Mutual Antagonism Between Antigen-and Lipopolysaccharide-Induced Antibody Production

B cells are induced to antibody production by antigens or by mitogens, such as lipopolysaccharide (LPS). We observed a mutually antagonistic relationship between activation through the antigen-receptor (AgR) and LPS-receptor (LPSR) in vitro. Prior exposure of B cells to AgR-ligating antibody prevented antibody forming cell (AFC) production induced by LPS, but not that induced by specific antigen (SRBC, TNP-Ficoll, or TNP-LPS). AFC production induced by antigen could be abrogated by concomitant exposure to LPS; the shutdown of the antigen-driven response was apparent when LPS-induced AFC were prevented by pre-exposure to antibody against the AgR. The ability of signaling through the AgR to inhibit antibody production stimulated by LPS was seen in DBA/2 and BALB/c mouse strains, and not in the New Zealand Black (NZB) strain. The results suggest that mutual antagonism is distinct from other forms of immune hyporesponsiveness, and that defects in antagonism may be a factor in the development of autoimmune disease.     

Protective Effect of Anti-P-Selectin Monoclonal Antibody in Lipopolysaccharide-Induced Lung Hemorrhage

Excessive leukocyte accumulation is involved in the pathogenesis of the sepsis-induced acute lung injury. Selectins are essential to the interaction between leukocytes and endothelial cells. In this report, we investigated the role of selectins in the severe lung injury induced by lipopolysaccharide (LPS). Significant lung hemorrhage was observed 24 h after the intravenous administration of LPS (1 mg/kg). First, we evaluated the effect of sialyl Lewis X-oligosaccharide (SLeX-OS), a derivative of sialyl Lewis X which is one of the ligands for E-, P- and L-selectins. The treatment with SLeX-OS (26.5 mg/kg iv bolus + 19.8 mg/kg iv infusion) resulted in a decrease of lung hemorrhage by 49.5% (P < 0.05 versus the control group). Second, we tested the effect of anti-P-selectin monoclonal antibody (MAb), PB1.3, to investigate the role of P-selectin. The bolus administration of PB1.3 at a dose of 5 mg/kg attenuated the lung hemorrhage by 74.6% (P < 0.05 versus the control group). In addition, we also detected an increase of soluble P-selectin in plasma 24 h after the injection of LPS. These results suggest that P-selectin has a substantial role in the pathogenesis of the lung injury induced by LPS.     

A Quantitative Relationship Between Antibody Affinity and Antibody Avidity

The relationship between antibody avidity, measured by the dissociation of the antigen-antibody bond in antigen excess, and antibody affinity was studied. Complexes of radiolabelled antigen and antibody of known affinity were prepared in vitro and allowed to stand for seven days to reach equilibrium. Then nonlabelled antigen in one hundred fold excess was added to dissociate the complexes. After an appropriate incubation the fraction of antigen bound to antibody was measured by the ammonium sulfate precipitation method. The dissociation index was the fraction bound in the experimental sample divided by the fraction bound in the control. The correlation coefficient between the dissociation index and the antibody binding constant was 0.92 for early dissociation and 0.98 for late dissociation. The regression equation relating the binding constant to the dissociation index was K = 6.4(DI) + 6.25, where DI is the late dissociation index and K is the logarithm to the base 10 of the binding constant. There is a high correlation between avidity and affinity of antibody. Antibody affinity can be estimated from avidity data. The stability of antigen-antibody complexes can be predicted from antibody affinity.     

Carrageenan Primes Leukocytes To Enhance Lipopolysaccharide-Induced Tumor Necrosis Factor Alpha Production

We have previously reported that pretreatment with carrageenan (CAR) enhances lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-alpha) production in and lethality for mice. Whole blood cultured in vitro was used to show that CAR pretreatment results in about a 200-fold increase in LPS-induced TNF-alpha production. CAR by itself did not induce TNF-alpha production. However, CAR-treated cultured medium sensitized whole blood to make more LPS-induced TNF than did saline-treated cultured medium in vitro. It was also demonstrated that CAR pretreatment increases TNF-alpha mRNA levels of both blood cells and peritoneal exudate cells, but not of bone marrow cells. Immunoelectron microscopic analysis revealed that polymorphonuclear leukocytes and macrophages are TNF-alpha-producing cells in CAR-treated mice. In CAR-treated mice, TNF-alpha was seen early after LPS injection in leukocytes in hepatic sinusoids and on the surfaces of endothelial cells. TNF-alpha was also detected late after LPS injection in hepatocytes which become edematous. These results suggest that CAR primes leukocytes to produce TNF-alpha in response to LPS and that they play an important role in the pathogenesis of liver injury.     

Polyclonal Antibody Production Against Chito-Oligosaccharides

Chitin hexamer was conjugated to mono-BOC-diaminoethane, γ-aminobutyric acid or glycine using reductive amination. Each hapten was conjugated to ovalbumin (OVA) or mouse serum albumin (MSA) for immunization and immunoassay, respectively. Serum from a mouse immunized with the diaminoethane conjugate, demonstrated competition with chitins in a modified indirect immunoassay.     

