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Generation of Ag-specific humoral responses requires the orchestrated development and function of highly specialized immune cells in secondary lymphoid organs. We used a multiparametric approach combining flow cytometry, confocal microscopy, and histocytometry to analyze, for the first time to our knowledge in children, tonsils from seasonal influenza-vaccinated children. We used these novel imaging assays to address the mucosal immune dynamics in tonsils investigating the spatial positioning, frequency, and phenotype of immune cells after vaccination. Vaccination was associated with a significantly higher frequency of follicular helper CD4 T cells compared with the unvaccinated control group. The imaging analysis revealed that potential suppressor (FOXP3hi) CD4 T cells are mainly located in extrafollicular areas. Furthermore, a significantly reduced frequency of both follicular and extrafollicular FOXP3hi CD4 T cells was found in the vaccine group compared with the control group. Levels of circulating CXCL13 were higher in those vaccinated compared with controls, mirroring an increased germinal center reactivity in the tonsils. Notably, a strong correlation was found between the frequency of tonsillar T follicular helper cells and tonsillar Ag-specific Ab-secreting cells. These data demonstrate that influenza vaccination promotes the prevalence of relevant immune cells in tonsillar follicles and support the use of tonsils as lymphoid sites for the study of germinal center reactions after vaccination in children. [ABSTRACT FROM AUTHOR]

Background: Middle East respiratory syndrome coronavirus (MERS-CoV), which belongs to beta group of coronavirus, can infect multiple host species and causes severe diseases in humans. Multiple surveillance and phylogenetic studies suggest a bat origin. In this study, we describe the detection and full genome characterization of two CoVs closely related to MERS-CoV from two Italian bats, Pipistrellus kuhlii and Hypsugo savii. Methods: Pool of viscera were tested by a pan-coronavirus RT-PCR. Virus isolation was attempted by inoculation in different cell lines. Full genome sequencing was performed using the Ion Torrent platform and phylogenetic trees were performed using IQtree software. Similarity plots of CoV clade c genomes were generated by using SSE v1.2. The three dimensional macromolecular structure (3DMMS) of the receptor binding domain (RBD) in the S protein was predicted by sequence-homology method using the protein data bank (PDB). Results: Both samples resulted positive to the pan-coronavirus RT-PCR (IT-batCoVs) and their genome organization showed identical pattern of MERS CoV. Phylogenetic analysis showed a monophyletic group placed in the Beta2c clade formed by MERS-CoV sequences originating from humans and camels and bat-related sequences from Africa, Italy and China. The comparison of the secondary and 3DMMS of the RBD of IT-batCoVs with MERS, HKU4 and HKU5 bat sequences showed two aa deletions located in a region corresponding to the external subdomain of MERS-RBD in IT-batCoV and HKU5 RBDs. Conclusions: This study reported two beta CoVs closely related to MERS that were obtained from two bats belonging to two commonly recorded species in Italy (P. kuhlii and H. savii). The analysis of the RBD showed similar structure in IT-batCoVs and HKU5 respect to HKU4 sequences. Since the RBD domain of HKU4 but not HKU5 can bind to the human DPP4 receptor for MERS-CoV, it is possible to suggest also for IT-batCoVs the absence of DPP4-binding potential. More surveillance studies are needed to better investigate the potential intermediate hosts that may play a role in the interspecies transmission of known and currently unknown coronaviruses with particular attention to the S protein and the receptor specificity and binding affinity. [ABSTRACT FROM AUTHOR]

The 2014/15 influenza season in Europe was characterised by the circulation of influenza A(H3N2) viruses with an antigenic and genetic mismatch from the vaccine strain A/Texas/50/2012(H3N2) recommended for the Northern hemisphere for the 2014/15 season. Italy, differently from other EU countries where most of the subtyped influenza A viruses were H3N2, experienced a 2014/15 season characterized by an extended circulation of two influenza viruses: A(H1N1)pdm09 and A(H3N2), that both contributed substantially to morbidity. Within the context of the existing National sentinel influenza surveillance system (InfluNet) a test-negative case-control study was established in order to produce vaccine effectiveness (VE) estimates. The point estimates VE were adjusted by age group (<5; 5–15; 15–64; 65+ years), the presence of at least one chronic condition, target group for vaccination and need help for walking or bathing. In Italy, adjusted estimates of the 2014/15 seasonal influenza VE against medically attended influenza-like illness (ILI) laboratory-confirmed as influenza for all age groups were 6.0% (95%CI: −36.5 to 35.2%), 43.6% (95%CI: −3.7 to 69.3%), −84.5% (95%CI: (−190.4 to −17.2%) and 50.7% (95% CI: −2.5 to 76.3%) against any influenza virus, A(H1N1)pdm09, A(H3N2) and B, respectively. These results suggest evidence of good VE against A(H1N1)pdm09 and B viruses in Italy and evidence of lack of VE against A(H3N2) virus due to antigenic and genetic mismatch between circulating A(H3N2) and the respective 2014/15 vaccine strain. [ABSTRACT FROM AUTHOR]

