Antibodies ; immunology ; Antibody Formation ; Complement C4b ; immunology ; pharmacology ; Diagnosis ; Graft Rejection ; diagnosis ; immunology ; Humans ; Kidney Transplantation ; immunology ; Peptide Fragments ; immunology ; pharmacology ; Transplantation, Homologous ; immunology

OBJECTIVELeukemia is the most common hematopoietic malignancies in children. Chemotherapy is currently the primary modality of treatment for this fatal disease. Although chemotherapy is very effective in terms of cell killing, severe side effects such as severe infections, intracranial hemorrhage etc. are frequently encountered due to its poor selective damage between normal and malignant cells or tissues. Thus, a new therapy with highly selective killing of malignant cells which leaves the normal cells unaffected is desperately desired. The aim of this study was to investigate the targeting efficacy in vitro with a new clone of anti-human CD19 antibody immunotoxin 2E8-Genistein on B lineage leukemia cell line Nalm-6 cells and its mechanisms in order to provide the evidence of target therapy on B lineage leukemia and lymphoma.

METHODS2E8-Genistein immunotoxin was generated by conjugating Mab 2E8 with a tyrosine kinase inhibitor, Genistein (Gen) via the Sulfo-SANPAH, an ultra-violet sensitive reagent. Nalm-6, a CD19+ B cell leukemia cell line, was used as target cells, while Molt-3, a CD19-T cell leukemia cell line, was taken as the negative control. The morphology of the cells was observed under the reverted reversed light microscope and the viability was checked with either trypan blue exclusion or MTT methods. Two-color flow cytometry was applied to study the mechanism of cell killing.

RESULTSAfter 24 hours of culture, 2E8-Genistein showed marked target killing on Nalm-6 cells at nine different concentrations from 20 nmol/L through 100 nmol/L with cell survival rates from (71.8 +/- 7.9)% down to (16.6 +/- 12.9)%, respectively (n = 3), which were all significantly lower than that of control group (100 +/- 13.9)% (P < 0.05). The killing effect was even more significant when the concentration was over 80 nmol/L. The growth inhibition rates of this immunotoxin on Nalm-6 cells were 82%, 84% and 94%, respectively at 24, 48 and 72 hours of culture in a time dependent manner. Significant difference was observed between the cell growth curve of Nalm-6 cultured with 100 nmol/L of 2E8-Gen and those of Nalm-6 cultured with medium (blank), PBS (negative control) or the same concentration of pure 2E8 antibody (negative control) groups (F = 152.15, P = 2.15 x 10(-7)), but there was no significant difference among the three control groups (F = 1.51, P = 0.29). When Molt-3 cells were used as target cells, the cell growth curves of Molt-3 cultured with 2E8-Gen (100 nmol/L) and with negative control of blank did not show any significant difference (F = 0.34, P = 0.59). PI/FITC Annexin V double staining analysis with flow cytometry showed that the positive rate (33.45 +/- 8.77)% of early apoptosis on Nalm-6 cells induced by 100 nmol/L of 2E8-Genistein was significantly higher than that of negative control of blank (10.44% +/- 1.28%, t = -4.39, P = 0.001) at 24 hours of culture.

CONCLUSION2E8-Genistein immunotoxin can significantly target the Nalm-6 cells in vitro in a time response manner and the apoptosis induction is involved in the course of this killing effect.

Antibodies, Monoclonal ; immunology ; pharmacology ; Antigens, CD19 ; Apoptosis ; drug effects ; Cell Line, Tumor ; Flow Cytometry ; Genistein ; immunology ; pharmacology ; Humans ; Immunotoxins ; immunology ; pharmacology ; Leukemia, B-Cell ; immunology

OBJECTIVESTo study the effect of monoclonal antibody (McAb) against helicobacter pylori (Hp) ureB, 1F11 on platelet aggregation and activation, and its mechanism.

METHODSThe relativity between human platelet glycoproteins (GPs) and Hp ureB was identified by Western blot and FCM. Platelet aggregation was measured by turbidimetry, and P-selectin and TXB2 assay by ELISA.