Enhancement of Lipopolysaccharide-Induced Neutrophil Oxygen Radical Production by Tumor Necrosis Factor Alpha

Although tissues become exposed to both exogenous and endogenous cell-activating mediators during infection, there is little appreciation of the effects of subjecting cells to multiple mediators. We examined the hypothesis that the response of neutrophils to bacterial lipopolysaccharide (LPS) is significantly altered in the presence of the endogenous mediator tumor necrosis factor alpha (TNF). The data showed that human neutrophils pretreated with TNF for 10 to 30 min, displayed significantly enhanced superoxide production in response to LPS (from either Escherichia coli K-235 or E. coli 0127:B8), measured as lucigenin-dependent chemiluminescence (CL), seen as an increase in the initial peak rate as well as the total CL accumulated over the incubation period. TNF amplified the response to LPS at 1 to 100 U of TNF/10⁶ neutrophils and was able to enhance the response to a wide range of concentrations of LPS (0.01 to 1,000 ng/ml). The TNF-induced increase in the LPS response was paralleled by an increase in LPS binding to the neutrophils, which could be abrogated by an anti-CD14 monoclonal antibody. The results demonstrate that TNF significantly increases the LPS-induced release of oxygen radicals in neutrophils through the upregulation of cell surface CD14.     

Graves病患者TRAb与抗TSHAb抗体关系的初步研究

根据自身免疫性甲状腺疾病发病机制的独特型－抗独特型免疫免疫学说，用兔抗人ＴＳＨＡｂ检测ＴＳＨ抗独特型抗体（ＴＳＨＡｂ２）。以正常人为对照，以其结合率＾－ｘ＋２ｓ为正常值上限，大于此值为阳性。６０例ＴＲＡｂ阳性病人，６５％病人ＴＳＨＡｂ２阳性，而４０例ＴＲＡｂ阳性病人中，只有５％病人ＴＳＨＡｂ２阳性。两组差异显著（Ｐ〈０．０５）。ＴＲＡｂ和ＴＳＨＡｂ２呈正相关（ｒ＝０．６４５，Ｐ〈０．０１）。同时用     

Production of Antibody in Induced Granulomas

A method of producing antibodies in artificially induced granulomas with various microbial antigens is examined.     

Antibody Production by Human Colostral Cells

The production of antibody by human colostral cells was assayed by the hemolysis-in-gel technique. When sheep erythrocytes coated with O antigens from frequently encountered Escherichia coli bacteria were used as detector cells and anti-IgA serum was added for development, numerous plaque-forming cells (PFC) were demonstrated in all samples tested. In contrast, plaques were rarely seen in the presence of anti-IgG developing serum. The direct (IgM) plaques occasionally noted with both antigen-coated and uncoated sheep erythrocytes were mainly due to the production of heterophil antibodies, since they were not formed when human erythrocytes were used as O-antigen carriers. A strikingly high number of the colostral lymphocytes formed antibodies to the E. coli antigens, up to 8% This suggests that these cells represent a rather selective population–possibly cells from the gastrointestinal tract exposed to enteric bacteria. The large number of plaques observed, the predominance of the cells forming IgA antibodies, and the marked changes in PFC number in relationship to parturition pose a number of questions relevant to the antibody-producing colostrum cells and their relationship to the secretory immune system     

Lipoprotein(a) Inhibits Lipopolysaccharide-Induced Tumor Necrosis Factor Alpha Production by Human Mononuclear Cells

Lipoproteins can bind lipopolysaccharide (LPS) and decrease LPS-stimulated cytokine production. Lipoprotein(a) [Lp(a)] was as potent as low-density lipoproteins (LDL) in inhibiting LPS-stimulated tumor necrosis factor synthesis by human mononuclear cells. The kinetics of LPS inhibition by Lp(a) was similar to that of LDL. This suggests that circulating Lp(a) may be an important factor determining the amplitude of the response to LPS in humans.     

肺炎衣原体特异性单克隆抗体的研制及应用

采用肺炎衣原体(Chlamydia pneumoniae, Cpn)TW-183的纯化原体免疫BALB/C雄性小鼠, 将小鼠脾脏细胞与SP2/0细胞融合, 杂交细胞通过有限稀释法克隆, 获得1株稳定分泌Cpn-单克隆抗体(Cpn-McAb)的细胞株, 单抗属IgG2b亚型及抗Cpn-MOMP抗体.自制Cpn-McAb与鹦鹉热衣原体原体有较弱的交叉反应; 与沙眼衣原体原体无交叉反应, 特性与进口Cpn-McAb一致.为了评估Cpn-McAb, 用自制和进口Cpn-McAb同时检测外周血单核细胞标本454例, Cpn-Ag阳性率分别为53.3%和52.6%, Kappa值0.714, 两者有较高的一致性.结果提示,自制Cpn-McAb几乎和进口Cpn-McAb一样有较高的特异性和敏感性,可替代进口单抗用于临床Cpn感染的检测, 有助于相关疾病的诊治.     

Production of Anti-idiotypic Monoclonal Antibody Mimics for Coronatine

Coronatine (COR) is composed of two structural components, coronafacic acid (CFA) and the amino acid coronamic acid (CMA), which are joined by an amide bond. Monoclonal anti-idiotypic antibodies were prepared and used in competitive ELISAs. Monoclonal antibodies (MAbs) were secreted by hybridoma cell lines prepared from mice immunized with two different idiotypic MAbs, 11B8 and 11G8 that predominantly recognized the CMA or CFA residues, respectively. Hybridoma cell lines secreting high affinity MAbs 4D5 (anti 11B8) and 4H10 (anti 11G8) were isolated. MAb 4D5 predominantly mimicked the coronamyl amide features of coronatine whereas 4H10 mimicked the coronafacoyl amide of COR. Immunoassays were developed using each of these antibodies. COR could be quantified in the range 1-1000 ngml m 1 (limit of detection <150 pgml m 1 ) in direct and modified indirect assays for 4D5/11B8 and in direct assays for 4H10/11G8. For modified indirect assays using 4H10/ 11G8 COR was quantified in the range 3-1000 ngml m 1 (limit of detection <1 ngml m 1 ).