Immunoglobulin responses to echovirus type 11 by enzyme linked immunosorbent assay: Single-serum diagnosis of acute infection by specific IgM antibody

An indirect solid-phase enzyme-linked immunosorbent assay (ELISA) for the determination of specific IgM and IgG antibodies to echovirus type 11 in a single dilution of serum was developed using partially purified echovirus type 11 bound to microplates. Whole serum was used for IgG antibody but prior to assaying for IgM antibody interfering IgG was removed by ion exchange chromatography. The ELISA for echovirus type 11 IgG antibody was a more sensitive, rapid, technically easier and less costly alternative to the neutralisation test. With the IgG ELISA 12 of 132 sera (10.6%) known to contain enterovirus antibodies other than echovirus type 11 were positive but it could not be determined to what extent this was due to the greater sensitivity of the ELISA or cross-reactions. The IgM ELISA was even more sensitive than the IgG ELISA with acute sera, and showed a reactivity in 4 of 36 sera (11.1%) with no detectable echovirus type 11 neutralising antibodies. Echovirus type 11 IgM antibody was detected in all sera collected after the first week of infection and up to 30 days after infection. However, it was only detected in 58% of sera collected during the first week after onset thus limiting its use for rapid diagnosis. The echovirus type 11 IgM ELISA appears to have considerable laboratory diagnostic potential when a rising antibody level cannot be demonstrated in paired sera or when virus is not cultured.     

Diagnostic Relevance and Clinical Significance of the New Enhanced Performance M2 (MIT3) ELISA for the Detection of IgA and IgG Antimitochondrial Antibodies in Primary Biliary Cirrhosis

Background/aims: Antimitochondrial antibodies (AMAs) are the serological hallmark of primary biliary cirrhosis (PBC). We evaluated the sensitivity and specificity of a new M2 enhanced performance enzyme-linked immunosorbent assay (ELISA) (MIT3) for the detection of IgG- and IgA-specific isotypes of AMA in PBC patients including a number of PBC patients negative for AMA by indirect immunofluorescence (IIF) as well as in patients with diverse, non-PBC disorders. We also investigated the clinical significance of IgG and IgA AMA in PBC. Methods: One hundred and three Greek PBC patients including 27 with AMA IIF-negative at the time of the investigation, 29 with autoimmune hepatitis-1 (AIH-1), 12 with primary sclerosing cholangitis (PSC), 26 with hepatitis C virus (HCV), 15 with hepatitis B virus (HBV), and 29 healthy were investigated for AMA (IgG and IgA) using the MIT3-based ELISAs (INOVA Diagnostics, San Diego, CA). The samples were also tested by conventional anti-M2 ELISA (INOVA Diagnostics, Inc.). Results: The IgG MIT3-based ELISA significantly increased AMA detection in the cohort of PBC patients, over 26% of whom were AMA IIF-negative, from 63.1% by the conventional anti-M2, and 73.7% by IIF to 79.6% by MIT3-based ELISA (p<0.001). IgA AMAs were detected in 47.6% patients. Overall, IgG/IgA AMAs were detected in 84/103 (81.6%). IgG MIT3-based ELISA detected 12/27 IIF AMA-negative samples (44.4%), while IgG/IgA MIT3-based ELISAs detected 13/27 IIF AMA-negative patients (48.1%). The specificities of MIT3-based ELISAs (IgG and IgA) were 82.8% and 89.7%, respectively, in AIH-1, 100% and 93.3%, respectively, in HBV, 100% in PSC, and 96% and 93.3%, respectively, in HCV. Patients positive for IgG AMA had significantly more severe disease as shown by worse histology and elevated biochemical markers; IgG and IgA AMA titers were associated positively with the Mayo risk score but none of the isotypes were able to predict disease outcome. Conclusions: The new IgG and IgA MIT3-based ELISAs seem to have higher specificity and sensitivity for AMA detection than IIF and the conventional anti-M2. Interestingly, these assays were able to unmask AMA presence in almost half of the AMA-negative samples by IIF. These findings may suggest the use of MIT3-based ELISAs as first-line investigation for AMA detection, particularly, when the laboratories are unfamiliar with the use and interpretation of the IIF patterns of AMA. The presence of IgG AMA seems to characterize PBC patients with more severe disease, but both IgG and IgA isotypes of AMAs were not predictive markers of disease outcome.     

