Antoaneta Michova

National Centre of Infectious and Parasitic Diseases, Bulgaria, Ulpia Serdica, Sofia-Capital, Bulgaria

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Publications (13)19.25 Total impact

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    ABSTRACT: House dust mites Dermatophagoides pteronyssinus (Dpt) are among the most frequent causes of allergy symptoms in Europe. Der p 1 is one of the major allergenic compounds of Dpt and the pathological Der p 1-specific B cells play a key role as producers of allergen-binding antibodies. The selective elimination of these cells by artificial protein molecules which inhibit the production of Dpt-recognizing IgE antibodies is a perspective therapeutic goal of allergy. A protein engineered chimeric molecule has been constructed, which binds Der p 1-specific B cells via their BCR and suppresses selectively the production of anti-Der p 1 antibodies via CR1. The synthetic peptide Der p 1 p52-71 and an anti-CD35 monoclonal antibody were used for the construction of Der p 1 chimera. The functional effects of engineered antibodies were analyzed in vitro using PBMCs from allergy patients. Significant inhibition of allergen-specific proliferation and reduction of Der p 1-IgE antibody production were observed after treatment of PBMCs from allergic patients with Der p 1-peptide chimera. Culturing of these PBMCs in the presence of the chimeric molecule increased the percentage of apoptotic (Annexin V-positive) B lymphocytes, but not T lymphocytes.
    Immunobiology 08/2013; · 2.81 Impact Factor
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    ABSTRACT: Sterically stabilized DPPC:CHOL:DSPE-PEG-2000 liposomal formulations of the lipophilic complexes of salinomycin with Na(I), K(I), Mn(II), Co(II), and Ni(II) ions were prepared by film-hydration method at different drug-to-DPPC molar ratios. For the K(I) and Na(I) complexes, optimal loading was established at a drug-to-DPPC molar ratio of 0.5:1, whereas for the Me(II) complexes, it was encountered at 0.1:1. DLS revealed uniform LUV populations (130-160 nm) with monomodal size distribution, further corroborated by AFM. Free and entrapped salinomycinates exhibited cytotoxicity in three human tumor cell lines, whereby the liposomal agents were superior vs. free complexes. DNA-fragmentation and flow cytometric assays showed that the cytotoxicity of free and liposomal salinomycinates is mediated by the induction of apoptosis and G1 arrest. The ability of the carriers to retain the bio-activity of the entrapped cargo gives us reason to conclude that the presented DPPC:CHOL:DSPE-PEG-2000 liposomes are suitable platforms for the salinomycin complexes, needing further evaluation and optimization.
    Journal of Drug Delivery Science and Technology 01/2013; 23(3):215. · 1.09 Impact Factor
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    ABSTRACT: A total of 50 patients with chronic lymphocytic leukaemia (CLL), as well as the B-cell leukaemia cell lines MEC-1, JVM-3, and BV-173 were studied in order to assess the incidence of CD13/aminopeptidase N (APN) immunolabelling with a monoclonal antibody 7H5 compared to LeuM7 and to CD13 mRNA levels, and to correlate these data with the cytotoxic and apoptosis-induction activity of the natural phenolic APN inhibitor curcumin. CD13/APN was detected in a significant proportion of B-CLL patients (42/50, 84%), immunolabelled by 7H5 (42/50) ± LeuM7 (10/50). Molecular analysis for CD13 transcripts confirmed these data, resulting in a specific RT-PCR product in CD13 positive cases. Curcumin showed concentration-dependent cytoreductive efficacy and apoptosis-induction activity in all tested cell lines and primary cultures from CLL mononuclear cells. There was a clear tendency for a better response in CD13 positive cases. The incidence of CD13/APN in CLL suggests that the inhibition of APN/CD13 by curcumin may be an effective new molecular target for a more efficient therapy for these patients and warrants further investigations.
    Hematology (Amsterdam, Netherlands) 05/2012; 17(3):132-9. · 1.33 Impact Factor
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    ABSTRACT: Anti-Echinococcus serum immunoglobulin (Ig)E was assessed by the ImmunoCAP system and compared with anti-Echinococcus serum IgG assessed by enzyme-linked immunosorbent assay (ELISA) and Western blot. The ImmunoCAP system revealed very high specificity (one false positive of 110 healthy individuals), low cross-reactivity (one false positive of 58 patients with other diseases) and decreased sensitivity (73.55%). Receiver operating characteristic analysis displayed a beneficial diagnostic value with high accuracy. Comparison of the ImmunoCAP system with ELISA and Western blot showed significantly higher specificity and significantly lower cross-reactivity compared with the ELISA. Examination of sera from 155 patients with cystic echinococcosis (CE) showed varying levels of anti-Echinococcus IgE (range, 0.01-118.33 kUA/L). However, most samples had moderately elevated IgE levels. Analysis of serum-specific IgE revealed significantly higher sensitivity of the ImmunoCAP system and significantly higher antibody levels in hepatic CE compared with pulmonary CE.
    Parasite Immunology 07/2011; 33(7):371-6. · 2.21 Impact Factor