RESULTS1F11 could bind to platelet GPIIIa, and ADP-induced platelet aggregation was inhibited by 1F11 in a dose-dependent manner. However, 1F11 had no effect on plasma P-selectin and TXB2 induced by ADP. The FCM results show that the positive rates of platelet binding to FITC-SZ21 was decreased from 99.5% to 77.4% after addition of 1F11.

CONCLUSIONMcAb against Hp ureB 1F11 inhibits platelet aggregation through binding to platelet GPIIIa but does not block platelet activation. There might be crossed-epitopes on Hp ureB and platelet GPIIIa, and Hp infection might be involved in ITP immunopathology.

Antibodies, Bacterial ; pharmacology ; Antibodies, Monoclonal ; pharmacology ; Bacterial Proteins ; immunology ; metabolism ; Helicobacter pylori ; immunology ; Humans ; Integrin beta3 ; immunology ; P-Selectin ; immunology ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Urease ; immunology ; Urokinase-Type Plasminogen Activator ; immunology

OBJECTIVETo study the regulation of Fc receptor expression by immune complexes (ICs) on neutrophils and U937 cells.

METHODSIgA ICs, IgG1 ICs, IgG2 ICs, IgG3 ICs, IgG4 ICs, and IgM ICs were incubated with neutrophils or U937 cells for 1 h. Then their surface Fc receptors were stained by anti-Fc gammaR I, anti-Fc gammaR II , anti-Fc gammaR III, and anti-Fc alphaR I monoclonal antibodies and analyzed by fluorescent activated cell sorting (FACS).

RESULTSIgG1 ICs and IgG3 ICs up-regulated Fc gammaR II and Fc gammaR III on U937 cells, Fc gammaR I and Fc alphaR I on neutrophils. Almost all ICs down-regulated Fc gammaR II on neutrophils.

CONCLUSIONSICs can regulate Fc receptor expression on neutrophils and U937 cells, among which IgG1 ICs and IgG3 ICs are most effective.

Antibodies, Anti-Idiotypic ; immunology ; Antibodies, Monoclonal ; pharmacology ; Antigen-Antibody Complex ; immunology ; metabolism ; Antigens, CD ; immunology ; Humans ; Immunoglobulin A ; classification ; immunology ; Immunoglobulin G ; chemistry ; classification ; immunology ; metabolism ; Neutrophils ; metabolism ; Receptors, Fc ; biosynthesis ; genetics ; Receptors, IgG ; immunology ; U937 Cells ; immunology

OBJECTIVETo study and compare the biologic activity of two anti-PSA/anti-CD3 bispecific single-chain antibodies.

METHODSFlow cytometry (FCM) was used to detect the binding activity of two antibodies to CD3-positive cell line Jurkat and prostate carcinoma cell line LNCaP. The effect of the two antibodies in mediating tumor cell lysis in vitro was determined by using the 51Cr-release test. For in vivo evaluation of the two antibodies activity, a nude mouse model was used. The mice were inoculated with LNCaP prostate cancer cells.

RESULTSFCM showed that both the antibodies could bind Jurkat and LNCaP cells with high specificity. The percentages of the cells bond by the bispecific single-chain antibodies were 56.3% and 55.4%, and those by the multivalent antibodies were 74.0% and 83.0% respectively. Both the antibodies mediated a specific lysis of LNCaP cells in vitro, with activated CTLs as effector cells, and significantly reduced tumor growth of nude mice in vivo as compared with the untreated controls and the group treated with CTLs only (P <0.05). The experiment also showed that the multivalent antibody had a better activity than the bispecific antibody in binding antigens, mediating lysis of LNCaP cells and reducing tumor growth (P < 0.05).

CONCLUSIONBoth the anti-PSA/anti-CD3 bispecific single-chain antibody and multivalent antibody have good biologic activity, and the formation of the tetramerization of single-chain antibody can improve its biologic activity.