Quantification of Blo t 5 in mite and dust extracts by two-site ELISA

BACKGROUND: Blomia tropicalis is an important mite species in the tropical and sub-tropical regions of the world. Blo t 5 is the major allergen with up to 70% sensitization rates in B. tropicalis allergic populations. METHODS: Mice were immunized intramuscularly with naked plasmid DNA encoding Blo t 5 gene with in vivo electroporation. Blo t 5 monoclonal antibodies were generated using methylcellulose-based hybridoma kit. Monoclonal antibody (mAb) 4A7 was characterized by two-dimensional electrophoresis immunoblotting. A specific quantitative two-site enzyme-linked immunosorbent assay (ELISA) was developed with mAb 4A7 and guinea pigs Blo t 5 polyclonal antibody as capture and detection antibodies, respectively. This system was tested with Blo t 5 in crude extracts and dust samples. RESULTS: A high-affinity mAb 4A7 recognizing several isoforms of Blo t 5 has been generated. Monoclonal antibody 4A7 is useful for immunoblotting and two-site ELISA. The two-site ELISA developed has a high sensitivity, with a detection limit of 10 pg/ml. The assay is species-specific and recognized the same epitopes on both native and recombinant Blo t 5. The assay developed is able to detect Blo t 5 in commercial diagnostic and therapeutic B. tropicalis extract. Blo t 5 quantification in dust samples showed that Blo t 5 is present in a high quantity in Singapore dust. CONCLUSIONS: A highly sensitive and specific two-site ELISA has been developed. The assay system developed is useful for the quantification of Blo t 5 in mite and environmental dust extracts.     

Detection of IgM antibodies against cytomegalovirus: comparison of two radioimmunoassays, enzyme-linked immunosorbent assay and immunofluorescent antibody test

The sensitivity and specificity of direct antibody radioimmunoassay (RIA), M-antibody capture RIA (MACRIA), enzyme-linked immunosorbent assay (ELISA), and the immunofluorescent antibody (IFA) test for the detection of CMV-specific IgM was compared using 40 sera selected from different groups of patients. RIA, MACRIA, and ELISA gave concordant results with thirty-two sera but discordant results with eight sera, of which three were cord sera from congenitally infected babies, three were from immunocompromised patients with recurrent CMV infections, and two were from patients with lymphadenopathy and Paul-Bunnell-positive mononucleosis, respectively. RIA, MACRIA, and ELISA were of similar sensitivity with sera from adult patients, but ELISA was apparently less sensitive than RIA and MACRIA for the detection of CMV IgM in cord serum. By comparison IFA was significantly less sensitive than the other three tests. Rheumatoid factor is reactive in RIA, ELISA, and IFA but can efficiently be removed by absorption with latex-IgG beads or cross-linked human IgG.     

PBC screen: an IgG/IgA dual isotype ELISA detecting multiple mitochondrial and nuclear autoantibodies specific for primary biliary cirrhosis

A dual isotype (IgG, IgA) enzyme-linked immunosorbent assay (ELISA) designed to provide enhanced detection of primary biliary cirrhosis (PBC)-specific autoantibodies against both major mitochondrial and nuclear antigens has been developed and recently become commercially available. The assay (PBC Screen) simultaneously detects IgG and IgA autoantibodies to the immunodominant portions of the 3 major mitochondrial (MIT3) and nuclear (gp210, and sp100) antigens. The aim of this study was to compare the performance of the PBC Screen to the combined performance obtained with individual IgG ELISAs to MIT3, gp210, and sp100 on a large group of selected patients from multiple centers. A total of 1175 patients with PBC and 1232 subjects without PBC were evaluated. Non-PBC groups included healthy controls (624) as well as individuals with autoimmune hepatitis (281), primary sclerosing cholangitis (77), viral hepatitis (91 hepatitis B and 98 hepatitis C), other liver diseases (31), and other infectious or autoimmune diseases (30). The PBC Screen at the receiver operator characteristic optimized cutoff of 27.8 units, had an overall sensitivity of 83.8%, specificity of 94.7% and area under curve of 0.9212. This was similar to the specificity of 96.1% obtained by the combined results of individual MIT3, sp100, and gp210 IgG ELISAs (kappa index at 0.898). Of the 253 PBC patients without AMA detectable by immunofluorescence, 113 (44.7%) were interpreted as positive for PBC-specific autoantibodies. In conclusion, the PBC Screen is an appropriate first-line test for the diagnosis of PBC, including for patients negative for markers assessed using conventional methods.     

