Cryptococcosis of the nasopharynx in mice and rats

Summary An attempt to infect the upper respiratory tract of mice and rats with various bacteria and fungi by intranasally instillation was performed. Cryptococcus neoformans was the only agent to invade the tissue. The infection was limited to the nasopharynx, a phenomenon which probably indicates the presence of a specific chemotaxis or receptor.Dedicated to Prof. W. Kaplan, DVM, MPH     

Screening for plant lectins by latex agglutination tests

The latex agglutination test has been applied as a detection system for lectins, the method being especially useful in locations where the dependence on blood for hemagglutination tests could be minimised. The binding of various glycoproteins and sugars individually to the latex particles facilitated the agglutination with lectins having varying sugar specificities. The glycoproteins used were ovalbumin, horseradish peroxidase, porcine mucin and fetuin, while N-acetylglucosamine, N-acetylgalactosamine comprised the sugars used for binding to latex. The sensitivity of the latex agglutination tests was comparable with that of hemagglutination tests. Sugar binding specificity of the lectins could also be determined by inhibition of the agglutination in the presence of corresponding free sugars. The method proved to be useful in screening crude seed extracts for the presence of lectins.     

乙型肝炎IgA类HBsAg循环免疫复合物的检测及意义

本文报道用捕捉法ELISA检测各型乙肝IgA型HBsAg循环免疫复合物。结果表明,慢性乙肝IgA型HBsAg循环免疫复合物检出率显著高于急性乙肝;在慢性乙肝中,IgA型HBsAg循环免疫复合物的出现与HBVe系统关系密切,主要存在于HBeAg阳性血清中,并与HBeAg滴度有关。故IgA型HBsAg循环免疫复合物可作为HBV慢性感染的血清诊断标志之一;也可作为反映HBV在增殖并有传播危险的标志之一。     

Rapid Serodiagnosis of Mycobacterium avium-intracellulare Complex Infection by ELISA with Cord Factor (Trehalose 6, 6′-Dimycolate), and Serotyping Using the Glycopeptidolipid Antigen

Mycobacterium avium-intracellulare complex (MAC) is one of the most important opportunistic pathogens, particularly in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to determine whether an enzyme-linked immunosorbent assay (ELISA) using trehalose 6,6′-dimycolate (TDM) as an antigen can be used for the rapid serodiagnosis of MAC infection. We also identified MAC serotypes by ELISA using serotype-specific glycopeptidolipid (GPL) antigen. To confirm our findings, the thin-layer chromatographic (TLC) behavior of serotype-specific GPL of the strains isolated from MAC-infected patients was also tested. Forty patients infected with MAC and 30 healthy controls were tested. Thirty-two of the 40 MAC-infected patients had higher titers of serum antibodies against MAC TDM than against MTB TDM, while all 30 healthy control sera were unreactive to MAC TDM and MTB TDM. Results of the GPL ELISA indicated that 20 of the 40 MAC-infected patients' sera were reactive against serotype 4 GPL, 3 against serotype 8 GPL, and 1 against serotype 16 GPL. A TLC analysis of the GPL of the 40 MAC isolates showed that 16 strains were of serotype 4, 5 of serotype 8, and 2 of serotype 16. Results of the GPL ELISA were in good accord with those of the TLC analysis for most patients. Our findings suggest that ELISA using TDM is useful for rapid serodiagnosis of MAC infection, and that complementary ELISA testing using serotype-specific GPL gives additional detailed information concerning MAC serotypes.     

Advantage of Dimeric Peptide Antigens in Serodiagnosis of HIV-1 Infection

The reactivity of antibodies with dimeric and monomelic peptide antigens was compared by ELISA. A panel of highly purified synthetic peptides of HIV-1 representing defined regions, 598–609 and 524 533 (fusion domain) of gp41 and 306–320 of gpl20, were used as antigens in the ELISA. These peptides were selected and synthesized taking into account the level of sequence conservation of various strains and hydrophilicity. The analysis included sera from 52 HIV-1 infected individuals and 53 HIV-1 negative controls. Both peptides from gp41 were found to be particularly immunoreactive with sera from HIV-1 infected individuals. The frequency of reactivity to the selected peptide from gp120 (V₃ loop) in infected individuals was 82%. An interesting observation was that the dimeric peptide antigens had a detection rate more than 4-fold higher than the monomeric antigens. We found that lower levels of antibodies could be detected with dimeric antigens. The peptides reacted with few sera other than HIV-1 positive sera. These results implicate the potential dimeric peptide antigens to be utilized in the serodiagnosis of HIV-1 infection.     

