanced production of IgE anti-Japanese cedar pollen specific antibodies by peripheral blood B cells from patients with Japanese cedar pollinosis

BACKGROUND: IgE antibodies against Japanese cedar pollen (JCP) play an important role for the pathogenesis of the cedar pollinosis, but the mechanism of their production has been unclear. We explored the capacity of peripheral blood B cells from pollinosis patients to produce anti-JCP specific IgE. METHODS: Peripheral blood B cells from 16 pollinosis patients and 9 normal subjects were cultured with mitomycin-C treated T cells with immobilized anti-CD3 for 10 days. RESULTS: B cells from pollinosis patients produced higher amounts of anti-JCP specific IgE than those from normal subjects upon stimulation with immobilized anti-CD3 activated autologous T cell, whereas the production of anti-JCP specific IgM were comparable between normal subjects and patients. Exogenous IL-4/IL-5 or anti-CD3 stimulated patients' T cells could not induce the production of anti-JCP specific IgE from normal B cells. CONCLUSIONS: These results indicate that B cells from normal individuals contain comparable numbers of precursors that are committed to produce anti-JCP specific IgM to patients' B cells. Moreover, the data confirm that the class switching of IgM to IgE within anti-JCP specific B cells contributes to development of Japanese cedar pollinosis.     

Production of human monoclonal IgG antibodies against Rhesus (D) antigen.

An Epstein-Barr virus (EBV)-transformed human B-cell line ( LB4r ) producing anti-Rhesus [Rho(D) antigen] antibody was fused with a non-immunoglobulin-producing mouse-human heteromyeloma ( SHM - D33 ) and selected in hypoxanthine/aminopterin/thymidine medium containing 0.5 microM ouabain. Surviving hybrids found to secrete specific anti-Rho(D) antibody were cloned by limiting dilution. Two clones (D4-B2 and E10-C1) producing high levels (12 and 20 micrograms/ml per 10(6) cells per 24 hr, respectively) of monospecific antibody (IgG3, lambda chain) were selected for expansion and further characterization. Compared to the parental cell line ( LB4r ), these hybridoma cell lines presented several advantages: antibody production was increased 10-fold, cloning efficiency was improved, and the EBV genome was not retained. Antibody production has been stable for greater than 8 months. These human monoclonal anti-Rho(D) antibodies have demonstrated utility in routine blood-group typing. They may also prove useful in the biochemical and genetic characterization of the Rh antigen system. Most important, they offer a source of Rh-immune globulin for the prevention of Rh immunization and alloimmune hemolytic disease of the newborn.     

Semiquantitative measurement of IgG subclasses and IgM of platelet-specific antibodies in a glycoprotein-specific platelet-antigen capture assay

The detection of platelet-specific antibodies is of high clinical interest in diseases with immune thrombocytopenia. The glycoprotein-specific platelet-antigen capture (PAC)-assay developed in this study is especially suited to the differentiation of platelet-specific immunoglobulin (Ig) G subclasses and the determination of platelet-specific IgM in serum or on platelets. The problems with unspecific signals or low sensitivity usually seen with the detector antibodies available are effectively overcome, as unbound detector antibodies are removed at an early stage in the assay. We investigated 14 maternal alloantisera from cases of neonatal alloimmune thrombocytopenia (NAITP) and six sera from patients with autoimmune thrombocytopenic purpura (AITP). In NAITP sera, we found IgG1 alone in 57%, IgG1 + IgG3 in 21% and IgG1 + IgG2 in 14% of cases. One serum contained IgG1 + IgG2 + IgG3. In AITP, three out of the six sera contained IgG1 alone. One serum contained IgG1 + IgG2. One patient, with highly refractory AITP, had platelet-specific IgG1 + IgG2 + IgG3 in his serum. A patient with AITP in remission and normal platelet counts only showed platelet-bound IgG2. The detection of platelet-specific 'whole IgG' is possible too. However, at this time the commonly used monoclonal antibody-specific immobilization of platelet antigens (MAIPA) method should not be replaced for this purpose, as it is well standardized and used with similar results in many laboratories. The PAC assay sensitively detects the subclasses of platelet-specific IgG and human leucocyte antigen (HLA)-antibodies independently. It is easy to perform and takes less time than other platelet glycoprotein-specific methods.     

