Sequential determination of IgG subclasses and IgA specific antibodies in primary and reactivating toxoplasmosis

During the course of T. gondii infection, we have analysed serum IgG and IgA antibodies responses in 50 immunocompetent with acquired infection and 19 immunocompromised patients with evidence of reactivated toxoplasmosis. Using an ELISA, IgG1, IgG2, IgG3 and IgA antibodies were found in sera of all patients, whereas IgG4 antibodies were usually not detectable. In immunocompetent patients, the predominant antibody isotype was IgG1 at the different stages of infection, presumably in relation with a T-cell control of humoral response during toxoplasmosis. In immunocompromised hosts (kidney or bone marrow transplanted and HIV infected patients), a sequential study was performed on serum samples taken before and after reactivation had occurred. The isotypic distribution of antibodies was similar to that observed in immunocompetent patients, but differences between groups of immunocompromised patients were detected when the kinetics of the antibody response was considered. The IgG and IgA antibody rise was lower in HIV1 infected patients with clinical toxoplasmosis; whatever was the peak antibody value, clinical symptoms appeared earlier in patients with a slower antibody response. This presumably reveals a functional T-cell abnormality, which may rely to the defective containment of the parasite in these patients.     

Acquired hemolytic anemia associated with IgA anti-e

Acquired hemolytic anemia in a Caucasian female patient with direct antiglobulin test positive only with anti-IgA is described. The patient's serum contained 7S IgA anti-e antibody. The significance of this, from the point of view of broad spectrum antiglobulin sera, is discussed. The patient's serum contained 7S IgA anti-e antibody. The significance of this, from the point of view of broad spectrum antiglobulin sera, is discussed.     

Systemic immune response to oral polio immunization in patients with IgA nephropathy

The systemic immune response to a booster dose of attenuated polio vaccine has been studied in a group of patients with IgA nephropathy, their parents and healthy unrelated controls. The serum IgA and IgG antibody response and the antibody response in cultured lymphocyte supernatants was quantitated by a sensitive radio-immunoassay. Three of eight patients and two of their parents had elevated serum IgA antibody to polio pre-immunization. There was no significant rise in serum IgA or IgG antibody to polio post-immunization in any group. However, the five subjects with elevated pre-immunization levels fell into the normal range post-immunization, suggesting IgA specific suppression. Total and antigen specific IgA rose post-immunization in culture supernatants in all groups. The rise did not differ among the groups. The patients and parents with high serum antibody also had high culture supernatant levels and these fell post-immunization. There was an increased antigen non-specific IgG response in four patients and three of their parents. The data provide additional in vivo evidence of an upregulated IgA immune response in patients with IgA nephropathy. In addition, the data provide the first in vivo evidence of aberrant immune responses in the first degree relatives of patients with IgA nephropathy. This appears to be one of perhaps several inherited traits which may predispose an individual to develop this common and progressive nephropathy.     

Natural antibodies in sera of patients with systemic lupus erythematosus

Sera obtained from fifty-five patients with active systemic lupus erythematosus (SLE) and from four patients with mixed connective tissue disease (MCTD) previously shown by immunofluorescence and by double immunodiffusion to possess antinuclear antibodies, were tested for the presence of natural antibodies of IgG, IgA, and IgM isotypes. Antibody activity to actin, myosin, DNA, TNP, albumin, and tubulin was examined, using an enzyme-linked immunosorbent assay (ELISA). It was found that, in comparison with the antibody titers in normal sera, most of the SLE and MCTD sera possessed statistically greater amounts of IgG, IgA, and IgM antibodies directed against all the antigens tested. Furthermore, the IgG, IgA, and IgM antibody activity to DNA and TNP, compared to that found with all the other antigens, was significantly higher. Antibodies reacting with a saline extract of calf thymus (ECT) were studied by ELISA and by immunodiffusion. No correlation was observed between the natural antibody titers and the serum antibody levels to ECT detected either by ELISA or by immunodiffusion.     

