Biomimetics ; Blood Cells ; metabolism ; CD55 Antigens ; blood ; CD59 Antigens ; blood ; Cell Membrane ; Humans ; Male ; Submarine Medicine

CD55 Antigens ; Complement Activation ; Humans ; Membrane Cofactor Protein ; Pemphigoid, Bullous ; Recombinant Fusion Proteins

The complement is a part of the immune system that plays several roles in removing pathogens. Despite the importance of the complement system, the exact role of each component has been overlooked because the complement system was thought to be a nonspecific humoral immune mechanism that worked against pathogens. Decay-accelerating factor (DAF or CD55) is a known inhibitor of the complement system and has recently attracted substantial attention due to its role in various diseases, such as cancer, protein-losing enteropathy, and malaria. Some protein-losing enteropathy cases are caused by CD55 deficiency, which leads to complement hyperactivation, malabsorption, and angiopathic thrombosis. In addition, CD55 has been reported to be an essential host receptor for infection by the malaria parasite. Moreover, CD55 is a ligand of the seven-span transmembrane receptor CD97. Since CD55 is present in various cells, the functional role of CD55 has been expanded by showing that CD55 is associated with a variety of diseases, including cancer, malaria, protein-losing enteropathy, paroxysmal nocturnal hemoglobinuria, and autoimmune diseases. This review summarizes the current understanding of CD55 and the role of CD55 in these diseases. It also provides insight into the development of novel drugs for the diagnosis and treatment of diseases associated with CD55.
Antigens, CD55 ; Autoimmune Diseases ; Complement System Proteins ; Diagnosis ; Hemoglobinuria, Paroxysmal ; Immune System ; Immunotherapy ; Malaria ; Parasites ; Protein-Losing Enteropathies ; Thrombosis

BACKGROUND: Final diagnosis of paroxysmal nocturnal hemoglobinuria (PNH) may take years demanding a quick diagnosis measure. We used the facts that PNH cells are damaged in acid, and reagents for measuring reticulocytes in Coulter DxH800 (Beckman Coulter, USA) are weakly acidic and hypotonic, to create a new PNH screening marker. METHODS: We analyzed 979 complete blood counts (CBC) data from 963 patients including 57 data from 44 PNH patients. Standard criteria for PNH assay for population selection were followed: flow cytometry for CD55 and CD59 on red blood cells (RBCs) to a detection level of 1%; and fluorescent aerolysin, CD24 and CD15 in granulocytes to 0.1%. Twenty-four PNH minor clone-positive samples (minor-PNH+) were taken, in which the clone population was <5% of RBCs and/or granulocytes. Excluding PNH and minor-PNH+ patients, the population was divided into anemia, malignancy, infection, and normal groups. Parameters exhibiting a distinct demarcation between PNH and non-PNH groups were identified, and each parameter cutoff value was sought that includes the maximum [minimum] number of PNH [non-PNH] patients. RESULTS: Cutoff values for 5 selected CBC parameters (MRV, RDWR, MSCV, MN-AL2-NRET, and IRF) were determined. Positive rates were: PNH (86.0%), minor-PNH+ (33.3%), others (5.0%), anemia (13.4%), malignancy (5.3%), infection (3.7%), normal (0.0%); within anemia group, aplastic anemia (40.0%), immune hemolytic anemia (11.1%), iron deficiency anemia (1.6%). Sensitivity (86.0%), specificity (95.0%), PPV (52.1%), and NPV (99.1%) were achieved in PNH screening. CONCLUSION: A new PNH screening marker is proposed with 95% specificity and 86% sensitivity. The flag identifies PNH patients, reducing time to final diagnosis by flow cytometry.
Antigens, CD15/metabolism ; Antigens, CD24/metabolism ; Antigens, CD55/metabolism ; Antigens, CD59/metabolism ; Biomarkers/metabolism ; Blood Cell Count ; Erythrocytes/cytology/metabolism ; Flow Cytometry ; Granulocytes/cytology/metabolism ; Hemoglobinuria, Paroxysmal/*diagnosis/metabolism ; Humans ; Sensitivity and Specificity

