Results Of Antibody Detection Research Articles

Antibody Detection of Toxoplasma gondii on Blood Donor at PMI Kota Yogyakarta by Rapid Diagnostic Methods in 2022

Toxoplasmosis is a disease that caused by Toxoplasma gondii parasite. Toxoplasma gondii is a group of protozoa, and it belongs to intracellular obligate parasites. This parasite mostly found in animal, and it can be dangerous, on many cases, it can cause death with no symptoms. The purpose of this study is to find out the percentage of IgG and IgM antibodies examination of Toxoplasma gondii on blood donor in PMI Kota Yogyakarta. This study belongs to descriptive observational type, with cross-sectional design to find out the results of antibody detection on Toxoplasma gondii. The detection was carried out by Rapid Diagnostic Methods that can detect the presence of IgG and IgM antibodies. This study was also using questionnaires to know the relationship between the daily behaviours with toxoplasmosis case. The results show that 14 samples were reactive on IgG antibody parameter (76%) and 11 samples were non-reactive (24%). From the questionnaires known that the daily behaviour’s such as having a cat, eating raw/undercooked meat products, eating unwashed fruits and vegetables related to the case of toxoplasmosis.

Epidemiological survey of feline viral infectious diseases in China from 2018 to 2020

AbstractTo analyze the prevalence of feline viral diseases in China, including feline panleukopenia virus (FPV), feline calicivirus (FCV), feline herpesvirus 1 (FHV‐1), and feline coronavirus (FCoV) infectious diseases from 2018 to 2020, swab samples from 304 cats and serum samples from 193 cats in 18 cities were collected. The etiological investigation results of 304 cats showed that 256 (84.21%) cats were positive, infected with at least one virus, and the positive rates for FPV, FCV, FHV‐1, and FCoV were 61.51%, 10.86%, 4.61%, and 55.92%, respectively. The mixed infection exhibited high complexity, and a total of eight mixed infection patterns were detected. The risk factor analysis of each pathogen in different clinical scenarios indicated that FPV positive status was significantly related to all the studied diseases, FCV positive status exhibited the most significant association with gingivostomatitis and conjunctivitis, and FHV‐1 positive status was significantly related to upper respiratory tract disease, but FCoV positive status was not significantly related to any disease. Additionally, the prevalence of FPV exhibited a strong seasonality and was related to age, while the prevalence of FCV, FHV‐1, and FCoV had nothing to do with season or age. FCV infection was sex related in cats, whereas the prevalence of FCV, FHV‐1, and FCoV was not sex related. FPV, FCV, FHV‐1, and FCoV were unrelated to breed or residential density. Antibody detection results of 193 serum samples by the virus neutralizing method indicated that the current commercial vaccines might not protect hosts against wild strains of FPV, FCV, and FHV‐1 in China. In general, this study enriches epidemiological survey data of common viral diseases in cats in China and provides a theoretical basis for further development of vaccines.

Breastfeeding vs. breast milk transmission during COVID-19 pandemic, which is more important?

The catastrophic coronavirus disease 2019 (COVID-19) pandemic has raised many health questions, and whether breast milk from SARS-CoV-2 infected mothers may be a vector for SARS-CoV-2 transmission has become a hot topic of concern worldwide. Currently, there are extremely limited and conflicting data on the risk of infection in infants through breastfeeding. For this reason, we investigated almost all current clinical studies and systematically analyzed the presence of SARS-CoV-2 and antibodies in the breast milk of mothers infected with SARS-CoV-2, their effects on newborns, and the mechanisms involved. A total of 82 studies were included in this review, of which 66 examined the presence of SARS-CoV-2 in breast milk samples from mothers diagnosed with COVID-19, 29 reported results of antibody detection of SARS-CoV-2 in breast milk, and 13 reported both nucleic acid and antibody test results. Seventeen studies indicated the presence of detectable SARS-CoV-2 nucleic acid in breast milk samples, and only two studies monitored viral activity, both of which reported that infectious viruses could not be cultured from RNA-positive breast milk samples. All 29 studies indicated the presence of at least one of the three antibodies, IgA, IgG and IgM, in breast milk. Five studies indicated the presence of at least one antibody in the serum of breastfed newborns. No COVID-19-related deaths were reported in all 1,346 newborns. Our study suggests that direct breastfeeding does not pose an additional risk of infection to newborns and that breast milk is a beneficial source of anti-SARS-CoV-2 antibodies that provide passive immune protection to infants. In addition, direct breastfeeding would provide maternal benefits. Our review supports the recommendation to encourage direct breastfeeding under appropriate infection control guidelines. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#myprospero, identifier: 458043.

