Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain (VHH). The recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. In particular, they might be very useful for molecular mimicry. The present study demonstrated an alpaca immunized with the F(ab')2 fragment of anti-aflatoxin B1 mAb and developed an important anti-idiotypic (anti-Id) responses. Antigen-specific elution method was used for panning private anti-Id VHHs from the constructed alpaca VHH library. The selected VHHs were expressed, renatured, purified, and then identified by a competitive enzyme-linked immunosorbent assay (ELISA). Our findings indicated that the VHH would be an alternative tool for haptens mimicry studies.
Aflatoxin B1 ; immunology ; Amino Acid Sequence ; Animals ; Antibodies, Anti-Idiotypic ; biosynthesis ; chemistry ; isolation & purification ; Camelids, New World ; immunology ; Immunoglobulin Heavy Chains ; chemistry ; isolation & purification ; Molecular Sequence Data

OBJECTIVETo understand the infection status of enterovirus 71 (EV71) and coxsackievirus A16 (Cox A16) among children receiving health examination for child care setting entrance in Beijing and their related medical care seeking practice and provide evidence for the estimation of disease burden caused by hand foot and mouth disease (HFMD).

METHODSSerological survey was conducted in the local children receiving health examination for child care setting entrance. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect anti-EV71 and anti-Cox A16 IgG and IgM.

RESULTSA total of 813 children were surveyed (mean age: 3.5 ± 1.0 year old). The seropositive rate was 61.9% and 4.4% for anti-Cox A16 IgG and IgM. The seropositive rate was 9.3% and 1.1% for anti-EV71 IgG and IgM. No significant difference was observed in sex specific seropositive rate (P > 0.05). However, significant differences were found in seropositive rate among different age groups (P < 0.05). Among the children who were anti-Cox A16 positive, 7.8% had ever had rashes on their hands and feet, mouth or buttocks (HFMD-like rashes). Among the children who were anti-EV71 positive, 10.7% had ever had HFMD-like rashes. For the children who were anti-Cox A16 or anti-EV71 positive, only 7.1% were brought to see doctors by their parents. However, among the seropositive children with rashes, 80.5% were brought to see doctors.

CONCLUSIONIn the healthy children at the age to go to child care setting in Beijing, most had ever infected with Cox A16. The anti-EV71 positive rate was much lower than the anti-Cox A16 positive rate. It was necessary to strengthen the prevention and control of EV71 infection in child cares settings.

Antibodies, Anti-Idiotypic ; blood ; Beijing ; epidemiology ; Child Health Services ; utilization ; Child, Preschool ; Cost of Illness ; Enterovirus A, Human ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Female ; Hand, Foot and Mouth Disease ; epidemiology ; virology ; Humans ; Male ; Parents ; psychology ; Patient Acceptance of Health Care ; statistics & numerical data

Human transferrin receptor (TfR) was isolated from homogenates of placental tissues by affinity chromatography on transferrin-Sepharose, and then used to screen human scFv against it from a fully-synthesized phage scFv library. After verifying the specificity, gene fragment of one of the selected scFv was inserted into the plasmid pET22b(+) and transformed into E. coli BL21(DE3) . Expression of scFv in transformant was induced with 0.5mmol/L IPTG. ELISA assay on HeLa cells showed that scFv protein could recognize and bind to TfR on the surface of HeLa cells. The scFv was purified by one-step affinity chromatography with Ni+ -NTA agarose, and injected into Kunming mouse via tail veins. This scFv was detected in brain tissues 1h later by capillary depletion method, which indicates that scFv protein can permeate through the blood brain barrier by mediation of the TfR receptor. Our works lay the foundation for the treatment of tumors and central nervous system diseases.
Animals ; Antibodies, Anti-Idiotypic ; genetics ; isolation & purification ; metabolism ; Escherichia coli ; genetics ; metabolism ; HeLa Cells ; Humans ; Immunoglobulin Fragments ; biosynthesis ; genetics ; immunology ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; immunology ; Mice ; Receptors, Transferrin ; genetics ; immunology ; Recombinant Proteins ; biosynthesis ; genetics ; Transferrin ; metabolism

