Biomedical subjects

Adrienn Bíró

Publications and source records attributed to Adrienn Bíró.

9 recordsLinked to original sources

PubMed2006

Novel anti-cholesterol monoclonal immunoglobulin G antibodies as probes and potential modulators of membrane raft-dependent immune functions.

Natural autoantibodies against cholesterol are present in the sera of all healthy individuals; their function, production, and regulation, however, are still unclear. Here, we managed to produce two monoclonal anti-cholesterol antibodies (ACHAs) by immunizing mice with cholesterol-rich liposomes. The new ACHAs were specific to cholesterol and to some structurally closely related 3beta-hydroxyl sterols, and they reacted with human lipoproteins VLDL, LDL, and HDL. They bound, usually with low avidity, to live human or murine lymphocyte and monocyte-macrophage cell lines, which was enhanced substantially by a moderate papain digestion of the cell surface, removing some protruding extracellular protein domains. Cell-bound ACHAs strongly colocalized with markers of cholesterol-rich lipid rafts and caveolae at the cell surface and intracellularly with markers of the endoplasmic reticulum and Golgi complex. These data suggest that these IgG ACHAs may serve as probes of clustered cholesterol (e.g., different lipid rafts) in live cells and thus may also have immunomodulatory potential.

Antibodies, Monoclonal↗

PubMed2006

Determination of complement factor H functional polymorphisms (V62I, Y402H, and E936D) using sequence-specific primer PCR and restriction fragment length polymorphisms.

BACKGROUND: Complement factor H (CFH; HF) is an essential regulatory protein that plays a critical role in the homeostasis of the complement system in plasma. Several polymorphisms and mutations in the complement factor H gene (CFH; HF1) have been identified. These have revealed interesting associations with hemolytic-uremic syndrome and age-related macular degeneration. METHODS AND RESULTS: The aim of this study was to develop a rapid and reliable assay for determining genotypic variants of the CFH gene. Sequence-specific primer PCR and restriction fragment length polymorphism techniques were chosen for the analysis of CFH polymorphisms. The assays detected the following published single nucleotide polymorphisms of CFH in our Caucasian population (n = 271): rs800292, 257G-->A (V62I); rs1061170, 1277T-->C (Y402H); and rs1065489, 2881G-->T (E936D). The allele frequencies (257G = 0.850, 1277T = 0.574, and 2881G = 0.839) that we obtained from a healthy Hungarian population were consistent with previously published results. CONCLUSION: These analytical methods are simple, reliable, and rapid to perform, and are amenable to automation. Therefore, they could facilitate large-scale genotypic analyses of the CFH gene in various diseases, such as hemolytic-uremic syndrome, age-related macular degeneration, and cardiovascular diseases.

Adult↗

PubMed2005

Dramatic changes in the serum levels of anti-cholesterol antibodies after eversion endarterectomy in patients with severe carotid atherosclerosis.

Our goal was to study changes in anti-cholesterol antibodies (ACHA) levels in patients with severe carotid stenosis after eversion endarterectomy. Seventy consecutive patients who underwent eversion endarterectomy at the Department of Cardiovascular Surgery, Semmelweis University, Budapest, were included in the study. Serum samples from 66 healthy volunteers served as controls. Patients had medical check up at 5.7 (4.6-8.0) weeks (median (interquartile range)), 6.8 (6.2-7.9) months as well as 13.8 (12.3-19.0) months after endarterectomy. In all patients the carotid arteries were investigated by color duplex ultrasound. ACHA concentrations were determined in the serum samples taken before operation as well as at the first and last follow-up visits by using an ELISA method. ACHA concentrations (median (interquartile range) were found to be significantly (p<0.0001) lower in the sera of the patients with carotid atherosclerosis (13.5 (8.4-21.3)AU/ml) than in the healthy subjects (26.1 (20.9-33.2)AU/ml) (Mann-Whitney test). Strong negative correlation was found between the preoperative ACHA and LDL-cholesterol levels (r=-0.413, p=0.0004). Serum ACHA concentrations significantly (p<0.0001) increased from the values measured before operation (13.5 (8.4-21.3)AU/ml) to 27.1 (19.9-34.7)AU/ml measured at the end of the 14 months long follow-up. Increase occurred only in patients with low or medium baseline ACHA concentration. Our present findings indicate that after surgical removal of atherosclerotic plaques from the carotid arteries the reduced baseline levels of ACHA reach normal values in 1 year. Different not mutually exclusive mechanisms (binding of ACHA to lipid/lipoproteins particles, to advanced plaques or reversibly injured endothelial cells in CNS) can be responsible for this novel finding.

