Objective To prepare monoclonal antibodies against bovine CD4 and identify their basic biological characteristics. Methods Recombinant bovine CD4 (rHis-BoCD4 and rGST-BoCD4) was successfully expressed and purified by constructing a prokaryotic plasmid of bovine CD4 gene. The bovine CD4 monoclonal antibody was produced using hybridoma technology. The subtype and potency of the monoclonal antibody were identified and analyzed by ELISA, while specificity was analyzed through indirect immunofluorescence assay (IFA) and Western-blot. Results Four hybridoma cell lines, namely, 1H4, 6A10, 3F9 and 4G10, stably secreting monoclonal antibodies against BoCD4 were successfully obtained. The subclasses of the monoclonal antibodies subclass 6A10 was IgG2b and the rest of the monoclonal antibodies were of IgM type. Western-blot results showed that the four anti-bovine CD4 mAb strains were able to specifically bind to the bovine CD4 protein expressed in vitro. Indirect immunofluorescence assay showed that four monoclonal antibodies were able to specifically recognize the natural bovine CD4 protein. Flow cytometry assay showed that 3F9 was best to recognize bovine natural CD4 molecules. Conclusion Four monoclonal antibody strains with high specificity to natural bovine CD4 protein were successfully prepared, which lays the foundation for the subsequent studies on the function of bovine CD4 and diagnosis and treatment of bovine T-lymphocyte diseases.
Animals ; Antibodies, Monoclonal/isolation & purification* ; Cattle ; CD4 Antigens/genetics* ; Hybridomas/immunology* ; Antibody Specificity/immunology* ; Mice ; Mice, Inbred BALB C ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique, Indirect

OBJECTIVE: To observe the clinical effect of plasma exchange and tocilizumab in treatment of patients with severe coronavirus disease 2019 (COVID-19). METHODS: Six patients with severe COVID-19 admitted in First Affiliated Hospital of Bengbu Medical College from January 25 to February 25, 2020. Three patients were treated with plasma exchange and three patients were treated with tocilizumab. The effect on excessive inflammatory reaction of plasma exchange and tocilizumab was observed. RESULTS: The C-reactive protein (CRP) and IL-6 levels were significantly decreased and the lymphocyte and prothrombin time were improved in 3 patients after treatment with plasma exchange; while inflammation level was not significantly decreased, and lymphocyte and prothrombin time did not improve in 3 patients treated with tocilizumab. CONCLUSIONS For severe COVID-19 patients with strong inflammatory reaction, plasma exchange may be preferred.
Antibodies, Monoclonal, Humanized ; administration & dosage ; Betacoronavirus ; isolation & purification ; Coronavirus Infections ; blood ; immunology ; therapy ; Cytokine Release Syndrome ; therapy ; Humans ; Pandemics ; Plasma Exchange ; standards ; Pneumonia, Viral ; blood ; immunology ; therapy ; Prothrombin Time ; Treatment Outcome

Feline leukemia virus (FeLV) causes a range of neoplastic and degenerative diseases in cats. To obtain a more sensitive and convenient diagnosis of the disease, we prepared monoclonal antibodies specific for the FeLV p27 to develop a rapid diagnostic test with enhanced sensitivity and specificity. Among these antibodies, we identified two clones (hybridomas 8F8B5 and 8G7D1) that specifically bound to FeLV and were very suitable for a diagnostic kit. The affinity constants for 8F8B5 and 8G7D1 were 0.35 x 10(9) and 0.86 x 10(9), respectively. To investigate the diagnostic abilities of the rapid kit using these antibodies, we performed several clinical studies. Assessment of analytical sensitivity revealed that the detection threshold of the rapid diagnostic test was 2 ng/mL for recombinant p27 and 12.5 x 10(4) IU/mL for FeLV. When evaluating 252 cat sera samples, the kit was found to have a kappa value of 0.88 compared to polymerase chain reaction (PCR), indicating a significant correlation between data from the rapid diagnostic test and PCR. Sensitivity and specificity of the kit were 95.2% (20/21) and 98.5% (257/261), respectively. Our results demonstrated that the rapid diagnostic test would be a suitable diagnostic tool for the rapid detection of FeLV infection in cats.
Animals ; Antibodies, Monoclonal/blood ; Cats ; Diagnostic Tests, Routine/*veterinary ; Female ; Gene Products, gag/*blood ; Leukemia Virus, Feline/immunology/*isolation & purification ; Leukemia, Feline/*diagnosis ; Mice, Inbred BALB C ; Sensitivity and Specificity

OBJECTIVETo identify the self-preparation monoclonal antibody which target to clenbuterol, and set up the standard curve to clenbuterol (CL) detection.

