Class and subclass anti-pneumococcal antibody responses in splenectomized patients

Antibody titres against pneumococcal capsular and cell wall antigens and the immune response to polyvalent pneumococcal vaccine were measured in 21 splenectomized patients and 12 healthy controls. Most individuals possessed anti-pneumococcal capsular polysaccharide antibodies of IgG, IgA and IgM classes. The anti-capsular IgG was predominantly of the IgG1 and IgG2 subclasses; only occasional individuals had any detectable titre in IgG3 or IgG4 subclass. Most individuals responded to immunization with Pneumovax. There was no clear difference between groups of control and splenectomized subjects, although three of the splenectomized patients had undetectable pre-immunization anti-capsular titres in one or more subclass which failed to rise following immunization. All subjects tested had anti-phosphocholine antibodies in IgG, IgA and IgM classes with the exception of a single splenectomized patient who lacked detectable anti-phosphocholine IgM. Pre-immunization titres where similar in healthy controls and splenectomized patients. There was no demonstrable rise in anti-phosphocholine titre following immunization with Pneumovax.     

The postvaccination antibody response to influenza virus proteins

The radio-immunoblot (RIB) assay was used to examine the antibody response to proteins of the vaccine strains induced after influenza vaccination. Vaccination stimulated an antibody response to the surface glycoproteins (HA and NA) and to the internal antigens (NP and M) of the three vaccine strains. Antibodies were detected to both the monomeric form of the haemagglutinin (HA) and its two subunits HA1 and HA2. In addition, antibody to the monomeric form of NA was detected. A wide range of response patterns was observed to the viral proteins. All three major antibody classes (IgG, IgA and IgM) were induced after vaccination and in the majority of volunteers the antibody reactivity increased one week after vaccination. IgM antibodies had a wider reactivity pattern, recognising proteins and subunits which were not fully processed or slightly degraded. The varied antibody response induced after influenza vaccination reflects the differing infection histories of the volunteers with influenza. We show some of the practical limitations of studying the antibody response to influenza vaccination.     

Rheumatoid factor as a cause of positive reactions in tests for Epstein–Barr virus-specific IgM antibodies

Sera from twenty-eight patients with rheumatoid arthritis (RA) were titrated in indirect immunofluorescence tests for Epstein–Barr virus (EBV) specific antibodies. All had IgG antibodies to viral capsid antigen (VCA), 64% at titres [unk] 320, and 71% reacted also in tests for VCA-specific IgM antibodies at titres ranging from 20 to 640. The reactions observed in the IgM test were not due to VCA-specific IgM antibodies, however, but rather to rheumatoid factor (RF) usually an IgM antibody to the Fc regions of IgG. The titres recorded in the anti-VCA IgM test correlated significantly with the RF titres and both reactivities were abolished by adsorption onto IgG coated latex particles. In addition, they clearly depended upon the height of the IgG antibody titre to VCA, indicating that the more VCA-specific IgG molecules are present the more likely it is that RF will combine with them in sufficient quantity before or after their attachment to VCA-positive test cells so as to become detectable by the fluorescent antibodies to human IgM. Results comparable in every aspect were obtained with those sera from patients with Hodgkin's disease, nasopharyngeal or cervical carcinomas which reacted in the anti-VCA IgM test. Sera from patients with infectious mononucleosis may also contain RF, but in such cases its removal by adsorption onto IgG-coated latex particles did not generally reduce the VCA-specific IgM antibody titre. Removal of RF from any of the sera studied did not affect the titres of VCA-specific IgG and, where applicable, IgA or heterophil antibody titres. These results re-emphasize the pitfall created by RF noted previously in tests for virus-specific IgM antibodies.     