Animals ; Antibodies, Anti-Idiotypic ; immunology ; Antibodies, Bispecific ; immunology ; pharmacology ; CD3 Complex ; immunology ; Cytotoxicity, Immunologic ; immunology ; Flow Cytometry ; Humans ; Jurkat Cells ; Male ; Mice ; Mice, Nude ; Prostate-Specific Antigen ; immunology ; Prostatic Neoplasms ; immunology ; pathology

Infectious bursal disease virus (IBDV) was inactivated by two different chemicals--formaldehyde and binary ethylenimine (BEI). Formaldehyde was used at 0.1% and 0.2%, while BEI was used at concentrations of 0.001 and 0.002 mol/L. These four vaccines were tested for their efficiency in generating humoral immune response in different groups of broiler chicks. Both BEI-inactivated vaccines gave relatively higher antibody titers and were almost twice as efficient as formaldehyde-inactivated ones.
Animals ; Antibodies, Viral ; blood ; Aziridines ; pharmacology ; Chickens ; Formaldehyde ; pharmacology ; Infectious bursal disease virus ; immunology ; Vaccination ; Vaccines, Inactivated ; immunology ; Viral Vaccines ; immunology

In order to study how to activate T cells and their immunological characteristics, the anti-CD3 and anti-CD28 McAbs were used to stimulate PBMNC, then their related immunological changes, such as lymphocyte transformation function, the percentage of CD8(+)CD25(+) cells and TGF-beta expression were deleted by lymphocyte transformation assay, flow cytometry and RT-PCR respectively. The results showed that in costimulation with anti-CD28 antibody stimulation, the activity of anti-CD3 antibody was significantly enhanced, the ratio of CD8(+)CD25(+) cells of T cells was obviously increased, while TGF-beta expression was down-regulated. It was concluded that the anti-CD28 antibody costimulation could provide stimulatory signal II, which make T cells more active, while the expression of TGF-beta significantly down-regulated.
Antibodies, Monoclonal ; pharmacology ; CD28 Antigens ; immunology ; CD3 Complex ; immunology ; Down-Regulation ; Humans ; Leukocytes, Mononuclear ; immunology ; metabolism ; Lymphocyte Activation ; drug effects ; T-Lymphocytes ; immunology ; Transforming Growth Factor beta ; biosynthesis

In order to investigate the effect of anti-TGF-beta1 monoclonal antibody on the expansion of cord blood CD34(+) cells, the purified cord blood CD34(+) cells were divided into three groups: blank control group: purified cord blood CD34(+) cells cultured on day 0; control group: cells cultured for 3 days in the culture system, containing SCF, IL-3, IL-6 and FLT3-L; test group: cells cultured for 3 days in the same culture system as control group, but with anti-TGF-beta1 monoclonal antibody. The mononuclear cell counting (MNC), the expression of CD34 and c-kit, and CFU-GEMM, BFU-E and CFU-GM counting were detected in all three groups. The result showed that the expansion of MNCs, CD34(+) cells and CD34(+)c-kit(+) cells in test group [(2.35 +/- 0.25) x 10(5), (1.16 +/- 0.29) x 10(5), (1.09 +/- 0.26) x 10(5)] was significantly higher than that in control group [(1.25 +/- 0.13) x 10(5), (0.55 +/- 0.19) x 10(5), (0.51 +/- 0.2) x 10(5)](p < 0.01). The expansion of more primitive CD34(+)c-kit(-) subpopulation in test group [(12.95 +/- 3.17) x 10(3)] was even significantly higher than in control group (1.71 +/- 0.83) x 10(3) (p < 0.01). Colony forming assay showed that the number of earlier progenitor colony CFU-GEMM, BFU-E in test group [(16.3 +/- 4.72) x 10(3), (60.5 +/- 20.96) x 10(3)] was higher than that in control group [(5.0 +/- 2.58) x 10(3), (16.25 +/- 7.93) x 10(3)] (p < 0.01). The number of relatively mature CFU-GM between test group and control group was not statistical significance [(6.33 +/- 2.85) x 10(3) vs (4.0 +/- 2.28) x 10(3)](p > 0.05), but both were higher than that in blank group (0.75 +/- 0.29) x 10(3). These results demonstrated that anti-TGF-beta1 monoclonal antibody promoted the expansion of MNC and CD34(+) cells, and even more marked expansion of the more primitive progenitor cells-CD34(+)c-kit(-) cells. Meanwhile, it enhanced the output of more immature colony CFU-GEMM and BFU-E, but had no evident influence on the mature myeloid colony CFU-GM. It is concluded that the anti-TGF-beta1 monoclonal antibody can synergize other cytokines to enhance the proliferation of cord blood CD34(+) progenitor cells effectively, and it is more important that can reserve more primitive progenitor cells.
Antibodies, Monoclonal ; immunology ; pharmacology ; Antigens, CD34 ; immunology ; metabolism ; Cell Division ; drug effects ; Cells, Cultured ; Fetal Blood ; cytology ; drug effects ; immunology ; Humans ; Transforming Growth Factor beta1 ; immunology