METHODSThe affinity constants and activity of the monoclonal antibody which target to CL were determined by ELISA. ELISA was also used to confirm whether the monoclonal antibody had any across-reaction with BSA and CL analogues. The rat ascites which contains the monoclonal antibody target to CL was purified by (NH4)2SO4 salt-out method and further by affinity column. At last, the CL detection standard curve which based on indirect competition ELISA was established.

RESULTSThe ELISA experiment showed that the antibody titer was 10(6) and the monoclonal antibody affinity constants was 2.90 x 10(10) L/mol. The result of the indirect competition ELISA confirmed that the monoclonal antibody had no cross-reaction with BSA and a few kind of CL analogue. CL detection standard curve based on indirect competition ELISA was established, which R2 was 0.9812, and the lowest detectable limit was 1.0 ng/ml.

CONCLUSIONThe standard curve based on indirectly competitioning ELISA was established. The self-preparation monoclonal antibody which target to CL has high affinity and high specific to CL, which had established the foundation to the advanced development of the CL immune test paper and CL ELISA kit.

Animals ; Antibodies, Monoclonal ; chemistry ; isolation & purification ; Antibody Affinity ; Clenbuterol ; immunology ; Cross Reactions ; Enzyme-Linked Immunosorbent Assay ; Limit of Detection ; Rats

A field applicable diagnostic technique, the dipstick assay, was evaluated for its sensitivity and specificity in diagnosing human Schistosoma mansoni infection. A monoclonal antibody (mAb) against S. mansoni adult worm tegumental antigen (AWTA) was employed in dipstick and sandwich ELISA for detection of circulating schistosome antigen (CSA) in both serum and urine samples. Based on clinical and parasitological examinations, 60 S. mansoni-infected patients, 30 patients infected with parasites other than schistosomiasis, and 30 uninfected healthy individuals were selected. The sensitivity and specificity of dipstick assay in urine samples were 86.7% and 90.0%, respectively, compared to 90.0% sensitivity and 91.7% specificity of sandwich ELISA. In serum samples, the sensitivity and specificity were 88.3% and 91.7% for dipstick assay vs. 91.7% and 95.0% for sandwich ELISA, respectively. The diagnostic efficacy of dipstick assay in urine and serum samples was 88.3% and 90.0%, while it was 90.8% and 93.3% for sandwich ELISA, respectively. The diagnostic indices of dipstick assay and ELISA either in serum or in urine were statistically comparable (P>0.05). In conclusion, the dipstick assay offers an alternative simple, rapid, non-invasive technique in detecting CSA or complement to stool examinations especially in field studies.
Animals ; Antibodies, Helminth/diagnostic use/isolation & purification ; Antibodies, Monoclonal/diagnostic use/isolation & purification ; Antigens, Helminth/*blood/*urine ; Diagnostic Tests, Routine/*methods ; Humans ; Immunoassay/methods ; Parasitology/*methods ; *Point-of-Care Systems ; Schistosoma mansoni/immunology/*isolation & purification ; Schistosomiasis mansoni/*diagnosis ; Sensitivity and Specificity