Antibodies to polyclonal IgA,IgA1, and IgA2 and isotype-specific immune complexes in IgA nephropathy

The concentrations of serum IgG and IgM antibodies to polyclonal IgA (IgA_p), IgA₁, and IgA₂ were determined by enzyme immunoassay in 31 patients with IgA nephropathy and 30 healthy controls. Patients with IgA nephropathy had significantly raised concentrations of serum IgA compared to controls (Mann-WhitneyU test,P=0.001) and increased concentrations of conglutinin-binding IgA immune complexes (P=0.024). No differences in the median concentrations of IgG and IgM anti-IgA antibodies were found between the patients and the controls. In serum samples from healthy controls there was a significant positive correlation between IgM anti-IgA_p and IgA immune complex concentrations (P=0.05), which contrasted with the finding of an inverse correlation between IgM anti-IgA_p and IgA immune complex concentrations in patients with IgA nephropathy (P<0.05). In addition, the concentrations of conglutinin binding IgM immune complexes in serum were found to correlate with the concentration of IgM anti-IgA_p (0.010<P<0.025), IgM anti-IgA₁, and IgM anti-IgA₂ (P«0.005 for both) in patients with IgA nephropathy but not in controls. IgM anti-IgA antibodies may be important in augmenting the clearance of IgA immune complexes from the serum of patients with IgA nephropathy.     

Bacteroides gingivalis-specific serum IgG and IgA subclass antibodies in periodontal diseases

The level of serum IgM, IgG and IgA antibodies including IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2 subclass-specific antibodies to Bacteroides (Porphyromonas) gingivalis fimbriae and to lipopolysaccharide (LPS) were analysed in patients with different forms of periodontal disease (PD) and control subjects by ELISA. Among PD subjects, sera obtained from adult periodontitis (AP), rapidly progressive periodontitis (RPP) and gingivitis contained high titres of fimbriae-specific IgG antibodies (7500-15,000 ELISA units) followed by IgA (90-700 units) and IgM (30-90 units). In contrast, sera from localized juvenile periodontitis (LJP) subjects exhibited much lower titres of fimbriae-specific IgG (89 +/- 11 units), IgA (31 +/- 5 units) and IgM (17 +/- 3 units) antibodies. A similar response pattern was also seen in sera from normal subjects aged 35-41 years who practice normal oral hygiene, while sera of younger adults (aged 18-24) with superior hygiene did not have any antigen-specific antibodies. Analysis of IgG subclass anti-fimbriae responses revealed that the major response was IgG3 followed by IgG1, IgG2 and IgG4 in AP, RPP and gingivitis. Although lower, a similar pattern of IgG subclass titre was seen in LJP and normal subjects aged 35-41 years. When IgA subclass responses were measured in AP and RPP, higher titres of the fimbriae-specific response were noted with IgA1 when compared with IgA2. However, lower but approximately equal levels of fimbriae-specific IgA1 and IgA2 titres were seen in other PD groups. When anti-B. gingivalis LPS-specific responses were measured, the sera of AP patients contained high levels of IgG antibodies (2265 +/- 224 units) followed by IgA (411 +/- 90 units) and IgM (214 +/- 56 units). Further, IgG anti-LPS responses were mainly IgG2 followed by IgG4, IgG3 and IgG1. For IgA subclass responses, higher titres of anti-LPS-specific antibodies were noted in IgA2 subclass over IgA1. These results showed that higher anti-B. gingivalis antibody responses occur in PD when compared with healthy individuals and protein and lipid-carbohydrate antigens of B. gingivalis induce distinct patterns of antigen-specific IgG and IgA subclass responses.     

Systemic immune response after mucosal immunization in patients with IgA nephropathy

Increased IgA production has been proposed as a portion of the etiology of IgA nephropathy. Indirect human data suggest that IgG and complement may be equally important. We have immunized 17 patients with IgA nephropathy and 27 controls with tetanus toxoid. They were nasally immunized and, 2 weeks later, received an im booster immunization. This protocol has been shown to result in an increased serum IgA1 antibody response to tetanus toxin (TT). Patients had higher serum IgG antibodies to TT before and after the im immunization than did controls (pre, 42 vs 13 U; post, 155 vs 71 U;P=0.004). Patients also had a greater increase in serum IgG antibodies (118 vs 58;P=0.02). After the im TT, patients had lower levels of serum IgA1 antibody to TT (115 vs 180;P=0.005) but the change in IgA1 antibodies was not significant. These data suggest that patients with IgA nephropathy may produce inappropriately large amounts of serum IgG antibodies to antigens encountered in the upper respiratory tree. Such antigens also induce a serum IgA1 response. Such a response could result in the formation of potentially nephritogenic immune complexes containing IgG, IgA1, and C3.     

