Biology subjects

Ovali, E.

Publications and source records attributed to Ovali, E..

7 recordsLinked to original sources

bioRxiv2023

The Effect of Amniotic Fluid On Haıir Follicle Growth

Human amniotic fluid stem cell (hAFSC) exhibit significantly as a new treatment modality in hair loss, wound, scar and regenerative plastic surgery/dermatology. The difference of our study from previous amniotic fluid studies on the hair growth model was studied through the direct effect of human amniotic fluid (hAF). In our study, amniotic fluid was made acellular, pooled and freezed, making it more standardized in terms of its contents. Therefore, the present study is aimed at investigating the efficacy and safety of amniotic fluid in hair loss model on rat. Using the hair loss model rats, we investigated the therapeutic potential of freezing amniotic fluid (FAF) and freezing gama irradiated amniotic fluid (FAFI). Our results showed that FAF and especially FAFI increased number of total hair follicles and accelerated number of transition to anagenic hair follicle. We observed that increased rate of arginase+1(Arg+1)/CD68 activity around the hair follicles treated with hAF. Our study suggests that FAFI may represent a safe and effective tool for increasing hair follicle and accelerating to anagen stage during hair loss model.

pathology↗

bioRxiv2023

Phytohemagglutinin-Activated CAR-T Cells: Prolonged Persistence and Enhanced Anti-Tumor Response in CD19-Specific Acute Lymphoblastic Leukemia

In recent times, chimeric antigen receptor (CAR)-T cell therapy has shown rapid advancements and gained clinical approval for use in cancer immunotherapy. CAR, a synthetic receptor integrated into autologous T cells, has yielded highly successful results in patients with leukemia. The significant potential of CAR-T cells has been validated through clinical trials in adult and pediatric cancer treatments. Our therapy developed specifically for CD19-specific Acute Lymphoblastic Leukemia (ALL) has shown promising results in in vitro and in vivo tests. To enhance the response against cancer, provide a bistimulatory effect, and increase stability, we designed two different CAR structures specific to CD19. These designs incorporate the CD28 and 41BB costimulatory domains. Through in vitro analysis, we evaluated the population ratios and cytotoxic activities of Central Memory T cells (TCM) and Stem Cell Memory T cells (TSCM) in CAR-T (CAR1928-T and CAR19BB-T) cells. Our initial design, CAR1928-T, produced an effective anti-tumor response. With our second design, CAR19BB-T, we not only achieved an anti-tumor effect but also conferred memory capabilities, leading to a comprehensive treatment approach. We demonstrated that CAR-T cells produced using Phytohemagglutinin (PHA) exhibited increased persistence in vitro and in vivo compared to anti-CD3 and anti-CD28 stimulation. The use of PHA to activate CAR19BB-T cells developed a long-lasting and effective CAR-T cell production method in vivo using cancerous animal models. CAR-T cell-treated mice survived tumor-free for up to 60 days, surpassing the survival of mice that received tumors only. Additionally, CAR19BB-T cell production with PHA remained stable over time. These results highlight a novel CAR-T cell production approach with a high-memory T cell profile capable of delaying or preventing cancer relapse. We optimized the method for the production of long-term and effective CAR-T cells and tested it in preclinical experiments. As a result, it was demonstrated that CAR-T cells generated with PHA, when administered as a co-stimulatory dose, can provide continuous proliferation and long-term persistence without compromising their anti-cancer efficacy. Preclinical studies have been completed to obtain valuable data for enhancing the long-term effectiveness of CAR-T therapy in clinical trials and transitioning to clinical applications.

immunology↗

bioRxiv2022

CAR-T Cells with Phytohemagglutinin (PHA) Provide Anti-Cancer Capacity with Better Proliferation, Rejuvenated Effector Memory, and Reduced Exhausted T Cell Frequencies

The development of genetic modification techniques has led to the opening of a new era in cancer treatments that have been limited to conventional treatments such as chemotherapy. Since not only cancerous cells but also healthy cells are damaged by the drugs, intensive efforts are made to develop cancer-targeted techniques. The most promising approach is genetically modified CAR-T cell therapy. The high central memory T cell (Tcm) and stem cell-like memory T cell (Tscm) ratios in the CAR-T cell population increase the effectiveness of immunotherapy. Therefore, it is important to increase the populations of CAR-expressing Tcm and Tscm cells to ensure that CAR-T cells remain long-term and have cytotoxic (anti-tumor) efficacy. In this study, we aimed to improve CAR-T cell therapys time-dependent efficacy and stability, increasing the survival time and reducing the probability of cancer cell growth. To increase the subpopulation of Tcm and Tscm in CAR-T cells, we investigated to produce a long-term stable and cytotoxic efficient CAR-T cell by modifications in the cell activation-dependent production method using Phytohemagglutinin. Phytohemagglutinin (PHA), a lectin that binds to the membranes of T cells and increases metabolic activity and cell division, is studied to increase the Tcm and Tscm population. Although it is known that PHA significantly increases Tcm cells, B-lymphocyte antigen CD19 specific CAR-T cell expansion, its anti-cancer and memory capacity has not yet been tested compared to aCD3/aCD28. Two different types of CAR (aCD19 scFv CD8- (CD28 or 41BB)-CD3z-EGFRt) expressing T cells were generated and their immunogenic phenotype, exhausted phenotype, Tcm-Tscm populations, and cytotoxic activities were determined in this study. The proportion of T cell memory phenotype in the CAR-T cell populations generated by PHA was observed to be higher than that of aCD3/aCD28-amplified CAR-T cells with similar cytotoxic (anti-tumor) and higher proliferation capacity. Here, we show that PHA provides long-term and efficient CAR-T cell production, suggesting a potential alternative to aCD3/aCD28-amplified CAR-T cells.