Solid-phase radioimmunoassay of serum IgG, IgM, and IgA antibodies to cytomegalovirus

A radioimmunoassay (RIA) using polystyrene beads as the solid phase for cytomegalovirus (CMV) antigen and iodinated immunosorbent purified anti-human IgG, IgM, and IgA as indicator antibodies was developed for the detection of immunoglobulin class-specific antibodies to CMV. An antigen prepared from extracellular virus was essential for reliable results, and a preparation ultracentrifuged and sonicated twice was better than a crude antigen. The optimal antigen gave low cpm values with a negative reference serum, resulting in cpm ratios of 10 or higher between early convalescent phase serum and negative reference serum. Of six patients with an increase in CMV CF titres, all six had an increase in RIA IgG titres, four had an increase in IgA titres, and all had IgM antibodies. The IgG titres were high, up to 1/64,000. In a group of 17 infants negative in CMV CF test, 14 had CMV IgG antibodies in RIA test, indicating mainly low levels of maternal antibodies. In six of seven patients with CMV isolations from urine specimens, an increase in IgG or IgA titres or the presence of IgM antibodies was found, and only one of these patients had an increase in CMV CF titre. The specificity of the developed CMV RIA test was further demonstrated by detecting no significant increase in RIA titres in serum specimens of patients with primary herpes simplex infection, chickenpox, herpes zoster, or infectious mononucleosis.     

Recent changes in prevalence pattern of Japanese encephalitis virus in Hyogo Prefecture, Japan, using a two-dimensional distribution of IgG and IgM class antibody levels in swine sera

Surveillance of antibody to Japanese encephalitis (JE) virus in swine sera was performed during the epidemic season from July to September, 1978 to 1983, in Hyogo Prefecture, Japan, using enzyme-linked immunosorbent assay (ELISA). Two-dimensional distribution analyses of ELISA values for IgG and IgM class antibodies indicated recent changes in the prevalence pattern. Time courses of antibody levels observed from 1978 to 1980 were similar to those in the 1960s of major epidemics, indicating a synchronous infection during the second wave of infection. In 1982 and 1983, however, the JE prevalence pattern implies an incessant infection cycle between vector mosquitoes and pigs during the latter half of the epidemic season. The delay of the occurrence of JE in patients confirms the longer period of exposure to infectious vectors.     

Use of a monoclonal antibody in a double-sandwich ELISA for detection of IgM antibodies to Toxoplasma gondii major surface protein (P30)

A double-sandwich ELISA, developed for detection of IgM antibodies to the major surface protein of Toxoplasma gondii (P30), is proposed for the diagnosis of acute acquired toxoplasmosis. The method is based on the capture of serum IgM antibodies, which are revealed indirectly by the sequential addition of a Toxoplasma extract and a beta-galactosidase-conjugated anti-P30 monoclonal antibody. All 57 patients tested with serological characteristics of recently acquired toxoplasmosis showed high levels of IgM anti-P30 antibodies. In addition, 5 out of the 24 patients with chronic toxoplasmosis and all 7 patients with a clinical acute infection in which the classical IgM serology was negative, also presented significant anti-P30 IgM antibodies. Patients with either rheumatoid factor or antinuclear antibodies were all negative. In view of its simplicity, specificity and sensitivity, this method is recommended for the current diagnosis of T. gondii infection.     

Coxsackievirus B1-based antibody-capture enzyme-linked immunosorbent assay for detection of immunoglobulin G (IgG), IgM, and IgA with broad specificity for enteroviruses.

