The pathogenesis of COVID-19 involves both humoral and cellular immunological responses, with cell-mediated immunity being discussed as the primary and most effective immune response to viral infection. It is supposed that COVID-19 vaccines also elicited effective cell immune response, and specifically IFNγ secreted by SARS-CoV-2-specific T-helper 1 and Tcytotoxic cells. Using an interferon-gamma release assay (IGRA) test, we aimed to monitor cellular post-vaccination immunity in healthy subjects vaccinated with BNT162b2 mRNA COVID-19 vaccine (Comirnaty). We tested 37 healthcare workers (mean age 54.3 years, range 28-72, 22 females, 15 males) following COVID-19 mRNA COVID-19 vaccine and 15 healthy unvaccinated native persons as control subjects using QuantiFERON SARS-CoV-2 RUO test, performed approximately 1 month after vaccination. We also measured virus-neutralizing antibodies. Thirty-one out of 37 tested subjects had significantly raised levels of SARS-CoV-2 specific IFNγ against SARS-CoV-2 Ag1 and Ag2 1 month following COVID-19 vaccination. In addition, we found a significant difference between the IFNγ levels in fully vaccinated subjects and the control group (p < 0.01).We also found a substantial correlation (r = 0.9; p < 0.01) between virus-neutralizing antibodies titers and IFNγ concentrations released by T cells. We believe that IGRA tests are an excellent tool to assess the development of a post-vaccination immune response when immunized against SARS-CoV-2. However, IGRA-based tests should be performed within a few weeks following vaccination. Therefore, we can speculate that the application of these tests to assess long-term immune response is debatable. KeywordsCOVID-19 • Interferon-gamma • Interferon-gamma release assay • SARS-CoV-2 • mRNA COVID-19 vaccine • BNT162b2 vaccine • T cytotoxic cells • T helper cells • Cellular immune response • Immune memory

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Mesenchymal stem cells (MSCs) possess immunosuppressive properties and have been described in the tumor microenvironment of glioblastoma multiforme (GBM). This manuscript has two major topics—first, to describe isolated and cultured MSCs derived from GBM (GB-MSCs) and second, to examine their in vitro immunosuppressive capacity. Our results display cells with morphology and phenotype, clonogenic ability, and osteogenic potential, typical for MSCs. Furthermore, the cultured cells show intracellular expression of the neural markers Nestin and GFAP. They express PD-L1 and secrete TGFβ, CCL-2, PGE2, IL-6, and sVEGF. Coculturing of GB-MSCs with PBMCs isolated from healthy donors results in a decreased percentage of Th17 lymphocytes and an increased percentage of Tregs. Regarding the impact of GB-MSCs on monocytes, we establish an augmented expression of CD14 and CD86 along with diminished expression of HLA-DR and CD80, which is associated with tolerogenic phenotype monocyte-derived cells. In conclusion, our results describe in detail GBM-derived and cultured cells that meet the criteria for MSCs but at the same time express Nestin and GFAP. GB-MSCs express and secrete suppressive molecules, influencing in vitro T cells and monocytes, and are probably another factor involved in the immune suppression exerted by GBM.