Evidence for Circulating Immune Complexes in Thyroid Disease

Anti-complementary activity was detected in the sera of 23 (59%) out of 39 patients with Hashimoto thyroiditis; in 10 (29%) out of 34 patients with primary hypothyroidism; in six (17%) out of 36 patients with thyrotoxicosis; and in only six (8%) out of 78 control subjects. Fractionation of Hashimoto sera by Sephadex G-200 chromatography showed that the anti-complementary activity was founding fractions of larger molecular size than monomeric IgG, being localized predominantly in the ascending limb of the second elution peak, suggesting that it was in the form of small immune complexes.     

The changing face of AIDS-related opportunism: Cryptococcosis in the highly active antiretroviral therapy (HAART) era. Case reports and literature review

Only nine cases of AIDS-related cryptococcosis have been reported until now in patients receiving highly active antiretroviral therapy (HAART),all of them with abnormal clinical features. Two HIV-infected patients who experienced an atypical relapse of cryptococcosis shortly after the start of HAART and despite maintenance antifungal treatment, are described. Six different relapses of cryptococcal meningitis were observed in a 28-month period in a patient who obtained a poor immune recovery after HAART (as shown by a CD⁴⁺ lymphocyte count ranging from 78 to 149 cellsL, opposed to a baseline level of 98 cellsL). On the other hand, a patient with favorable immunological response to HAART(as expressed by a CD⁴⁺ count growing from 7 to 186 cellsL),experienced isolated multiple indolent cryptococcal abscesses involving head,neck, the anterior thoracic wall, and regional lymph nodes, with repeatedly negative cultures, and diagnosis obtained by both histopathologic study and positive serum antigen assay. Both our case reports are representative of novel correlations between opportunistic pathogens and immune reactivity, descending from the introduction of HAART. The first episode describes an exceedingly elevated number of disease relapses despite HAART and antifungal maintenance treatment, which may descend from an incomplete immune response to antiretroviral therapy, possibly responsible for failure in obtaining eradication of yeasts, but also for lack of disease dissemination (usually leading to a lethal multivisceral involvement in the pre-HAART era). The abnormal disease course and localization of second reported patient well depicts an immune reconstitution syndrome probably representing a flare-up of a latent fungal infection, caused by a rapidly effective HAART. In patients treated with HAART, AIDS-related cryptococcosis cannot therefore be ruled out by the absence of neurological involvement, and by persistingly negative cultures.This revised version was published online in October 2005 with corrections to the Cover Date.     

Suppression of ADCC by Immune Complexes Formed in Vitro in Mycobacterium leprae-Infected Mice

Antibody-dependent cellular cytotoxicity (ADCC) was assessed in mice infected experimentally with Mycobacterium leprae and injected simultaneously with in vitro-formed immune complexes (IC). Significant decrease in the ADCC function was observed in animals given IC at zero day (OdIC) and 3 months (3mIC) post inoculation with M. leprae, when ADCC activity was assessed at 3, 6 and 9 months period. From the data obtained we believe that ADCC is suppressed by IC formed in vitro.     

Serodiagnosis of cancers by ELISA of anti-histone H2B antibody

An enzyme-linked immunosorbent assay method for serodiagnosis of cancers was developed by employing histone H2B. This method measures anti-histone H2B antibody levels in sera and includes a device for coating the plastic immunoplate with a mixture of histone H2B and diluted fetal calf serum. The coating of immunoplates with this mixture decreased apparent sensitivity of the assay compared with that in the absence of fetal calf serum, but effective reduction of nonspecific background enabled a specific assay of anti-histone H2B antibody with excellent reproducibility. By this method cancer patients were discriminated from normal healthy subjects at detection rates of 37% for lung cancer, 33% for liver cancer, 50% for pancreatic cancer, 42% for colon cancer, and 78% for cervical cancer. However, stomach and esophagus cancers showed detection rates of less than 17%, which are comparable to the values for benign diseases. It is likely that this assay method detects squamous cell carcinomas at relatively high rates.     

