Insertion of foreign genes into the simian varicella virus genome by Tn7-mediated site-specific transposition.

A Tn7-transposition approach was utilized for site-specific insertion of foreign genes into the genome of simian varicella virus (SVV), the causative agent of simian varicella in nonhuman primates. The severe acute respiratory syndrome coronavirus (SARS-CoV-2) nucleocapsid (N) gene and receptor binding domain (RBD) of the spike gene were inserted into the ORF 14 region of the SVV genome cloned into a bacterial artificial chromosome and then transfected into Vero cells to generate the infectious recombinant SVV (rSVV). The rSVV replicated efficiently in infected Vero cells and expressed the N and RBD antigens as indicated by immunoblot and immunofluorescence assays. Tn7-mediated transposition provides a rapid and efficient method for constructing rSVVs which may be evaluated as live-attenuated vaccines.

Recombinant Simian Varicella Virus-Simian Immunodeficiency Virus Vaccine Induces T and B Cell Functions and Provides Partial Protection against Repeated Mucosal SIV Challenges in Rhesus Macaques.

HIV vaccine mediated efficacy, using an expanded live attenuated recombinant varicella virus-vectored SIV rSVV-SIVgag/env vaccine prime with adjuvanted SIV-Env and SIV-Gag protein boosts, was evaluated in a female rhesus macaques (RM) model against repeated intravaginal SIV challenges. Vaccination induced anti-SIV IgG responses and neutralizing antibodies were found in all vaccinated RMs. Three of the eight vaccinated RM remained uninfected (vaccinated and protected, VP) after 13 repeated challenges with the pathogenic SIVmac251-CX-1. The remaining five vaccinated and infected (VI) macaques had significantly reduced plasma viral loads compared with the infected controls (IC). A significant increase in systemic central memory CD4+ T cells and mucosal CD8+ effector memory T-cell responses was detected in vaccinated RMs compared to controls. Variability in lymph node SIV-Gag and Env specific CD4+ and CD8+ T cell cytokine responses were detected in the VI RMs while all three VP RMs had more durable cytokine responses following vaccination and prior to challenge. VI RMs demonstrated predominately SIV-specific monofunctional cytokine responses while the VP RMs generated polyfunctional cytokine responses. This study demonstrates that varicella virus-vectored SIV vaccination with protein boosts induces a 37.5% efficacy rate against pathogenic SIV challenge by generating mucosal memory, virus specific neutralizing antibodies, binding antibodies, and polyfunctional T-cell responses.

Comparative Analysis of the Simian Varicella Virus and Varicella Zoster Virus Genomes.

Varicella zoster virus (VZV) and simian varicella virus (SVV) cause varicella (chickenpox) in children and nonhuman primates, respectively. After resolution of acute disease, the viruses establish latent infection in neural ganglia, after which they may reactivate to cause a secondary disease, such as herpes zoster. SVV infection of nonhuman primates provides a model to investigate VZV pathogenesis and antiviral strategies. The VZV and SVV genomes are similar in size and structure and share 70-75% DNA homology. SVV and VZV DNAs are co-linear in gene arrangement with the exception of the left end of the viral genomes. Viral gene expression is regulated into immediate early, early, and late transcription during in vitro and in vivo infection. During viral latency, VZV and SVV gene expression is limited to transcription of a viral latency-associated transcript (VLT). VZV and SVV are closely related alphaherpesviruses that likely arose from an ancestral varicella virus that evolved through cospeciation into species-specific viruses.

An enzyme-linked immunosorbent assay (ELISA) to determine Simian Varicella Virus antibody titers in infected rhesus monkeys (Macaca mulatta).

BACKGROUND: Simian varicella virus (SVV) is a primate herpesvirus that causes a natural varicella-like disease in Old World monkeys and may cause epizootics in facilities housing nonhuman primates. SVV infection of nonhuman primates is used as an experimental model to investigate varicella pathogenesis and to develop antiviral strategies. METHODS: An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect SVV antibodies in infected rhesus macaque monkeys. RESULTS: An ELISA determined SVV antibody titers following experimental infection. SVV IgG was detected by day 14 post-infection and remained elevated for at least 84 days. CONCLUSIONS: The SVV ELISA is a safe and rapid approach to confirm SVV seropositivity and to determine SVV antibody titers in naturally and experimentally SVV-infected monkeys. In addition to being a useful diagnostic assay to rapidly confirm acute disease or past SVV infection, the SVV ELISA is a valuable epidemiological tool to determine the incidence of SVV in non-human primate facilities.

Editors' Introduction to Tasks, Tools, and Techniques.