BACKGROUND: Decay accelerating factor (DAF/CD55), regulates the complement system by accelerating decay of the C3 convertase, has been described in several malignancies, however, the clinicopathologic significance of CD55 and its receptor CD97 has not been fully investigated. We examined the expression patterns of both CD55 and CD97 and their association with clinicopathologic parameters in colorectal cancers (CRCs). METHODS: Expression patterns of CD55 and CD97 in the stroma and tumor cells at tumor center and invasive front were examined in 130 CRCs, and their significance was statistically evaluated. RESULTS: CD55-high stroma was correlated with tumor border (p=0.006) and invasion depth (p=0.013). CD55-high tumor cells at tumor center and invasive front were correlated with histologic grade, and CD55-high tumor cells at invasive front with tumor, node and metastasis (TNM) stage (p<0.05). CD97-high stroma was correlated with lymph node metastasis (p=0.016) and TNM stage (p=0.030). CD97-high tumor cells at tumor center and invasive front were correlated with tumor size and CD97-high tumor cells at tumor center with tumor border (p<0.05). Patients with CD55-high stroma showed poor overall and recurrence-free survival (p<0.05) in univariate analysis, and were independently associated with short recurrence-free survival (p=0.025) in multivariate analysis. CONCLUSIONS: Stromal CD55 overexpression would be an indicator of adverse clinical outcome and a useful prognostic factor.
Antigens, CD55 ; Calcium Hydroxide ; Colorectal Neoplasms ; Complement C3-C5 Convertases ; Complement System Proteins ; Humans ; Immunohistochemistry ; Lymph Nodes ; Neoplasm Metastasis ; Zinc Oxide

BACKGROUND: Endogenous complement inhibitors in the brain may protect against the neuroinflammation in Alzheimer's disease. Human neuroblastoma cells were stimulated by Abeta1 - 4 2 to investigate whether the expression of various complement regulator genes is upregulated. METHODS: SK-N-SH cells were incubated overnight with a single dose of 20 microM of Abeta1-42 or 0.5 ng/ml - 5 ng/ml of TNFalpha or both. Actinomycin D (2.5 microM) or cycloheximide (2.5 microM) was also added to the cell suspension. Messenger RNA expression of decay accelerating factor (DAF), membrane cofactor protein (MCP), CD59, complement-receptor 1(CR1), C1 inhibitor (C1-INH), C4-binding protein, factor H, factor I, clusterin and S-protein was measured by RT-PCR. RESULTS: Abeta1-42 and TNFalpha upregulated the expression of C1- INH significantly but increased expression of mRNA for factor H was not statistically significant. The expression of mRNAs for DAF and MCP was at low a level after stimulation. Factor I, CD59 and clusterin were not changed in their mRNA level. The mRNAs for S-protein, C4-binding protein and CR1 were not detected. Actinomycin D suppressed mRNA levels of C1-INH and CD59 significantly. Cycloheximide also inhibited the expression of both C1-INH and CD59. CONCLUSIONS: Early upregulated expression of C1-INH in Abeta1-42 stimulated neuroblastoma cell may contribute to a host defense mechanism against complement-mediated neuronal cell damage.
Alzheimer Disease ; Amyloid beta-Peptides ; Antigens, CD46 ; Antigens, CD55 ; Antigens, CD59 ; Brain ; Clusterin ; Complement Factor H ; Complement System Proteins* ; Cycloheximide ; Dactinomycin ; Fibrinogen ; Genes, Regulator* ; Humans* ; Neuroblastoma* ; Neurons ; RNA, Messenger ; Tumor Necrosis Factor-alpha