An antibody-capture enzyme-linked immunosorbent assay (ELISA) with coxsackievirus B1 as the antigen was evaluated for detection of immunoglobulin G (IgG), IgM, and IgA antibodies and showed broad specificity for enteroviruses. In total, 116 serum or cerebrospinal fluid samples from 62 patients were tested by ELISA and the complement fixation test (CFT). Additionally, 15 serum samples that contained poliovirus-specific IgM antibody were tested. Serum samples from 200 healthy blood donors were used for standardization of the assays. The sensitivity of the ELISA varied with time of serum sampling, with a relatively low sensitivity when serum was collected within 3 days after the onset of symptoms (23%; 5 of 22) but good sensitivity when serum was collected later (83%; 20 of 24). The sensitivity was better than that of the CFT. The ELISAs were broadly reactive as concluded from typing of virus isolates that were simultaneously obtained. The assay did, furthermore, detect antibody against poliovirus type 3. Sera that contained rheumatoid factor, antinuclear antibody, or cardiolipin antibody (by the Venereal Disease Research Laboratory test) did not react in this ELISA. Nonspecific reactivity did occur, however, in cases of infectious mononucleosis and in Mycoplasma pneumoniae infection. The enterovirus-specific ELISA is found to be simple to perform, more sensitive than the CFT, and far less laborious than the neutralization test.     

Evaluation of a commercial IgE ELISA in comparison with IgA and IgM ELISAs, IgG avidity assay and complement fixation for the diagnosis of acute toxoplasmosis

A panel of sera from patients with known case histories representative of acute toxoplasmosis (primarily lymphadenopathy, n = 106), latent toxoplasmosis (asymptomatic, n = 368) and negative samples (n = 54) was used to evaluate the capacity of five serological tests to differentiate among patients with acute or latent toxoplasmosis and non-infected individuals. Positive IgA, IgE and IgM ELISA results and low IgG avidity and complement fixation test (CFT) titres of >or=256 were considered to be indicative of acute toxoplasmosis. The most sensitive methods were IgM ELISA (98.1%) and CFT (97.1%), albeit with low specificity (65.0% and 64.5%, respectively) and positive predictive values (43.3% and 42.7%, respectively). IgG avidity assay and IgE ELISA had the highest specificity (97.7% and 91.7%, respectively) and the highest positive predictive values (89.4% and 75.6%, respectively). The best association between serological results and clinical findings was obtained with IgE ELISA (86%, as expressed via Youden's index). In a subset of 259 samples categorised by the period between the onset of clinical symptoms and sampling, >50% of patients had enlarged lymph nodes for <4 months, despite a broad range of differences. However, IgM remained positive for 12-18 months, IgA for 6-9 months and IgE for 4-6 months. IgG avidity remained low for a maximum of 4 months, after which avidity increased despite the persistence of enlarged lymph nodes and a positive IgE assay. Detection of IgE appears to be a highly specific test for confirming the acute nature of Toxoplasma infections that have been detected by other sensitive methods.     

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.     

Establishment of an indirect ELISA method for antibody detection of porcine pseudorabies by recombinant gB,gC, and gD proteins

Pseudorabies virus (PRV), as a neuroherpes virus, leads to heavy economic losses in the pig industry worldwide. This study was designed to establish recombinant PRV glycoprotein B (gB), C, and D proteins as PRV diagnostic antigens. The gB/C, gC/D, and gB/C/D fusion sequences were synthesized and inserted into pET-28a⁺ vector to generate the recombinant plasmids. The identified positive recombinant plasmids were transformed into BL21 Escherichia coli. The results of the polymerase chain reaction and enzyme digestion showed that the gB/C, gC/D, and gB/C/D fusion proteins were successfully expressed. An indirect sandwich ELISA was developed with the gB/C, gC/D, and gB/C/D as coating antigens. The results of indirect enzyme-linked immunosorbent assay (ELISA) analysis of 184 PRV-positive porcine sera showed that the positive coincidence rates of three recombinant proteins ELISAs relative to IDEXX kit were 98.25%, 95.32%, and 98.83%, and the negative coincidence rates were 85.71%, 75% and 100%, respectively. The inter and intra batch repeatability tests showed that the coefficient of variations of our kits were all less than 5%. Especially, the gB/C/D-ELISA has the highest specificity and sensitivity among the ELISA methods developed in this study. We established a series expression system of gB/C, gC/D, and gB/C/D antigen epitope genes and Recombinant protein-based indirect ELISA, providing new ideas for PV diagnosis and vaccine development.     