Background Immunodeficiency is an integral aspect of Down syndrome, as demonstrated by the increased susceptibility to infection of affected. Mortality is still higher than in general population, with respiratory infections among the major causes of death. As more people with Down syndrome are living today than ever before, it is indispensable to develop strategies to prevent and cure the associated disorders. Vaccination is the most successful instrument of preventive medicine. Special seasonal influenza and pneumococcal vaccination strategies have been designed for individuals with risk conditions of all ages. Down syndrome individuals are not included in the high-risk categories. Methods We enrolled in our study 15 children with Down syndrome and their siblings, vaccinated for the first time with seasonal influenza vaccine and receiving a booster dose of a glyco-conjugated pneumococcal vaccine. We compared the immunological features and response to vaccination measuring serum antibody titers and frequency of specific memory B cells. Results We confirm that a severe reduction of switched memory B cells is always associated to Down syndrome. After primary vaccination Down syndrome children generate significantly less specific switched memory B cells than their siblings. The response to a booster dose of vaccine is instead comparable in both groups. The production of specific antibodies was equally effective in Down syndrome and controls both after primary and secondary immunization. Conclusions Down syndrome individuals should be considered a high risk group, because of their increased susceptibility to infection and reduced number of switched memory B cells. Tailored vaccination protocols are needed in order to reduce their burden of infections throughout life. [ABSTRACT FROM AUTHOR]

During an influenza A(H7N7) virus outbreak among poultry in Italy during August-September 2013, infection with a highly pathogenic A(H7N7) avian influenza virus was diagnosed for 3 poultry workers with conjunctivitis. Genetic analyses revealed that the viruses from the humans were closely related to those from chickens on affected farms. [ABSTRACT FROM AUTHOR]

Highlights: [•] Anti-vector immunity affects the immunogenicity of foreign epitopes in mice. [•] Vaginal immunization with recombinant influenza virus elicits HIV-specific immunity. [•] Vaginal immunization with recombinant virus overcomes preexisting vector immunity. [ABSTRACT FROM AUTHOR]

Highlights: [•] HIV+ patients had protective HI titers prior to vaccination and did not seroconvert. [•] Influenza-specific memory B-cell responses were detected by B-cell ELISpot in HIV+. [•] Decreasing antibody but not memory B-cell responses are in HIV+ vaccinated yearly. [Copyright &y& Elsevier]

Abstract: Effective vaccination strategies for infectious diseases take into account the induction, long-term maintenance and recall of memory T-cell populations. To understand the immunological cross-talk within the mucosal compartments, we compared intranasal to vaginal immunization and demonstrated that vaginal infection of BALB/c mice with influenza A virus provides protective mucosal immunity against both homosubtypic and heterosubtypic virus challenge in the respiratory tract. We found that, prior to the viral challenge, in vaginally primed mice, antigen-specific CD8+ T cells were not detected in the lung airways and levels of serum antibodies were lower than those observed in intranasally immunized mice. However, following pulmonary challenge, NP147-specific CD8+ T cells were recruited and amplified in vaginally primed mice to the same extent as those in intranasally primed mice. Thus, the long-term memory immune response elicited by vaginal immunization with influenza virus is efficiently recalled and offers reasonable protection against infection in the respiratory tract. [Copyright &y& Elsevier]