BACKGROUND: Endogenous complement inhibitors in the brain may protect against the neuroinflammation in Alzheimer's disease. Human neuroblastoma cells were stimulated by Abeta1 - 4 2 to investigate whether the expression of various complement regulator genes is upregulated. METHODS: SK-N-SH cells were incubated overnight with a single dose of 20 microM of Abeta1-42 or 0.5 ng/ml - 5 ng/ml of TNFalpha or both. Actinomycin D (2.5 microM) or cycloheximide (2.5 microM) was also added to the cell suspension. Messenger RNA expression of decay accelerating factor (DAF), membrane cofactor protein (MCP), CD59, complement-receptor 1(CR1), C1 inhibitor (C1-INH), C4-binding protein, factor H, factor I, clusterin and S-protein was measured by RT-PCR. RESULTS: Abeta1-42 and TNFalpha upregulated the expression of C1- INH significantly but increased expression of mRNA for factor H was not statistically significant. The expression of mRNAs for DAF and MCP was at low a level after stimulation. Factor I, CD59 and clusterin were not changed in their mRNA level. The mRNAs for S-protein, C4-binding protein and CR1 were not detected. Actinomycin D suppressed mRNA levels of C1-INH and CD59 significantly. Cycloheximide also inhibited the expression of both C1-INH and CD59. CONCLUSIONS: Early upregulated expression of C1-INH in Abeta1-42 stimulated neuroblastoma cell may contribute to a host defense mechanism against complement-mediated neuronal cell damage.
Alzheimer Disease ; Amyloid beta-Peptides ; Antigens, CD46 ; Antigens, CD55 ; Antigens, CD59 ; Brain ; Clusterin ; Complement Factor H ; Complement System Proteins* ; Cycloheximide ; Dactinomycin ; Fibrinogen ; Genes, Regulator* ; Humans* ; Neuroblastoma* ; Neurons ; RNA, Messenger ; Tumor Necrosis Factor-alpha

OBJECTIVETo analyze the mechanisms of surrogate tolerogenesis induced by chimeric donors.

METHODSHematopoietic stem cells (HSCs) from human cord blood were transplanted into fetal rats via intrauterine injection and infused into the liver of the neonatal rats to establish chimeric rat models with human HSCs. Four weeks after birth, flow cytometry was performed to analyze the percentages of human CD45 (hCD45), CD55 (hCD55) and CD59 (hCD59)-positive cells in the peripheral blood cells of the chimeric rats. The distributions of hCD55- and hCD59-positive cells in different hCD45/SSC gating regions were observed. The resistance of the peripheral blood lymphocytes to complements-mediated cytolysis was assessed by complement-dependent cytotoxicity (CDC) test in the chimeric rats and compared with that in control rats. The correlation between CDC and the human complement-regulating proteins in the chimeric rats were analyzed statistically.

RESULTSOn hCD45/SSC gating, the percentages of hCD55- and hCD59-positive cells in hCD45-positives region were (53.69-/+18.23)% and (31.8-/+27.5)%, accounting for (2.0-/+1.32)% and (0.76-/+0.56)% of the total cell population, respectively, which were significantly lower than the cell percentages in the extensive region (t=2.71, P=0.043 and t=3.64, P=0.015). The cytolytic rate of PBLs incubated with normal human serum was (22.32-/+15.10)% in the chimeric rats, significantly lower than that in the non-chimeric rats [(60.7-/+22.65)%, t=4.16, P<0.001). In the chimeric rats, hCD55-positive cell percentage was inversely correlated in the peripheral blood karyocytes the cytolysis rate in CDC (r=-0.679, P=0.031), and positively correlated to hCD45-positive cell percentage (r=0.658, P=0.038).

CONCLUSIONThe hCD45-positives region is the cluster of chimeric human cells expressing human complement-regulating proteins. The peripheral blood lymphocytes from chimeric donor can resist the cytolysis mediated by human complement. The presence of allogenic CD55 and CD59 antigens in chimeric donors may be the basis of surrogate tolerogenesis for xenotransplantation.

Animals ; CD55 Antigens ; blood ; CD59 Antigens ; blood ; Complement System Proteins ; analysis ; Cord Blood Stem Cell Transplantation ; methods ; Female ; Humans ; Leukocyte Common Antigens ; blood ; Male ; Models, Animal ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Transplantation Chimera ; blood ; genetics ; immunology ; Transplantation Tolerance ; Transplantation, Heterologous

OBJECTIVETo study the expressions of CD55 and CD59 in patients with hyperlipidemia and the effects of atorvastatin on it, and to identify the possible influential factors.

METHODSWe selected 67 patients with hyperlipidemia, and 24 healthy people matched in terms of age, sex and body weight as control. The expressions of CD55 and CD59 on white blood cells were detected by flow cytometry, and their relationships to blood lipids, complement activation indexes (C(5a), sC(5b-9)), inflammatory factors (high sensitivity C-reactive protein (hsCRP), TNF-alpha, IL-6 were analyzed. 24 patients with hyperlipidemia were treated with atorvastatin for 8-12 weeks and the expressions of CD55 and CD59 were measured before and after atorvastatin therapy.