Low cross reactivity between wild type and deamidated AAV can lead to false negative results in immune monitoring T-cell assays.

During gene therapy trials, immune responses against adeno-associated virus (AAV) vectors are monitored by antibody assays that detect the humoral and T-cell mediated cellular responses to AAV vectors. T cell assays commonly utilize the collection of patients' peripheral blood mononuclear cells (PBMCs) and stimulation with AAV-derived overlapping peptides. We recently described that spontaneous deamidation coincides with T cell epitopes in AAV capsids and that spontaneous deamidation may enhance or decrease immunogenicity in some individuals. This raised the concern for false negative results of antibody detection and PBMC immune monitoring assays because these assays use wild-type (WT) AAV or WT peptides for T cell re-stimulation and these peptides may not re-activate T cells that were stimulated with deamidated AAV capsid. To investigate this concern, we modeled the scenario by expanding T cells with deamidated peptides and evaluated the cross-reactivity of expanded T cells to WT peptides. In the majority of samples, cells that were expanded with deamidated peptides and restimulated with WT peptide had significantly lowered IL-2 and IFN-γ production. Spiking the four deamidated peptides to the WT peptide pool used for re-stimulation, restored the signal and corrected the performance of the assay. We also evaluated the impact of deamidation on anti AAV binding antibodies and did not observe a major impact on seroprevalence detection of AAV9. These data indicate that a high level ofdeamidation in AAV therapy may result in underestimation or even failure todetect immune responses against WT peptides during cellular immune monitoring.

Epidemiological characteristics and serum antibody detection of a COVID-19 aggregated outbreak in vaccinated population

An epidemiological investigation was conducted on a cluster epidemic of COVID-19 in the vaccinated population in Beijing in 2022, and serum samples were collected from 21 infected cases and 61 close contacts (including 20 cases with positive nucleic acid in the isolation observation period). The results of antibody detection showed that the IgM antibody of two infected persons was positive, and the IgG antibody positive rates of patients who were converted, not converted to positive and infected persons were 36.84% (7/19), 63.41% (26/41) and 71.43% (15/21), respectively. About 98.78% of patients had been vaccinated with the SARS-CoV-2 inactivated vaccine. The positive rate of IgG antibody in patients immunized with three doses of vaccine was 86.00% (43/50), which was higher than that in patients with one or two doses [16.12% (5/31)]. The antibody level of M (Q1, Q3) in patients immunized with three doses was 4.255 (2.303, 7.0375), which was higher than that in patients with one or two doses [0.500 (0.500, 0.500)] (all P values<0.001). The antibody level of patients who were vaccinated less than three months [7.335 (1.909, 7.858)] was higher than that of patients vaccinated more than three months after the last vaccination [2.125 (0.500, 4.418)] (P=0.007). The positive rate and level of IgG antibody in patients who were converted to positive after three doses were 77.78% (7/9) and 4.207 (2.216, 7.099), respectively, which were higher than those in patients who were converted after one or two doses [0 and 0.500 (0.500, 0.500)] (all P values<0.05).

Analysis of Nucleic Acid and Antibody Detection Results for SARS-CoV-2 Infection.