Acute-Phase Proteins↗

PubMed2005

Antibodies against heat shock proteins and cholesterol in HIV infection.

This review summarizes data on the presence and function of different heat shock proteins (Hsp) in the HIV virions and the infected cells. A 60 kD heat shock protein-like molecule is present in the envelope of the human immunodeficiency virus type 1 which can specifically interact with the transmembrane glycoprotein gp41. The role of cholesterol in the so-called cholesterol-rich lipid raft where HIV is budding from the infected cells as well as the consequential insertion of cholesterol into the envelope of HIV virion are also discussed. Natural antibodies against 60 kD (Hsp60) and 70 kD (Hsp70) families of Hsp and cholesterol can be detected in most healthy individuals. HIV infection results in a sharp increase in the serum concentration of anti-Hsp70 and cholesterol antibodies whereas no difference in the concentration of anti-Hsp60 antibodies can be detected. Highly active antiretroviral therapy leads to normalization of the levels of both anti-Hsp70 and anti-cholesterol antibodies.

Autoantibodies↗

PubMed2004

Knock-out of the histidine decarboxylase gene modifies the repertoire of natural autoantibodies.

Natural antibodies (NA) are antibodies produced in the absence of known immunization with specific antigens. NA are found in the blood of healthy humans and mice. Histamine influences many aspects of the immune response, including antibody production. However, the role of histamine in the generation of NA has not yet been studied. In this work, we used an ELISA assay to characterize the self-antigen binding repertoires of NA in wild type (WT) mice and in histidine decarboxylase knock-out (HDC-KO) mice, unable to synthesize histamine. We now report that HDC-KO and WT mice differed in the patterns of autoreactivity of their IgM and IgG NA. The NA in HDC-KO sera manifested a larger repertoire of IgM autoantibodies than did the WT sera. The self-antigens bound by IgM from HDC-KO mice included structural proteins, enzymes associated with cellular metabolism, double-stranded and single-stranded DNA, and tissue-specific antigens like insulin. There were relatively fewer differences in the NA repertoire of IgG autoantibodies of the mice: notably, the HDC-KO sera reacted with glutamic acid decarboxylase (GAD), an antigen associated with autoimmune diabetes. These results demonstrate that endogenous histamine can influence the self-reactivity of the NA repertoire.

Amino Acid Sequence↗

PubMed2004

Paradoxical alteration of acute-phase protein levels in patients with chronic hepatitis C treated with IFN-alpha2b.

Previously we observed elevation of the serum concentration of two acute-phase protein (AFP) complement components (C9 and C1-inhibitor) in patients with chronic hepatitis C who responded (R) to IFN-alpha therapy, but not in non-responders (NR). In the present study we investigated the effect of high-dose IFN-alpha therapy on serum concentrations of two positive [orosomucoid (OROSO) and C-reactive protein (CRP)] and two negative [transferrin (TF) and fetuin/alpha2HS-glycoprotein (AHSG)] AFP in an outpatient setting. We investigated blood samples of 40 patients with chronic hepatitis C at the onset and at the end of a 3-month treatment with high-dose IFN-alpha2b (5 MIU/day for 6 weeks, followed by 5 MIU t.i.w.) and of 52 healthy individuals. Serum concentrations of OROSO, TF and AHSG were measured by radial immunodiffusion; CRP levels were determined by immunotubridimetry. Compared to controls, patients with chronic hepatitis C had significantly lower OROSO and CRP, and higher AHSG levels. By the end of treatment, OROSO concentration increased in R (P = 0.0054), but not in NR patients. In contrast, TF levels decreased in R (P = 0.0040), but did not change in NR patients. Similarly, in R patients, AHSG levels tended to decrease (P = 0.0942) following IFN-alpha treatment. We conclude that the acute-phase reaction is suppressed in patients with chronic hepatitis C that may be potentially related to the responsiveness to IFN-alpha therapy.

