Investigation of Different Group A Immunoassays following One Dose of Meningococcal Group A Conjugate Vaccine or A/C Polysaccharide Vaccine in Adults

A double-blind, randomized, controlled phase I study to assess the safety, immunogenicity, and antibody persistence of a new group A conjugate vaccine (PsA-TT) in volunteers aged 18 to 35 years was previously performed. Subjects received one dose of either the PsA-TT conjugate vaccine, meningococcal A/C polysaccharide vaccine (PsA/C), or tetanus toxoid vaccine. The conjugate vaccine was shown to be safe and immunogenic as demonstrated by a standardized group A-specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) and by a serum bactericidal antibody (SBA) assay using rabbit complement (rSBA). This report details further analysis of the sera using four additional immunologic assays to investigate the relationship between the different immunoassays. The immunoassays used were an SBA assay that used human complement (hSBA), a group A-specific IgG multiplexed bead assay, and two opsonophagocytic antibody (OPA) assays which used two different methodologies. For each vaccine group, geometric mean concentrations or geometric mean titers were determined for all assays before and 4, 24, and 48 weeks after vaccination. Pearson''s correlation coefficients were used to assess the relationship between the six assays using data from all available visits. An excellent correlation was observed between the group A-specific IgG concentrations obtained by ELISA and those obtained by the multiplexed bead assay. hSBA and rSBA titers correlated moderately, although proportions of subjects with putatively protective titers and those demonstrating a ≥4-fold rise were similar. The two OPA methods correlated weakly and achieved only a low correlation with the other immunoassays. The correlation between hSBA and group A-specific IgG was higher for the PsA-TT group than for the PsA/C group.Within the African meningitis belt, unpredictable epidemics of meningococcal disease continue to occur every 5 to 15 years. To prevent these epidemics, a novel serogroup A conjugate meningococcal vaccine was developed. The Meningitis Vaccine Project, a partnership between the World Health Organization (WHO) and PATH (Seattle, WA) with core funding from the Bill and Melinda Gates Foundation, was created in 2001 with the goal of eliminating meningococcal epidemics in sub-Saharan Africa through the development, testing and licensure, and widespread use of serogroup A meningococcal conjugate vaccines (11) (http://www.meningvax.org).A group A meningococcal conjugate vaccine using tetanus toxoid as a carrier protein (PsA-TT) was developed at the Serum Institute of India Ltd., using a new licensed conjugation technique from the Center for Biologics Evaluation and Research/Food and Drug Administration (CBER/FDA, Bethesda, MD) (15). The results from a double-blind, randomized, controlled phase I study to assess safety, immunogenicity, and antibody persistence in healthy volunteers aged 18 to 35 years have been reported elsewhere (13). Subjects received either the PsA-TT vaccine, meningococcal A/C polysaccharide vaccine (PsA/C), or the tetanus toxoid vaccine. Blood samples were taken on the day of immunization and 4, 24, and 48 weeks later. Assessment by standardized enzyme-linked immunosorbent assay (ELISA) for group A-specific immunoglobulin G (IgG) and serum bactericidal antibody (SBA) assay using rabbit complement (rSBA) showed the vaccine to be immunogenic and able to elicit persistent functional antibody titers (13). Sera from this study were analyzed by additional immunologic assays, data from which have been used to investigate the relationship between different group A immunologic assays. Previously, knowledge of the relationship between group A immunoassays has been limited, with the majority of studies comparing only two assays; therefore, the goal of this study was to investigate the relationship between six different group A immunoassays, knowledge of which may aid our understanding of the immune response to this and other vaccines.     

Fatal necrotizing esophagitis due toPenicillium chrysogenum in a patient with acquired immunodeficiency syndrome

Although blue-green molds of the genusPenicillium are ubiquitous in the human environment, invasive penicilliosis is uncommon and primarily encountered among immunosuppressed patients. A patient with HIV infection who died of severe necrotizing esophagitis caused byPenicillium chrysogenum is reported and the relevant English language literature on human penicilliosis is reviewed. Although infectious esophagitis is commonly associated with AIDS,Penicillium esophagitis has not been described in such patients.     