Total mRNA was extracted from lymphocytes separated from the peripheral blood of allergic patients, and then variable region of heavy chain (VH) and variable region of light chain (VL) cDNA library were constructed by RT-PCR. Human scFv templates for rabbit reticulocyte lysate ribosome display were assembled by primers and linker peptide (Gly4Ser)3. mRNA bound in antibody-ribosome-mRNA complexes was recovered using in-situ single primer RT-PCR, and three rounds of anti-IgE scFv DNA were enriched. The target DNA fragments were double enzyme digested and ligated into plasmid pET22b (+), followed by transformation in E. coli Rosseta (DE3). Positive clones were screened using clone PCR, Dot blotting and antigen ELISA. The correct lengths of VH (400 bp) and VL (710 bp) PCR products were obtained. The expected 1,000 bp ribosome display templates were also observed in agarose gel electrophoresis. After three rounds of ribosome display target sequences were effectively enriched, leading to a library of 10(13) members. Antibodies with the highest ELISA value for IgE were generated in the strain pET-IgE-6. A human anti-IgE scFv library was successfully constructed as described herein. Ribosome display using single primer in-situ RT-PCR as the recovery procedure effectively enriched target sequences. Anti-IgE scFv with high affinity and specificity were identified. The prepared human anti-IgE scFv fragment might be self-developed to a lead drug for treating asthma. Our study provides an alternative method for rapid discovery of human antibodies of therapeutic importance.
Amino Acid Sequence ; Antibodies, Anti-Idiotypic ; genetics ; isolation & purification ; Antibody Affinity ; Asthma ; blood ; Base Sequence ; DNA, Complementary ; metabolism ; Escherichia coli ; metabolism ; Humans ; Immunoglobulin Heavy Chains ; genetics ; Immunoglobulin Light Chains ; genetics ; Immunoglobulin Variable Region ; genetics ; Lymphocytes ; chemistry ; Peptide Library ; RNA, Messenger ; isolation & purification ; Recombination, Genetic ; genetics ; Ribosomes ; chemistry ; genetics ; immunology ; Single-Chain Antibodies ; genetics ; isolation & purification ; Transformation, Genetic

PURPOSE: Since few reports had been published on the prevalence of toxocariasis in ankylosing spondylitis (AS) patients with acute non-granulomatous anterior uveitis (ANGAU), the aim of this work was to determine the presence of antibodies against Toxocara canis in AS patients with ANGAU. METHODS: Thirty-six patients (14 female and 22 male) with AS were enrolled in the study. The history of ANGAU was accepted only if diagnosed by an ophthalmologist. The detection of IgG antibodies to T. canis was determined by enzyme-linked immunosorbent assay. In addition, antibodies to Ascaris lumbricoides were also tested to verify non-specific reactions. RESULTS: The prevalence of ANGAU in the AS patients was 58% (21 / 36), and 38% (8 / 21) of the patients with ANGAU were positive for antibodies to Toxocara, while 7% (1 / 15) of AS patients without ANGAU were positive for T. canis (p = 0.038, two tails; mid-p exact). No antibodies were detected to A. lumbricoides antigens in the serum samples of patients with AS. CONCLUSIONS: These data suggest that the seroprevalence of antibodies to T. canis is high in Mexican patients with AS-associated uveitis, suggesting a chronic asymptomatic toxocariosis, which could be associated with the pathogenesis of ANGAU; however, further larger-scale studies are needed to confirm this observation.
Acute Disease ; Adult ; Aged ; Animals ; Antibodies, Anti-Idiotypic/*isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Eye Infections, Parasitic/complications/*immunology/parasitology ; Female ; Humans ; Immunoglobulin G/*immunology ; Male ; Middle Aged ; Seroepidemiologic Studies ; Spondylitis, Ankylosing/*complications/immunology/parasitology ; Toxocara canis/*immunology/isolation & purification ; Toxocariasis/complications/*immunology/parasitology ; Uveitis, Anterior/complications/*immunology/parasitology ; Young Adult