Monitoring of cellular responses after vaccination against tetanus toxoid: comparison of the measurement of IFN-gamma production by ELISA, ELISPOT, flow cytometry and real-time PCR

One of the challenges for immunomonitoring in clinical trials is to detect an antigen specific T cell-mediated immune response. In an attempt to define the most suitable assay, tetanus toxoid was used to compare the capacity of 4 different methods to detect cytokine responses, before and after recall vaccination, in peripheral blood mononuclear cells (PBMC) of 14 healthy volunteers. ELISA, ELISPOT, intracytoplasmic detection and real-time RT-PCR were chosen to measure IFN-gamma production before and after vaccination. As far as the detection of memory T cell status (before vaccination) was concerned, we found that ELISPOT was the most sensitive method to discriminate TT-induced from spontaneous responses. On the other hand, intracytoplasmic cytokine detection was the most efficient method to detect the restimulating effect of TT vaccination.     

Solid-phase radioimmunoassay of IgA, IgG, and IgM antibodies to human rotavirus.

A solid-phase radioimmunoassay (RIA) has been developed for the detection of human rotavirus-specific IgA, IgG, and IgM antibodies. Nebraska calf diarrhea virus grown in LLC-MK2 cell cultures in the presence of trypsin was directly adsorbed onto polystyrene balls, and antibodies that attached to the virus-coated balls were detected by subsequent binding of 125I-labeled antibodies specific to human alpha, gamma or mu chains of human Iga, IgG, or IgM immunoglobulins. A total of 116 serum specimens from 58 adult patients were tested. Binding ratios between the positive and the negative serum varied between 5 and 15, occasionally being 20 or more in the IgA and IgG assays, but rarely exceeding 3 in the IgM assay. The RIA was found to be more sensitive in detecting antibodies to rotavirus than the complement fixation (CF) test, the RIA titers obtained being 50--100 times as high as the CF titers. The method described offers a possibility of evaluating the immune response to human rotavirus and of detecting recent infection.     

Development of a high‐sensitivity ELISA detecting IgG,IgA and IgM antibodies to the SARS‐CoV‐2 spike glycoprotein in serum and saliva

Detecting antibody responses during and after SARS‐CoV‐2 infection is essential in determining the seroepidemiology of the virus and the potential role of antibody in disease. Scalable, sensitive and specific serological assays are essential to this process. The detection of antibody in hospitalized patients with severe disease has proven relatively straightforward; detecting responses in subjects with mild disease and asymptomatic infections has proven less reliable. We hypothesized that the suboptimal sensitivity of antibody assays and the compartmentalization of the antibody response may contribute to this effect. We systematically developed an ELISA, optimizing different antigens and amplification steps, in serum and saliva from non‐hospitalized SARS‐CoV‐2‐infected subjects. Using trimeric spike glycoprotein, rather than nucleocapsid, enabled detection of responses in individuals with low antibody responses. IgG1 and IgG3 predominate to both antigens, but more anti‐spike IgG1 than IgG3 was detectable. All antigens were effective for detecting responses in hospitalized patients. Anti‐spike IgG, IgA and IgM antibody responses were readily detectable in saliva from a minority of RT‐PCR confirmed, non‐hospitalized symptomatic individuals, and these were mostly subjects who had the highest levels of anti‐spike serum antibodies. Therefore, detecting antibody responses in both saliva and serum can contribute to determining virus exposure and understanding immune responses after SARS‐CoV‐2 infection.     

Specific serum IgA, IgG and IgM antibody determination by a modified indirect ELISA-technique in primary and recurrent herpes simplex virus infection

Twenty-three patients with a herpetic infection as diagnosed by a positive culture of herpes simplex virus (HSV) were studied with respect to serological responses of IgA, IgG and IgM antibodies in paired serum samples by an indirect (sandwich) enzyme linked immunosorbent assay (ELISA). Eight of the patients had a primary infection and 15 a recurrent one. In the ELISA test a detergent treated cell lysate of HSV type 1 was used as antigen. In the IgM assay all sera were pretreated with antihuman IgG with the purpose to precipitate IgG of the samples. The conjugate was a F(ab)2-fragment of antihuman-IgM. In primary infections all patients had significant titre rises of IgG and presence of high IgM titres in the convalescent serum. IgA antibodies were found in all of them, while titre rises were detected in 5/8. In recurrent infections titre rises of IgG and IgA antibodies were found in 4 and 5, respectively. Six had detectable IgM in one or both of the paired samples. The IgG titres were higher in recurrent infections than in primary, in contrast to IgM of which much higher titres were found in primary infections. It is concluded that in primary infections a conclusive serological diagnosis was established in all patients, whereas in recurrent infections this was achieved in two of three patients. The indirect ELISA method used for IgM detection was sensitive, reliable and convenient. Interfering rheumatoid factor was effectively eliminated by treatment with antihuman IgG.     