Real-time polymerase chain reaction (RT-PCR) of virus nucleic acid test (NAT) has become the standard method to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, there are still many limitations, especially the problem of the high false negative rate. Therefore, the aim of this study was to investigate the positive rate of SARS-CoV-2 NAT and evaluate the diagnostic performance of SARS-CoV-2 IgM and IgG antibody detection in novel coronavirus infection. A total of 10309 suspected or high-risk cases of infection with SARS-CoV-2 in Wuhan Hubei, China, were tested for virus NAT by RT-PCR. Among those cases, 762 COVID-19 patients and 143 patients with non-COVID-19 who were tested for SARS-CoV-2 IgM and IgG during the NAT period were screened. The difference between the two test methods was analyzed using the chi-square test. The positive rate of 10309 cases was about 36% (95% CI: 33.39%-39.67%). SARS-CoV-2 was present in various types of specimens, and alveolar lavage fluid had the highest positive rate [52.38% (95% CI: 31.02-73.74)]. The clinical sensitivity of serum SARS-CoV-2 IgM and IgG was 77.17% (588/762) and 94.88% (723/762), respectively, and the clinical specificity was 93.71% (134/143) and 90.21% (129/143). The area under the curve (AUC) of SARS-CoV-2 IgG and combination of IgG with IgM were equally larger than IgM [0.973 (95% CI: 0.964-0.983) vs 0.930 (95% CI: 0.910-0.949)]. IgG antibody had the highest specificity [100.0% (95% CI: 100.00%-100.00%)] and sensitivity [94.0% (95% CI: 92.45%-95.55%)] when detected alone or in combination with IgM antibody. The total coincidence rate of SARS-CoV-2 antibodies detection and SARS-CoV-2 NAT for the diagnosis of SARS-CoV-2 infection was 92.04% (833/905). Among the 34 SARS-CoV-2 NAT-negative patients with clinical symptoms and CT imaging features, 29 (85.29%) patients were positive for SARS-CoV-2 IgM, and 31 (91.76%) were positive for IgG. SARS-CoV-2 NAT should be considered for many types of specimens, and the combined test of SARS-CoV-2 IgM and IgG can make up for the problem of missed NAT in COVID-19 patients.

Erythrocyte antigens and antibodies in the Chilean population

Abstract Chile does not have a national registry of immunohematologic test results; there are no data on the prevalence of erythrocyte antigens and the frequency of antibodies in this population. Therefore, foreign references are used for decision-making. In this study, a standard questionnaire was used in 74 laboratories of public and private establishments. The information from tests conducted in 2015 was requested: ABO and D typing, antibody detection, antibody identification, and erythrocyte phenotype. Prevalence for the ABO-D phenotypes were obtained at the country level (D+ [94.4%] and D– [5.5%]) and differ from those recorded in the white population (85% and 15%, respectively). Positive antibody detection results were found in 0.4 and 1.3 percent of blood donors and patients, respectively; the main specificities were anti-Lea, -E, and -D in donors and anti-D, -E, and -K in patients. Inconclusive results were observed in ABO-D typing and antibody identification in donors and patients; these samples were referred to immunohematology reference laboratories for resolution. From this study, it was possible to estimate the prevalence of erythrocyte antigens and the frequency of antibodies at the national level, and this step allows us to characterize Chile’s population of blood donors and transfusion recipients and to compare the results and frequencies with other populations or countries.

A retrospective comparison of drugs against COVID-19

Coronavirus disease 19 (COVID-19) has posed serious threats to the general population. To relieve the crisis, a comparison of drug effects against COVID-19 is instructive. Between January 27, 2020 and March 21, 2020, a total of 333 patients treated with arbidol, corticosteroids, hydroxychloroquine, lopinavir/ritonavir, or oseltamivir monotherapy, having definite outcomes and serological antibody detection results, were retrospectively analyzed. The hydroxychloroquine group had a significantly reduced duration of hospital stay than the arbidol and corticosteroids groups. The oseltamivir group had a significantly shorter length of hospital stay than the arbidol, corticosteroids, and lopinavir/ritonavir groups. The hydroxychloroquine group had a significantly higher IgM titer than the other four groups and exhibited significantly higher IgG levels than the arbidol, lopinavir/ritonavir, and oseltamivir groups. Our findings indicated that hydroxychloroquine might have the potential for efficient COVID-19 management, while oseltamivir should be prudently considered in combination therapy.