Antibody responses to Toxoplasma gondii in sera, intestinal secretions, and milk from orally infected mice and characterization of target antigens.

Toxoplasma gondii-specific antibody responses in serum, intestinal secretions, and milk were identified with an enzyme-linked immunosorbent assay following a single oral infection of mice with strain 76K cysts of T. gondii. Immunoglobulin A (IgA) production began during week 2 of infection in serum and milk and during week 3 of infection in intestinal secretions and persisted in all three throughout the experiment (17 weeks). IgG but not IgM antibodies were detected in intestinal secretions later in the infection. Serum and milk IgG and IgM production began at the same time after infection as did the IgA response. In Western blotting (immunoblotting), intestinal IgA antibodies were shown to react with antigens comigrating with the T. gondii proteins p22, p23, p30, and p43, the 28-kilodalton antigen, and the 55- and 60-kilodalton rhoptry proteins, as recognized by specific monoclonal antibodies. Milk IgA antibodies reacted with antigens comigrating with p30 and p43. Most of the antigens recognized by IgA antibodies were also detected by IgG antibodies. IgA antibodies from all three biological samples detected the same major T. gondii antigens; thus, there was apparently no specific antibody production unique to one locality.     

IgA and IgG Subclass Deficiency in a Poor Population in a Developing Country

The levels of IgG, IgG subclasses, IgM and IgA were determined in serum from 17 patients with IgA deficiency and severe or frequent infections, allergy and/or autoimmunity (median age 7 years, range 2–19), 11 healthy IgA-deficient adults and 35 controls (median age 7 years, range 2–19). In serum from all groups IgG, IgM and IgA antibodies were determined against β-lactoglobulin, E. coli O antigens and poliovirus type 1 antigen. In saliva of 15 IgA-deficient patients and 12 of the controls IgG, IgM and secretory component-carrying antibodies against E. coli O antigens and poliovirus type I were determined. The majority of the studied individuals lived under poor socio-economic conditions in Brazil, with consequent heavy microbial exposure. One IgA-deficient patient with rheumatoid arthritis also had IgG2 deficiency but no infectious problems. Four out of the 35 controls without any obvious infectious problems were found with IgA or IgG subclass deficiency. One of the 11 healthy IgA-deficient adults was low in the IgG2 subclass, one in IgGl and one in IgG3. Those with symptomatic IgA deficiency had significantly higher serum IgG than the controls, especially in the age group 6–11 years. This latter group also had significantly increased serum IgG 1 and IgG2 levels when compared with the age-matched controls. Salivary IgM antibodies to E. coli and poliovirus antigens were significantly higher among the symptomatic IgA-deficient individuals than among the controls. It is not clear at present whether these increased Ig levels are secondary to frequent infections and/or part of mechanisms that may compensate for the IgA deficiency.     

Characterization of the antibody response to a Haemophilus influenzae type b conjugate vaccine in children with recurrent lower respiratory tract infection

Children with recurrent lower respiratory tract infection (RLRI) may respond poorly to polysaccharide antigens. To examine how such children respond to a polysaccharide coupled to a protein carrier, we immunized 15 children with RLRI aged 8–69 months and 15 carefully age-matched healthy controls once with a Haemophilus influenzae type b (Hib) conjugate vaccine. Total IgG subclasses, total antipolysaccharide Hib antibodies, and antipolysaccharide Hib antibodies of IgM, IgG, IgA, and IgG 1–4 specificity were determined by ELISA. There were no significant differences between the two groups in any single total IgG subclass, but total IgG measured as the sum of all four subclasses was significantly lower in the children with RLRI than in the controls ( P = 0.036). Before vaccination, the children with RLRI had significantly less IgG antipolysaccharide Hib antibody than the controls ( P = 0.005), whereas 1 month later they had significantly more IgM antibody (P = 0.038). No other significant differences were found between the groups before or after immunization with respect to antipolysaccharide Hib antibodies. Since naturally occurring IgG antibodies are thought to be aquired partly as a consequence of antigenic stimulation on mucosal surfaces, we hypothesize that the low level of specific IgG found before immunization, as well as the low total IgG in the children with RLRI, may reflect an impaired ability to prime through mucosal surfaces. This is supported by our finding of an increased IgM response to Hib conjugate vaccine in these children, since this isotype predominates in the primary immune response, i.e., in the absence of immunologic memory. In conclusion, children with RLRI can be protected against invasive Hib infection as well as healthy children, but may have an immunodeficiency characterized by defective ability to respond to antigenic stimulation on mucosal surfaces.     

