Potential false-positive urine Legionella enzyme immunoassay test results.

The objective of this study was to identify potential false-positive urine Legionella pneumophila (Legionella) enzyme immunoassay test results. A total of 107 consecutive patients with positive EIA tests were retrospectively analyzed over a 34-month period. Concurrent blood, urine, and sputum cultures, as well as chest radiographic findings, were reviewed in these patients.

Multigenic DNA vaccine induces protective cross-reactive T cell responses against heterologous influenza virus in nonhuman primates.

Recent avian and swine-origin influenza virus outbreaks illustrate the ongoing threat of influenza pandemics. We investigated immunogenicity and protective efficacy of a multi-antigen (MA) universal influenza DNA vaccine consisting of HA, M2, and NP antigens in cynomolgus macaques. Following challenge with a heterologous pandemic H1N1 strain, vaccinated animals exhibited significantly lower viral loads and more rapid viral clearance when compared to unvaccinated controls.

Differential gene expression elicited by children in response to the 2015-16 live attenuated versus inactivated influenza vaccine.

Background: In recent influenza seasons, the live attenuated influenza vaccine (LAIV) has not demonstrated the same level of vaccine effectiveness as that observed among children who received the inactivated influenza vaccine (IIV). To better understand this difference, this study compared the mRNA sequencing transcription profile (RNA seq) in children who received either IIV or LAIV.

Methods: Children 3-17years of age receiving quadrivalent influenza vaccine were enrolled.

Are children's vitamin D levels and BMI associated with antibody titers produced in response to 2014-2015 influenza vaccine?

Background: Vitamin D is an immunomodulating hormone, which has been associated with susceptibility to infectious diseases.

Methods: Serum vitamin D levels in 135 children ages 3-17 y were measured at baseline and hemagglutinin influenza antibody titers were measured pre- and 21 d post influenza vaccination with live attenuated influenza vaccine (LAIV) or inactivated influenza vaccine (IIV). Height and weight were derived from the electronic medical record and were used to calculate body mass index (BMI).

Neutralizing Antibody Responses to Antigenically Drifted Influenza A(H3N2) Viruses among Children and Adolescents following 2014-2015 Inactivated and Live Attenuated Influenza Vaccination.

Human influenza A(H3N2) viruses that predominated during the moderately severe 2014-2015 influenza season differed antigenically from the vaccine component, resulting in reduced vaccine effectiveness (VE). To examine antibody responses to 2014-2015 inactivated influenza vaccine (IIV) and live-attenuated influenza vaccine (LAIV) among children and adolescents, we collected sera before and after vaccination from 150 children aged 3 to 17 years enrolled at health care facilities. Hemagglutination inhibition (HI) assays were used to assess the antibody responses to vaccine strains.

Cell-Mediated Immunity Against Antigenically Drifted Influenza A(H3N2) Viruses in Children During a Vaccine Mismatch Season.

Background: Emergence of antigenically drifted influenza A(H3N2) viruses resulted in reduced vaccine effectiveness in all age groups during the 2014-2015 influenza season. In children, inactivated influenza vaccine (IIV) elicited neutralizing antibodies (Abs) against drifted strains at significantly lower levels than against the vaccine strain. Little is known about the cross-reactivity of cell-mediated immunity against drifted strains in children.

Respiratory and oral vaccination improves protection conferred by the live vaccine strain against pneumonic tularemia in the rabbit model.

Tularemia is a severe, zoonotic disease caused by a gram-negative bacterium, Francisella tularensis We have previously shown that rabbits are a good model of human pneumonic tularemia when exposed to aerosols containing a virulent, type A strain, SCHU S4. We further demonstrated that the live vaccine strain (LVS), an attenuated type B strain, extended time to death when given by scarification. Oral or aerosol vaccination has been previously shown in humans to offer superior protection to parenteral vaccination against respiratory tularemia challenge.

Live attenuated mutants of Francisella tularensis protect rabbits against aerosol challenge with a virulent type A strain.

Francisella tularensis, a Gram-negative bacterium, is the causative agent of tularemia. No licensed vaccine is currently available for protection against tularemia, although an attenuated strain, dubbed the live vaccine strain (LVS), is given to at-risk laboratory personnel as an investigational new drug (IND). In an effort to develop a vaccine that offers better protection, recombinant attenuated derivatives of a virulent type A strain, SCHU S4, were evaluated in New Zealand White (NZW) rabbits.

Development of novel mechanisms for housing, handling, and remote monitoring of common marmosets at animal biosafety level 3.

