Specific immune responses after BNT162b2 mRNA vaccination and COVID-19 infection.

Although vaccines against COVID-19 are effective tools in preventing severe disease, recent studies have shown enhanced protection after vaccine boosters. The aim of our study was to examine the dynamics and duration of both humoral and cellular immune responses following a three-dose regimen of the BNT162b2 mRNA vaccine. In a longitudinal prospective study we enrolled 86 adults who received the BNT162b2 vaccine, 35 unvaccinated individuals with a history of mild COVID-19 and a control group of 30 healthy SARS-CoV-2 seronegative persons. We assessed the SARS-CoV-2-specific T cell responses and IgG production up to 12 months post the third BNT162b2 dose in 24 subjects. The vaccinated group had significantly higher IgG antibody levels after two doses compared to the convalescent group (p<0.001). After the third dose, IgG levels surged beyond those detected after the second dose (p<0.001). Notably, these elevated IgG levels were maintained 12 months post the third dose. After two doses, specific T cell responses were detected in 87.5% of the vaccinated group. Additionally, there was a significant decrease before the third dose. However, post the third dose, specific T cell responses surged and remained stable up to the 12-month period. Our findings indicate that the BNT162b2 vaccine induces potent and enduring humoral and cellular responses, which are notably enhanced by the third dose and remain persistant without a significant decline a year after the booster. Further research is essential to understand the potential need for subsequent boosters.

[A case of botulism in the Czech Republic and current possibilities for detecting the neurotoxin produced by Clostridium botulinum].

In the Czech Republic, botulism is a rare life-threatening disease. A total of 155 cases have been reported since 1960; according to the ISIN (formerly EPIDAT) database, there have been only three isolated cases since 2013, with the exception of a single occurrence of familial botulism in 2013. In our work, we present the occurrence of botulism after ingestion of pâté of untraceable origin by a couple who were hospitalized for botulotoxin food poisoning in July 2022. Their neurological symptoms were dominated by dysarthria. After administration of antibotulinum serum, their condition improved significantly. Patient samples were analyzed using affinity carriers and MALDI mass spectrometry, a modern highly sensitive technique for detecting the presence of botulinum neurotoxins. Unlike traditional detection by a difficult and costly biological experiment on mice, the above analysis does not require the killing of laboratory animals.

Elevated regulatory T cells after antibiotic treatment of infectious spondylodiscitis as biomarker of recovery?

Dysregulated systemic immune responses during infectious spondylodiscitis (IS) may impair microbial clearance and bone resorption. Therefore, the aim of the study was to examine whether circulating regulatory T cells (Tregs) are elevated during IS and whether their frequency is associated with alterations in T cells and the presence of markers of bone resorption in the blood. A total of 19 patients hospitalized with IS were enrolled in this prospective study. Blood specimens were obtained during hospitalization and 6 weeks and 3 months after discharge. Flow cytometric analysis of CD4 and CD8 T cell subsets, the percentage of Tregs and serum levels of collagen type I fragments (S-CrossLap) were performed. Out of 19 enrolled patients with IS, microbial etiology was confirmed in 15 (78.9%) patients. All patients were treated with antibiotics for a median of 42 days, and no therapy failure was observed. Next, a significant serum C-reactive protein (S-CRP) decrease during the follow-up was observed, whereas the frequencies of Tregs remained higher than those of controls at all-time points (p < 0.001). In addition, Tregs demonstrated a weak negative correlation with S-CRP and S-CrossLap levels were within the norm at all-time points. Circulating Tregs were elevated in patients with IS and this elevation persisted even after the completion of antibiotic therapy. Moreover, this elevation was not associated with treatment failure, altered T cells, or increased markers of bone resorption.

Acute phase of COVID-19 is associated with elevated plasmablasts in the blood.

OBJECTIVES: The study was aimed at the characterization of humoral immunity in acute SARS-CoV-2 infection. BACKGROUND: Humoral immunity plays a central role in the protection from infection due to SARS-CoV-2, causative agent of coronavirus diseases 2019 (COVID-19). PATIENTS AND METHODS: In 24 adult patients hospitalized with COVID-19, the functional subsets of circulating B-lymphocytes and SARS-CoV-2 specific IgA and IgG antibodies were analyzed using a flow cytometry and immunoassays, respectively. RESULTS: Circulating plasmablasts and memory B-lymphocytes were significantly elevated and regulatory B-lymphocytes significantly decreased in the patients in comparison with 11 age- and sex-matched SARS-CoV-2 seronegative healthy adults. Next, circulating plasmablasts correlated negatively with the levels of SARS-CoV-2 specific IgG antibodies, which were detectable in 9 out of 15 tested patients. In addition, SARS-CoV-2 specific IgA antibodies were detectable in 13 of 15 tested patients and did not demonstrate correlation with any B-lymphocyte subset. CONCLUSION: Severe course of COVID-19 is associated with significant changes of phenotypes of circulating B-lymphocytes and elevated circulating plasmablasts correlate with decreased SARS-CoV-2-specific IgG antibodies (Tab. 2, Fig. 3, Ref. 14).