Aberrantly glycosylated IgA1 in IgA nephropathy patients is recognized by IgG antibodies with restricted heterogeneity

IgA nephropathy (IgAN) is characterized by circulating immune complexes composed of galactose-deficient IgA1 and a glycan-specific IgG antibody. These immune complexes deposit in the glomerular mesangium and induce the mesangioproliferative glomerulonephritis characteristic of IgAN. To define the precise specificities and molecular properties of the IgG antibodies, we generated EBV-immortalized IgG-secreting lymphocytes from patients with IgAN and found that the secreted IgG formed complexes with galactose-deficient IgA1 in a glycan-dependent manner. We cloned and sequenced the heavy- and light-chain antigen-binding domains of IgG specific for galactose-deficient IgA1 and identified an A to S substitution in the complementarity-determining region 3 of the variable region of the gene encoding the IgG heavy chain in IgAN patients. Furthermore, site-directed mutagenesis that reverted the residue to alanine reduced the binding of recombinant IgG to galactose-deficient IgA1. Finally, we developed a dot-blot assay for the glycan-specific IgG antibody that differentiated patients with IgAN from healthy and disease controls with 88% specificity and 95% sensitivity and found that elevated levels of this antibody in the sera of patients with IgAN correlated with proteinuria. Collectively, these findings indicate that glycan-specific antibodies are associated with the development of IgAN and may represent a disease-specific marker and potential therapeutic target.     

Studies on IgA class circulatory red cell antibodies--I. Preparation and identification of IgA class anti-A,anti-B

To elucidate the role of IgA class alloantibodies in transfusion practice, anti-A,anti-B was prepared using pooled serum from healthy group O donors. IgG was removed by protein A and protein G, whilst IgM was extracted by concanavalin A and anti-human mu chain. The final preparation contained both IgA1 and IgA2; it had an IgA concentration similar to the original serum pool and an environment as near to normal as possible; the absence of IgG and IgM was confirmed by sensitive enzyme-linked antiglobulin tests, and extensive haemagglutination studies showed that anti-A,anti-B was the only red cell antibody present.     

Human cytomegalovirus salivary antibodies as related to stress

Human cytomegalovirus (HCMV) is prevalent in 50-80% of the population worldwide. After primary infection it remains in a latent state until reactivation. Stressful events induce the release of corticosteroids which activate HCMV. The effect of examination stress on HCMV reactivation among first year female students was studied by detecting the values of HCMV specific salivary IgG and IgA antibodies before, during and after two important examinations. Hepatitis A virus (HAV) salivary antibodies served as a non-latent virus control. A statistically significant increase in the level of HCMV specific IgG and IgA antibodies was detected in saliva samples collected during the two examinations, as compared with the samples collected one month before them and two weeks after the grades were posted (p<0.05), whereas HAV antibody levels did not change significantly.     

Antibiodies of the IgG, IgM, and IgA classes in newborn and adult sera reactive with gram-negative bacteria

Umbilical cord serum and adult serum antibodies reactive with heat-stable somatic antigens of Gram-negative bacteria (Neisseria gonorrhoeae, Escherichia coli, and Salmonella typhosa) were assayed by using an indirect fluorescent antibody test. Reactive IgG, IgM, and IgA antibodies were identified by using fluoresceinconjugated antisera specific for these immunoglobulin classes.IgG antibody titers in cord serum approximated those found in the corresponding maternal sera. IgM and IgA antibodies were present in adult sera but were not demonstrable or were present only in small amounts in cord sera. The presence of IgG and IgM antibodies reactive with Gram-negative bacteria was confirmed by the testing of purified 7S and 19S fractions. In addition, both IgG and IgM reactivities were inhibited by the prior incubation of serum with purified specific lipopolysaccharide preparations.The ubiquity and magnitude of these natural IgG antibodies in the sera of both adults and neonates have apparently eluded detection in previous studies. The use of bactericidal and agglutination tests, which are apparently more sensitive to the presence of IgM than to IgG antibodies, may account for the failure of previous studies to detect adult and cord IgG antibodies reactive with somatic antigens of Gram-negative bacteria. The presence of these IgG antibodies may be correlated with the resistance to infection demonstrated by most newborns as they are challenged by the septic extrauterine environment.     

The Incidence of Antibodies to Leukocytes and Gammaglobulin IgG and IgA in a Population of Multitransfused Southern African Negroes

Posttransfusion samples of serum from Southern African Negroes who suffered mild to severe hypersensitivity reactions possessed more antileukocyte than antiglobulin antibodies to IgG and IgA. On the other hand, multitransfused patients who did not develop adverse transfusion reactions showed a lower incidence of antileukocyte antibodies and a higher incidence of antiglobulin antibodies. The reduced incidence of antiglobulin antibodies found in posttransfusion samples of serum from patients who developed transfusion reactions may reflect in vivo consumption of such antibodies by antigenin‐excess conditions. For the increased incidence of antileukocyte antibodies in the same group of patients the infusion of relatively small amounts of incompatible leukocytes appears to be inadequate to reduce the corresponding antibody levels.     