Tasks, tools, and techniques that we perform, use, and acquire, define the elements of expertise which we value as the hallmarks of goal-driven behavior. Somehow, the creation of tools enables us to define new tasks, or is it that the envisioning of new tasks drives us to invent new tools? Or maybe it is that new tools engender new techniques which then result in new tasks? This jumble of issues will be explored and discussed in this diverse collection of papers. Individually, few of the papers are related to each other by topic or by techniques of analysis. Collectively, all focus on tasks performed using tools and discuss the techniques of tool use which enable differences in performance and expertise across individuals, societies, and (even) species.

Constructing Expertise: Surmounting Performance Plateaus by Tasks, by Tools, and by Techniques.

Acquiring expertise in a task is often thought of as an automatic process that follows inevitably with practice according to the log-log law (aka: power law) of learning. However, as Ericsson, Chase, and Faloon (1980) showed, this is not true for digit-span experts and, as we show, it is certainly not true for Tetris players at any level of expertise. Although some people may simply "twitch" faster than others, the limit to Tetris expertise is not raw keypress time but the techniques acquired by players that allow them to use the tools provided by the hardware and software to compensate for the game's relentlessly increasing drop speed. Unfortunately, these increases in drop speed between Tetris levels make performance plateaus very short and quickly followed by game death. Hence, a player's success at discovering, exploring, and practicing new techniques for the tasks of board preparation, board maintenance, optimal placement discovery, zoid rotation, lateral movement of zoids, and other tasks important to expertise in Tetris is limited. In this paper, we analyze data collected from 492 Tetris players to reveal the challenges they confronted while constructing expertise via the discovery of new techniques for gameplay at increasingly difficult levels of Tetris.

SpotLight on Dynamics of Individual Learning.

Averaging performance over a group of individuals implicitly assumes that there is only one set of methods for accomplishing the task and that all learners acquire those methods in the same sequence. We maintain that the average subject is a mythical beast and, rather than profiling a mythical beast, we ask "how do different people each learn the same complex task?" To answer our question, we use SpotLight-a tool for analyzing changes in individual performance as skill is acquired. Specifically, in this report, we use the SpotLight on 40 scores and measures of performance (some collected at millisecond level, others collected once per game), to investigate the skill acquisition of nine individuals each of whom devoted 31 h to becoming skilled players of the classic cognitive psychology game of Space Fortress (Mané & Donchin, 1989). Turning the SpotLight on our best and worst players reveals patterns of performance plateaus, dips, and leaps. Examining these patterns reveals differences as well as commonalities in the evolution of methods discovered and used by each individual across 31 hours of skill acquisition.

Current In Vivo Models of Varicella-Zoster Virus Neurotropism.

Varicella-zoster virus (VZV), an exclusively human herpesvirus, causes chickenpox and establishes a latent infection in ganglia, reactivating decades later to produce zoster and associated neurological complications. An understanding of VZV neurotropism in humans has long been hampered by the lack of an adequate animal model. For example, experimental inoculation of VZV in small animals including guinea pigs and cotton rats results in the infection of ganglia but not a rash. The severe combined immune deficient human (SCID-hu) model allows the study of VZV neurotropism for human neural sub-populations. Simian varicella virus (SVV) infection of rhesus macaques (RM) closely resembles both human primary VZV infection and reactivation, with analyses at early times after infection providing valuable information about the extent of viral replication and the host immune responses. Indeed, a critical role for CD4 T-cell immunity during acute SVV infection as well as reactivation has emerged based on studies using RM. Herein we discuss the results of efforts from different groups to establish an animal model of VZV neurotropism.

Distinguishing experts from novices by the Mind's Hand and Mind's Eye.

Tetris is a complex task notable for the increasingly substantial demands it makes on perception, decision-making, and action as the game is played. To investigate these issues, we collected data on 39 features of Tetris play for each Tetris zoid (piece), for up to 16 levels of difficulty, as each of 240 players played an hour of Tetris under laboratory conditions. Using only early (level 1) data, we conducted a Principle Component Analysis which found intriguing differences among its three, statistically significant, principle components. Each of these components captures different combinations of perception, decision-making, and action which suggests differing higher level skills, tactics, and strategies. Each component is presented and discussed, and then used in a series of principle component regression analyses on subsets of these data (a) from different Tetris levels, as well as (b) from players of different levels of expertise. We validate these models with data collected at a locally held Tetris tournament. These components represent elements of expertise; namely, correlations among perceptual, decision-making, and motor features that represent processing stages and hierarchical control and which distinguish expert from novice Tetris players. These components provide evidence for an integrated complex of processes - the Mind's Hand and the Mind's Eye - that are the essence of expertise in the real-time, sequential-decision-making task of Tetris.