4-烷硫基-4-脱氧-4′-去甲表鬼臼毒素的合成和抗肿瘤活性

对4’-去甲表鬼臼毒素的C₄位进行化学修饰,合成和筛选了10个4-烷硫基-4-脱氧-4’-去甲表鬼臼毒素衍生物以进一步研究C₄位不同的原子和取代基与活性之间的关系及寻找结构简单、活性更强的抗肿瘤新药。4’-去甲表鬼臼毒素与硫醇在三氟化硼·乙醚或三氟乙酸存在下生成相应的硫醚,也可用硫醇与4β-溴-4-脱氧-4’-去甲表鬼臼毒素反应生成相应的硫醚。在体外筛选中,化合物10和12抑制L1210白血病细胞的活性与依托泊甙相当或更强,化合物9,10,12和15抑制KB细胞的活性与依托泊甙相当或更强。     

ROLE OF NITRIC OXIDE IN THE DEVELOPMENT OF CORTICOTROPIN-INDUCED HYPERTENSION IN SHEEP

1. The possibility that altered synthesis of vascular nitric oxide (NO) plays a role in the development of corticotropin-induced hypertension in sheep was examined by determining the effect of concomitant infusion of L-arginine, a precursor of NO, on the development of the hypertension. 2. Corticotropin (5 μg/kg per h) infused over 2 days increased mean arterial pressure (MAP) from 83 ± 4 to 99 ± 4 mmHg in five conscious sheep. Concomitant infusion of L-arginine (60 mg/kg per h) did not alter this response; infusion of L-arginine alone had no effect on blood pressure. 3. The dose of L-arginine (60 mg/kg per h) used blocked the rise in MAP (+16 mmHg) in response to a 5 h infusion of N-nitro-L-arginine (1 mg/kg per h). 4. These findings suggest that disruption of NO synthesis does not play a role in the development of corticotropin hypertension in sheep.     

锌酞菁脂质体光动力作用引起小鼠肿瘤的细胞程序性死亡

电镜观察了锌酞菁脂质体光动力作用引起小鼠ＭＳ－２纤维肉瘤的形态学变化。发现其作用很强，并对肿瘤细胞有明显的直接影响。肿瘤细胞的结构表现出明显的程序性细胞死亡（ａｐｏｐｔｏｓｉｓ，ｐｒｏｇｒａｍｍｅｄｃｅｌｄｅａｔｈ）的特点：胞核染色质凝聚边集、核固缩、核破裂、染色质凝块流失、胞质内吞噬现象、胞膜表面肿胀粗钝的胞突形成、细胞碎裂等。加深了对锌酞菁脂质体光敏作用机理的认识，但其详细的发生机制和调节途径有待阐明。     

Signal transduction and the regulation of actin conformation during myeloid maturation: studies in HL60 cells

Maturation of human myeloid cells is associated with quantitative and qualitative changes in protein kinase C (PKC) and increases in N-formyl- L-methionyl-L-leucyl-L-phenylalanine (FMLP) receptors, actin, and actin regulatory proteins. We have studied the actin responses and cell shape changes caused by FMLP and its second messenger pathways in HL60 cells undergoing neutrophilic maturation. In uninduced cells, the PKC activators 12-O-tetradecanoyl phorbol-13-acetate (TPA), bryostatin, and 1-oleyl-2-acetylglycerol (OAG) resulted in 15% to 30% decreases in F- actin, whereas FMLP had no effect. Ionomycin had no effect on actin but did cause a 10-fold increase in intracellular calcium. Cells grown for 24 hours in 1% dimethyl sulfoxide (DMSO) acquired the ability to polymerize actin in response to FMLP and ionomycin. TPA continued to cause a decrease in F-actin at 24 hours, but caused an increase in F- actin at 48 to 72 hours of maturation. The PKC inhibitor 1-5- isoquinolinesulfonyl 2-methylpiperazine (H7) partially blocked the F- actin increase caused by TPA in induced cells, but had no effect on the decrease in F-actin caused by TPA in uninduced cells or the increase in F-actin seen in FMLP-treated neutrophils. F-actin rich pseudopods developed following TPA or FMLP stimulation of induced HL60 cells; in uninduced cells neither agent caused pseudopod formation but TPA caused a dramatic loss of surface ruffles. The ability of FMLP and ionomycin to elicit a neutrophil-like actin response in HL60 cells within 24 hours after DMSO treatment shows that the actin regulatory mechanism is mature by that time. The inability of ionomycin to increase F-actin in uninduced cells supports the view that calcium increases alone are insufficient for actin polymerization. The longer maturation time required for HL60 cells to develop an actin polymerization response to TPA compared with FMLP, coupled with the inability of H7 to block the FMLP-mediated F-actin increase in neutrophils, suggests that the F- actin increase caused by FMLP is not mediated solely by PKC. Lastly, the TPA-induced F-actin decrease and shape changes in uninduced HL60 cells, and the longer time required for a "mature" response to TPA, may reflect immaturity in the PKC isoenzyme pattern rather than immaturity of the actin regulatory mechanism.     