The use of common marmosets as an alternative non-human primate model for infectious disease research using BSL-3 viruses such as Rift Valley fever virus (RVFV) presents unique challenges with respect to housing, handling, and safety. Subject matter experts from veterinary care, animal husbandry, biosafety, engineering, and research were consulted to design a pilot experiment using marmosets infected with RVFV. This paper reviews the caging, handling, and safety-related adaptations and modifications that were required to humanely utilize marmosets as a model for high-hazard BSL-3 viral diseases.

Challenges and Practices in Building and Implementing Biosafety and Biosecurity Programs to Enable Basic and Translational Research with Select Agents.

Select agent research in the United States must meet federally-mandated biological surety guidelines and rules which are comprised of two main components: biosecurity and biosafety. Biosecurity is the process employed for ensuring biological agents are properly safeguarded against theft, loss, diversion, unauthorized access or use/release. Biosafety is those processes that ensure that operations with such agents are conducted in a safe, secure and reliable manner.

Decontamination and digestion of infectious animal waste using a tissue dissolver in an animal biosafety level 3 facility.

Alkaline hydrolysis-based tissue dissolvers (TDs) are commercially available tools for the digestion and decontamination of infectious animal waste. The authors carried out a series of experiments to verify whether the TD in their facility completely digested animal carcasses and inactivated infectious agents. Using the manufacturer's recommended cycle parameters, the TD inactivated a high concentration of chemically resistant bacterial spores used as a surrogate for the infectious agents in use in the facility.

Pneumonic tularemia in rabbits resembles the human disease as illustrated by radiographic and hematological changes after infection.

Background: Pneumonic tularemia is caused by inhalation of the gram negative bacterium, Francisella tularensis. Because of concerns that tularemia could be used as a bioterrorism agent, vaccines and therapeutics are urgently needed. Animal models of pneumonic tularemia with a pathophysiology similar to the human disease are needed to evaluate the efficacy of these potential medical countermeasures.

Naïve and memory B cells in the rhesus macaque can be differentiated by surface expression of CD27 and have differential responses to CD40 ligation.

The rhesus macaque (RM) model has the potential to be an invaluable tool for studying B cell populations during pathogenic infections, however, to date, there has been no definitive delineation of naïve and memory B cell populations in the RM. This has precluded a rigorous analysis of the generation, persistence and resolution of a pathogen-specific memory B cell response. The present study utilized multiple analyses to demonstrate that CD27 expression on B cells is consistent with a memory phenotype.

Nonpathogenic simian immunodeficiency virus infection of sooty mangabeys is not associated with high levels of autologous neutralizing antibodies.

Simian immunodeficiency virus (SIV) infection of natural-host species, such as sooty mangabeys (SMs), is characterized by a high level of viral replication and a low level of generalized immune activation, despite evidence of an adaptive immune response. Here the ability of SIV-infected SMs to mount neutralizing antibodies (Nab) against autologous virus was compared to that of human immunodeficiency virus type 1 (HIV-1) subtype C-infected subjects. While high levels of Nab were observed in HIV-1 infection, samples obtained at comparable time points from SM exhibited relatively low titers of autologous Nab.

Induction of antibody-mediated neutralization in SIVmac239 by a naturally acquired V3 mutation.

Achieving humoral immunity against human immunodeficiency virus (HIV) is a major obstacle in AIDS vaccine development. Despite eliciting robust humoral responses to HIV, exposed hosts rarely produce broadly neutralizing antibodies. The present study utilizes simian immunodeficiency virus (SIV) to identify viral epitopes that conferred antibody neutralization to clone SIV/17E-CL, an in vivo variant derived from neutralization resistant SIVmac239.

Evidence of early B-cell dysregulation in simian immunodeficiency virus infection: rapid depletion of naïve and memory B-cell subsets with delayed reconstitution of the naïve B-cell population.

Despite eliciting a robust antibody response in humans, several studies in human immunodeficiency virus (HIV)-infected patients have demonstrated the presence of B-cell deficiencies during the chronic stage of infection. While several explanations for the HIV-induced B-cell deficit have been proposed, a clear mechanistic understanding of this loss of B-cell functionality is not known. This study utilizes simian immunodeficiency virus (SIV) infection of rhesus macaques to assess B-cell population dynamics beginning at the acute phase and continuing through the chronic phase of infection.

A feline immunodeficiency virus vif-deletion mutant remains attenuated upon infection of newborn kittens.

