For almost nearly a century, memory functions have been attributed only to acquired immune cells. Lately, this paradigm has been challenged by an increasing number of studies revealing that innate immune cells are capable of exhibiting memory-like features resulting in increased responsiveness to subsequent challenges, a process known as trained immunity (known also as innate memory). In contrast, the refractory state of endotoxin tolerance has been defined as an immunosuppressive state of myeloid cells portrayed by a significant reduction in the inflammatory capacity. Both training as well tolerance as adaptive features are reported to be accompanied by epigenetic and metabolic alterations occurring in cells. While training conveys proper protection against secondary infections, the induction of endotoxin tolerance promotes repairing mechanisms in the cells. Consequently, the inappropriate induction of these adaptive cues may trigger maladaptive effects, promoting an increased susceptibility to secondary infections—tolerance, or contribute to the progression of the inflammatory disorder—trained immunity. This review aims at the discussion of these opposing manners of innate immune and non-immune cells, describing the molecular, metabolic and epigenetic mechanisms involved and interpreting the clinical implications in various inflammatory pathologies.

Aim: The aim of our study was to compare the durability of BNT162b2 antibody response between male and female healthcare workers (HCWs), before vaccination and at 3, 9 and 12 months after administration of the second dose of the Pfizer/BioNTech BNT162b2 vaccine, using three antibody assays: Maglumi® SARS-CoV-2 Neutralizing Antibody (CLIA), Maglumi® SARS-CoV-2 S-RBD IgG (CLIA) and VIDAS® SARS-CoV-2 IgG (ELFA). Material and methods: This study included 200 HCWs and the gender structure of the participants consisted of 41% males and 59% females. We utilized blood samples collected from HCWs who had not previously been infected with SARS-CoV-2. All procedures strictly followed the manufacturer's instructions. Results: Male and female HCWs had similar serum anti-S-RBD IgG concentrations before vaccination. Our findings showed the highest concentration of antibodies three months after vaccination in both genders, where females had non-significantly higher serum anti-S-RBD IgG antibodies with all three methods. Nine months after vaccination, females had significantly lower serum anti-S-RBD IgG measured with Maglumi Neutralizing Antibody (median 161 vs. 167 BAU/mL, p=0.017). However, at this time point, the difference between males and females was statistically insignificant regarding the serum values of anti-S-RBD IgG measured with Maglumi RBD (median 171.54 vs. 165.22 BAU/mL, p=0.38) and VIDAS RBD (68.16 vs. 103.3 BAU/mL, p=0.75). The level of anti-spike-RBD antibodies significantly decreased during 12 months after vaccination in males and females, (p<0.0001) determined by all three methods. Conclusion: Our results demonstrated that there were no significant differences in SARS-CoV-2 IgG antibody concentrations between male and female HCWs.

Stress can be a reason for some physiological and biological disorders in the body. The antioxidative defense system is necessary for the maintenance of redox homeostasis in the organisms. Alkaline water (AW) is in the focus of the scientific interest due to its antioxidative effect. The treatment with AW and sodium ascorbate (SA) is expected to have potential preventive effect on the organism to hyperthermic stress. The aim of this study was to investigate the effect of AW and SA on glucose and cortisol levels during acute hyperthermic stress, in white female Wistar laboratory rats. The rats were divided into three groups, each having 10 subjects. They were exposed in hyperthermic conditions (41˚C) for 80 min, in 21 consecutive days in order to induce oxidative stress. The first group received drinkable water (control group), the second AW, and the third, AW and SA. Plasma glucose levels were determined by colorimetric method. Cortisol level was measured by the enzyme-linked immunosorbent assay method (ELISA). The means were compared using the Tukey test. Differences were considered significant at a level of p<0.05. Our results showed that levels of glucose and cortisol were significantly higher in the group treated with AW on the 21^st day after treatment (p<0.0001), but not on the 7^th and 14^th day as compared to the control group. Also, co-treatment of animals with AW and SA had significantly increased the levels of glucose and cortisol on the 21^st day after treatment, indicating a synergistic effect. In conclusion, the individual action of AW or in synergism with SA caused a high protective effect on oxidative damage in white Wistar laboratory rats.

Objectives: The aim of this study was to describe the effectiveness of the vaccines (Tozinameran and Sputnik V), administered on a convenience sample of healthcare workers, and also to describe the relationship between the levels of neutralizing antibodies (NAbs) and the type of vaccine used, as well as their association with incident cases during follow-up. Methods: The study included 262 participants, who underwent vaccination during the period from September 2021 until August 2022. For determining the levels of NAbs we used the CLIA based method, and all the samples were processed with the SNIBE Maglumi 800 analyzer. The patients were observed for one year for occurrence of incident infection. Results: The participants with prior SARS-CoV-2 positivity showed substantially higher titer of NAbs (8.86 vs. 0.94, p<0.001). The participants in the Gam-COVID-Vac group had median levels of NAbs of 1.57 (IQR 0.42–5.73), while they in the Tozinameran group showed substantially higher levels of 2.37 (IQR 0.9–6.27). The incident cases after immunization had substantially lower median values of NAbs when compared to the rest (0.48 vs. 3.97, p<0.001), and the interval between the second dose and the serological measurements were similar. Conclusions: The current study showed that the tested vaccines demonstrated vaccine effectiveness of over 50 % during the first year after the vaccination in a sample of health care workers. Although health care workers remain separate population group, when compared to the rest, the results could be extrapolated to populations with similar age and immune experience.