Antibodies to Epstein-Barr virus in nasopharyngeal carcinoma, tonsillar carcinoma and control groups

In the sera of 17 patients with nasopharyngeal carcinoma (NPC) and of 19 patients with tonsillar carcinoma (TC) the titres of IgA, IgG and IgM antibodies to EBV VCA (viral capsid antigen) and of IgG antibodies to EBV EA (early antigen) were determined by the indirect immunofluorescence (IF) method. Significant difference was observed in the frequency of IgA antibodies to EBV VCA and IgG antibodies to EBV EA between NPC patients and controls. There was also a significant difference between the frequency of IgM antibody to EBV VCA and EBV EA antibody titres in TC patients and controls. The geometric mean titre (GMT) of IgG antibodies to EBV VCA was significantly higher in the NPC and TC patients as compared to controls.     

Humoral immune response in patients with IgA and IgM glomerulonephritis.

A single dose of inactivated mumps virus vaccine was administered to male patients with IgA glomerulonephritis (IgA-GN), IgM glomerulonephritis (IgM-GN) and to healthy males. Antibodies to mumps virus were determined using an enzyme-linked immunosorbent assay. Patients with IgA-GN showed a higher and more sustained IgG and IgA antibody response compared to patients with IgM-GN or healthy controls. Before vaccination, patients with IgM-GN had higher levels of IgG antibodies than the controls or those with IgA-GN. However, the IgA antibody and IgG responses after vaccination were low. IgM antibody responses did not vary among the groups studied. It is concluded that patients with IgA-GN are high responders for IgA and IgG antibody production. Patients with IgM-GN are low responders, especially for IgA antibody.     

Comparison of IgM, IgG and IgA responses to M.leprae specific antigens in leprosy

Antibodies of IgM, IgG and IgA classes against M.leprae specific antigens (PGL-I, ND-O-BSA, and NT-O-BSA) were determined in the sera of 80 leprosy patients (28 untreated, 34 treated lepromatous and 18 tuberculoid), 25 tuberculosis patients and 33 normal individuals of Northern Thailand. No strong distinction in reactivity could be found between the three antigens. The IgM antibody assay yielded more positive results than assays for IgG and IgA. It was found that the positivity rates of IgM antibodies to all three antigens were highest in untreated lepromatous leprosy (82%). In tuberculoid leprosy, the positivity rates of IgM, IgG and IgA to the antigens were more variable, ranging from 22 to 50 percent. Patients with tuberculosis and normal individuals did not produce IgM antibodies against the antigens. The results suggested that the determination of IgM against the three antigens is a more sensitive and specific test for active leprosy than those of IgG and IgA. The relationship between the duration of treatment and IgM antibody levels in lepromatous leprosy (LL) was studied. Untreated LL patients had significantly higher IgM and IgA antibody levels than treated patients. There was no difference in IgG antibody levels between the two groups, and the levels of both groups were higher than normal controls. Serial determination of IgM antibodies in 7 LL patients revealed that treatment was strongly associated with progressive decrease in IgM antibody levels against all three antigens.     

Antibody response to Epstein-Barr virus antigens in patients with chronic viral infection

We tested antibody titres against Epstein-Barr virus (EBV) antigens in patients suffering from chronic viral disease and compared them with those determined in sex- and age-matched healthy controls. Patient sera showed signs of active EBV infection [antibodies against early antigen (EA) and/or viral capsid antigen (VCA) in the IgM or IgA classes] significantly more frequently than the control group. Correspondingly, geometric mean titres (GMT) of antibodies against all viral antigens were elevated in the patients. The strongest association with EBV was observed in patients whose clinical symptoms closely resembled infectious mononucleosis: 92% of the subjects in this subgroup possessed anti-EA and 41 and 25% had IgM and IgA anti-VCA antibody, respectively. In patients with signs of lymphoproliferation only and in those suffering from frequent respiratory infections the association with EBV was less marked but still significant. Patients with transient defects in humoral and cellular immunity mounted higher titres against VCA in the IgG class than those without immune defects.     