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    ABSTRACT: A mathematical model for leukopoiesis has been proposed in literature, consisting of a system of ordinary differential equations with two delays. The aim of this study was to verify the assumption that the model is applicable also for T, B and NK cell recovery after stem cell transplantation and to tune the model parameters on the base of clinical data. The numerical tests illustrate the influence of the model parameters to the behavior of the monitored white blood cell populations. They also show that for certain parameter values the numerically obtained behaviour of B cells is in agreement with the clinical data.
    Mathematical Modeling and Computational Science - International Conference, MMCP 2011, Stará Lesná, Slovakia, July 4-8, 2011, Revised Selected Papers; 01/2011
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    ABSTRACT: Fetal stem cells possess some intriguing characteristics, which delineate them as promising cellular therapeutics. They are less immunogenic, at lower stage of differentiation and have higher potential for repopulation and migration. Furthermore, the fetal stem cells secrete a set of cytokines and growth factors, which stimulate the regeneration of the recipient tissue. The present study indicated that the adhesive fraction of human fetal liver cells possessed the morphological characteristics of mesenchymal stem cells, as well as potential to differentiate into adipocyte and osteoblast lineages. The immunophenotypic analysis showed that the cells expressed CD13, CD73, CD90 and CD105 (typical for mesenchymal stem cells) and lacked the haematopoietic lineage markers CD34 and CD45. Addressing the issue of the low-temperature storage of the human fetal liver cells, four different methods for cryopreservation were assessed: conventional slow freezing, program freezing and two vitrification protocols. The obtained results demonstrated that the cells were cryotolerant and maintained their properties and differentiation potential after thawing. Program freezing showed to be the most efficient method for cryopreservation of the investigated cells.
    Cell Biology International 05/2010; 34(5):455-62. · 1.64 Impact Factor
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    ABSTRACT: The presently used approaches to silence autoreactive disease-associated B cells act indiscriminately and more specific therapies are obviously needed. In the present study, we analyze the ability of a chimeric antibody to suppress selectively pathological autoreactive B-lymphocytes in lupus-prone mice by cross-linking their surface Ig receptors with the inhibitory IgG Fc gamma RIIb receptors. The chimera was constructed by coupling an immunodominant mouse Histone 1 peptide to a rat monoclonal anti-mouse CD32 (Fc gamma RIIb) antibody. The administration of these chimeric molecules to MRL/lpr mice with initial and with full-blown disease resulted in the reduction of the levels of IgG anti-Histone 1 antibodies, of the albuminuria levels, of the size of lymphoid organs and in prevention of the development of skin lesions. The observed effect was limited to lupus-associated B cells only, as the treatment did not decrease the IgG antibody response to an administered foreign antigen. This study demonstrates the possibility to silence selectively autoreactive B cells and to delay the progression of an autoimmune disease using chimeric antibody molecules.
    International Immunology 03/2008; 20(2):165-75. · 3.14 Impact Factor
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    Biotechnology & Biotechnological Equipment 04/2007; · 0.62 Impact Factor
  • World Allergy Organization Journal. 01/2007;
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    ABSTRACT: Two-flow cytometry methods for quantification of degranulated basophil after allergen-specific activation were discussed. The methods are discerned by used membrane receptors--FcepsilonRI or IL-3Ralpha Our goal was to evaluate the diagnostic potential of the methods and to correlate them to allergen-specific IgE detection and skin prick test (SPT). Patient's and control's groups were studied with Bulgarian grass pollen allergen B1 simultaneously by flow cytometry kits: Basotest and BD FastImmune test. Allergy diagnosis was based on clinical history and SPT. The determination of specific IgE was performed by ELISA--RIDASCREEN. There were no significant differences between the patient's results from Basotest and FastImmune (P>0.05). A significant correlation between values, analyzed by Basotest and by FastImmune was found (r=0.88). The sensitivity and specificity of the Basotest, FastImmune, specific IgE and SPT were 85%, 72%, 92% and 92% sensitivity and 100%, 92%, 100% and 85% specificity respectively. The efficiency was between 82% and 97%. There were a significant correlation between the specific IgE and flow cytometry tests: tau=0.92 (Basotest) and tau=0.71 (FastImmune) and a moderate significant correlation between the SPT and the in vitro tests: tau=0.26 (Basotest) and tau=0.31 (FastImmune). The successful use of the Bulgarian grass pollen allergen B1 and both flow cytometry tests was presented. These methods could be as specific tools for IgE-mediated diagnosis especially FastImmune in the case of low IgE receptor expression.
    Allergy 09/2006; 61(9):1078-83. · 5.88 Impact Factor