Utilization of Proteinase K-Treated Cells as Lipopolysaccharide Antigens for the Serodiagnosis of Helicobacter pylori Infections

We have evaluated the use of proteinase K (PK)-treated cells isolated from Helicobacter pylori as lipopolysaccharide (LPS) antigens in an immunoblot assay and an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of H. pylori infection. The sera from patients with chronic gastritis, gastric ulcer, duodenal ulcer or gastric cancer, and from healthy adults with or without H. pylori infection were assayed with three commercial serodiagnostic kits (HM-CAP, Helico-G, and G.A.P. II) and novel methods relying on the use of PK-treated cells. The PK-treated cells used in these assays were selected on the basis of their possibility to possess a common epitope in the O-polysaccharides of H. pylori, which is known to be highly immunogenic in humans. Of the sera from these patients, 71-94% were positive with the commercial kits, 97% with immunoblot assay, and 90% with ELISA. On the other hand, of the healthy adults infected with H. pylori, 72-97% were positive with the commercial kits, 86% with immunoblot assay, and 72% with ELISA. PK-treated cells that did not contain the common epitope were unsuitable as an antigen for immunoblot assay or ELISA. Furthermore, the reactivity of these sera reacted specifically with H. pylori PK-treated cells but not with LPSs from other gram-negative bacteria, such as Campylobacter, Proteus, Bordetella, and Salmonella. These results demonstrate that the serological assays relying on the use of H. pylori PK-treated cells possessing a highly antigenic epitope are potentially useful as a serodiagnostic test for H. pylori infection.     

A nested PCR assay to detect DNA in sera for the diagnosis of deep-seated trichosporonosis

Deep-seated trichosporonosis caused by Trichosporon asahii has a high mortality rate and a very poor prognosis. New species-specific oligonucleotide primers for T. asahii were developed from a sequence analysis of rRNA genes that included the internal transcribed spacer regions. A nested PCR assay with specific primers was used to examine 11 serum samples from 7 patients, who were diagnosed with deep-seated trichosporonosis histologically at autopsy. In addition, Trichosporon cell wall polysaccharide (PS) was detected by a latex agglutination (LA) test. Of 11 samples, seven had a positive LA test, and T. asahii DNA was also detected with the nested PCR assay. Of the four samples in which PS antigen was not detected, the nested PCR of two samples was positive. Our new nested PCR assay may be used as an adjunct to conventional methods for diagnosing T. asahii infection.     

脂质体、免疫刺激复合物和壳聚糖作为黏膜免疫载体的研究现状

查阅国内外文献,采用整理归纳、引用和分析的方法,概述了鼻黏膜免疫载体材料脂质体、免疫刺激复合物和壳聚糖的生物学特性及其在气溶胶疫苗领域的应用。脂质体、免疫刺激复合物和壳聚糖作为气溶胶疫苗鼻黏膜免疫的载体,能够增强疫苗的免疫原性,提高机体的体液免疫和细胞免疫水平,因此,可作为疫苗抗原激发特异免疫应答的生物材料。     

Cryo-EM Studies of Virus-Antibody Immune Complexes

Antibodies play critical roles in neutralizing viral infections and are increasingly used as therapeutic drugs and diagnostic tools. Structural studies on virus-antibody immune complexes are important for better understanding the molecular mechanisms of antibody-mediated neutralization and also provide valuable information for structure-based vaccine design.Cryo-electron microscopy(cryo-EM) has recently matured as a powerful structural technique for studying bio-macromolecular complexes. When combined with X-ray crystallography, cryo-EM provides a routine approach for structurally characterizing the immune complexes formed between icosahedral viruses and their antibodies. In this review, recent advances in the structural understanding of virus-antibody interactions are outlined for whole virions with icosahedral T = pseudo 3(picornaviruses) and T = 3(flaviviruses) architectures, focusing on the dynamic nature of viral shells in different functional states. Glycoprotein complexes from pleomorphic enveloped viruses are also discussed as immune complex antigens. Improving our understanding of viral epitope structures using virus-based platforms would provide a fundamental road map for future vaccine development.     