This report characterizes lentivirus attenuation associated with a vif mutation by inoculation of newborn kittens with a vif-deleted feline immunodeficiency virus provirus plasmid (FIV-pPPRDeltavif). Virus in peripheral blood, antiviral antibody or CD4 T-cell count alterations were not detected in kittens inoculated with FIV-pPPRDeltavif plasmid, with the exception of one kitten that demonstrated FIV Gag antibody production at 42 weeks after inoculation. In contrast, wild-type FIV-pPPR-infected kittens were viraemic, seropositive and exhibited a decrease in the CD4 T-cell subset in peripheral blood.

Mucosal innate immune response associated with a timely humoral immune response and slower disease progression after oral transmission of simian immunodeficiency virus to rhesus macaques.

Mucosal transmission is the predominant mode of human immunodeficiency virus (HIV) infection worldwide, and the mucosal innate interferon response represents an important component of the earliest host response to the infection. Our goal here was to assess the changes in mRNA expression of innate mucosal genes after oral simian immunodeficiency virus (SIV) inoculation of rhesus macaques (Macaca mulatta) that were followed throughout their course of disease progression. The SIV plasma viral load was highest in the macaque that progressed rapidly to simian AIDS (99 days) and lowest in the macaque that progressed more slowly (>700 days).

Dissecting the humoral immune response to simian immunodeficiency virus: mechanisms of antibody-mediated virus neutralization.

The ultimate goal of an AIDS vaccine is to elicit potent cellular and humoral immune responses that will result in broadly enduring protective immunity. During the past several years, we have focused on characterizing the quantitative and qualitative properties of the antibody response, principally working to define the mechanism(s) of antibody-mediated neutralization in vitro. We have utilized a panel of monoclonal antibodies generated from monkeys infected with attenuated SIV for more than 8 mo to dissect the early events of virus infection involved in antibody-mediated neutralization.

Vaccination of cats with attenuated feline immunodeficiency virus proviral DNA vaccine expressing gamma interferon.

A feline immunodeficiency virus (FIV) provirus with a vif gene deletion (FIVDelta vifATGgamma) that coexpresses feline gamma interferon (IFN-gamma) was tested as a proviral DNA vaccine to extend previous studies showing efficacy with an FIV-pPPRDelta vif DNA vaccine. Cats were vaccinated with either FIVDelta vifATGgamma or FIV-pPPRDelta vif proviral plasmid DNA or with both FIV-pPPRDelta vif DNA and a feline IFN-gamma expression plasmid (pCDNA-IFNgamma). A higher frequency of FIV-specific T-cell proliferation responses was observed in cats immunized with either FIVDelta vifATGgamma or FIV-pPPRDelta vif plus pCDNA-IFNgamma, while virus-specific cytotoxic-T-lymphocyte responses were comparable between vaccine groups.

Lentivirus-like particles without reverse transcriptase elicit efficient immune responses.

Following infection by HIV or SIV, reverse transcriptase (RT) directs the conversion of the single-stranded RNA genome into a double-stranded DNA molecule that integrates into the host cell genome. RT encodes for several immunogenic epitopes that are desirable for inclusion in a human vaccine for HIV infection, however, issues of safety have dampened enthusiasm for inclusion of an enzymatically-active RT molecule into an AIDS vaccine. In this study, virally-regulated, replication-incompetent lentiviral particles were expressed from DNA plasmids.

Rhesus macaque polyclonal and monoclonal antibodies inhibit simian immunodeficiency virus in the presence of human or autologous rhesus effector cells.

Although antibodies can prevent or modulate lentivirus infections in nonhuman primates, the biological functions of antibody responsible for such effects are not known. We sought to determine the role of antibody-dependent cell-mediated virus inhibition (ADCVI), an antibody function that inhibits virus yield from infected cells in the presence of Fc receptor-bearing effector cells, in preventing or controlling SIVmac251 infection in rhesus macaques (Macaca mulatta). Using CEMx174 cells infected with simian immunodeficiency virus mac251 (SIVmac251), both polyclonal and monoclonal anti-SIV antibodies were capable of potent virus inhibition in the presence of human peripheral blood mononuclear cell (PBMC) effector cells.

Kinetic rates of antibody binding correlate with neutralization sensitivity of variant simian immunodeficiency virus strains.

Increasing evidence suggests that an effective AIDS vaccine will need to elicit both broadly reactive humoral and cellular immune responses. Potent and cross-reactive neutralization of simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) by polyclonal and monoclonal antibodies is well documented. However, the mechanisms of antibody-mediated neutralization have not been defined.