OBJECTIVETo develop a monoclonal antibody (mAb) directed to FVIII C2 domain and investigate its effect on FVIII activity.

METHODSFVIII C2 protein was expressed in E. coli and purified. A murine antihuman FVIII C2 domain mAb SZ-132 was developed by standard hybridoma technology and characterized. In coagulation assays, different concentrations of SZ-132 were incubated with freshly collected pooled human plasma and the residual activity of FVIII and activated partial thromboplastin time (APTT) were determined. The effects of SZ-132 on rhFVIII binding to purified human vWF, phosphatidylserine (PS) and platelets were assessed by enzyme linked immunosorbent assays (ELISA).

RESULTSSZ-132 could inhibit FVIII procoagulant activity in a dose-dependent manner within the concentrations of 0-25 microg/ml and the FVIII activity was completely inhibited on above 25 microg/ml. It could also prevent rhFVIII from binding to vWF, PS and platelets.

CONCLUSIONSSZ-132 is a neutralizing mAb against FVIII C2 domain and can inhibit FVIII procoagulant activity by preventing FVIII from binding to vWF and PS.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Neutralizing ; biosynthesis ; immunology ; Factor VIII ; immunology ; metabolism ; Humans ; Male ; Mice ; Mice, Inbred BALB C

OBJECTIVEScreening and characterizing high affinity completely humanized single-chain antibody (ScFv) against PreS1 of hepatitis B virus.

METHODSA combinatorial library of phage-displayed human ScFv, genes of which were derived from peripheral blood lymphocytes immunized by PreS1 of Hepatitis B Virus in vitro, was constructed. The library contained 7 10(8) clones.

RESULTSAfter 3 rounds panning, a high affinity (K=10(7) to 10(8) mol/L) ScFv specific to PreS1 was obtained. The V(H) belonged to human V(H4) family, and V(1) to V(4) by sequence analysis.

CONCLUSIONThis study suggests that the method of antigen stimulation in vitro is an expeditious way for the source of human immune antibody. And the ScFv may provide a more satisfactory therapy.

Antibodies, Monoclonal ; biosynthesis ; Antibody Affinity ; Hepatitis B Antibodies ; biosynthesis ; Hepatitis B Surface Antigens ; immunology ; Humans ; Peptide Library ; Protein Precursors ; immunology

OBJECTIVE: To prepare monoclonal antibody (MAb) against carboxy-terminus of E-phA4 and to analyze the immunological characteristics and significance of the antibody. METHODS: Mice were immunized with a chemically synthesized peptide that had been conjugated to KLH (keyhole limpet hemocyamin). A panel of antibodies specifically against EphA4 were obtained by hybridoma technique. The immunological properties and significance of the MAb were analyzed by immunological and immunochemistry techniques. RESULTS: A hybridoma cell line secreting anti-EphA4 MAb was established. The MAb reacted specifically with human, chicken and mouse EphA4, but did not cross-react with EphA5 and EphA7. The antibody could be used for immunochemical techniques such as ELISA, immunoprecipitation, Western blot and immunohistochemistry. CONCLUSION The anti-EphA4 MAb generated by immunizing a synthetic peptide possesses excellent immunological properties. MAb can be applied for immunological and immunohistochemical purpose and will become an important tool in the study of EphA4 and its ligand.
Animals ; Antibodies, Monoclonal ; biosynthesis ; Hybridomas ; Mice ; Mice, Inbred BALB C ; Peptide Fragments ; immunology ; Receptor, EphA4 ; immunology

Monoclonal antibodies (mAbs) contribute a lot to the development of numerous fields in life science as a pivotal tool in modern biological research. Development of the PCR methods and maturation of antibody production have made it possible to generate mAbs from single human B cells by single cell RT-PCR with successional cloning and expression in vitro. Compared to traditional monoclonal antibody technologies, single B cell technologies require relatively fewer cells, which are highly efficient in obtaining specific mAbs in a rapid way with preservation of the natural heavy and light chain pairing. With so many advantages, single B cell technologies have been proved to be an attractive approach for retrieval of naive and antigen-experienced antibody repertoires generated in vivo, design of rationale structure-based vaccine, evaluation and development of basic B cell biology concepts in health and autoimmunity, and prevention of infectious diseases by passive immunization and therapy for disorders. Accordingly, this review introduced recent progresses in the single B cell technologies for generating monoclonal antibodies and applications.
Antibodies, Monoclonal ; biosynthesis ; genetics ; immunology ; Antibody Specificity ; B-Lymphocytes ; cytology ; immunology ; metabolism ; Humans ; Immunologic Techniques