Detection of SFTS virus RNA and antibodies in severe fever with thrombocytopenia syndrome surveillance cases in endemic areas of China

BackgroundSevere fever with thrombocytopenia syndrome (SFTS) is a newly identified severe infectious disease caused by SFTS phlebovirus (SFTSV). SFTS monitoring has been carried out since 2010 in mainland China. We analysed the detection results of SFTSV RNA and antibody in SFTS surveillance cases to provide basic data for SFTS diagnosis.MethodsThis study was conducted in Shandong Province. Sera of SFTS surveillance cases were collected to detect SFTSV RNA and antibody by real-time RT-PCR and enzyme-linked immunosorbent assay, respectively. Detection rates were calculated. SPSS 18.0 (Chicago, IL, USA) was used for statistical analysis to compare the detection rates of SFTSV RNA and antibodies among different sera groups.ResultsA total of 374 SFTS surveillance cases were enrolled. Overall, 93.3% (349/374) of the sera samples were collected within 2 weeks after onset, and 6.7% (25/374) were collected between 15 days and 45 days. Of these, 183 (48.9%) were positive for SFTSV RNA. The SFTSV RNA-positive rate peaked (52.2%) in samples collected ≤7 days after onset and then showed a decreasing trend. The detection rate of SFTSV-specific IgM antibody was 30.5% (46/151) and was highest in samples collected between 8 and 14 days (43.3%, 26/60). The positive rate of SFTSV-specific IgG antibody (17.9%, 27/151) showed an increasing trend with the specimen collection time. In total, 74.8% (113/151) of sera samples had the same SFTSV RNA and IgM antibody detection results. However, 23.2% (29/125) of SFTSV RNA-negative cases were IgM antibody-positive, and 8.6% (9/105) of IgM antibody-negative cases were SFTSV RNA-positive.ConclusionsSFTSV RNA detection was preferred for SFTSV infection during disease surveillance. For highly suspected SFTS cases, IgM antibody is suggested to make a comprehensive judgement.

The effectiveness of colostral antibodies for preventing bovine leukemia virus (BLV) infection in vitro

BackgroundBovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). The incidence of EBL in Japan is increasing annually; and the cases of EBL in cattle younger than 2 years old has been reported. Therefore, it is vital to find a method to control BLV infection, especially in young calves. In this study, to evaluate the protective ability of colostral antibodies against BLV infection, as well as the potential for BLV infection mediated by colostrum/milk, we investigated temporal fluctuations in the anti-BLV antibody titer and BLV proviral load (PVL) in colostrum/milk and peripheral blood of six infected dams during lactation. The association between PVL and antibody titer in colostrum and peripheral blood was then investigated using samples from a further twenty-seven cattle. Antibody concentrations were measured with a Syncytium-induction Inhibition Assay using colostral/milk whey and serum. PVL in peripheral blood and colostrum was measured by real-time PCR.ResultsColostral antibodies showed high inhibitory activity until day 3 of lactation. The antibody titer and PVL in peripheral blood showed lesser changes than those in colostrum/milk throughout lactation. The colostral antibody titer was significantly higher than the serum antibody titer in all samples, whereas the colostrum PVL was significantly lower than the blood PVL. The blood PVL showed a significant correlation with serum antibody titer, colostrum PVL, and colostral antibody titer. However, there were no major correlations between the serum and colostral antibody titers.ConclusionsThis is the first report investigating the temporal changes in colostral antibody titer in terms of inhibiting BLV infection in vitro. The results of antibody detection by Syncytium-induction Inhibition Assay suggested that the protective activity of the colostral antibodies against BLV infection would be conferred by anti-BLV gp51 antibody. The high antibody titer of colostral whey suggests that colostral whey could be a potential source of antibodies with a low risk of infection in neonatal calves.