Measurement of IgE and IgG4 antibodies against purified grass pollen allergens (Phl p 1, Phl p 2, Phl p 5 and Bet v 2) and natural extracts after short-term grass immunotherapy

We wanted to define allergen-specific antibodies that change due to specific immunotherapy. We conducted a study with grass pollen-allergic patients and compared allergen-specific IgE and IgG4 before and 5 months after the onset of immunotherapy. Twenty-seven patients were treated with a mixture of two grass species: Phleum pratense and Dactilis glomerata. Sera of patients were tested for IgE and IgG4 against four recombinant allergens (RA): rPhl p 1, 2, 5 and rBet v 2. Specific IgE and IgG4 to timothy and olive pollen were also evaluated. No change in total and specific IgE levels to RA was seen, except to rPhl p 5. We found a decrease in specific IgE levels to olive after immunotherapy. Ten of 10 patients with specific IgE against a single recombinant allergen or two RA showed the same pattern of sensitization before and after 5 months of immunotherapy and the administration of 4000 U/mL allergen extract. Interestingly, we found a significant increase in specific IgG4 to rBet v 2 and olive after grass immunotherapy. These results indicate that application of two grass species in immunotherapy may be sufficient to induce an IgE and IgG4 response to RA, grass and olive extracts. The observations in the present study indicate that monitoring of antibodies against RA is necessary to evaluate patients' pattern of sensitization and emphasize the need of component-resolved immunotherapy.     

IgG subclasses serum concentrations in a population of children with Down syndrome: Comparative study with siblings and general population

Serum total IgG and subclasses were determined in three different groups of children: with Down syndrome, their siblings and general pediatric population. Several cases of IgG2 and IgG4 deficiency were identified, predominantly in children with Down syndrome. The differences, considering three age groups, were statistically significant for both groups in relation to the general population group, with an increase of IgG1 and IgG3 and a decrease in serum concentrations of IgG2 and IgG4. Down syndrome children and their siblings tend o have a similar variation of the IgG4 serum concentration levels (P < 0.05). The mechanisms of this concordance are not well understood. The results point out that an adequate strategy to improve the immune status of Down syndrome children could have a positive manifestation in the immune profile of their brothers.     

肠易激综合征患者食物特异性抗体IgE和IgG的检测

目的观察食物过敏后，机体的体液免疫情况，探讨食物过敏在肠易激综合征（IBS）发病中的作用和作用机制。方法对腹泻型IBS患者55例、便秘型IBS患者32例和健康对照组18例，采集外周静脉血，应用酶联免疫方法，进行14种食物抗原的特异性抗体IgE和IgG检测。结果腹泻型IBS血清食物特异性IgE抗体的阳性率43．64％，高于正常对照组，而便秘型IBS仅为15．63％，与正常对照差异无统计学意义。腹泻型IBS和便秘型IBS的IgE抗体阳性率存在差异。在食物特异性IgE抗体阳性的IBS患者中，多种食物阳性者48．28％。腹泻型IBS食物特异性IgG抗体的阳性率63．64％，便秘型IBS的阳性率为43．75％，两者均高于对照组，并且两组间比较差异无统计学意义。在食物特异性IgG抗体阳性的IBS中，多种食物阳性者51．02％。结论食物过敏介导的体液免疫反应异常在肠易激综合征的发病机制中，具有重要的作用。腹泻型肠易激综合征同时存在IgE和IgG介导的免疫异常反应，便秘型肠易激综合征只存在IgG介导的免疫异常反应。