Assessing anti-SARS-CoV-2 cellular immunity in 571 vaccines by using an IFN-γ release assay.

Memory T cell responses have been analyzed only in small cohorts of COVID-19 vaccines. Herein, we aimed to assess anti-SARS-CoV-2 cellular immunity in a large cohort using QuantiFERON assays, which are IFN-γ release assays (IGRAs) based on short-term whole blood culture. The study included 571 individuals receiving the viral spike (S) protein-expressing BNT162b2 mRNA vaccine. QuantiFERON assays revealed antigen-specific IFN-γ production in most individuals 8 weeks after the second dose. Simultaneous flow cytometric assays to detect T cells expressing activation-induced markers (AIMs) performed for 28 randomly selected individuals provided data correlating with the QuantiFERON data. Simultaneous IFN-γ enzyme-linked immunospot and AIM assays for another subset of 31 individuals, based on short-term peripheral blood mononuclear cell culture, also indicated a correlation between IFN-γ production and AIM positivity. These observations indicated the acquisition of T cell memory responses and supported the usability of IGRAs to assess cellular immunity. The QuantiFERON results were weakly correlated with serum IgG titers against the receptor-binding domain of the S protein and were associated with pre-vaccination infection and adverse reactions after the second dose. The present study revealed cellular immunity after COVID-19 vaccination, providing insights into the effects and adverse reactions of vaccination.

Dynamics of antibody titers and cellular immunity among Japanese healthcare workers during the 6 months after receiving two doses of BNT162b2 mRNA vaccine.

BACKGROUND: The antibody titer is known to wane within months after receiving two doses of the Pfizer-BioNTech BNT162b2 mRNA SARS-CoV-2 vaccine. However, knowledge of the cellular immune response dynamics following vaccination is limited. This study to aimed to determine antibody and cellular immune responses following vaccination, and the incidence and determinants of breakthrough infection. METHODS: This prospective cohort study a 6-month follow-up period was conducted among Japanese healthcare workers. All participants received two doses of BNT162b2 vaccine. Anti-SARS-CoV-2 antibody titers and T-cell immune responses were measured in serum samples collected at several timepoints before and after vaccination. RESULTS: A total of 608 participants were included in the analysis. Antibody titers were elevated 3 weeks after vaccination and waned over the remainder of the study period. T-cell immune responses showed similar dynamics. Six participants without predisposing medical conditions seroconverted from negative to positive on the IgG assay for nucleocapsid proteins, indicating breakthrough SARS-CoV-2 infection. Five of the six breakthrough infections were asymptomatic. CONCLUSIONS: Both humoral and cellular immunity waned within 6 months after BNT162b2 vaccination. The incidence of asymptomatic breakthrough infection within 6 months after vaccination was approximately one percent. UMIN CLINICAL TRIALS REGISTRY ID: UMIN000043340.

Young age, female sex, and presence of systemic adverse reactions are associated with high post-vaccination antibody titer after two doses of BNT162b2 mRNA SARS-CoV-2 vaccination: An observational study of 646 Japanese healthcare workers and university staff.

BACKGROUND: SARS-CoV-2 vaccination has started worldwide, including Japan. Although high rates of vaccine response and adverse reactions of BNT162b2 vaccine have been reported, knowledge about the relationship between sex differences and antibody response is limited. Furthermore, it is uncertain whether adverse reactions are associated with the vaccine response. METHODS: This prospective observational study included 673 Japanese participants working in a medical school and its affiliated hospital in Tokyo, Japan (UMIN000043340). Serum samples were collected before the first dose and three weeks after the second dose of BNT162b2 vaccine, and antibody titers against the receptor-binding domain of the spike protein of SARS-CoV-2 were measured. Answers to questionnaires about background characteristics and adverse reactions were obtained at the time of sample collection, and the relationship between antibody titers was analyzed. RESULTS: After excluding participants who did not complete receiving two doses of vaccination or two series of serum sample collection, 646 participants were analyzed. Although all participants became sero-positive after vaccination, antibody titers were highly variable among individuals (260.9-57,399.7A U/mL), with a median titer of 13478.0AU/mL. Mean titer was higher in females than in males and higher in young (≤45 years old) participants than in aged (>45 years old) participants. Participants who experienced adverse reactions demonstrated a higher antibody titer after vaccination than those without adverse reactions. Multivariable analysis demonstrated that young age, female sex, and adverse reactions after the second dose were independently related to higher antibody titers after the second dose. DISCUSSION: A favorable antibody response was observed after two doses of BNT162b2 vaccination among mostly healthy Japanese participants, especially among female and young participants. Although further investigation is essential, our results imply that the systemic adverse reactions (i.e., fever and general fatigue) are associated with a higher antibody response that indicates the acquisition of humoral immunity.

