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Recombinant glycoproteins resembling carbohydrate-specific IgE epitopes from plants, venoms and mites
Pia Gattinger, Irene Mittermann, Christian Lupinek, Gerhard Hofer, Walter Keller, Urška Bidovec, Peter Korošec, Christine Koessler, Natalija Novak, Rudolf Valenta, 2019

Abstract: Background: N-linked glycans present in venoms, pollen and mites are recognized by IgE antibodies from >20% of allergic patients but have low or no allergenic activity. Objectives: To engineer recombinant glycoproteins resembling carbohydrate-specific IgE epitopes from venoms, pollen and mites which can discriminate carbohydrate-specific IgE from allergenic, peptide-specific IgE. Methods: One or two N-glycosylation sites were engineered into the N-terminus of the non-allergenic protein horse heart myoglobin (HHM) using synthetic gene technology. HHM 1 and HHM 2 containing one or two N-glycosylation sites were expressed in baculovirus-infected High-FiveTM insect cells and a non-glycosylated version (HHM 0) was obtained by mutating the glycosylation motif. Recombinant HHM proteins were analyzed regarding fold and aggregation by circular dichroism and gel filtration, respectively. IgE reactivity was assessed by ELISA, immunoblotting and quantitative ImmunoCAP measurements. IgE inhibition assays were performed to study cross-reactivity with venom, plant and mite-derived carbohydrate IgE epitopes. Results: HHM-glycovariants were expressed and purified from insect cells as monomeric and folded proteins. The HHM-glycovariants exhibited strictly carbohydrate-specific IgE reactivity, designed to quantify carbohydrate specific IgE and resembled IgE epitopes of pollen, venom and mite-derived carbohydrates. IgE-reactivity and inhibition experiments established a hierarchy of plant glcyoallergens (nPhl p 4 > nCyn d 1 > nPla a 2 > nJug r 2 > nCup a 1 > nCry j 1) indicating a hitherto unknown heterogeneity of carbohydrate IgE epitopes in plants which were completely represented by HHM 2. Conclusion: Defined recombinant HHM-glycoproteins resembling carbohydrate-specific IgE epitopes from plants, venoms and mites were engineered which made it possible to discriminate carbohydrate- from peptide-specific IgE reactivity.
Keywords: allergy and immunology, allergens, glycoproteins, molecular diagnostic technique, recombinant glycoproteins, molecular allergology, component-resolved diagnosis
DiRROS - Published: 16.10.2020; Views: 869; Downloads: 579
.pdf Fulltext (2,07 MB)

Chemokines during anaphylaxis : the importance of CCL2 and CCL2-dependent chemotactic activity for basophils
Romana Vantur, Maruša Rihar, Ana Koren, Matija Rijavec, Peter Kopač, Urška Bidovec, Renato Eržen, Peter Korošec, 2020

Abstract: Background: The role of chemokines in anaphylaxis is unclear. Methods: We prospectively recruited 49 patients presenting to the emergency department with an acute episode of anaphylaxis and 28 healthy subjects. We measured serum levels of the chemokines CCL2, CCL5, CCL7, CCL8, CCL11, CCL13, CCL17, CCL21, CCL22, CCL24, and CCL26, tryptase, the absolute number of circulating basophils, monocytes, lymphocytes, and PMNs, and whole blood FCER1A, CPA3 and HDC gene expression at two time points: during the anaphylactic episode and in convalescent samples collected approximately 3 months later. We then investigated the in vitro chemotactic activity of chemokines induced during anaphylaxis for the in vitro migration of the corresponding cells. Results: Only CCL2 chemokine levels were signifcantly increased in anaphylaxis samples (median 514 pg/ml) compared to convalescent samples (284 pg/ml, P<0.0001) and healthy subjects (279 pg/ml, P<0.0001); there was no signifcant diference in any of the other chemokines. There was a signifcant positive correlation between the rates of increase of serum CCL2 (median [range]: 106.0% [-44.7% to 557.4%]) and tryptase (133.8% [-6.6% to 893.4%]; r=0.68, P<0.0001) and between the acute concentration of serum CCL2 and the acute concentration of serum tryptase (r=0.77, P<0.0001). The number of circulating basophils, but not other blood cells, signifcantly decreased during anaphylaxis (median 5.0 vs. 19.1 cells/[micro]l in convalescent samples; P<0.0001); a decrease in whole-blood gene expression of basophil markers (PKeywords: anaphylaxis, chemokines, tryptases, basophils, chemotaxis, CCL2, cell migration
DiRROS - Published: 18.01.2021; Views: 770; Downloads: 318
.pdf Fulltext (2,04 MB)

Usefulness of rapid antigen testing for SARS-CoV-2 screening of healthcare workers : ǂa ǂpilot study
Anja Šterbenc, Viktorija Tomič, Urška Bidovec, Katja Vrankar, Aleš Rozman, Mihaela Zidarn, 2021

