Researcher:
Barlas, Tayfun

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Researcher

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Tayfun

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Barlas

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Barlas, Tayfun

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2022 - 20233

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Researcher Of Publications: search.filters.isAuthorOfPublication.87500e14-323a-4d44-aac2-f91c37b9d58e

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Now showing 1 - 3 of 3
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    A complicated case of monkeypox and viral shedding characteristics
    (Elsevier, 2023) N/A; N/A; Kapmaz, Mahir; Uymaz, Derya Salim; Özcan, Gülin; Barlas, Tayfun; Esken, Gülen Güney; Manici, Mete; Keske, Şiran; Kuşkucu, Mert Ahmet; Can, Füsun; Ergönül, Önder; Doctor; Teaching Faculty; Researcher; Researcher; Researcher; Faculty Member; Faculty Member; Researcher; Faculty Member; Faculty Member; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); N/A; School of Medicine; Graduate School of Health Sciences; N/A; N/A; School of Medicine; School of Medicine; N/A; School of Medicine; School of Medicine; Koç University Hospital; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 175554; N/A; N/A; N/A; 113502; 125555; N/A; 103165; 110398
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    Effect of BTN162b2 and CoronaVac boosters on humoral and cellular immunity of individuals previously fully vaccinated with CoronaVac against SARS-CoV-2: A longitudinal study
    (Wiley, 2022) Midilli, Kenan; Tok, Yesim; Yavuz, Serap Simsek; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; Kuloğlu, Zeynep Ece; El, Rojbin; Esken, Gülen Güney; Talay, Zeynep Gülce; Barlas, Tayfun; Kuşkucu, Mert Ahmet; Albayrak, Özgür; Doğan, Özlem; Ergönül, Önder; Can, Füsun; Researcher; Master Student; Other; Researcher; Researcher; Faculty Member; Researcher; Faculty Member; Faculty Member; Faculty Member; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); N/A; Graduate School of Sciences and Engineering; N/A; N/A; N/A; School of Medicine; N/A; School of Medicine; School of Medicine; School of Medicine; N/A; N/A; N/A; N/A; N/A; N/A; Koç University Hospital; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 170418; 110398; 103165
    Background It is essential to know about immune response levels after booster doses of the two different types of vaccines, mRNA, and the inactivated, currently used against COVID-19. For this purpose, we aimed to determine the effects of BNT162b2 (BNT) and CoronaVac (CV) boosters on the humoral and cellular immunity of individuals who had two doses of CV vaccination. Methods The study was conducted in three centers (Koc University Hospital, Istanbul University Cerrahpasa Hospital, and Istanbul University, Istanbul Medical School Hospital) in Istanbul, Turkey. Individuals who had been previously immunized with two doses of CV and no history of COVID-19 were included. The baseline blood samples were collected 3-5 months after the second dose of CV. Follow-up blood samples were taken 1 and 3 months after administration of third doses of CV, or one dose of BNT boosters. Neutralizing antibody titers were measured by plaque reduction assay. The CD4+ T cell, CD8+ T cell, effector CD4+CD38+CD69+ T cell, and effector CD8+CD38+CD69+ T cell ratios were determined by flow cytometry. The intracellular IFN-gamma and IL-2 responses were measured by ELISpot assay. Results We found a 3.38-fold increase in neutralizing antibody geometric mean titers (NA GMT, 78.69) 1 month after BNT booster and maintained at the third month (NA GMT, 80). Nevertheless, in the CV booster group, significantly lower NA GMT than BNT after 1 month and 3 months were observed (21.44 and 28.44, respectively) (p < .001). In the ELISpot assay, IL-2 levels after BNT were higher than baseline and CV booster (p < .001) while IFN-gamma levels were significantly higher than baseline (p < .001). The CD8+CD38+CD69+ and CD4+CD38+CD69+ T cells were stimulated predominantly in the third month of the BNT boosters. Conclusion The neutralizing antibody levels after 3 months of the BNT booster were higher than the antibody levels after CV in fully vaccinated individuals. On the contrary, ratio of the effector T cells increased along with greater IFN-gamma activation after BNT booster. By considering the waning immunity, we suggest a new booster dose with BNT for the countries that already had two doses of primary CV regimens.
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    PublicationOpen Access
    Protein scaffold-based multimerization of soluble ACE2 efficiently blocks SARS-CoV-2 infection in vitro and in vivo
    (Wiley, 2022) Ulbegi Polat, Hivda; Yıldırım, İsmail Selim; Kayabölen, Alişan; Akcan, Uğur; Özturan, Doğancan; Şahin, Gizem Nur; Değirmenci, Nareg Pınarbaşı; Bayraktar, Canan; Söyler, Gizem; Sarayloo, Ehsan; Nurtop, Elif; Özer, Berna; Esken, Gülen Güney; Barlas, Tayfun; Doğan, Özlem; Karahüseyinoğlu, Serçin; Lack, Nathan Alan; Kaya, Mehmet; Albayrak, Cem; Can, Füsun; Solaroğlu, İhsan; Önder, Tuğba Bağcı; PhD Student; PhD Student; Master Student; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Health Sciences; School of Medicine; Koç University Hospital; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 170418; 110772; 120842; 10486; N/A; 103165; 102059; 184359
    Soluble ACE2 (sACE2) decoys are promising agents to inhibit SARS-CoV-2, as their efficiency is unlikely to be affected by escape mutations. However, their success is limited by their relatively poor potency. To address this challenge, multimeric sACE2 consisting of SunTag or MoonTag systems is developed. These systems are extremely effective in neutralizing SARS-CoV-2 in pseudoviral systems and in clinical isolates, perform better than the dimeric or trimeric sACE2, and exhibit greater than 100-fold neutralization efficiency, compared to monomeric sACE2. SunTag or MoonTag fused to a more potent sACE2 (v1) achieves a sub-nanomolar IC50, comparable with clinical monoclonal antibodies. Pseudoviruses bearing mutations for variants of concern, including delta and omicron, are also neutralized efficiently with multimeric sACE2. Finally, therapeutic treatment of sACE2(v1)-MoonTag provides protection against SARS-CoV-2 infection in an in vivo mouse model. Therefore, highly potent multimeric sACE2 may offer a promising treatment approach against SARS-CoV-2 infections.