SUMMARY Pathogenic H7N9 avian influenza viruses continue to represent a public health concern and several candidate vaccines are currently being developed. It is vital to assess if protective antibodies are induced following vaccination, and to characterize the diversity of epitopes targeted. Here we characterized the binding and functional properties of twelve H7-reactive human antibodies induced by a candidate A/Anhui/1/2013 (H7N9) vaccine. Both neutralizing and non-neutralizing antibodies protected mice in vivo during passive transfer challenge experiments. Mapping the H7 hemagglutinin antigenic sites by generating escape mutant variants against the neutralizing antibodies identified unique epitopes on the head and stalk domains. Further, the broadly cross-reactive non-neutralizing antibodies generated in this study were protective through Fc-mediated effector cell recruitment. These findings reveal important properties of vaccine-induced antibodies and provide a better understanding of the human monoclonal antibody response to influenza in the context of vaccines.

Exacerbations of asthma are often associated with respiratory infection caused by rhinoviruses. To study the effects of rhinovirus infection on respiratory epithelium, a primary target for respiratory viruses, human rhinovirus (HRV)-2 and HRV-14 were infected to primary cultures of human tracheal epithelial cells. Viral infection was confirmed by showing that viral titers of supernatants and lysates from infected cells increased with time and by polymerase chain reaction. HRV-2 and HRV-14 infections upregulated the expression of intercellular adhesion molecule-1 (ICAM-1) mRNA, the major rhinovirus receptor, on epithelial cells, and they increased the production of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α in supernatants. Antibodies to ICAM-1 inhibited HRV-14 infection of epithelial cells and decreased the production of cytokines after HRV-14 infection, but they did not alter HRV-2 infection-induced production of cytokines. IL-1β upregulated ICAM-1 mRNA expression and increased susceptibility to HRV-14 infection, whereas other cytokines failed to alter ICAM-1 mRNA expression. Furthermore, a neutralizing antibody to IL-1β significantly decreased viral titers of supernatants and ICAM-1 mRNA expression after HRV-14 infection, but a neutralizing antibody to TNF-α was without effect. Immunohistochemical studies revealed that both HRV-14 infection and IL-1β increased ICAM-1 expression on cultured epithelial cells. These findings imply that HRV-14 infection upregulated ICAM-1 expression on epithelial cells through increased production of IL-1β, thereby increasing susceptibility to infection. These events may be important for amplification of airway inflammation after viral infection in asthma.

We report on the role of specific CD8+ T cells in the pathogenesis of a highly lethal human viral disease, hantavirus pulmonary syndrome (HPS). HPS is a zoonotic disease caused by transmission of Sin Nombre virus (SNV) from chronically infected deer mice. In humans, this fulminant infection is characterized by lung capillary leakage, respiratory failure, and cardiogenic shock. Individuals with HLA-B*3501 have an increased risk of developing severe HPS, suggesting that CD8+ T cell responses to SNV contribute to pathogenesis. We identified three CD8+ T cell epitopes in SNV presented by HLA-B*3501 and quantitated circulating SNV-specific CD8+ T cells in 11 acute HPS patients using HLA/peptide tetramers. We found significantly higher frequencies of SNV-specific T cells in patients with severe HPS requiring mechanical ventilation (up to 44.2% of CD8+ T cells) than in moderately ill HPS patients hospitalized but not requiring mechanical ventilation (up to 9.8% of CD8+ T cells). These results imply that virus-specific CD8+ T cells contribute to HPS disease outcome. Intense CD8+ T cell responses to SNV may be induced by the encounter of the unnatural human host to this zoonotic virus without coevolution. This may also be the immunopathologic basis of other life-threatening human virus infections.

Cerebrospinal fluid from 70 patients with Alzheimer's disease (AD) and 96 patients with non-AD neurological diseases as well as 19 normal control subjects was surveyed by sandwich enzyme-linked immunosorbent assay to quantitate levels of the microtubule-associated protein tau in cerebrospinal fluid. The tau level was significantly increased in AD patients as compared with that in patients with non-AD neurological diseases and control subjects. Increased tau levels were found irrespective of age at onset, apolipoprotein E genotype, and clinical stage. Western blots of AD cerebrospinal fluid proteins revealed two to three tau-immunoreactive bands with an apparent molecular mass between 50 and 65 kd consistent with phosphorylated cerebrospinal fluid tau. Taken together, our results suggest that cerebrospinal fluid tau might reflect the progressive accumulation of altered tau due to the progressive death of neurons in the AD brain, and that the enzyme-linked immunosorbent assay of cerebrospinal fluid tau may prove to be a reliable and early diagnostic test for AD.