Acute-Phase Proteins↗

PubMed2003

Elevated levels of antibodies against 70 kDa heat shock proteins in the sera of patients with HIV infection.

Heat shock proteins (Hsp), especially 70 kDa heat shock protein (Hsp70) play an important role in the life cycle of HIV-1 virus. Hsp70 is overexpressed in HIV-infected cells and this is the most abundant Hsp associated with HIV virions. The aim of our study was to investigate whether HIV infection increases the extent of specific humoral immune response against Hsp70. The serum concentration of anti-Hsp70 IgG antibodies was measured in 47 HIV-infected patients, and 62 healthy, HIV-seronegative persons. Nineteen patients on highly active anti-retroviral therapy (HAART) were followed for 24 months in a longitudinal study. Anti-Hsp70 antibodies were measured by ELISA, using recombinant human Hsp70. Levels of anti-Hsp70 antibodies were significantly (P < 0.0001) higher in the HIV-infected patients (median: 1409 (25th-75th percentile: 1031-2214) AU/ml) than in healthy control subjects (626 (429-970) AU/ml). In 19 HIV patients, serum levels of anti-Hsp70 antibodies significantly (P < 0.001) decreased during 24 (11-41) months HAART (1309 (887-2213) AU/ml before and 640 (386-959) AU/ml during HAART), accompanied by viral load reduction and CD4+ count elevation. It is concluded that HIV-infection induces a marked increase in the anti-Hsp70 antibody levels, which is consistent with the enhanced expression of Hsp70 on the surface of HIV-infected cells and/or incorporation of the protein into the membrane of HIV virions.

Adolescent↗

PubMed2003

Anti-cholesterol antibodies in human sera.

In the last 30 years many research showed that high serum cholesterol level is a great risk for the atherosclerosis. In recent years, it has become clear that the immune system has a major role in atherosclerosis development and progression, and has binding capacity to cholesterol as well. It has been demonstrated in animal experiments, that anti-cholesterol antibodies (ACHA) can prevent cholesterol diet induced atherosclerosis. Our group is looking for the answer, whether ACHA have the same function in animals and in humans, or not. In this review we summarize our studies in human sera. We measured serum ACHA levels in different groups of patients with atherosclerotic diseases in patients with viral infections and in healthy population. In the summary we write about the possible functions of ACHA in the human immune system.

Animals↗

PubMed2002

Relationship of anti-60 kDa heat shock protein and anti-cholesterol antibodies to cardiovascular events.

BACKGROUND: Several recent studies have indicated an association between key inflammatory mediators and atherosclerotic diseases. We evaluated whether high levels of antibodies against heat shock proteins and cholesterol (ACHA) predicted cardiovascular (CV) events. METHODS AND RESULTS: We used blood samples from the Heart Outcomes Prevention Evaluation (HOPE) study to conduct a nested case-control study of 386 cases with CV events and 386 age- and sex-matched HOPE study controls without events. We explored the relationship between anti-hsp antibodies, ACHA, and subsequent outcomes (incident myocardial infarction, stroke, or CV death) during a mean follow-up of 4.5 years using conditional logistic regression. High levels of anti-hsp65 antibodies (> or =90th percentile) predicted CV events (OR, 2.1; 95% CI, 1.2 to 3.9, P=0.01). Anti-hsp60 antibodies did not predict any event type, whereas incident stroke developed significantly less frequently in patients with high ACHA levels. Anti-hsp antibodies and ACHA did not correlate with inflammatory (fibrinogen, C-reactive protein, interleukin-6, intracellular adhesion molecule-1) or infectious markers (C pneumoniae or cytomegalovirus antibodies). Anti-hsp65 antibodies (> or =90th percentile) and fibrinogen (highest tertile) had a strong joint effect: patients with high concentrations of both had more CV events (OR, 5.5; 95% CI, 1.8 to 17.5, P=0.004) than patients with low levels of both. A similar joint effect (OR, 2.7; 95% CI, 1.3 to 5.7, P=0.01) was found for high levels of anti-hsp65 and presence of cytomegalovirus antibodies. CONCLUSIONS: Serum antibodies to hsp65 were associated with subsequent CV events in this study of high-risk patients, independent of conventional cardiovascular risk factors and other inflammatory markers.

Aged↗