OBJECTIVETo develop human recombinant neutralizing IgG monoclonal antibodies to hepatitis A virus (HAV) by baculovirus expression system.

METHODSThe heavy and light chain genes of two human-derived neutralizing Fab antibodies to HAV were cloned into baculovirus expression vector Pac-kappa-Fc and Pac-L-Fc, and further expressed in insect cells as IgG antibodies. The IgG products were purified and well characterized.

RESULTSThe baculovirus expressed McAb HAFc16 fully retained the specificity of binding to hepatitis A virus and the competition with mouse anti-hepatitis A virus McAb using ELISA. The viral neutralization assay in vitro demonstrated the retention of antibody function after expression of the human antibody in insect cells. The other expressed antibody HAFc78 also has the neutralizing activity but it is directed against different epitopes of HAV when compared with HAFc16.

CONCLUSIONThe recombinant baculovirus/insect cells expressed human neutralizing IgG antibodies to hepatitis A virus retained all biological functions specific for hepatitis A virus. The results provided the possibility of using these antibodies to rapidly protect high risk or early exposure populations from hepatitis A virus infection.

Antibodies, Monoclonal ; biosynthesis ; immunology ; Baculoviridae ; genetics ; Hepatitis A virus ; immunology ; Hepatitis Antibodies ; biosynthesis ; immunology ; Humans ; Immunoglobulin Fab Fragments ; biosynthesis ; immunology ; Immunoglobulin G ; biosynthesis ; immunology ; Immunoglobulin Heavy Chains ; genetics ; Immunoglobulin Light Chains ; genetics ; Recombinant Proteins ; biosynthesis ; immunology

OBJECTIVETo prepare and identify monoclonal antibodies (mAbs) against Helicobacter pylori (Hp).

METHODSBALB/c mice were immunized with the supernatant and precipitation of cultured Hp after ultrasonication and mAbs were obtained by means of hybridoma technique. The resultant mAbs was evaluated for subtype, titer, affinity, and further identified with Lpp20, HspA, urease A, CagA, urease B, and catalase prepared by recombinant expression.

RESULTSTotally 34 hybridoma cell lines were established which secreted specific mAbs, including 31 against the supernatant and 3 against the precipitation of Hp, and the prepared mAbs showed specific reaction against Lpp20 (3 strains), HspA (2 strains), urease A (4 strains), CagA (1 strain), urease B (5 strains), and catalase (2 strains) antigens, respectively. The mAbs was all identified as immunoglobulin G1 (IgG1) and theirs titer in the culture supernatant and ascites was 1:16 to 1:32 and 1:32000 to 1:64000 respectively with affinity constants (K(aff)) ranging from 1 x 10(-10) to 5.2 x 10(-12) mol/L.

CONCLUSIONThe mAbs specially against Hp have been obtained, which may facilitate further study of detection and vaccine development of Hp.

Animals ; Antibodies, Bacterial ; biosynthesis ; immunology ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibody Specificity ; Female ; Helicobacter pylori ; immunology ; Humans ; Hybridomas ; immunology ; Mice ; Mice, Inbred BALB C

OBJECTIVETo obtain monoclonal antibodies (McAbs) against severe acute respiratory syndrome (SARS) associated coronavirus (SARS-CoV) nucleocapsid (N) protein to develop diagnostic test for SARS and study the pathogenesis of the disease.

METHODSBALB/c mice were immunized with purified N protein of SARS-CoV. Hybridoma cell lines secreting monoclonal antibodies against SARS-associated coronavirus nucleocapsid were established after cell fusion with mouse splenic cells and SP2/0 cells. The specificity of the McAbs obtained was examined by Western blot and indirect fluorescence assay. Epitopes reacted with the McAbs were preliminarily located through Western blot by expressing truncated N proteins.