Simple Summary: Most of the newly emerging infections arise from animal reservoirs, frequently represented by wildlife species. Western European hedgehogs (Erinaceus europaeus) are mammalian hibernators, mainly nocturnal and insectivorous, living in natural open and green spaces as well as artificial, rural and urban, areas. They are generalist predators of macro-invertebrates, but they may also eat meat, bird eggs and on occasion pet food. These ecological and feeding habits, along with their high population densities, notable synanthropic attitudes, frequent contacts with sympatric wild and domestic species, including humans, implicate the possibility of intra- and interspecies interactions accounting for the possible involvement of E. europaeus in the ecology of several potentially emerging pathogens, including coronaviruses. Using PCR-based and virus isolation methods, we found that 58.3% of 24 hedgehogs' fecal samples were PCR-positive for Erinaceus coronaviruses (EriCoVs). We did not observe any clinical disease related to the EriCoV infection in hedgehogs. However, the high mutation rates characterizing members of the Coronaviridae family and their potential successful interspecies host jumps—as that likely occurred in the Novel coronavirus (2019-nCoV) emergence—should be considered in the management of hedgehogs admitted to multi-species wildlife rehabilitation centers, recommending their return back to the original recovery areas. The Western European Hedgehog (Erinaceus europaeus) is one of the four hedgehog species belonging to the genus Erinaceus. Among them, E. amurensis is extant in East Asia's areas only, whereas E. europaeus, E. roumanicus and E. concolor are mainly found in Europe. E. europaeus is endemically distributed from western to central and southern Europe, including Italy. Western European hedgehogs' ecological and feeding habits, along with their high population densities, notable synanthropic attitudes, frequent contacts with sympatric wild and domestic species, including humans, implicate the possible involvement of E. europaeus in the ecology of potentially emerging viruses, such as coronaviruses, influenza A and influenza D viruses, canine distemper virus, pestiviruses and Aujeszky's disease virus. We examined 24 E. europaeus individuals found injured in urban and rural areas of Northern Italy. Of the 24 fecal samples collected and tested for the above-mentioned pathogens by both PCR-based and virus isolation methods, 14 were found PCR-positive for betacoronaviruses belonging to lineage C and related to the known Erinaceus coronaviruses (EriCoVs), as determined by partial sequencing of the virus genome. Our findings suggest that hedgehogs could be considered natural reservoirs of CoVs, and also act as chronic shedding carriers of these potentially emerging RNA viruses. [ABSTRACT FROM AUTHOR]

Background: Since 1985, two antigenically distinct lineages of influenza B viruses (Victoria-like and Yamagata-like) have circulated globally. Trivalent seasonal influenza vaccines contain two circulating influenza A strains but a single B strain and thus provide limited immunity against circulating B strains of the lineage not included in the vaccine. In this study, we describe the characteristics of influenza B viruses that caused respiratory illness in the population in Italy over 13 consecutive seasons of virological surveillance, and the match between the predominant influenza B lineage and the vaccine B lineage, in each season.Methods: From 2004 to 2017, 26,886 laboratory-confirmed influenza cases were registered in Italy, of which 18.7% were type B. Among them, the lineage of 2465 strains (49%) was retrieved or characterized in this study by a real-time RT-PCR assay and/or sequencing of the hemagglutinin (HA) gene.Results: Co-circulation of both B lineages was observed each season, although in different proportions every year. Overall, viruses of B/Victoria and B/Yamagata lineages caused 53.3 and 46.7% of influenza B infections, respectively. A higher proportion of infections with both lineages was detected in children, and there was a declining frequency of B/Victoria detections with age. A mismatch between the vaccine and the predominant influenza B lineage occurred in eight out of thirteen influenza seasons under study. Considering the seasons when B accounted for > 20% of all laboratory-confirmed influenza cases, a mismatch was observed in four out of six seasons. Phylogenetic analysis of the HA1 domain confirmed the co-circulation of both lineages and revealed a mixed circulation of distinct evolutionary viral variants, with different levels of match to the vaccine strains.Conclusions: This study contributes to the understanding of the circulation of influenza B viruses in Italy. We found a continuous co-circulation of both B lineages in the period 2004-2017, and determined that children were particularly vulnerable to Victoria-lineage influenza B virus infections. An influenza B lineage mismatch with the trivalent vaccine occurred in about two-thirds of cases. [ABSTRACT FROM AUTHOR]

Correction: After Publication of the article [1], it has been brought to our attention that an author's name has been spelt incorrectly. The correct spelling should be "Massimo Ciccozzi", but it was previously included as "Massimo Cicozzi". The original version has now been revised to reflect this. [ABSTRACT FROM AUTHOR]