Improved clinicopathologic assessments of acute liver damage due to trauma in Indian ring-necked parakeets (Psittacula krameri manillensis).

Increased activities of certain biochemical enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], lactate dehydrogenase [LDH], alkaline phosphatase [ALP]) have been associated with blunt liver injury in many species. To evaluate changes in plasma hepatic biochemical parameters in acute avian liver disease caused by trauma and to compare biochemical changes with histologic lesions in hepatic parenchyma, 30 healthy fasted Indian ring-necked parakeets (Psittacula krameri manillensis) were divided into 2 groups, and traumatic liver injury was caused by endoscopic liver biopsy (group 1) or by liver biopsy and crushing injury to the hepatic parenchyma with endoscopic forceps (group 2) in anesthetized birds. Blood samples were collected at baseline and at 12, 24, 36, 48, 60, 72, 84, 96, 108, and 120 hours in alternate groups to compare analyte values after injury with those at baseline. Results showed consistently decreased plasma ALP activity (excluding 1 time point) throughout the study, which was thought to be associated with isoflurane administration. Plasma glutamate dehydrogenase activity initially increased but rapidly declined thereafter and was attributed to acute focal hepatocellular injury. In both groups, increases in plasma AST, ALT, and LDH activities was most likely caused by muscle injury because creatine kinase activity was concurrently increased. Compared with baseline values, bile acid concentration and y-glutamyl transferase activity were not affected by liver biopsy or crush injury. Plasma sorbitol dehydrogenase activity was the most specific indicator of liver injury in both groups. Histologic changes correlated poorly with biochemical results, possibly because the small area of hepatic parenchyma that was damaged did not affect enzyme values substantially.

Functional and metabolic fitness of human CD4+ T lymphocytes during metabolic stress.

Human CD4+ T cells are essential mediators of immune responses. By altering the mitochondrial and metabolic states, we defined metabolic requirements of human CD4+ T cells for in vitro activation, expansion, and effector function. T-cell activation and proliferation were reduced by inhibiting oxidative phosphorylation, whereas early cytokine production was maintained by either OXPHOS or glycolytic activity. Glucose deprivation in the presence of mild mitochondrial stress markedly reduced all three T-cell functions, contrasting the exposure to resveratrol, an antioxidant and sirtuin-1 activator, which specifically inhibited cytokine production and T-cell proliferation, but not T-cell activation. Conditions that inhibited T-cell activation were associated with the down-regulation of 2',5'-oligoadenylate synthetase genes via interferon response pathways. Our findings indicate that T-cell function is grossly impaired by stressors combined with nutrient deprivation, suggesting that correcting nutrient availability, metabolic stress, and/or the function of T cells in these conditions will improve the efficacy of T-cell-based therapies.

A Public Health Antibody Screening Indicates a 6-Fold Higher SARS-CoV-2 Exposure Rate than Reported Cases in Children.

BACKGROUND: Antibody responses to virus reflect exposure and potential protection. METHODS: We developed a highly specific and sensitive approach to measuring antibodies against SARS-CoV-2 for population-scale immune surveillance. Antibody positivity was defined as a dual-positive response against both the receptor-binding domain and nucleocapsid proteins of SARS-CoV-2. Antibodies were measured by immunoprecipitation assays in capillary blood from 15,771 children aged 1 to 18 years living in Bavaria, Germany, and participating in a public health type 1 diabetes screening program (ClinicalTrials.gov: NCT04039945), in 1,916 dried blood spots from neonates in a Bavarian screening study (ClinicalTrials.gov: NCT03316261), and in 75 SARS-CoV-2-positive individuals. Virus positive incidence was obtained from the Bavarian health authority data. FINDINGS: Dual-antibody positivity was detected in none of the 3,887 children in 2019 (100% specificity) and 73 of 75 SARS-CoV-2-positive individuals (97.3% sensitivity). Antibody surveillance in children during 2020 resulted in frequencies of 0.08% in January to March, 0.61% in April, 0.74% in May, 1.13% in June, and 0.91% in July. Antibody prevalence from April 2020 was 6-fold higher than the incidence of authority-reported cases (156 per 100,000 children), showed marked variation between the seven Bavarian regions (p < 0.0001), and was not associated with age or sex. Transmission in children with virus-positive family members was 35%. 47% of positive children were asymptomatic. No association with type 1 diabetes autoimmunity was observed. Antibody frequency in newborns was 0.47%. CONCLUSIONS: We demonstrate the value of population-based screening programs for pandemic monitoring. FUNDING: The work was supported by funding from the BMBF (FKZ01KX1818).

CD4+ T cell activation, function, and metabolism are inhibited by low concentrations of DMSO.

Dimethyl sulfoxide (DMSO) is a polar organic solvent used in a wide range of biological applications. DMSO is routinely used as a cryoprotectant for long-term cell freezing as well as to dissolve peptides and drugs for immune cell functional assays. Here, human CD4+ T cell activation, cytokine production, proliferation, and metabolism were investigated after stimulation in the presence of 0.01% to 1%, DMSO, representing concentrations commonly used in vitro. Surface expression of the activation markers CD69, CD25 and CD154 after polyclonal activation of CD4+ T cells was inhibited by 0.25% or higher concentrations of DMSO. The frequencies of IL-21+, IL-4+, and IL-22+ CD4+ T cells, following polyclonal activation were variably inhibited by DMSO at concentrations ranging from 0.25% to 1%, whereas IFNγ+ cells were unaffected. CD4+ T cell proliferation after anti-CD3 or antigen stimulation was inhibited by 0.5% DMSO and abolished by 1% DMSO. After polyclonal stimulation, glucose uptake was inhibited in the presence of 1% DMSO, but only minor effects on CD4+ T cell respiration were observed. Consistent with the immune effects, the gene expression of early signaling and activation pathways were inhibited in CD4+ T cells in the presence of 1% DMSO. Our study revealed that DMSO at concentrations generally used for in vitro studies of T cells impacts multiple features of T cell function. Therefore, we urge care when adding DMSO-containing preparations to T cell cultures.