Association of CagA-positive infection with Helicobacter pylori antibodies of IgA class

cagA gene, the best known virulence factor of Helicobacter pylori, codes for an immunodominant CagA protein. In this study, CagA antibodies of the IgG class were measured by immunoblot or enzyme immunoassay in subjects with positive H. pylori serology, and the presence of CagA antibodies was compared with that of H. pylori antibodies of IgA and IgG classes. Serum samples were available for a total of 1,481 subjects, including gastroscopied patients with biopsy-verified H. pylori infection, smoking men with a normal or low serum pepsinogen I level indicating atrophic corpus gastritis, and subjects who later developed gastric cancer and their matched controls. CagA antibodies were significantly more prevalent among individuals with elevated H. pylori antibody titres of the IgA class than in those with IgG antibodies only, with the exception of a small subgroup of individuals who later developed gastric cancer. CagA-positive H. pylori strains seem to induce an immune response with a markedly higher frequency of IgA than what is found in inflammation caused by CagA-negative strains. The presence of serum IgA antibodies to H. pylori seems to indicate a higher risk for CagA-positive H. pylori infection and possibly more severe late sequelae of the disease.     

Antibacterial mechanisms of the lower respiratory tract. I. Immunoglobulin synthesis and secretion

Immunoglobulin synthesis and secretion have been studied in the rabbit lower respiratory tract, both in the normal state and after infection with Diplococcus pneumoniae or Listeria monocytogenes. In vitro synthesis of immunoglobulin and specific antibody was assessed by incorporation of 14C-labeled amino acids into protein. Lower respiratory tract secretions and serum were analyzed for immunoglobulin and antibody against the infecting organism. Normal respiratory tract produced small quantities of immunoglobulin, most of which was IgG. After bacterial infection of the lower respiratory tract, there was a marked increase in local synthesis of immunoglobulin, especially IgG. Specific antibody of IgG class was produced in all lungs infected with listeria by the 11th day, and in lungs infected with pneumococcus by the 8th day. Secretions from all normal and infected lower respiratory tracts contained IgA and IgG. The IgA to IgG ratios in secretions of normal animals, and animals infected with listeria or pneumococcus, were 2.3, 2.5, and 2.6, respectively. Sera of animals infected with L. monocytogenes contained specific antibody of IgG class but lacked IgA antibody, whereas secretions had both IgA and IgG class antibody against listeria. Similarly, sera of animals infected with D. pneumoniae had IgG class antibody but no IgA antibody, whereas only IgA antibody was found in secretions. The evidence that locally synthesized immunoglobulin (especially IgA), including specific antibody, is secreted into the lower respiratory tract lumen is discussed. Further definition of the role of "local" antibacterial antibody in the respiratory tract is of considerable importance.     

Autoimmune hemolytic anemia with predominance of IgA autoantibody

A 71-year-old woman with severe autoimmune hemolytic anemia had negative direct antiglobulin tests using commercial broad spectrum antisera. Her unwashed cells agglutinated spontaneously in the potentiating medium polyvinylpyrrolidone (PVP) solution or in hexadimethrine bromide (Polybrene) solution. A strongly positive direct antiglobulin test was obtained with specific antihuman IgA sea with or without PVP. In PVP solution, small amounts of IgG, IgM, and complement components were also detected on her cells. The findings illustrate the ability of anti-human IgA to detect autoimmune red blood cell sensitization when other immunoglobulin classes of autoantibody are below detectable levels or absent. Also illustrated is the value of PVP and Polybrene in detecting agglutination in the evaluation of "antiglobulin negative" hemolytic anemia.     

Sjogren's Syndrome: 2. CLINICAL ASSOCIATIONS AND IMMUNOLOGICAL PHENOMENA

The diverse clinical associations and wide variety of immunologicalphenomena and their incidence occurring in a large series ofpatients with Sjøgren's syndrome is presented and discussed,with reference to individual cases where relevant. Althoughthere was an increased prevalence of organ-specific auto-antibodies,we were unable to show an association between organ-specificauto-immune diseases and Sjøgren's syndrome. The previouslyreported increased prevalence of mitochondrial antibody andliver disease have been confirmed, as has renal tubular dysfunction.Drug allergy and eosinophilia were commonly found. Serum IgG, IgM, and IgA levels were elevated, and serum secretory-IgAlevels were markedly raised. The increased incidence of non-organ-specificauto-antibodies has been confirmed, and sera negative for rheumatoidfactor by conventional tests were found to have a high prevalenceof antiglobulin factors. Three patients without other evidenceof systemic lupus erythematosus had raised serum native-DNA-bindingcapacities, and another eight patients had antibodies to heat-denaturedDNA.     

