This study sought to construct a recombinant vector that expresses anti-GD2/anti-CD16 bispecific single-chain antibody(sc-BsAb), and to assess its biological activities. The anti-GD2 gene and the anti-CD16 gene (NM3E2) were obtained using PCR amplification technique, and then the fusion gene was constructed by overlapping PCR. The sc-BsAb gene was subcloned into the pET-22b(+) plasmid from the pMD18-T easy vector by digestion with NcoI, Hind III restriction endonucleases, whose sites exist in both the vectors. Then the combinant plasmids were transferred into E. coli BL21 (DE3). The expression product in the periplasmic was analyzed by both SDS-PAGE and Western blot technique, then was purified with Ni2+ -NTA superflow affinity chromatography. It was demonstrated that the linker in the sc-BsAb fusion protein is SerGly4Ser. and the molecular is 53 KD.
Antibodies, Bispecific ; biosynthesis ; genetics ; Antibodies, Neoplasm ; biosynthesis ; genetics ; Base Sequence ; Cell Line, Tumor ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Gangliosides ; immunology ; HeLa Cells ; Humans ; Melanoma ; pathology ; Molecular Sequence Data ; Receptors, IgG ; immunology ; Recombinant Fusion Proteins ; biosynthesis ; genetics

Prostaglandin E2(PGE2) has been implicated as an immunosuppressive agent and plasma levels of PGE2 are elevated in patients sustaining thermal injury. We examined the effect of 10(-7) M prostaglandin E2(PGE2) on human polymorphonuclear leukocytes (PMN) to determine whether it directly inhibits stimulated responses of these cells. At this concentration, PGE2 alone was incapable of stimulating PMN intracellular hydrogen peroxide production (indirectly assayed by fluorescence of 2',7'ichlorofluorescin) or expression of the PMN CD11b/CD16 surface glycoproteins. PMN incubated in the presence of the soluble stimul phorbol myristate acetate(PMA, 100 ng/ml) or recombinant human C5a(rHC5a, 10(-8) M) generated significant amounts of hydrogen peroxide, increased their CD11b expression and decreased their CD16 expression. Pre-incubation of cells with PGE2 caused significant inhibition of all the observed changes stimulated by rHC5a. In contrast, events stimulated by PMA were not affected by preincubation of cells with PGE2. We conclude that PGE2, in concentrations identical to those found in the plasma of patients with burn injuries, is capable of selectively inhibiting some stimulated events and phenotypic expression of PMN in vitro study.
Dinoprostone/*pharmacology ; Dose-Response Relationship, Drug ; Human ; Hydrogen Peroxide/metabolism ; Immunosuppressive Agents/*pharmacology ; Macrophage-1 Antigen/biosynthesis ; Neutrophils/*drug effects/immunology ; Receptors, IgG/biosynthesis ; Support, Non-U.S. Gov't ; Temperature ; Tetradecanoylphorbol Acetate/pharmacology ; Time Factors

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

This study was aimed to evaluate expression levels of CD166, Fas and apoptosis-related proteins in bone marrow neutrophils of PNH patients and normal controls, and to analyze their correlation in order to explore whether exist apoptosis abnormality in BM neutrophils of PNH patients. The expression levels of CD16b, Fas and Bax, Bcl-2 in BM neutrophils of PNH patients and normal controls were assayed by flow cytometry; the difference of expression levels between patients and controls, and expression correlation between CD16b and apoptosis-related proteins were compared. The results showed that (1) the expression levels of CD16b on BM neutrophils of patients and controls were (20.36 +/- 9.05)% and (71.34 +/- 26.8)% respectively (P = 0.01); (2) the expression levels of CD95 on BM neutrophils of patients and controls were (62.83 +/- 32.11)% and (48.00 +/- 38.52)% respectively, there were no significant difference between CD95 expressions in BM neutrophils of PNH patients and controls and no significant correlation between expression of CD95 and CD16b on BM neutrophils of PNH patients (P > 0.05); (3) the expression levels of Bcl-2 in BM neutrophil cytoplasma of patients and controls were (8.64 +/- 5.40)% and (16.82 +/- 15.39)% respectively, there were no significant difference between Bcl-2 expression of patients and controls, and no significant correlation between the expression of Bcl-2 and CD16b in BM neutrophil cytoplasma of PNH patients (P > 0.05); (4) the expression levels of Bax in BM neutrophil cytoplasma of patients and control were (30.47 +/- 22.15)% and (48.47 +/- 15.99)% respectively, there were no significant difference between the Bax expressions of patients and controls, and no significant correlation between the Bax and CD16b expressions in BM neutrophil cytoplasma of PNH patients. In conclusion, BM neutrophils of PNH patients expressed apoptosis-related CD95, Bcl-2 and Bax without significant difference from the normal controls, and without significant correlation with the CD16b expression. It is suggested that the cell growth and decrease of PNH patients possibly are independent of abnormal apoptosis.
Adolescent ; Adult ; Apoptosis Regulatory Proteins ; biosynthesis ; Bone Marrow Cells ; metabolism ; pathology ; Female ; Flow Cytometry ; GPI-Linked Proteins ; Hemoglobinuria, Paroxysmal ; metabolism ; pathology ; Humans ; Male ; Middle Aged ; Neutrophils ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; Receptors, IgG ; biosynthesis ; bcl-2-Associated X Protein ; biosynthesis ; fas Receptor ; biosynthesis