Powerful tools for resolving antibody problems

BackgroundIdentifying the specificity of antibodies in a patient's plasma can be as straightforward as testing selected reagent red cells on the basis of the antibody detection results. Many investigations, however, require the use of additional methods or supplemental tests for resolution.AimsSpecifics related to performance of these procedures, their interpretations and their limitations were reviewed.DiscussionGel microcolumn or solid phase methods, polyethylene glycol or low‐ionic strength saline enhancement media or unenhanced tests have appropriate uses for detecting or avoiding antibody reactivity. Useful red cell treatments include enzymes or thiol compounds to destroy antigens or enhance the antigen–antibody interaction and EDTA–glycine acid or chloroquine diphosphate to remove bound IgG from autologous cells. Separating autologous red cells from transfused donor cells for phenotyping or testing with plasma or eluate is critical. Alloantibodies or autoantibodies can be removed or separated by appropriate adsorption tests. Inhibition of antibody reactivity by a known soluble blood group substance confirms specificity or neutralizes interfering reactivity.ConclusionCombined into a logical investigation, these additional tests will aid in resolution of most antibody‐containing samples.

Added Value of Antigen ELISA in the Diagnosis of Neurocysticercosis in Resource Poor Settings

BackgroundNeurocysticercosis (NCC) is the most common cause of acquired epilepsy in Taenia solium endemic areas, primarily situated in low-income countries. Diagnosis is largely based upon the “Del Brutto diagnostic criteria” using the definitive/probable/no NCC diagnosis approach. Neuroimaging and specific T. solium cysticercosis antibody detection results are at the mainstay of this diagnosis, while antigen detection in serum has never been included. This study aimed at evaluating the addition of antigen detection as a major diagnostic criterion, especially in areas where neuroimaging is absent.MethodsThe B158/B60 monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) for the detection of circulating cysticercus antigen was carried out retrospectively on serum samples collected during a hospital-based study from 83 people with epilepsy (PWE) in an endemic area.ResultsThe addition of antigen results as a major criterion allowed the correct diagnosis of definitive NCC in 10 out of 17 patients as opposed to 0/17 without antigen results in the absence of neuroimaging. A sensitivity of 100% and a specificity of 84% were determined for the diagnosis of active NCC using antigen ELISA. While the use of a higher cutoff improves the specificity of the test to 96%, it decreases its sensitivity to 83%.ConclusionsIn areas where neuroimaging is absent, NCC diagnosis according to the existing criteria is problematic. Taking into account its limitations for diagnosis of inactive NCC, antigen detection can be of added value for diagnosing NCC in PWE by supporting diagnostic and treatment decisions. Therefore, we recommend a revision of the “Del Brutto diagnostic criteria” for use in resource poor areas and suggest the inclusion of serum antigen detection as a major criterion.

Real-time observation of antigen–antibody association using a low-cost biosensing system based on photonic bandgap structures

In this letter, we present experimental results of antibody detection using a biosensor based on photonic bandgap structures, which are interrogated using a power-based readout technique. This interrogation method allows a real-time monitoring of the association process between the antigen probes and the target antibodies, allowing the instantaneous observation of any interaction event between molecules. because etunable lasers and optical spectrum analyzers are avoided for the readout, a drastic reduction of the final cost of the platform is obtained. Furthermore, the performance of the biosensing system is significantly enhanced due to the large number of data values obtained per second.

Synthetic biotinylated tetra β(1→5) galactofuranoside for in vitro aspergillosis diagnosis

The synthesis of a tetra β(1→5) galactofuranoside was achieved using a thioglycoside donor with a methyl tert-butyl phenyl thio leaving group. This tetrasaccharide was conjugated to biotin and validated as antigen with the monoclonal antibody used for clinical detection of Aspergillus fumigatus galactomannan on streptavidin-coated microplates. Then we have shown its ability to detect antibodies associated with A. fumigatus induced disease by using sera from patients with Allergic broncho-pulmonary aspergillosis (ABPA) and correlated the results of antibody detection with those gained with a commercially available diagnostic test.