cancer biology↗

bioRxiv2020

Gamma-irradiated SARS-CoV-2 vaccine candidate, OZG-38.61.3, confers protection from SARS-CoV-2 challenge in human ACEII-transgenic mice

The SARS-CoV-2 virus caused the most severe pandemic around the world, and vaccine development for urgent use became a crucial issue. Inactivated virus formulated vaccines such as Hepatitis A, oral polio vaccine, and smallpox proved to be reliable approaches for immunization for prolonged periods. During the pandemic, we produced an inactivated SARS-CoV-2 vaccine candidate, having the advantages of being manufactured rapidly and tested easily in comparison with recombinant vaccines. In this study, an inactivated virus vaccine that includes a gamma irradiation process for the inactivation as an alternative to classical chemical inactivation methods so that there is no extra purification required has been optimized. The vaccine candidate (OZG-38.61.3) was then applied in mice by employing the intradermal route, which decreased the requirement of a higher concentration of inactivated virus for proper immunization, unlike most of the classical inactivated vaccine treatments. Hence, the novelty of our vaccine candidate (OZG-38.61.3) is that it is a non-adjuvant added, gamma-irradiated, and intradermally applied inactive viral vaccine. Efficiency and safety dose (either 1013 or 1014 viral copy per dose) of OZG-38.61.3 was initially determined in Balb/c mice. This was followed by testing the immunogenicity and protective efficacy of OZG-38.61.3. Human ACE2-encoding transgenic mice were immunized and then infected with a dose of infective SARS-CoV-2 virus for the challenge test. Findings of this study show that vaccinated mice have lower SARS-CoV-2 viral copy number in oropharyngeal specimens along with humoral and cellular immune responses against the SARS-CoV-2, including the neutralizing antibodies similar to those shown in Balb/c mice without substantial toxicity. Subsequently, plans are being made for the commencement of Phase 1 clinical trial of the OZG-38.61.3 vaccine for the COVID-19 pandemic.

immunology↗

bioRxiv2020

Preliminary report of preclinical efficacy and safety analysis of gamma-irradiated inactivated SARS-CoV-2 vaccine candidates, SK-01 version 1 and OZG-3861 version 1

COVID-19 outbreak caused by SARS-CoV-2 created an unprecedented health crisis since there is no vaccine for this novel virus. Therefore, SARS-CoV-2 vaccines have become crucial for reducing morbidity and mortality. In this study, in vitro and in vivo safety and efficacy analyzes of lyophilized vaccine candidates inactivated by gamma-irradiation were performed. The candidate vaccines in this study were OZG-3861 version 1 (V1), an inactivated SARS-CoV-2 virus vaccine, and SK-01 version 1 (V1), a GM-CSF adjuvant added vaccine. The candidate vaccines were applied intradermally to BALB/c mice to assess toxicity and immunogenicity. Preliminary results in vaccinated mice are reported in this study. Especially, the vaccine models containing GM-CSF caused significant antibody production with neutralization capacity in absence of the antibody-dependent enhancement feature, when considered in terms of T and B cell responses. Another important finding was that the presence of adjuvant was more important in T cell in comparison with B cell response. Vaccinated mice showed T cell response upon restimulation with whole inactivated SARS-CoV-2 or peptide pool. This study shows that the vaccines are effective and leads us to start the challenge test to investigate the gamma-irradiated inactivated vaccine candidates for infective SARS-CoV-2 virus in humanized ACE2+ mice.

immunology↗

bioRxiv2020

SARS-CoV-2 Isolation and Propagation from Turkish COVID-19 patients

The novel coronavirus pneumonia, which was named later as Coronavirus Disease 2019 (COVID-19), is caused by the Severe Acute Respiratory Syndrome Coronavirus 2, namely SARS-CoV-2. It is a positive-strand RNA virus that is the seventh coronavirus known to infect humans. The COVID-19 outbreak presents enormous challenges for global health behind the pandemic outbreak. The first diagnosed patient in Turkey has been reported by the Republic of Turkey Ministry of Health on March 11, 2020. Today, over ninety thousand cases in Turkey, and two million cases around the world have been declared. Due to the urgent need for vaccine and anti-viral drug, isolation of the virus is crucial. Here, we report one of the first isolation and characterization studies of SARS-CoV-2 from nasopharyngeal and oropharyngeal specimens of diagnosed patients in Turkey. This study provides an isolation and replication methodology, and cell culture tropism of the virus that will be available to the research communities. Article SummaryScientists have isolated virus from Turkish COVID-19 patients. The isolation, propagation, and plaque and immune response assays of the virus described here will serve in following drug discovery and vaccine testing.

microbiology↗

bioRxiv2017

Production of Multilayer Cell Mass from Olfactory Stem Cell and Its Utilization Potential in Nervous Tissue Regeneration

BackgroundExperimental studies performed with human olfactory nerve stem cells haveshown that these cells can ameliorate nerve cell regeneration. Developing a method of repairing nerve damage solely using stem cells without the need of any supporting material is important.\n\nMethodsA multilayer cell mass was obtained from olfactory tissue-derived mesenchymal stem cells with high viability and proliferation capability using a protocol devoid of scaffolds or any other artificial supporting material. First, human olfactory tissue-derived mesenchymal stem cells were isolated, cultured, and characterized. Next, consecutive passages were conducted to obtain multilayer cell growth. The resulting cell mass could be suitable for tissue engineering models as well as nerve cell or tissue regeneration studies in the future.\n\nResultsViability and adhesive properties of the resulting cell mass were examined and found to be suitable for use in nerve tissue regeneration.\n\nConclusionIt is suggested that an in vitro-produced olfactory stem cell mass can be applied to a very small damaged region and could have a high potential for microenvironment formation.

bioengineering↗