RESULTSAfter cell fusion and three rounds of cell cloning, six hybridoma cell lines secreting monoclonal antibodies specifically against SARS-CoV nucleocapsid were obtained. Western blot and indirect fluorescence assay showed that the McAbs reacted specifically with nucleocapsid protein and SARS-CoV. Among the six McAbs, three recognize the epitopes located in the N-terminus of the protein, whereas the others reacted with those located in the C-terminus.

CONCLUSIONThe anti-SARS-CoV nucleocapsid McAbs were developed and these McAbs may be useful in the development of diagnosis assays and basic research of SARS.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Viral ; biosynthesis ; immunology ; Antibody Specificity ; Female ; Hybridomas ; secretion ; Mice ; Mice, Inbred BALB C ; Nucleocapsid Proteins ; immunology ; isolation & purification ; SARS Virus ; chemistry ; immunology

A novel human ScFv H12 against SARS-CoV has been selected from a SARS immune library. In order to produce a large amount of ScFv H12, pET28a-H12 expression vector was constructed and ScFv H12 was expressed at yield about 30% of total proteins in E. coli . Here two different refolding procedures were used to refold ScFv H12 from inclusion body: gel filtration chromatography and dilution. The results showed that ScFv H12 could be efficiently refolded by both procedures. However, the refolding via gel filtration was 1.5 time more effective than that of dilution. The affinity of ScFv H12 to SARS-CoV virion was detected as Kd = 73.5 nmol/mL.
Antibodies, Monoclonal ; biosynthesis ; genetics ; Antibodies, Viral ; immunology ; Escherichia coli ; genetics ; metabolism ; Humans ; Immunoglobulin Fragments ; biosynthesis ; genetics ; immunology ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; immunology ; Inclusion Bodies ; genetics ; immunology ; Protein Renaturation ; Recombinant Proteins ; biosynthesis ; chemistry ; immunology ; SARS Virus ; immunology

Platelet plays an important role in bleeding and thrombotic diseases. Humanized anti-platelet antibodies have great clinical effects in treatment of ITP and preventing thrombosis. The important role of platelet in bleeding and thrombotic diseases, the present status of development on study of humanized anti-platelet antibody and its application in treatment of bleeding and thrombotic diseases were summarized in this review.
Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; therapeutic use ; Autoantibodies ; immunology ; Blood Platelets ; immunology ; Humans ; Platelet Glycoprotein GPIIb-IIIa Complex ; biosynthesis ; immunology ; Platelet Glycoprotein GPIb-IX Complex ; immunology

Citrus tristeza virus (CTV) was purified from a citrus sample by a modified protocol, and the yield was about 1 mg from 100 g citrus tissues. Polyclonal antibody was prepared by immunizing rabbits with the purified CTV preparation with a titer 1:25600 in indirect ELISA test. Eighteen hybridoma-cell lines secreting monoclonal antibodies (MAbs) against CTV were screened after the fusion of mouse myeloma cells (SP2/0) with spleen cells from BALB/c immunized with the virus preparation. Four hybridoma-cell lines were selected randomly for later analysis. The results indicated that the titers of ascetic fluids against these hybridoma cell lines ranged from 1:51200 to 1:204800 in indirect ELISA, and their isotypes and subclasses were IgG2a for 2G and 3H and IgG2b for IE and 4H. These four Mabs were used to detect CTV in citrus samples in different sources. Results showed that TAS-ELISA with polyclonal antibody as trapping antibody and monoclonal antibody as testing antibody had a higher specificity and sensitivity than PAS-ELISA. Four Mabs showed different intensities of serological reaction with different CTV isolates. However, much work remains for realizing the characteristics and the serological relationships among these isolates.
Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Viral ; biosynthesis ; immunology ; Blotting, Western ; Citrus ; virology ; Closterovirus ; immunology ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Mice ; Mice, Inbred BALB C ; Rabbits