Differentiated HL-60 is an effector cell widely used for the opsonophagocytic-killing assay (OPKA) to measure efficacy of pneumococcal vaccines. We investigated the correlation between phenotypic expression of immunoreceptors and phagocytic ability of HL-60 cells differentiated with N,N-dimethylformamide (DMF), all-trans retinoic acid (ATRA), or 1alpha, 25-dihydroxyvitamin D3 (VitD3) for 5 days. Phenotypic change was examined by flow cytometry with specific antibodies to CD11c, CD14, CD18, CD32, and CD64. Apoptosis was determined by flow cytometry using 7-aminoactinomycin D. Function was evaluated by a standard OPKA against serotype 19F and chemiluminescence-based respiratory burst assay. The expression of CD11c and CD14 gradually increased upon exposure to all three agents, while CD14 expression increased abruptly after VitD3. The expression of CD18, CD32, and CD64 increased during differentiation with all three agents. Apoptosis remained less than 10% until day 3 but increased after differentiation by DMF or ATRA. Differentiation with ATRA or VitD3 increased the respiratory burst after day 4. DMF differentiation showed a high OPKA titer at day 1 which sustained thereafter while ATRA or VitD3-differentiated cells gradually increased. Pearson analysis between the phenotypic changes and OPKA titers suggests that CD11c might be a useful differentiation marker for HL-60 cells for use in pneumococcal OPKA.
Antibodies, Bacterial/immunology ; Antigens, CD11c/metabolism ; Antigens, CD14/metabolism ; Antigens, CD18/metabolism ; Apoptosis/*immunology ; Biological Assay ; Cell Differentiation ; Cell Line, Tumor ; Cholecalciferol/pharmacology ; Dimethylformamide/pharmacology ; Flow Cytometry ; HL-60 Cells ; Humans ; Phagocytosis/*immunology ; Pneumococcal Vaccines/*immunology ; Receptors, IgG/metabolism ; Receptors, Immunologic/*biosynthesis ; Respiratory Burst/immunology ; Streptococcus pneumoniae/*immunology ; Tretinoin/pharmacology

Differentiated HL-60 is an effector cell widely used for the opsonophagocytic-killing assay (OPKA) to measure efficacy of pneumococcal vaccines. We investigated the correlation between phenotypic expression of immunoreceptors and phagocytic ability of HL-60 cells differentiated with N,N-dimethylformamide (DMF), all-trans retinoic acid (ATRA), or 1alpha, 25-dihydroxyvitamin D3 (VitD3) for 5 days. Phenotypic change was examined by flow cytometry with specific antibodies to CD11c, CD14, CD18, CD32, and CD64. Apoptosis was determined by flow cytometry using 7-aminoactinomycin D. Function was evaluated by a standard OPKA against serotype 19F and chemiluminescence-based respiratory burst assay. The expression of CD11c and CD14 gradually increased upon exposure to all three agents, while CD14 expression increased abruptly after VitD3. The expression of CD18, CD32, and CD64 increased during differentiation with all three agents. Apoptosis remained less than 10% until day 3 but increased after differentiation by DMF or ATRA. Differentiation with ATRA or VitD3 increased the respiratory burst after day 4. DMF differentiation showed a high OPKA titer at day 1 which sustained thereafter while ATRA or VitD3-differentiated cells gradually increased. Pearson analysis between the phenotypic changes and OPKA titers suggests that CD11c might be a useful differentiation marker for HL-60 cells for use in pneumococcal OPKA.
Antibodies, Bacterial/immunology ; Antigens, CD11c/metabolism ; Antigens, CD14/metabolism ; Antigens, CD18/metabolism ; Apoptosis/*immunology ; Biological Assay ; Cell Differentiation ; Cell Line, Tumor ; Cholecalciferol/pharmacology ; Dimethylformamide/pharmacology ; Flow Cytometry ; HL-60 Cells ; Humans ; Phagocytosis/*immunology ; Pneumococcal Vaccines/*immunology ; Receptors, IgG/metabolism ; Receptors, Immunologic/*biosynthesis ; Respiratory Burst/immunology ; Streptococcus pneumoniae/*immunology ; Tretinoin/pharmacology