Abstract: Background. Identification of infected healthcare workers (HCWs) is an important step in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) transmission control. Rapid antigen tests (RATs) are considered an important addition to molecular tests in diagnosing coronavirus disease 2019 (COVID-19), mainly because of their fast turnaround time, easier analytical procedure and lower price. However, real-life studies on the usefulness of such testing for screening of HCWs are limited. Methods. Physicians, nurses and hospital attendants currently working at the University Clinic of Respiratory and Allergic Diseases Golnik were invited to participate in the pilot study. Nasopharyngeal swabs were obtained three times per week for two consecutive weeks and tested with a point-of-care RAT and reverse transcription polymerase chain reaction (RT-PCR). Serum samples were obtained at the beginning of the study and 2 weeks after the last swab was collected to evaluate the serological status. Results. A total of 191 nasopharyngeal swabs from 36 HCWs were obtained. None of the samples tested was positive for the presence of SARS-CoV-2 antigen, whereas two HCWs tested positive on RT-PCR. Of these, one HCW had a newly identified SARS-CoV-2 infection, whereas RT-PCR probably detected a previous but recent infection in the other HCW. Conclusio.n Based on the results of this pilot study, it is unlikely that RAT will reliably detect novel SARS-CoV-2 infections among asymptomatic HCWs despite serial sampling. Although RT-PCR-based screening of HCWs may not be feasible due to high sample volume, molecular methods may identify SARS-CoV-2-infected HCWs already during the presymptomatic stage.
Keywords: SARS-CoV-2, health personnel, COVID-19 serological testing, real-time polymerase chain reaction, rapid antigen test, screening
DiRROS - Published: 28.05.2021; Views: 560; Downloads: 114

Heterogeneous response of airway eosinophilia to anti-IL-5 biologics in severe asthma patients
Maruša Kopač, Matija Rijavec, Peter Korošec, Urška Bidovec, Izidor Kern, Romana Vantur, Sabina Škrgat, 2022

Abstract: Many questions concerning responders (R) and nonresponders (NR) in severe eosinophilic asthma (SEA) after blocking the IL-5 (interleukin 5) pathway are still not clear, especially regarding the early parameters of response to biologics in personalized treatment strategies. We evaluated 17 SEA patients treated with anti-IL-5 biologics (16 patients mepolizumab, one patient benralizumab) before the introduction of biologics, and at a week 16 follow-up. Clinical, cellular and immunological parameters in peripheral blood were measured in R and NR. Sputum induction with the measurement of cellular and immunological parameters was performed at 16 weeks only. There were 12 R and 5 NR to biologics. After 16 weeks, there was a significant improvement in percentages of FEV1 (p = 0.001), and asthma control test (ACT) (p = 0.001) in the R group, but not in NR. After 16 weeks, the eosinophils in induced sputum were 27.0% in NR and 4.5% in R (p = 0.05), with no difference in IL-5 concentrations (p = 0.743). Peripheral eosinophilia decreased significantly in NR (p = 0.032) and R (p = 0.002). In patients with SEA on anti-IL-5 therapy, there was a marked difference in airway eosinophilic inflammation between R and NR already at 16 weeks, after anti-IL-5 introduction.
DiRROS - Published: 13.01.2022; Views: 284; Downloads: 150
.pdf Fulltext (805,99 KB)

Solid cancer patients achieve adequate immunogenicity and low rate of severe adverse events after SARS-CoV-2 vaccination
Urška Janžič, Urška Bidovec, Katja Mohorčič, Loredana Mrak, Nina Fokter Dovnik, Marija Ivanović, Maja Ravnik, Marina Čakš, Erik Škof, Jerneja Debeljak, Peter Korošec, Matija Rijavec, 2022

Abstract: Background: SARS-CoV-2 vaccination in cancer patients is crucial to prevent severe COVID-19 disease course. Methods: This study assessed immunogenicity of cancer patients on active treatment receiving mRNA-based SARS-CoV-2 vaccine by detection of anti-SARS-CoV-2 S1 IgG antibodies in serum, before, after the first and second doses and 3 months after a complete primary course of vaccination. Results were compared with healthy controls. Results: Of 112 patients, the seroconversion rate was 96%. A significant reduction in antibody levels was observed 3 months after vaccination in patients receiving immune checkpoint inhibitors versus control participants (p < 0.001). Adverse events were mostly mild. Conclusion: Immunogenicity after mRNA-based vaccine in cancer patients is adequate but influenced by the type of anticancer therapy. Antibody levels decline after 3 months, and thus a third vaccination is warranted.
Keywords: onkološko zdravljenje, imunogenost, osnovno cepljenje mRNA, čvrsti tumorji, anticancer treatment, immunogenicity, mRNA-based vaccination, solid cancer
DiRROS - Published: 24.06.2022; Views: 41; Downloads: 15
.pdf Fulltext (2,03 MB)

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