Effects of long-term administrations of aconitine on electrocardiogram and tissue concentrations of aconitine and its metabolites in mice.

Aconitum alkaloids are well known for their acute and high toxicity, for example, in the causation of severe arrhythmias leading to death. Aconitine, one of the major Aconitum alkaloids, is a highly toxic compound from the Aconitum species. However, there has been no studies reported on the influence of the chronic administration of aconitine. Thus, this study was conducted to investigate the influence of chronic administration of aconitine in experimental animal models. A dose of 1mg/kg per day was administered to the experimental animal models. We determined the concentration of aconitine and its metabolites (benzoylaconine and aconine) in organs and blood with gas chromatography/selected ion monitoring (GC/SIM). In addition, we concurrently recorded the electrocardiogram (ECG). Fifteen minutes after administration on day 0, the early aconitine administered group (acute group) revealed peak organ and blood concentration levels of aconitine with a gradual decrease, thereafter. The concentration of aconitine in organs and blood (from days 0 to 22; 90 min after the last administration of aconitine) gradually decreased according to repeated administration, whereas benzoylaconine and aconine increased. ECG revealed various types of arrhythmias. However, the frequency of arrhythmias remarkably decreased with time and repeated administration of aconitine. These results indicate two possibilities. First, the increase in the activity of aconitine metabolism. Secondly, the decrease of effectiveness to the heart due to long-term (chronic) administration of aconitine.

Ultrastructural changes during in situ early postmortem autolysis in kidney, pancreas, liver, heart and skeletal muscle of rats.

Many morphological studies of the postmortem interval were carried out under conditions in which the tissue was incubated in vitro after extirpation. However, the extirpation affects cell viability. We examined the ultrastructural changes in the kidney, pancreas, liver, heart and skeletal muscle of male Wistar rats occurring postmortem in situ. In each organ, cell edema (cell swelling), appearance of amorphous dense deposits in the mitochondria, loss of glycogen granules, dilation of the endoplasmic reticulum, clumping and margination of nuclear chromatin, and/or condensation of nuclear chromatin were observed, but the duration of the period of ultrastructural change was organ specific. Most of the ultrastructural changes occurred earlier in kidney. In hepatocytes, the morphological degeneration occurred later than in the renal tubule epithelium and earlier than that in the myocardium. Of the five organs we examined, skeletal muscle showed the greatest delay in postmortem change. In the distal tubule epithelium and pancreatic acinar cells, two forms of nuclear change were seen: one resembled necrotic change and the other resembled apoptotic change. The effect of lysosomes and hydrolytic enzymes was not as great as previous findings.

Dose and time changes in liver alcohol dehydrogenase (ADH) activity during acute alcohol intoxication involve not only class I but also class III ADH and govern elimination rate of blood ethanol.

BACKGROUND: The elimination rate of blood ethanol usually depends on the activity of liver alcohol dehydrogenase (ADH). During acute alcohol intoxication, however, it is unclear how liver ADH activity changes with dose and time and what the involvement is of the two major isozymes of liver ADH: the classically known class I ADH and the very high Km class III ADH. We investigated dose- and time-wise changes in liver ADH activity and the contents of both ADHs by administering ethanol to mice, and analyzed the relationship among these ADH parameters to assess the contributions of these ADHs to liver ADH activity and ethanol metabolism in vivo. METHODS: Mice were given ethanol doses of 0, 1, 3 or 5 g/kg body weight and killed 0.5, 1, 2, 4, 8 or 12 h after administration. The elimination rate of blood ethanol was calculated from the regression line fitted to the blood ethanol curve. The liver ADH activity of crude extract was conventionally measured with 15 mM ethanol as a substrate. The liver class I and class III ADH contents were determined by enzyme immunoassay. These three ADH parameters were statistically analyzed. RESULTS: The change in liver ADH activity depended on both dose and time (P<0.001 by two-way ANOVA, n=74), but the change in the class I content depended on dose alone (P<0.0001). The class III content depended on both dose and time (P<0.001) with a time course similar to that of liver ADH activity for each dose. The sum of the class I and class III contents exhibited a higher correlation with liver ADH activity (r=0.882, P<0.0001) than the class I content alone did (r=0.825). The mean liver ADH activity during ethanol metabolism for each dose correlated significantly with the elimination rate of blood ethanol (r=0.970, P<0.0001). CONCLUSION: Liver ADH activity changes dose and time dependently during acute alcohol intoxication and governs the elimination rate of blood ethanol through the involvement not only of class I but also of class III ADH.