Serodiagnosis of sheep hydatidosis with hydatid fluid, protoscolex, and whole body of Echinococcus granulosus antigens

Diagnosis of hydatidosis is based on immunodiagnostic methods along with radiological and ultrasound examinations. A great number of immunological assays have been developed for detection of anti-hydatid cyst antibodies. The principal intermediate host of Echinococcus granulosus in most endemic regions of the world is sheep. Antibodies to various antigens are detectable in the sera of some, but not all infected sheep. The objective of the present study was to develop a specific and simple antigen-based ELISA method for diagnosis of hydatidosis in sheep with different (hydatid fluid, protoscolices, and whole body of E. granulosus) antigens. A total of 100 sera were collected from sheep with hydatidosis proven by inspection of hydatid-infested livers and lungs of the sheep slaughtered in Mashhad abattoir. Hydatid fluid and protoscolex were isolated from livers or lungs of sheep with hydatid cyst in sterile conditions. Whole body of E. granulosus was isolated from intestine of infected dogs. Sera samples were examined by ELISA with different antigens. The results of antibody detection by indirect ELISA, using different antigens, showed that the hydatid fluid was the most effective antigen of those assessed for detection of infection with hydatidosis in sheep. Findings of this study indicated that antibody detection assay is a sensitive approach for diagnosis of hydatid cyst in sheep.

Immunogenicity of bone morphogenetic proteins

The object of this paper is to review the immunogenicity of bone morphogenetic proteins (BMPs) and to compare the results of the immunogenicity characterization and clinical consequences between recombinant human (rh)BMP-2 and recombinant human osteogenic protein-1 (rhOP-1/BMP-7). The immunogenicity of therapeutic proteins and its clinical effects were reviewed. The characteristics of BMPs were also described in terms of immunogenicity. The methods and results of antibody detection in various clinical trials of rhBMP-2 and rhOP-1 were compared, including the most recent studies using a systematic characterization strategy with both a binding assay and bioassay. Similar to all recombinant human proteins, rhBMPs induce immune responses in a select subgroup of patients. Adverse effects from this response in these patients, however, have not been reported with antibody formation to either rhBMP-2 or rhOP-1. Overall, the incidence of antibody formation was slightly higher in rhOP-1 trials than in rhBMP-2 trials. Although they occur in a subgroup of patients, the immune responses against rhBMPs have no correlation with any clinical outcome or safety parameter. Clinicians, however, must be aware of the potential complications caused by the immunogenicity of BMPs until more studies clearly elucidate their safety.

Assessment of antibody responses to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae in cerebrospinal fluid of chronic meningitis patients for definitive diagnosis as TBM/NCC by passive hemagglutination and immunoblot assays

Tanned sheep erythrocytes stabilized with pyruvic aldehyde and glutaraldehyde, called double-aldehyde-stabilized cells, were used to standardize passive hemagglutination assay (PHA) for detection of antibody responses to sonicate extract of Mycobacterium tuberculosis and Cysticercus cellulosae soluble antigens. PHA was performed in the following groups of cerebrospinal fluid (CSF) samples: group I – chronic infections of the central nervous system with the possible diagnosis of tuberculous meningitis (TBM), tuberculoma and neurocysticercosis (NCC) ( n=88), and group II – controls which included (a) non-infectious non-neurological conditions ( n=30), (b) infectious neurological conditions ( n=21) and (c) non-infectious neurological conditions ( n=133). PHA could detect anti-mycobacterial antibodies at the sensitivity level of 80.76% with a specificity of 92.4% and anti-cysticercal antibodies with a sensitivity of 100% and specificity of 92.94%. However, in 6.33% (i.e. 14/221) of group I and group II (c) CSFs both anti-mycobacterial and anti-cysticercal antibodies were detected. Immunoblot analysis of CSFs derived from TBM patients reacted predominantly to 120-kDa, 96-kDa, 65-kDa, 38-kDa, 26-kDa, 23-kDa, 19-kDa and 12–14-kDa and 4–6-kDa antigens of M. tuberculosis sonicate extract (MTSE), whilst CSFs of proven NCC reacted to >110-kDa, 96-kDa, 80-kDa, 66–68-kDa, 52-kDa and 26–28-kDa antigens of porcine whole cyst sonicate extract (PCSE). On immunoblot analysis, some of the CSFs of TBM patients were PHA positive for both MTSE and PCSE showed antibody reactivity to 70-kDa and 10-kDa antigens of C. cellulosae. Similarly CSF antibody of some Guillain Barre syndrome and myeloradiculopathy patients reacted with cysticercal antigens. But per se no cross-reactivity between MTSE and anti-cysticercal antibodies and vice-versa were observed. However, findings of this study should alert laboratory personnel especially in endemic areas to be extra careful in interpretation of antibody detection results.