Antibody response to the lipopolysaccharide and protein antigens of Salmonella typhi during typhoid infection. I. Measurement of serum antibodies by radioimmunoassay.

Serum antibody responses to the lipopolysaccharide and protein antigens of S. typhi in typhoid patients were studied using a solid-phase radioimmunoassay technique. Sera from 24 adult typhoid patients and 20 non-typhoid adult controls were compared. As a group, sera from typhoid patients showed increased IgA, IgG and IgM immunoglobulin levels and gave significantly higher anti-LPS and anti-protein antibody titres in all three major immunoglobulin classes than did non-typhoid controls. Levels of antibodies against LPS or protein in sera of typhoid patients were highly variable with a skew distribution. A good correlation was found between antibody titres to the LPS antigen and those to a protein antigen. No correlation, however, was found between the anti-LPS antibody titres measured by radioimmunoassay and the anti-O antibody titres measured by the Widal agglutination test. Titration of anti-LPS or anti-protein antibodies by radioimmunoassay was found to be more sensitive and specific than Widal test for the serological diagnosis of typhoid fever. The advantages of measuring antibody response by radioimmunoassay over conventional Widal test are discussed.     

Antibodies against antigens of Candida albicans in patients with fungaemia and bacteraemia, studied by ELISA, precipitation, passive haemagglutination and immunofluorescence techniques

Antibodies against commercially available antigens of Candida albicans were assayed in 54 sera from 24 patients with fungaemia and in 66 sera from 33 patients with bacteraemia. In patients with persistent fungaemia, antibody was found during the week after the fungus was first cultured from the blood, but peak titres did not usually occur until the end of the second week. A significant rise in titre in C. albicans infection was observed in 50% of paired sera tested by passive haemagglutination (PHA), indirect immunofluorescence (IF) and Ouchterlony immunodiffusion (ID). The same percentage was obtained by counterimmunoelectrophoresis (CIE) against candida metabolic antigens, whereas it was increased to 88% when somatic antigens were used. Enzyme-linked immunosorbent assay (ELISA) demonstrated a rise of titre in 25, 75 and 50% of sera in IgM, IgG and IgA assays, respectively. Sera from patients with transient fungaemia demonstrated persistent antibody titres. In paired sera from patients with bacteraemia, ID and CIE titres were low (greater than or equal to 4). There was an increase of candida antibodies in 0-9% of patients by ELISA, ID or CIE and in 18-21% by PHA or IF. Clinically significant fungaemia was most reliably differentiated serologically from bacteraemia by CIE S-antigen and ELISA IgG assays.     

Detection of class-specific antibodies against Micropolyspora faeni antigens in farmers'lung

Micropolyspora faeni antigens were used for specific IgA, IgG and IgM determination with an ELISA technique, and for specific IgE antibodies by means of RAST in eighteen patients with farmer's lung, in nineteen farmers with other chest conditions, and in twenty-nine controls. The farmers’lung group had significantly higher IgG antibody levels than the controls, while specific IgA levels were elevated in ten cases. Specific IgE and-except for three cases IgM levels did not differ from the controls. In the group of farmers with other lung diseases, only three had increased levels of specific IgG antibody. The correlation (0. 89) between IgG by ELISA and a complement-fixation test indicated that C activation by M. faeni antigens is mediated by IgG antibodies.     

IgA Rheumatoid Factor and IgG Dietary Protein Antibodies are Associated in Rheumatoid Arthritis

This study sought to determine whether patients with rheumatoid arthritis (RA) were immunologically sensitised to dietary protein (DP). Using an enzyme linked immunosorbent assay (ELISA), antibodies to milk and wheat proteins were measured in 93 unselected out-patients with classical or definite RA. Of these 93, 53 had raised levels of IgG antibodies to one or both dietary proteins (DP). In the DP antibody positive group, 48 patients (90%) also had raised levels of IgA rheumatoid factor (measured by ELISA) while only 7 (17%) of the 40 DP antibody negative patients had detectable IgA RF; P<0.02. There was no association between IgM rheumatoid factor and dietary protein antibodies. These results demonstrate that in RA, raised levels of IgA RF are associated with an increased IgG response to antigens which enter the body through the gastrointestinal tract. A breakdown in gastrointestinal tolerance to dietary antigens may play a role in the immunopathogenesis of RA in these patients who might therefore benefit from dietary manipulation.     