RESULTSThe mean fluorescence intensity (MFI) of CD55 lymphocytes and monocytes were decreased in patients with hyperlipidemia compared with control (2.07 +/- 0.28 vs 2.29 +/- 0.44 and 3.45 +/- 1.02 vs 4.33 +/- 2.32, P < 0.01 and P < 0.05, respectively). CD55 positive lymphocyte MFI was negatively correlated with waist circumference, waist-hip ratio, hsCRP and C(5a). C(5a) was negatively correlated with the MFIs of CD55 positive lymphocytes, monocytes, granulocytes, and positively with TG and diastolic blood pressure. After atorvastatin therapy, the MFIs of CD59 positive lymphocytes, monocytes and granulocytes increased (4.34 +/- 1.16 vs 3.69 +/- 0.76, 4.52 +/- 1.36 vs 3.91 +/- 0.89, 5.67 +/- 1.72 vs 4.56 +/- 1.03, P < 0.05, < 0.05 and < 0.01 respectively), which were not correlated with changes of blood lipids.

CONCLUSIONSThe expression of CD55 is down-regulated in hyperlipidemia, which might be influenced by obesity, abdominal distribution of adipose tissue and inflammatory status of hyperlipidemia, but not by blood lipids. The expression of CD55 is related with complement activation; The expression of CD59 is up-regulated after atorvastatin treatment independently of blood lipids.

Aged ; Atorvastatin Calcium ; CD55 Antigens ; metabolism ; CD59 Antigens ; metabolism ; Case-Control Studies ; Complement Activation ; Gene Expression Regulation ; Heptanoic Acids ; therapeutic use ; Humans ; Hyperlipidemias ; drug therapy ; immunology ; metabolism ; Hypolipidemic Agents ; therapeutic use ; Male ; Middle Aged ; Pyrroles ; therapeutic use

BACKGROUNDMacro- and microvascular diseases are the leading cause of morbidity and mortality in diabetic patients, but their mechanisms remain unclear. Recent reports provide evidence that the levels of CD55 and CD59 are decreased in diabetic microvascular diseases. However, very little is known about the levels of CD55 and CD59, the relationship between them and carotid artery intima-media thickness, and the effects of statins on CD55 and CD59 in diabetic macrovascular diseases.

METHODSThe mean fluorescence intensity (MFI) of CD55 and CD59 expression on peripheral blood leucocyte subsets (lymphocytes, monocytes and neutrophils) was studied using flow cytometry, and carotid artery intima-media thickness was measured using B-mode ultrasonography in 23 healthy subjects (controls), 19 patients with type 2 diabetes (T2DM), and 43 patients with type 2 diabetes and macrovascular diseases (T2DM-M). The patients with T2DM-M were assigned to two subgroups based on whether statins were used: group with statins (n = 23) and group without statins (n = 20).

RESULTSCompared with the controls and T2DM, the MFI of CD55 positive neutrophils was significantly lower in T2DM-M (P = 0.049 vs controls and P = 0.033 vs T2DM); similarly, the MFI of CD59 positive monocytes was also lower in T2DM-M (P = 0.038 vs controls and P = 0.043 vs T2DM). The MFI of CD59 positive neutrophils in T2DM-M was lower than in T2DM (P = 0.032). The levels of CD55 and CD59 were negatively associated with age and blood pressure (r = -0.245 - -0.352, P = 0.041 - 0.003), but not acute-phase reactants and carotid artery intima-media thickness. The levels of CD55 and CD59 increased after treatment with statins, but the results were not significantly different (P > 0.05).

CONCLUSIONSCD55 and CD59 expressions on peripheral blood leucocytes are decreased in T2DM patients with macrovascular diseases. The results suggest that the decreased levels of complement regulatory proteins might play an important role in diabetic macrovascular diseases.

Aged ; Aged, 80 and over ; CD55 Antigens ; immunology ; CD59 Antigens ; immunology ; Diabetes Mellitus, Type 2 ; immunology ; Diabetic Angiopathies ; immunology ; Female ; Flow Cytometry ; Gene Expression Regulation ; Humans ; Leukocytes ; immunology ; Male ; Middle Aged