ChAdOx1-S adenoviral vector vaccine applied intranasally elicits superior mucosal immunity compared to the intramuscular route of vaccination.

COVID-19 vaccines prevent severe forms of the disease, but do not warrant complete protection against breakthrough infections. This could be due to suboptimal mucosal immunity at the site of virus entry, given that all currently approved vaccines are administered via the intramuscular route. In this study, we assessed humoral and cellular immune responses in BALB/c mice after intranasal and intramuscular immunization with adenoviral vector ChAdOx1-S expressing full-length Spike protein of SARS-CoV-2. We showed that both routes of vaccination induced a potent IgG antibody response, as well as robust neutralizing capacity, but intranasal vaccination elicited a superior IgA antibody titer in the sera and in the respiratory mucosa. Bronchoalveolar lavage from intranasally immunized mice efficiently neutralized SARS-CoV-2, which has not been the case in intramuscularly immunized group. Moreover, substantially higher percentages of epitope-specific CD8 T cells exhibiting a tissue resident phenotype were found in the lungs of intranasally immunized animals. Finally, both intranasal and intramuscular vaccination with ChAdOx1-S efficiently protected the mice after the challenge with recombinant herpesvirus expressing the Spike protein. Our results demonstrate that intranasal application of adenoviral vector ChAdOx1-S induces superior mucosal immunity and therefore could be a promising strategy for putting the COVID-19 pandemic under control.

Effect of olive oil on brain's lipid and calcium content after partial hepatectomy in mice.

The aim of this study was to investigate the influence of olive oil (00) enriched diet on the lipid content of mice brain during the early phase of liver regeneration and to test a relationship of these changes with calcium content. C57BI mice were fed over 21 days with diet enriched with olive oil, containing predominantly oleic acid (18:1n-9). The animals were one-third partially hepatectomised (pHx) under aether anaesthesia. Total lipids were extracted from tissue samples with a chloroform-methanol (2:1, v/v) mixture according to Folch et al. Mineral concentration was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) after microwave brain tissue digestion. The diet containing 00 increased both total lipid content and the calcium concentration in brain during the early phase of liver regeneration (12hrs post pHx), suggesting that monounsaturated oleic acid might interact with some metal-dependent activities that control changes in the brain during liver regeneration.