The metabolite 1 alpha,25-dihydroxyvitamin D3 enhances lymphokine- mediated activation of the oxidative metabolism of the U937 cell line and phosphorylation of a 48-kD respiratory burst-associated protein

U937 cells respond to a variety of stimuli with increased differentiation as manifested by reduced growth, increased adherence, increased expression of several surface receptors, and increased capacity for phagocytosis and formation of reactive oxygen intermediates. In the present study the effects of lymphocyte conditioned media, recombinant interferon-gamma (IFN-gamma), and 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the ability to form reactive oxygen intermediates by U937 cells were measured by using the luminol-dependent luminescence (LDL) assay. Neither 1,25(OH)2D3 alone nor IFN-gamma alone enhanced competence for phorbol myristate acetate- stimulated LDL. Cells were capable of moderate LDL after exposure to lymphocyte conditioned media, and this was enhanced by 1,25(OH)2D3 (10(- 8) mol/L) and other vitamin D metabolites at higher concentrations. This effect was not secondary to accelerated production of myeloperoxidase, which is important in the LDL assay. Enhanced phorbol myristate acetate-stimulated phosphorylation of a 48-kd substrate was observed in 32P-labeled intact cells treated with 1,25(OH)2D3 alone or in combination with IFN-gamma. Treatment of cells with IFN-gamma or lymphocyte conditioned media did not alter phosphorylation. These results support the concept that 1,25(OH)2D3 plays a role in phagocyte differentiation and activation beyond the effects of lymphokines. Protein kinase C-mediated phosphorylation reactions may be necessary for the ability of U937 cells to reduce O2 and required for maximal activity under some conditions of incubation.     

Plasma P-selectin is increased in thrombotic consumptive platelet disorders

P-selectin is a 140-kD protein found in the alpha-granules of platelets and the Weibel-Palade bodies of endothelial cells that on cell activation is expressed on the cell surface and also secreted into the plasma. The secreted form of P-selectin, like plasma P-selectin, differed from platelet membrane P-selectin in that its molecular mass was approximately 3 kD lower under reducing conditions. Both the secreted and plasma forms of P-selectin contained cytoplasmic sequence as determined by Western blot analysis with an affinity-purified rabbit anti-P-selectin cytoplasmic peptide antibody. We have measured plasma P- selectin and beta-thromboglobulin (beta TG) concurrently in (1) patients with consumptive thrombotic disorders, including disseminated intravascular coagulation (DIC), heparin-induced thrombocytopenia (HIT), and thrombotic thrombocytopenic purpura (TTP)/haemolytic uremic syndrome (HUS); (2) patients with idiopathic thrombocytopenic purpura (ITP); and (3) healthy controls. Patients with DIC, HIT, and TTP/HUS, but not ITP, had significantly elevated plasma P-selectin and beta TG levels when compared with their age-matched healthy controls. The increased plasma P-selectin and beta TG in patients with thrombotic disorders were likely to be the result of in vivo platelet and endothelial cell damage or activation. We also found that avoidance of veno-occlusion and other tedious measures customarily taken during blood collection and sample preparation to prevent in vitro platelet activation did not affect plasma P-selectin assay results. In addition, plasma P-selectin levels were not influenced by the presence of renal failure or heparin administration. These results indicate that plasma P- selectin may be a useful new marker for thrombotic diseases.     

An endogenous glycosylphosphatidylinositol-specific phospholipase D releases basic fibroblast growth factor-heparan sulfate proteoglycan complexes from human bone marrow cultures

Basic fibroblast growth factor (bFGF) is a hematopoietic cytokine that stimulates stromal and stem cell growth. It binds to a glycosylphosphatidylinositol (GPI)-anchored heparan sulfate proteoglycan on human bone marrow (BM) stromal cells. The bFGF- proteoglycan complex is biologically active and is released by addition of exogenous phosphatidylinositol-specific phospholipase C. In this study, we show the presence of an endogenous GPI-specific phospholipase D (GPI-PLD) that releases the bFGF-binding heparan sulfate proteoglycan and the variant surface glycoprotein (a model GPI-anchored protein) from BM cultures. An involvement of proteases in this process is unlikely, because released proteoglycan contained the GPI anchor component, ethanol-amine, and protease inhibitors did not diminish the release. The mechanism of release is likely to involve a GPI-PLD and not a GPI-specific phospholipase C, because the release of variant surface glycoprotein did not reveal an epitope called the cross- reacting determinant that is exposed by phospholipase C-catalyzed GPI anchor cleavage. In addition, phosphatidic acid (which is specifically a product of GPI-PLD-catalyzed anchor cleavage) was generated during the spontaneous release of the GPI-anchored variant surface glycoprotein. We also detected GPI-PLD-specific enzyme activity and mRNA in BM cells. Therefore, we conclude that an endogenous GPI-PLD releases bFGF-heparan sulfate proteoglycan complexes from human BM cultures. This mechanism of GPI anchor cleavage could be relevant for mobilizing biologically active bFGF in BM. An endogenous GPI-PLD could also release other GPI-anchored proteins important for hematopoiesis and other physiologic processes.