Use of a sandwich-enzyme-linked immunosorbent assay (SEA) for the diagnosis of natural Fasciola hepatica infection in cattle from Galicia (NW Spain)

An indirect-enzyme immune-linked immunosorbent assay (IEA) was compared to a sandwich-enzyme-linked immunosorbent assay (SEA) to diagnose fasciolosis in naturally infected cattle. By means of a rabbit polyclonal IgG antibody to F. hepatica antigens, captured circulating antigens were detected by an SEA technique. A total of 85.1% of the samples examined was considered positive by using the IEA-test, whereas this percentage was of 37.3% by the SEA test. Using the two enzymatic probes, only the 38.3% resulted positive to both immunoassay probes. Our data indicate that circulating antigen detection assay in combination with results of antibody detection may offer a more reliable diagnostic technique than classic coprologic ones, with results very appropriate for epidemiologic studies carried out on a wide area.

Comparison of two assays for detection of HIV antibodies in saliva

The presence of HIV antibodies was screened in 241 paired samples of serum and saliva from seronegative subjects with risk factors for human immune deficiency virus (HIV) infection (n = 99), asymptomatic and symptomatic HIV-seropositive patients (n = 104) and healthy blood donors (n = 38) as negative controls, in order to assess the reliability of two saliva tests for the detection of HIV antibodies. These results were confirmed by Western blot. The saliva samples were collected using an oral device (Salivette) maintained in the lateral gingival fold until the individual perceived that it was becoming less rigid due to hydration with saliva. The two tests were a rapid one (Test Pack) and a conventional one (GACELISA). The results for antibody detection in saliva show 99% specificity and 99% sensitivity for the rapid test versus 100% sensitivity and 81% specificity for the conventional test. All results for the saliva samples which were positive in the rapid test were confirmed by Western blot (WHO criteria), and there were no indeterminate Western blot results among the samples which were false-positive in the conventional enzyme immunoassay. No statistically significant differences were observed between the absorbance values of HIV-infected symptomatic and asymptomatic patients. The correlation for the results of the HIV-antibody analysis in the paired sera was 98%. This method of saliva sampling in combination with a rapid and sensitive test for HIV-antibody detection may be applicable in studies conducted with limited technical resources or insufficiently trained health personnel or where blood sample collection is difficult.

Serodiagnosis of canine herpesvirus infection - Development of an enzyme-linked immunosorbent assay and its comparison with two improved methods of serum neutralization test.

An enzyme-linked immunosorbent assay (ELISA) for the diagnosis of canine herpesvirus (CHV) infection using antigen prepared by solubilizing infected cells was developed. The ELISA and two improved methods of serum neutralization test, the microplate serum neutralization test (MSNT) with complement and the 50% plaque reduction (PR) assay with complement, were compared for the results of antibody detection from a total of 557 field canine sera. Of 529 sample sera that were negative in the MSNT with complement, 119 were ELISA positive, and this result together with time course of serum antibody detection in a dog experimentally infected with CHV strongly suggested that the MSNT with complement is less sensitive for the detection of antibody in CHV infected dogs, especially those in early stages of infection. A correlation was found between the titers measured by the ELISA and 50% PR assay with complement, however, for field use, the ELISA is recommended as a highly sensitive test method of serodiagnosis of CHV infection adequate for dealing with a large number of samples with less demand on time and effort.