The study was purposed to investigate the effects of humanized recombined CD25 monoclonal antibody (rhCD25MAb) on activation and proliferation of T lymphocytes in vitro. Peripheral blood mononuclear cells (PBMNC) were incubated with phytohemagglutinin (PHA). Before or after T cell activation, the cells were cultured with or without rhCD25MAb or cyclosporine A (CsA) in vitro. After 72 hours incubation, the proliferation of lymphocytes was analyzed by MTT assay. The expression of CD3 and CD25 antigens on T lymphocytes were detected by flow cytometry. The levels of sIL-2R in the supernatants were determined with ELISA. The results showed that both rhCD25MAb and CsA could inhibit the proliferation of T lymphocytes significantly in concentration-dependent manner and CsA was more efficient than rhCD25MAb. Both rhCD25MAb and CsA could also decrease the levels of sIL-2R in the supernatant and inhibit the expression of CD25 antigen on T lymphocytes. The level of sIL-2R and the expression of CD25 on T lymphocytes decreases more profoundly in rhCD25MAb group. It is concluded that rhCD25MAb shows strong immunosuppressive activity both before and after T cell activation, suggesting that this agent may be useful in not only prophylaxis but also the treatment of acute graft-versus-host disease.
Antibodies, Monoclonal ; pharmacology ; CD3 Complex ; biosynthesis ; genetics ; Cell Proliferation ; Cells, Cultured ; Cyclosporine ; pharmacology ; Humans ; Immunosuppressive Agents ; pharmacology ; Interleukin-2 Receptor alpha Subunit ; biosynthesis ; genetics ; immunology ; Lymphocyte Activation ; immunology ; Receptors, Interleukin-2 ; analysis ; Recombinant Proteins ; immunology ; pharmacology ; T-Lymphocytes ; immunology

BACKGROUNDWe have previously developed and characterized a monoclonal anti-idiotype antibody, designated 6B11, which mimics an ovarian carcinoma associated antigen OC166 - 9 and whose corresponding monoclonal antibody is COC166 - 9 (Ab1). In this study, we evaluate the humoral immune responses induced by the fusion protein 6B11 single-chain variable fragment (scFv)/human granulocyte macrophage colony-stimulating factor (hGM-CSF) and 6B11scFv in BALB/c mice.

METHODSThe fusion protein 6B11scFv/hGM-CSF was constructed by fusing a recombinant single-chain variable fragment of 6B11scFv to GM-CSF. BALB/c mice were administrated by 6B11scFv/hGM-CSF and 6B11scFv, respectively.

RESULTSThe fusion protein 6B11scFv/hGM-CSF retained binding to the anti-mouse F (ab) 2' and was also biologically active as measured by proliferation of human GM-CSF dependent cell TF1 in vitro. After immunization with the 6B11scFv/hGM-CSF and 6B11ScFv, BALB/c mice showed significantly enhanced Ab3 antibody responses to 6B11scFv/hGM-CSF compared with the 6B11scFv alone. The level of Ab3 was the highest after the first week and maintained for five weeks after the last immunization. Another booster was given when the Ab3 titer descended, and it would reach to the high level in a week.

CONCLUSIONThe fusion protein 6B11scFv/hGM-CSF can induce humoral immunity against ovarian carcinoma in vivo. We also provide the theoretical foundation for the application of the fusion protein 6B11scFv/hGM-CSF for active immunotherapy of ovarian cancer.

Animals ; Antibodies, Anti-Idiotypic ; immunology ; Antibodies, Neoplasm ; blood ; Cancer Vaccines ; immunology ; Female ; Granulocyte-Macrophage Colony-Stimulating Factor ; pharmacology ; Humans ; Immunization ; Immunoglobulin Fragments ; immunology ; Mice ; Mice, Inbred BALB C ; Ovarian Neoplasms ; immunology ; Recombinant Fusion Proteins ; immunology