Measurement of porcine faecal IgA, IgG and IgM levels by a competitive enzyme-linked immunosorbent assay.

The concentrations of IgG, IgA and IgM were compared in faecal material of healthy and diarrhoeic pigs using a competitive enzyme-linked immunosorbent assay (ELISA). The relative concentrations of faecal immunoglobulins (Ig) in healthy piglets and adults were significantly different (P less than 0.01). IgA was the most important Ig in adult faeces while IgM was predominant in piglet faeces. IgG appears to be a relatively rare component. No significant differences could be detected between groups of healthy and diarrhoeic piglets. In adult faeces, significant changes (P less than 0.02 to P less than 0.001) in Ig relative concentrations were observed between diarrhoeic and healthy animals.     

A recombinant topoisomerase I ELISA: screening for IgG, IgM and IgA anti-topo I autoantibodies in human sera.

An ELISA for the detection of anti-topoisomerase I autoantibodies in sera from patients with suspected or manifest rheumatic diseases is described. The antigen source used in this assay consists of a recombinant protein containing the last 695 C-terminal amino acid residues of human topoisomerase I (topo I). The sensitivity of the assay was 61%, while the specificity was more than 98%. Using this ELISA, 47 sera from scleroderma patients and immunopositive for anti-topo I antibodies, were screened for the presence of the isotypes IgG, IgA and IgM to topo I. Our finding that relatively high levels of IgA antibodies to topo I are present in most of the sera tested is consistent with the results of Hildebrandt et al. [1]. In addition, it is demonstrated that the IgG and IgA antibodies in a serum may recognize different epitope regions on the topo I polypeptide.     

A prospective study of in vitro anti-HBs producing B cells (spot-ELISA) following primary and supplementary vaccination with a recombinant hepatitis B vaccine in insulin dependent diabetic patients and matched controls.

A prospective study of the immune response after hepatitis B vaccination was carried out in 32 insulin dependent diabetes mellitus (IDDM) patients and their age and sex matched healthy controls. A sensitive, immunoenzymatic technique was used, able to detect in vitro specific antibody production by mitogen stimulated individual B cells. In-vivo serologic response after vaccination with a standard scheme (0, 1 and 6 months) of 20 micrograms recombinant hepatitis B (HB) vaccine was significantly impaired in the IDDM patients both with respect to the number of nonresponders (25 versus 3%, P less than 0.05) and antibody titers reached (1,377 vs. 9,060 IU/L, P less than 0.05). The total number of in vitro IgM- and IgG-class immunoglobulin producing B cells as detected by the spot-ELISA, was found to be comparable in both groups. Specific IgG anti-HBs (and to a lesser extent IgM anti-HBs) showed impairment in the diabetic population as a whole. The number of IgG anti-HBs producing B cells was markedly depressed one month following vaccination, which is probably a reflection of homing of B cells outside the circulation. Responding subjects were identified early during their vaccination by the detection of in vitro anti-HBs production using the spot-ELISA. Non-responding healthy subjects and IDDM patients as a group showed a low number of IgG anti-HBs spots, suggesting a reduced specific memory B cell frequency. In 13 of 15 hypo- and nonresponders with positive IgG anti-HBs spots supplementary vaccination(s) resulted in improved anti-HBs levels.     

Study of specific immunoglobulins (total, IgG, IgM, IgA, IgE) in indirect immunofluorescence and ELISA in 40 patients with trichinosis followed over a 9-month period

The evolution of the classes of specific immunoglobulins (IgG, IgM, IgA, IgE) of 40 cases of human trichinosis was followed over a nine month period by means of an indirect immunofluorescence test (IF) and ELISA. Specific IgG and IgM appear between 4 and 6 weeks after infection and were still demonstrable after 9 months (respectively in 87.5% and 38.5% of the patients with IF, in 85% and 87.5% with ELISA). Specific IgA were mainly seen on the 2nd month and specific IgE were detected in 37.5% of the patients on the 4th month. In this outbreak, specific antibodies seem to appear later than in a second outbreak observed a few weeks later.