To identify human monoclonal HIV-l-neutralizing antibodies from an HIV-1 CRF07BC specific phage display antibody library by cell-based screening. 293T cells were transfected by pCH064. 2-Env plas mid and then used to biopan the phage antibody library. The positive phage clones were screened by cell based ELISA and sequenced for the variable region of heavy (VH) and light (VL) chains. The expressed Fabs were purified by Ni(+2) -NTA column and analyzed by SDS-PAGE. The cell- and gp120 protein-based ELISA as well as flow cytometry were used to measure Fab's binding activity. The neutralizing activity of Fabs was assessed by HIV-1 pseudoviruses. After 4-round biopanning, the binding phages to transfected cells were enriched about 650-folds. A total of 28 positive clones were screened out by cell ELISA and sequence analysis identified 5 different Fabs possessing unique VH and VL (2801, 2837, 2863, 2870 and 2920). Interestingly, these Fabs reacted with the Env-transfected 293T cells but not soluble gp120 proteins, suggesting that they might target conformation-dependent epitopes presenting on viral Env complex. We found that three Fabs (2801, 2863, 2870) exhibited potent neutralizing activity against CRF07_BC isolate CH120. 6 with IC50 of 2.24, 0.89 and 3.09 microg/mL respectively, and that 2801 and 2863 cross-neutral ized the subtype B isolate SF162 at IC50 of 0.69 and 3.52 microg/mL respectively. In conclusion, the HIV-1 Env-transfected 293T cells can be used to efficiently enrich and screen the phage antibody library and isolate human monoclonal HIV-1-neutralizing Fabs that target the Env complex-dependent conformational epitopes. Therefore, our studies provide a powerful platform for exploring the mechanism of HIV-1 neu tralizing response and for designing AIDS vaccines.
Antibodies, Monoclonal ; genetics ; immunology ; Antibodies, Neutralizing ; genetics ; immunology ; Enzyme-Linked Immunosorbent Assay ; methods ; HEK293 Cells ; HIV Antibodies ; genetics ; immunology ; HIV Envelope Protein gp120 ; genetics ; immunology ; HIV Infections ; immunology ; virology ; HIV-1 ; genetics ; immunology ; isolation & purification ; Humans ; Immunoglobulin Fab Fragments ; genetics ; immunology ; Neutralization Tests ; Peptide Library ; Transfection

This study was purposed to prepare eukaryotic expression vector of recombinant human platelet CD36 gene. The total RNA was extracted from human liver tissue and the cDNA encoding human platelet CD36 antigen extracellular region (Gly30-Asn439) was amplified by RT-PCR. The cDNA was cloned into the prokaryotic expression vector pMD18 and the recombinant vector was transformed into E. coli DH5α. The positive recombinant pMD18-CD36 plasmid was screened. After sequencing, this combinant vector was inserted into the transient eukaryotic expression vector pTE2, the pTE2-s-CD36-10 His transient eukaryotic expression vector was constructed. The recombinant CD36 Gly30-Asn439 expressed by HEK-293 cells was purified with Ni(2+) 2NTA chromatography. The results showed that 1.4 kb cDNA was amplified by RT-PCR, sequencing of the cDNA indicated the sequence was exactly the same to that in Genbank NM_001001547.2. The HEK293 cells with the plasmid were transfected, and SDS-PAGE confirmed that the transfect HEK293 cells expressed the human CD36 antigen extracellular protein fragments. Western-blot showed that the monoclonal antibody could recognize the recombinant CD36 with the sensitivity of 8 ng. It is concluded that the CD36 Gly30-Asn439 can be highly expressed by human embryonic kidney cells (HEK293), and the monoclonal antibody with biological activity has been obtained, which provide the basis for further study on platelet transfusion refractoriness.
Animals ; Antibodies, Monoclonal ; genetics ; isolation & purification ; Blood Platelets ; immunology ; Blotting, Western ; CD36 Antigens ; genetics ; immunology ; DNA, Complementary ; Genetic Vectors ; Humans ; Mice ; Plasmids ; Platelet Transfusion ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVEThis paper aims to develop a monoclonal antibodies (MAbs)- based ELISA for detecting Chlamydophila pneumoniae (C. pneumoniae) antigens in humans with the variable domains (VD) 2 and 3 of the major outer membrane protein (MOMPVD2-VD3) and to assess its sensitivity and specificity by comparing with a widely used MAb that is able to recognize the elementary bodies of C. pneumoniae.

METHODSMOMPVD2-VD3 were overexpressed in Escherichia coli and purified by affinity chromatography. Mice were immunized with the recombinant antigen, and hybridomas secreting MAbs were screened. Three stable hybridomas clones were selected and named 5D6, 7G3, and 8C9. The MAbs-based ELISA was scrutinized for species-specific recognition with a number of human throat swab samples from Group I (156 patients with typical respiratory illness clinically confirmed before) and Group II (57 healthy donors).