Serodiagnosis of Echinococcosis by ELISA Using Cystic Fluid from Uzbekistan Sheep

According to increase of travel, the cases of imported echinococcosis have been increasing in Korea. The present study was undertaken to develop a serodiagnostic system for echinococcosis in Korea. For diagnosis of echinococcosis, the fluid of Echinococcus granulosus hydatid cysts was collected from naturally infected sheep in Uzbekistan. Also serum samples of infected patients who were surgically confirmed were collected in a hospital in Tashkent, Uzbekistan. According to the absorbance of 59 echinococcosis positive and 39 negative control serum samples, the cut-off value was determined as 0.27. The sensitivity and specificity of ELISA with hydatid fluid antigen were 91.5% and 96%, respectively. The antigen cross-reacted with the serum of some cysticercosis or clonorchiasis patients. However, immunoblot analysis on the cystic fluid recognized antigenic proteins of 7-, 16-, and 24-kDa bands in their dominant protein quantity and strong blotting reactivity. In conclusion, the present ELISA system using hydatid cyst fluid antigen from Uzbekistan sheep is sensitive and specific for diagnosis of echinococcosis cases.     

Echinococcus granulosus Protoscolex DM9 Protein Shows High Potential for Serodiagnosis of Alveolar Echinococcosis

Alveolar echinococcosis (AE) caused by infection with E. multilocularis metacestode, represents one of the most fatal helminthic diseases. AE is principally manifested with infiltrative, proliferating hepatic mass, resembling primary hepatocellular carcinoma. Sometimes metastatic lesions are found in nearby or remote tissue. AE diagnosis largely depends on imaging studies, but atypical findings of imaging features frequently require differential diagnosis from other hepatic lesions. Serological tests may provide further evidence, while obtaining reliable AE materials is not easy. In this study, alternative antigens, specific to AE were identified by analyzing E. granulosus protoscolex proteins. An immunoblot analysis of E. granulosus protoscolex showed that a group of low-molecular-weight proteins in the range from 14 kDa to 16 kDa exhibited a sensitive and specific immune response to AE patient sera. Partial purification and proteomic analysis indicated that this protein group contained myosin, tubulin polymerization promoting protein, fatty-acid binding protein, uncharacterized DM9, heat shock protein 90 cochaperone tebp P-23, and antigen S. When the serological applicability of recombinant forms of these proteins was assessed using enzyme-linked immunosorbent assay, DM9 protein (rEgDM9) showed 90.1% sensitivity (73/81 sera tested) and 94.5% specificity (172/181 sera tested), respectively. rEgDM9 showed weak cross-reactions with patient sera from the transitional and chronic stages of cystic echinococcosis (3 to 5 stages). rEgDM9 would serve as a useful alternative antigen for serodiagnosis of both early- and advanced-stage AE cases.     

Serodiagnosis of Toxocariasis by ELISA Using Crude Antigen of Toxocara canis Larvae

Toxocariasis is a worldwide zoonosis caused by larvae of ascarid nematodes of dogs or cats, Toxocara canis or T. cati. Diagnosis of human toxocariasis currently relies on serology that uses T. canis excretory-secretory antigen to detect specific IgG antibodies by ELISA. We investigated the serodiagnostic efficacy of ELISA using crude antigen of T. canis larvae (TCLA). Serum specimens of 64 clinically confirmed toxocariasis, 115 healthy controls, and 119 other tissue-invading helminthiases were screened by ELISA using TCLA. The ELISA using TCLA showed 92.2% (59/64 patient samples) sensitivity and 86.6% (103/119) specificity. Its positive diagnostic predictivity was 78.7% and negative predictivity was 97.8%. No serum of healthy controls reacted but that of anisakiasis (45.5%), gnathostomiasis (19.2%), clonorchiasis (15.8%), sparganosis (11.1%), and cysticercosis (6.3%) cross-reacted. Immunoblot analysis on TCLA recognized antigenic proteins of 28- and 30-kDa bands in their dominant protein quantity and strong blotting reactivity. The present results indicate that the ELISA using our TCLA antigen is acceptable by the sensitivity and specificity for serodiagnosis of human toxocariasis. ELISA with TCLA is recommended to make differential diagnosis for patients with any sign of organ infiltration and eosinophilia.     

