Selective inhibition by alcohol and cortisol of natural killer cell activity of lymphocytes from cord blood

Natural killer cells immunosenescence and the impact of lifestyle management

Natural killer cells (NKs) are lymphocytes of the innate immune system that quickly respond to viruses, infections, and tumors during their short cell life cycle. However, it was recently found that NKs undergo quantitative, distributional, structural, and functional phenotypic changes during aging that suppress immune responses, which is known as immunosenescence. The aging host environment, cytokine regulation, cytomegalovirus status, and hypothalamic‒pituitary‒adrenal axis have significant effects on NK function. Different lifestyle management interventions modulate the number and cytotoxic activity of NKs, which are essential for rebuilding the immune barrier against pathogens in elderly individuals. Based on recent studies, we review the phenotypic changes of and potential threats of NKs during aging and explore the underlying mechanisms. By summarizing the effects of lifestyle management on NKs and their application prospects, we aim to provide evidence for enhancing immune system function against immune diseases in elderly individuals.

Effect of ethanol on mouse hepatitis virus-induced cytotoxicity

The effect of ethanol on cells infected with mouse hepatitis virus (MHV) was investigated. After MHV infection of competent cells, NCTC1469, ethanol was added to the culture at various concentrations, and the viability of cells was measured using 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide. To examine the possible involvement of the ethanol metabolite, acetaldehyde, alcohol dehydrogenase activity was measured in NCTC1469 cells. Ethanol alone did not show cytotoxicity against NCTC1469 cells at concentrations from 0.125% to 2%. After infection with MHV, the viability of cells decreased, and this decrease was further enhanced, dose-dependently, by the addition of ethanol. The activity of alcohol dehydrogenase in the cells was below the detectable level. The same phenomena were also demonstrated in cells infected with influenza virus and Herpes simplex virus. These results demonstrate that ethanol enhances MHV-mediated cytotoxicity; this exacerbation of cytotoxicity by ethanol is suggested to be an effect common to cytopathic virus-infected cells.