Swine hepatitis E virus (HEV) is widespread throughout pigs in both developing and industrialized countries. This virus is an important zoonotic agent and a public concern worldwide. Infected pigs are asymptomatic, so diagnosing swine HEV relies on detection of the virus or antibodies against the virus. However, several obstacles need to be overcome for effective and practical serological diagnosis. In this study, we developed an enzyme-linked immunosorbent assay (ELISA) that used a purified recombinant capsid protein of swine HEV. The potential clinical use of this assay was evaluated by comparing it with a commercial kit (Genelabs Technologies, Diagnostics, Singapore). Results of the ELISA were highly correlated with those of the commercial kit with a sensitivity of 97% and specificity of 95%. ROC (receiving operator characteristic) analysis of the ELISA data produced a value of 0.987 (95% CI, 0.977~0.998, p < 0.01). The cut-off value for the ELISA was also determined using negative pig sera. In summary, the HEV-specific ELISA developed in the present study appears to be both practical and economical.
Animals ; Antibodies, Anti-Idiotypic/*analysis/blood/genetics ; Capsid Proteins/*genetics/metabolism ; Enzyme-Linked Immunosorbent Assay/*methods/veterinary ; Hepatitis E/diagnosis/immunology/*veterinary/virology ; Hepatitis E virus/genetics/*isolation & purification/metabolism ; Immunoglobulin G/blood/genetics ; ROC Curve ; Recombinant Proteins/genetics/metabolism ; Swine ; Swine Diseases/*diagnosis/immunology/virology

PURPOSE: This study evaluated the prevalence of ocular toxocariasis (OT) in patients with uveitis of unknown etiology who visited a tertiary hospital in South Korea and assessed the success of serum anti-Toxocara immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) as a diagnostic test for OT. METHODS: The records of consecutive patients with intraocular inflammation of unknown etiology were reviewed. All participants underwent clinical and laboratory investigations, including ELISA for serum anti-Toxocara IgG. OT was diagnosed based on typical clinical findings. Clinical characteristics, seropositivity, and IgG titers were compared between patients diagnosed with OT and non-OT uveitis. The seropositivity and the diagnostic value of anti-Toxocara IgG was investigated among patients with different types of uveitis. RESULTS: Of 238 patients with uveitis of unknown etiology, 71 (29.8%) were diagnosed with OT, and 80 (33.6%) had positive ELISA results for serum anti-Toxocara IgG. The sensitivity and specificity of the ELISA test were 91.5% (65 / 71) and 91.0% (152 / 167), respectively. The positive predictive value of the serum anti-Toxocara IgG assay was 81.3%. Among patients with anterior, intermediate, posterior, and panuveitis, the prevalence rates of OT were 8.3%, 47.1%, 44.8%, and 7.1%, respectively; the seropositivity percentages were 18.1%, 47.1%, 43.7%, and 17.9%; and the positive predictive values were 38.5%, 95.8%, 92.1%, and 40.0%. The serum anti-Toxocara IgG titer also significantly decreased following albendazole treatment. CONCLUSIONS: OT is a common cause of intraocular inflammation in the tertiary hospital setting. Considering that OT is more prevalent in intermediate and posterior uveitis, and that the positive predictive value of the anti-Toxocara IgG assay is high, a routine test for anti-Toxocara IgG might be necessary for Korean patients with intermediate and posterior uveitis.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Animals ; Antibodies, Anti-Idiotypic/*blood ; Aqueous Humor/parasitology ; Child ; Enzyme-Linked Immunosorbent Assay ; Eye Infections, Parasitic/*diagnosis/epidemiology/parasitology ; Female ; Follow-Up Studies ; Humans ; Immunoglobulin G/blood/*immunology ; Incidence ; Male ; Middle Aged ; Republic of Korea/epidemiology ; Retrospective Studies ; *Tertiary Care Centers ; Toxocara canis/*immunology/isolation & purification ; Toxocariasis ; Uveitis/*diagnosis/epidemiology/parasitology ; Young Adult