The specific immunoglobulin in hydatid disease

The variation in the serum level of specific IgG, IgM and IgA antibodies during different stages of hydatid disease has been demonstrated by a technique of fluorescent microscopy that uses monospecific anti-human immunoglobulin conjugates and freeze-dried antigens. The technique is easy to perform and our results suggest that the test is sensitive and specific. Specific IgG antibodies are present in patients with either current or past infections. IgM antibodies, detected during periods of antigenic activity, disappear soon after removal of the cyst. In many cases IgA antibodies also disappear soon after removal of the cyst. Cross-reactions between the antigens and antibodies of hydatid disease and schistosomiasis are shown to be present mainly in the IgG immunoglobulin and only to a much smaller extent in the IgA.     

用重组汉坦病毒NP、GP检测急性期HFRS患者血清中特异性IgG、IgM、IgA抗体

目的 探讨肾综合征出血热(HFRS)患者急性期IgA、IgG、IgM抗体的变化规律。方法 使用套式RT-PCR检测此次病毒感染情况。用杆状病毒表达的汉坦病毒重组核蛋白(rNP)和糖蛋白(rGP)为抗原，使用ELISA方法检测了14例急性期肾综合征出血热患者的6l份系列血清中的IgA、IgG、IgM抗体。结果 14例肾综合征出血热患者中，ll例患者的血清用RT-PCR检出家鼠型汉坦病毒核酸。几乎所有肾综合征出血热患者早期即有IgA、IgM、IgG抗体的迅速升高，抗rNP抗体滴度明显高于rGP。3种抗rNP抗体中早期IgG上升趋势最为显著，IgM与IgA次之，IgM与IgA上升趋势相近，但IgA的滴度明显高于IgM。抗rGP抗体中XgA变化最显著，IgG次之。IgM发病2周内总的变化趋势不明显，但是发病l周内滴度上升趋势明显，而发病第2周内则呈下降趋势。其中l例RT-PCR阳性的患者，早期IgM未测出，IgA的滴度却较高。l例重度患者，抗糖蛋白IgG、IgM和IgA抗体滴度均低于其他患者，且整个急性期一直维持较低水平。结论 肾综合征出血热急性期IgA、IgG、lgM变化具有明显的规律，抗糖蛋白和核蛋白抗体病患规律不同，检测IgM的同时检测IgA，可以提高诊断的准确性。     

Antibody responses in acute and chronic Q fever and in subjects vaccinated against Q fever

An analysis is made of the antibody response to Coxiella burnettii Phase-1 and Phase-2 antigens, as measured by immunofluorescence in the IgM, IgG or IgA immunoglobulin classes, or by complement-fixation, in patients with acute and chronic Q fever and in vaccinated or skin-tested subjects. In acute (primary) Q fever, IgM specific antibodies to Phase-1 antigen are present in early convalescence together with IgM, IgG, IgA and CF antibodies to Phase-2 antigen. IgM specific antibody may persist for at least 678 days after onset of the acute illness. Patients with chronic Q fever have no IgM specific antibody to Phase-1 or -2 antigens, or only at very low levels; high levels of specific antibody in the IgG and IgA classes, together with CF antibody to both antigenic phases, appear to be characteristic. The serological response in initially seronegative, vaccinated subjects is mainly to Phase-1 antigen in the IgM fraction, and to a lesser degree to Phase-2 antigen by CF and in IgM and IgG classes. Subjects who were equivocally seropositive before vaccination showed IgA and IgG specific antibody responses to Phase-1 antigen and CF and IgG class responses to Phase-2 antigen. Similar antibody profiles were observed in patients who seroconverted after a positive skin-test. Data are also presented on the suitability of C. burnettii antigens for use in immunofluorescence and on the binding of IgM specific antibody by Phase-1 antigen but its failure to fix complement.