Serological response to plasmid-encoded antigens in children and adults with shigellosis

The immunological response to plasmid-encoded antigens of virulent Shigella was determined in Thai children less than 4 yr of age and in Thai adults by immunoblot analysis and ELISA. Forty-two percent (8/19) of Thai children and 4% (1/22) of Thai adults with shigellosis developed a greater than or equal to 4-fold rise in IgG antibody titer to water-extracted antigens of Shigella flexneri M90T by ELISA (p = 0.006). Two children and one lactating mother with shigellosis developed a 4-fold rise in serum IgA antibody titers to water-extracted antigens of M90T. The results of the ELISA were confirmed by immunoblot analysis in all of the 41 paired sera examined. Five patients developed IgA, and four developed IgM, antibodies as detected by immunoblot analysis, that were not detected by ELISA. The reciprocal log2 geometric mean titers of antibodies to plasmid-encoded antigens in acute sera was higher in Thai adults than Thai children: IgG 7,265 versus 1,659; IgM 879 versus 480; and IgA 662 versus 60 (p less than 0.001). Thai adults had high titers of antibodies to plasmid-encoded antigens in their acute sera, but were susceptible to Shigella infections, although they were historically less susceptible than Thai children.     

Human Antihapten Antibodies in Trimellitic Anhydride Inhalation Reactions: IMMUNOGLOBULIN CLASSES OF ANTI-TRIMELLITIC ANHYDRIDE ANTIBODIES AND HAPTEN INHIBITION STUDIES

Inhalational exposure to trimellitic anhydride (TMA) produces an immediate-type asthmatic or a late respiratory systemic syndrome in certain workers after a latent period of work exposure. TMA has been found to react with proteins to produce a hapten-protein complex (trimellitate [TM] protein) or become hydrolyzed in aqueous, alkaline solutions to produce a salt, NaTM. Using a solid-phase radioimmunoassay technique, antibodies of different Ig classes were detected against TM-protein conjugates. IgE antibody was detected in three of five workers with asthma. IgG and IgA antibodies were detected in most exposed workers but higher levels of antibody were found in symptomatic workers even after long periods without direct TMA exposure. IgM antibody activity against TM-human serum albumin (TM-HSA) was detected but did not differentiate symptomatic from asymptomatic workers. NaTM served as a hapten for study because it does not react with proteins to form a hapten-protein complex as TMA does. The NaTM only partially inhibited IgG antibody activity against TM-HSA and much smaller amounts of TM-HSA than of NaTM were required to neutralize IgG antibody. A similar result was found with TM-ovalbumin. The latter results suggest that some IgG antibody is directed against a TM-protein moiety, probably a TM-amino acid determinant. In contrast to IgG, marked inhibition by NaTM of IgA and IgM antibody against TM-HSA was found in the sera studied.     

Use of a solid-phase radioimmunoassay and formalin-fixed whole bacterial antigen in the detection of antigen-specific immunoglobulin in prostatic fluid.

The prostatic fluid of two patients with Escherichia coli bacterial prostatitis was analyzed for evidence of a local immune response to bacterial infection. A solid-phase radioimmunoassay was modified to measure the immunoglobulin (Ig)A and IgG antigen-specific antibody responses to infecting bacteria in serum and prostatic fluid from patient. Formalin-fixed whole E. coli were used as antigen. In one patient with acute E. coli prostatic infection, measurements of antigen-specific antibody confirm the presence of a systemic and local immune response. However, in another patient with a chronic E. coli prostatitis, a primarily local immune response was demonstrated. The response measured in the prostatic fluid appears to be locally stimulated and specific for the infecting bacteria. Furthermore, IgA was the predominant immunoglobulin involved in the local prostatic immune response to infection. Although elevations of serum IgA antigen-specific antibody levels were short-liver after treatment of prostatic infection, local IgA antigen-specific antibodies were detected for as long as 1 yr after the initial infection in both patients studied.     