A Rapid Latex Agglutination Assay for the Detection of Penicillin-Binding Protein 2′

A simple and rapid slide latex agglutination assay was developed to detect penicillin-binding protein 2′ (PBP2′) from isolates of staphylococi. PBP2′ present in the membranes of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant coagulase negative staphylococci (MRCNS) was rapidly extracted by alkaline treatment and, by combining with a slide agglutination reaction using latex particles sensitized with monoclonal antibodies raised against it, PBP2′ could be detected from a single loopful of cells taken from agar plates not containing beta-lactum antibiotics within 15 min. In a study of clinical isolates previously characterized as either MRSA or methicillin-susceptible Staphylococcus aureus (MSSA) by antibiotic susceptibility testing, 231 specimens of 232 MRSA were PBP2′ positive by latex agglutination, and the 87 specimens of MSSA were all negative. One specimen identified as MRSA by susceptibility testing but PBP2′ negative by latex agglutination was confirmed as mecA gene negative by PCR. This simple and rapid slide latex reagent should be useful in clinical diagnostics.     

Production and Evaluation of Toxoplasma gondii Recombinant GRA7 for Serodiagnosis of Human Infections

The precise diagnosis of the acute toxoplasmosis in pregnant women and immunocompromsied patients has critical importance. Most of the commercially available assays use the whole Toxoplasma soluble extract as the antigen. However, the assays currently available for the detection of specific anti-Toxoplasma antibodies may vary in their abilities to detect serum immunoglobulins, due to the lack of a purified standardized antigen. The aim of this study was production and evaluation of the usefulness of the recombinant Toxoplasma gondii GRA7 antigen for the serodiagnosis of Toxoplasma gondii IgM and IgG by ELISA. A total of 70 T. gondii IgM positive sera, 74 T. gondii IgG positive sera, and 60 sera from subjects who were not infected with T. gondii were examined. These sera were shown different absorbance values in ELISA test. To control the specificity of the rGRA7 other parasitic diseases, for example, echinococcosis, malaria, leishmaniasis, fascioliasis, and strongyloidiasis were tested of which none showed positive results. Sensitivity and specificity of the generated recombinant IgG ELISA in comparison with commercial ELISA (com ELISA) were 89% and 90%, and the sensitivity and specificity of the generated recombinant IgM ELISA were 96% and 90%, respectively. The results obtained here show that this antigen is useful for diagnostic purposes.     

Assessment of three simple techniques for the screening of circulating immune complexes: Correlation with a parameter of complement consumption

The sera of 36 normal controls, 45 patients with various diseases and 11 pregnant women were screened for circulating immune complexes using three relatively simple and inexpensive techniques. These included inhibition of agglutination of IgG coated latex particles with a serum having rheumatoid factor activity, polyethylene glycol precipitation and anti-complementary activity test. The circulating immune complexes were detected in a significantly higher proportion of patients as compared to normal controls. In the patients, the presence of circulating immune complexes did not always correlate with clinically detectable immunoinflammatory tissue damage indicating that pathogenic as well as nonpathogenic immune complexes were being detected by the above mentioned techniques. The alpha-1-antitrypsin/C3 ratio, however, correlated well with clinically apparent immuno-inflammation.     

Diagnostic Efficacy of a Recombinant Cysteine Protease of Spirometra erinacei Larvae for Serodiagnosis of Sparganosis

The mature domain of a cysteine protease of Spirometra erinacei plerocercoid larva (i.e., sparganum) was expressed in Escherichia coli, and its value as an antigen for the serodiagnosis of sparganosis was investigated. The recombinant protein (rSepCp-1) has the molecular weight of 23.4 kDa, and strongly reacted with the sparganum positive human or mice sera but not with negative sera by immunoblotting. ELISA with rSepCp-1 protein or sparganum crude antigen (SeC) was evaluated for the serodiagnosis of sparganosis using patient''s sera. The sensitivity and specificity of ELISA using rSepCp-1 protein were 95.0% (19/20) and 99.1% (111/112), respectively. In contrast, the sensitivity and specificity of ELISA with SeC were 100% (20/20) and 96.4% (108/112), respectively. Moreover, in experimentally infected mice, the sensitivity and specificity of both ELISA assays were 100% for the detection of anti-sparganum IgG. It is suggested that the rSepCp-1 protein-based ELISA could provide a highly sensitive and specific assay for the diagnosis of sparganosis.