Immunization with vaccinia virus resulted in long-lasting protection against smallpox and was the approach used to eliminate natural smallpox infections worldwide. Due to the concern about the potential use of smallpox virus as a bioweapon, smallpox vaccination is currently being reintroduced. Severe complications from vaccination were associated with congenital or acquired T cell deficiencies, but not with congenital agammaglobulinemia, suggesting the importance of T cell immunity in recovery from infection. In this report, we identified two CD8+ T cell epitopes restricted by the most common human major histocompatibility complex (MHC) class I allele, HLA-A*0201. Both epitopes are highly conserved in vaccinia and variola viruses. The frequency of vaccinia-specific CD8+ T cell responses to these epitopes measured by interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) assay and HLA/peptide tetramer staining peaked 2 wk after primary immunization and then declined, but were still detectable 1 to 3 yr after primary immunization. 2 wk after immunization, IFN-γ–producing cells specific to these two epitopes were 14% of total vaccinia virus-specific IFN-γ–producing cells in one donor, 35% in the second donor, and 6% in the third donor. This information will be useful for studies of human T cell memory and for the design and analyses of the immunogenicity of experimental vaccinia vaccines.

Objective The goal of the present study was to evaluate whether serologically confirmed maternal exposure to influenza is associated with an increased risk of bipolar disorder in the offspring and with subtypes of bipolar disorder, with and without psychotic features. Method The study utilized a nested case-control design in the Child Health and Development Study birth cohort. Eighty-five cases of bipolar disorder were identified following extensive ascertainment and diagnostic assessment and matched to 170 controls in the analysis. Serological documentation of maternal exposure to influenza was determined using the hemagglutination inhibition assay. Results There was no association between serologically documented maternal exposure to influenza and bipolar disorder in offspring. However, maternal serologic influenza exposure was related to a significant, fivefold increased risk of bipolar disorder with psychotic features. Conclusions These results suggest that maternal influenza exposure may increase the risk for the offspring developing bipolar disorder with psychotic features. Taken together with earlier associations between prenatal influenza exposure and schizophrenia, this may suggest that prenatal influenza is a risk factor for psychosis, rather than for a specific psychotic disorder diagnosis.

Vaccinia virus (VACV) was used as the vaccine strain to eradicate smallpox. VACV is still administered to healthcare workers or researchers who are at risk of contracting the virus, and to military personnel. Thus, VACV represents a weapon against outbreaks, both natural (e.g., monkeypox) or man-made (bioterror). This virus is also used as a vector for experimental vaccine development (cancer/infectious disease). As a prototypic poxvirus, VACV is a model system for studying host-pathogen interactions. Until recently, little was known about the targets of host immune responses, which was likely owing to VACVs large genome (>200 open reading frames). However, the last few years have witnessed an explosion of data, and VACV has quickly become a useful model to study adaptive immune responses. This review summarizes and highlights key findings based on identification of VACV antigens targeted by the immune system (CD4, CD8 and antibodies) and the complex interplay between responses. Keywords adaptive immunity; epitopes; immunodominant; protection; vaccinia virus Structure & taxonomy of poxviruses, & their relevance to human healthAmongst the viruses of relevance to human health, members of the poxvirus family have some of the largest viral genomes (ranging from 130 to 300 kb), with as many as 260 open reading frames (ORFs). All poxviruses replicate exclusively in the cytoplasm of their hosts and have an enveloped viral particle that carries the single, linear dsDNA genome. In general, the genes located in the center of the genome are relatively conserved among poxviruses and have essential molecular functions for replication and survival. By contrast, terminally located genes are more variable and encode proteins that interfere with the host response to infection (virulence factors) and determine host-range restriction [1].The poxviruses that infect vertebrate hosts comprise eight genera and, of these, the orthopox genus has the best-known members and also those most relevant to human health. The most prominent is variola virus (VARV), the causative agent of smallpox, and vaccinia virus (VACV), the vaccine used to prevent and eradicate this once dreaded disease. With smallpox conquered in the 1980s, attention was focused on the use of recombinant VACV as a vector for protein expression in the study of cancer and infectious disease vaccines [2]. A variety of strains of VACV have been used for these studies. The high rates of severe adverse events associated with the traditional smallpox vaccine led to the development of attenuated strains, exemplified by modified vaccinia virus Ankara (MVA). MVA was generated by extensive passaging of VACV Ankara on chicken embryo fibroblasts, resulting NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript in the loss of several genes compared with the parental genome and loss of the ability to replicate in most mammalian cells, including primary human cells [3]. By contrast to the extreme attenuation of MVA, the most commonly used VACV strain for laborat...

Yellow fever virus (YFV) is a re-emerging problem despite the existence of an effective live-attenuated vaccine. The induction of YFV-neutralizing antibodies undoubtedly contributes to vaccine efficacy, but T lymphocyte responses to YFV likely play a role in long-term efficacy. We studied the T lymphocyte responses to YFV in four vaccinees. Proliferation and cytolytic responses to YFV were demonstrated in all subjects. We isolated 13 YFV-specific CD8(+) CTL lines that recognized epitopes on the E, NS1, NS2b, and NS3 proteins; eight CTL lines were HLA-B35-restricted. YFV-specific T cell responses were detectable by IFN gamma ELISPOT assays 14 days postvaccination, with T cell frequencies sustained for up to 19 months. To our knowledge, this is the first report of human T lymphocyte responses following YFV vaccination. These results indicate that the live 17D YFV vaccine induced CD8(+) T cell responses directed against at least four different HLA-B35-restricted YFV epitopes.