The presence of IgA on the surface of rat thoractic duct lymphocytes which contain internal IgA

The presence of lymphocytes with internal IgA among cells from rat thoracic duct lymph wdy. The number of cells detected was greater in animals kept in a convential animal house compared with those maintained under specific pathogen-free conditions. Thoracic duct lymph from B rats and adult thymectomized rats also contained cell with internal IgA. The surface Ig of the IgA-containing cells was studied using a double-labeling technique with (126I) anti-Ig to detect surface Ig, and fluorescein-conjugated anti-IgA in large amounts, but very little IgM and no surface IgG2. The surface IgA was not acquired passively.     

Mechanism of neutralization of influenza virus by secretory IgA is different from that of monomeric IgA or IgG

We have found that bile is a useful source of secretory IgA (scIgA) which can specifically neutralize influenza virus infectivity. Using purified scIgA, we compared the mechanism of neutralization with that mediated by IgA monomers (prepared from scIgA by differential reduction) and IgG. At 4 degrees C, scIgA prevented the attachment of neutralized virus, while neither monomeric IgA nor IgG had any affect on this process or on the subsequent stages of infection by which virion RNA accumulates in nuclei. At 25 and 37 degrees C, scIgA permitted the attachment of approximately half the neutralized virus, but the virus was not internalized. Clearly, the neutralization depends on the character of the antibody used. scIgA may act by steric hindrance (with attachment or penetration, depending on temperature), whereas IgA and IgG neutralize infectivity at a stage subsequent to accumulation of the virus genome in the nucleus.     

儿童呼吸道合胞病毒感染血清特异性抗体IgM,IgG和IgA表达的相关性研究

目的 探讨住院儿童呼吸道合胞病毒(RSV)感染血清特异性抗体IgM,IgG和IgA表达的相关性,筛选具有早期辅助诊断意义的抗体指标。方法 运用荧光定量聚合酶链反应技术(FQ-PCR)筛选出2015～2017年50例咽拭子RSV阳性的住院患儿; 采用酶联免疫吸附试验(ELISA)检测患儿血清中的特异性抗体IgM,IgG和IgA; 同时以95例无呼吸道感染症状的儿童血清标本作为对照组; 采用卡方检验对结果进行统计学分析。结果 50例咽拭子RSV阳性患儿血清中IgM,IgG,IgA及三者同时出现阳性率分别为24.00%,60.00%,22.00%%和16.00%,差异有统计学意义(χ2=28.19,P<0.01); 同一性别患儿的IgM,IgG和IgA阳性率在实验组和对照组中差异有统计学意义(χ2=9.16,P<0.01),不同性别在同一实验组或对照组中各抗体阳性率差异无统计学意义(χ2=0.10,P>0.05); 急性喉气管支气管炎中未检出IgM,IgG和IgA,仅在急性上呼吸道感染中检测到1例IgG,支气管肺炎及急性支气管炎中以IgG的检出率41.38%和23.53%最高,且均未单独检测到IgA; <6个月年龄组患儿在7天和21天内均未检出IgM和IgA,1～5岁年龄组患儿在7天内产生IgM阳性率为50.00%最高,且在21天内均能检出IgM,IgG和IgA,5～10岁年龄组患儿在7天内产生IgG和IgA的阳性率为100%和66.67%。结论 RSV特异性抗体IgM,IgG和IgA不能单独作为早期感染RSV的诊断指标,特异性抗体产生不受性别因素影响,上呼吸道感染RSV较难产生IgM,IgG和IgA,患儿年龄越小产生IgM和IgA的速度越慢,同时IgG存在母婴垂直传播且对机体无保护作用,RSV感染人体引起临床呼吸道症状可能与自身免疫力有关; IgA产生最早且不单独出现。     

不育男子精浆中抗精浆免疫抑制因子IgG和IgA的相关性分析及临床意义

目的：研究抗人精浆免疫抑制因子（SPIF）IgG和IgA对男性不育的影响。方法：ELISA间接法对74例不育男子和37例生育男子精浆中抗SPIF IgG和IgA进行测定。结果：不育组与生育组中抗SPIF IgG和IgA的阳性率分别为35.2%、27.3%和5.4%、2.1%。结论：不育组抗SPIF IgG和IgA阳性率显著高于生育组（P＜0．01），而不育组间抗SPIF IgG和IgA两者阳性率无显著性差异，亦无相关关系。