Hamzeh Sarvnaz; Sahar Asadi-Asadabad; Mohammad Mehdi Amiri; Mojgan Ghaedi; Ulrike Protzer; Mahmood Jeddi-Tehrani; Forough Golsaz-Shirazi; Fazel Shokri
Abstract
Background: Human polyclonal plasma-derived hepatitis B immunoglobulin (HBIG) is currently used for immunoprophylaxis of HBV infection. The development of virus-neutralizing monoclonal antibodies (MAbs) requires the use of optimized cell culture systems supporting HBV infection.Objective: This study ...
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Background: Human polyclonal plasma-derived hepatitis B immunoglobulin (HBIG) is currently used for immunoprophylaxis of HBV infection. The development of virus-neutralizing monoclonal antibodies (MAbs) requires the use of optimized cell culture systems supporting HBV infection.Objective: This study aims to optimize the hepatitis B virus infectivity of NTCP-reconstituted HepG2 (HepG2-NTCP) cells to establish an efficient system to evaluate the HBV-neutralizing effect of anti-HBs MAbs.Methods: Serum-derived HBV (sHBV) and cell culture-derived HBV (ccHBV) were simultaneously used for the optimization of HBV infection in HepG2-NTCP cells by applying different modifications.Results: Our results for the first time showed that in addition to human serum, monkey serum could significantly improve ccHBV infection, while fetal and adult bovine serum as well as duck and sheep serum did not have a promotive effect. In addition, sHBV and ccHBV infectivity are largely similar except that adding 5% of PEG, which is commonly used to improve in vitro infection of ccHBV, significantly reduced sHBV infection. We showed that a combination of spinoculation, trypsinization, and also adding human or monkey serum to HBV inoculum could significantly improve the permissivity of HepG2-NTCP cells to HBV infection compared with individual strategies. All anti-HBs MAbs were able to successfully neutralize both ccHBV and sHBV infection in our optimized in vitro system.Conclusion: Our study suggests different strategies for improving ccHBV and sHBV infection in HepG2-NTCP cells. This cell culture-based system allows assessment of HBV neutralizing MAbs and may also prove to be valuable for the analysis of other HBV neutralizing therapeutics.
Danesh Hassani; Mohammad Mehdi Amiri; Faezeh Maghsood; Vahid Salimi; Gholam Ali Kardar; Omid Barati; Seyed Mohammad Reza Hashemian; Mahmood Jeddi-Tehrani; Amir-Hassan Zarnani; Fazel Shokri
Abstract
Background: Incidence and severity of SARS-CoV2 infection are significantly lower in children and teenagers proposing that certain vaccines, routinely administered to neonates and children may provide cross-protection against this emerging infection. Objective: To assess the cross-protection induced ...
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Background: Incidence and severity of SARS-CoV2 infection are significantly lower in children and teenagers proposing that certain vaccines, routinely administered to neonates and children may provide cross-protection against this emerging infection. Objective: To assess the cross-protection induced by prior measles, mumps and rubella (MMR) vaccinations against COVID-19. Methods: The antibody responses to MMR and tetanus vaccines were determined in 53 patients affected with SARS-CoV2 infection and 52 age-matched healthy subjects. Serum levels of antibodies specific for NP and RBD of SARS-CoV2 were also determined in both groups of subjects with ELISA. Results: Our results revealed significant differences in anti-NP (p <0.0001) and anti-RBD (p <0.0001) IgG levels between patients and healthy controls. While the levels of rubella- and mumps specific IgG were not different in the two groups of subjects, measles-specific IgG was significantly higher in patients (p <0.01). The serum titer of anti-tetanus antibody, however, was significantly lower in patients compared to healthy individuals (p <0.01). Conclusion: Our findings suggest that measles vaccination triggers those B cells cross-reactive with SARS-CoV2 antigens leading to the production of increased levels of measles-specific antibody.
Amir Hassan Zarnani; Pouneh Dokouhaki; Mahmood Jeddi-Tehrani
Volume 1, Issue 3 , December 2004, , Pages 143-153
Abstract
Indoleamine 2,3-dioxygenase (IDO), an enzyme involved in the catabolism of tryptophan, is expressed by a variety of cells and tissues such as macrophages, dendritic cells, cells of the endocrine system and by the placenta. IFN- γ is the main inducer of this enzyme. IDO acts as an important defense ...
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Indoleamine 2,3-dioxygenase (IDO), an enzyme involved in the catabolism of tryptophan, is expressed by a variety of cells and tissues such as macrophages, dendritic cells, cells of the endocrine system and by the placenta. IFN- γ is the main inducer of this enzyme. IDO acts as an important defense mechanism of innate immunity against pathogens. It also has tumor suppressive activity and prolongs the survival of allograft. One of the interesting functions of IDO is prevention of the allogenic fetus rejection during pregnancy by inhibiting alloreactive T cells. It was shown that inhibition of IDO activity by IDO inhibitor, 1-methyl tryptophan, during mouse pregnancy causes fetal rejection. The main mechanism by which IDO protects fetus is through reducing the tryptophan level and suppressing the T cell activity in the feto-maternal interface. In this review the biological functions of IDO with emphasis on its role in allogeneic fetus protection have been discussed.