RESULTSIn Group I, 55 positive cases were detected by anti-EB MAb-based ELISA, 51 cases were positive by MAbs 5D6-based ELISA, and 33 and 38 cases were positive by MAb 8C9 and 7G3-based ELISA respectively. Of the 57 samples from Group II "healthy donors", 5 were positive and 52 were negative with both anti-EB and 5D6-based tests, while 2 and 3 positive cases were identified by the other two MAb-based ELISAs respectively.

CONCLUSIONThe novel MOMPVD2-VD3 MAb-based assay may have higher specificity than the anti-EB MAb, which may possibly be used as an alternative tool for the diagnosis of C. pneumoniae infection.

Animals ; Antibodies, Monoclonal ; Bacterial Outer Membrane Proteins ; immunology ; Chlamydophila Infections ; diagnosis ; microbiology ; Chlamydophila pneumoniae ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; methods ; Humans ; Mice ; Protein Structure, Tertiary

OBJECTIVETo prepare monoclonal antibodies against a newly discovered and conserved linear epitope of Rabies virus nucleoprotein and to use them in a rabies diagnostic test.

METHODSSynthetic peptide containing the epitope was used as immunogen to prepare hybridoma cell lines by classical hybridoma technology. Anti-peptide monoclonal antibodies produced in ascites of inoculated Balb/c mice were labeled with fluorescein isothiocyanate (FITC) after purification and used in fluorescent antibody test (FAT).

RESULTSTwo positive hybridoma cell lines, RVNP-mAb1-CL and RVNP-mAb2-CL, were obtained. RVNP- mAb1-CL produced a higher concentration of monoclonal antibody RVNP-mAb1 in Balb/c ascites. FITC-labeled RVNP-mAb1 showed correct results on certain Rabies virus-positive canine brain tissue samples and cells of a small subclone of baby hamster kidney 21 cell line (BSR).

CONCLUSIONFITC-labeled RVNP-mAb1 has potential application for laboratory diagnosis of rabies.

Animals ; Antibodies, Monoclonal ; isolation & purification ; Cell Line ; Cricetinae ; Dogs ; Epitopes ; Fluorescein-5-isothiocyanate ; Fluorescent Dyes ; Hybridomas ; Mice ; Mice, Inbred BALB C ; Nucleoproteins ; immunology ; Rabies virus ; immunology ; Viral Proteins ; immunology

This study measured the clinical prevalence of peste des petits ruminants (PPR) among sheep and goats in India between 2003 and 2009 by analyzing clinical samples from suspected cases of PPR that were submitted to the Rinderpest and Allied Disease Laboratory, Division of Virology, IVRI, Mukteswar for PPR diagnosis. PPR outbreaks were confirmed by detecting PPR virus (PPRV)-specific antigen in the clinical samples. Clinical samples (blood, nasal swabs, spleen, lymph node, kidney, liver, intestine, and pooled tissue materials) were taken from a total of 592 sheep and 912 goats in different states of India and screened for the presence of PPRV antigen using a monoclonal antibody-based sandwich ELISA kit. A total of 20, 38, and 11 laboratory-confirmed PPR outbreaks occurred among sheep, goat, and combined sheep and goat populations, respectively. Our findings provide evidence of widespread PPR endemicity in India. The underlying reasons could be variations in husbandry practices in different geographical regions, agro-climatic conditions, and livestock migration. Furthermore, decrease in the number of PPR outbreaks over time might be due to the effectiveness of current live PPR vaccines and timely vaccination of target species. Vaccination against PPR has been practiced in India since 2002 to control this disease.
Animals ; Antibodies, Monoclonal/immunology ; Antigens, Viral/*blood ; Disease Outbreaks/*veterinary ; Enzyme-Linked Immunosorbent Assay/veterinary ; Goat Diseases/*epidemiology/immunology/prevention & control ; Goats ; India/epidemiology ; Nucleocapsid Proteins/immunology ; Peste-des-Petits-Ruminants/epidemiology/immunology/prevention & control/*veterinary ; Peste-des-petits-ruminants virus/*immunology/isolation & purification ; Prevalence ; Risk Factors ; Seasons ; Sheep ; Sheep Diseases/*epidemiology/immunology/prevention & control ; Vaccination/veterinary ; Viral Vaccines/*immunology/therapeutic use