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    ABSTRACT: To examine the clinical spectrum of complications in pulmonary system and changes of some parameters of humoral and cell mediated immunity related to heroin overdose. The study includes 16 patients who are long-term heroin abusers with acute heroin and mixed with other psychoactive drugs intoxications with an average age of 21,5 ± 5.04 years (12 men and 4 woman). All patients were hospitalized in the Clinic of Toxicology, MHATEM “N.I.Pirogov”, Sofia. We have used clinical, clinico-laboratory, immunological, chimicotoxicological, instrumental methods. In severe intoxications with heroin and other psychoactive drugs, we observed pulmonary system complications, i.e. pneumonia, aspiration of gastric contents, noncardiogenic pulmonary edema (NCPE) and acute respiratory distress syndrome (ARDS.). Of the 16 patients in our study, 3 patients died due to complications. Some changes in the immune reactivity observed in the study were (1) statistically significant lower mean levels of IgG and (2) tendency to lower mean levels of IgA, IgM and complement components — C3 in the studied patients in comparison with the values in healthy people. The changes were more demonstrative in the group with pulmonary complications compared to the group without pulmonary complications. We observed that the CD4 lymphocytes were significantly less in the studied patients; in addition, a lower level of CD56-bearing lymphocytes (natural killer /NK/ cells) was observed in comparison to healthy controls. The results show that the mixture of acute heroin with other psychoactive drugs leads to complications in the pulmonary system and changes of some parameters of cell-mediated and humoral immunity. KeywordsIntoxication-Heroin-Psychoactive drugs-Immune reactivity-Noncardiogenic pulmonary edema-Pneumonia-ARDS
    Central European Journal of Medicine 5(4):508-512. · 0.26 Impact Factor
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    ABSTRACT: The membrane endopeptidase CD13 has been widely applied in leukaemia phenotyping due to its myeloid-specific mode of expression. We developed a monoclonal antibody (Mab) 7H5 recognising a new CD13 epitope. To assess its diagnostic value, the binding pattern of 7H5 was compared to the reference CD13 antibody, LeuM7 on 109 clinical samples from patients with haematological malignancies by flow cytometry. Most acute myeloid leukaemia (AML) samples were CD13 positive (37/38, 98%), expressing both epitopes with similar or different intensity. In addition, 7H5 marked two undifferentiated and two biphenotypic leukaemia samples. A higher percentage of 7H5(+) blast cells correlated with CD4 positivity in AML (p = 0.025) but not with CD34 or aberrant markers expression. LeuM7 and 7H5 Mabs stained B-lineage acute lymphoblastic leukaemia (ALL) discordantly, revealing a heterogeneous pattern of CD13 epitopes expression in 12/33 (36 %) cases and did not correlate with CD34 or other aberrant phenotypes. Interestingly, we detected 7H5 in a significant proportion of leukaemic phase B-cell non- Hodgkin lymphomas (NHL) (81%) exceeding all previous data, while LeuM7 was generally absent. In conclusion, CD13 epitopes may be variably expressed by leukaemia/lymphoma proliferations proba- bly reflecting different maturation/functional characteristics of malignant cells. Therefore, an extension of the immunophenotyping panels might be worth of investigation.
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    ABSTRACT: Ambrosia artemisiifolia L. is a leading cause of allergies in many countries. In the last decade it has appeared and spread in Bulgaria as well. The aims of this study was to collect pollen from ragweed plants in Bulgaria, prepare the first Bulgarian ragweed allergen, and characterize it. The new allergen was studied in parallel with two other ragweed pollen extracts from the USA and Russia. The protein profile was studied through isoelectric focusing, and the total allergen activity was studied by a skin prick test and a basophil activation test. The proteins of the studied extracts were concentrated in the pI region 3.5–5.5 with an identical band number and location. The allergens showed similar total allergen activity in vivo:14/81 tested patients (17.3 %) were SPT positive either to a single ragweed extract or to all three. The allergens had identical histogram profiles and caused basophil degranulation above the test cut-off. The analysis of the flow cytometry results by parallel line bioassay shows linear dose-response relation between the extracts. The observed immunological properties of the Bulgarian allergen from Ambrosia artemisiifolia provide a possibility to use this product for a reliable diagnosis and effective specific immunotherapy of ragweed allergy in our country. KeywordsAmbrosia artemisiifolia L-Allergen preparation-Isoelectric focusing-Total allergen activity
    Central European Journal of Medicine 5(5):565-568. · 0.26 Impact Factor

Publication Stats

25 Citations
19.25 Total Impact Points

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Institutions

  • 2010–2013
    • National Centre of Infectious and Parasitic Diseases, Bulgaria
      Ulpia Serdica, Sofia-Capital, Bulgaria
  • 2006–2011
    • National Center of Infectious and Parasitic Diseases
      Ulpia Serdica, Sofia-Capital, Bulgaria