Topic
Virus
About: Virus is a research topic. Over the lifetime, 136914 publications have been published within this topic receiving 5209107 citations. The topic is also known as: infectious agent & viruses.
Papers published on a yearly basis
Papers
More filters
TL;DR: The described duration, specificity, and consistent relationship to immunity suggest that IgG antibody in respiratory secretions, derived entirely or partly from serum, is the most likely mediator of resistance to natural influenza.
Abstract: The observations summarized in this review indicate immunity to infection with type A influenza viruses is subtype specific since little or none is conveyed to subtypes possessing immunologically distinct HA and NA proteins. However, within a subtype, a prior antigenic experience with one variant may prevent or modify illness to another. The resulting degree of subtype immunity depends on the extent of relatedness between variants. Observations with H3N2 viruses indicate that homotypic resistance to subsequent infection and illness with the same virus is potent and of relatively long duration. The long lasting durability of such immunity was indicated by the epidemiologic pattern following the reappearance of H1N1 virus. Knowledge of the duration and specificity of immunity aids considerably in assessing mechanisms that account for host resistance to influenza. Recovery from influenza virus infection must involve a variety of humoral and cell-mediated immune mechanisms, and conclusions regarding the relative importance of each one are not possible at present. To prevent infection, involved immune mechanism(s) must account for: (a) subtype specificity, (b) reduced cross-reactivity of immunity for succeeding antigenic variants, (c) a long duration of immunity, and (d) immunity at the mucosal surface. Only antibody directed toward the HA molecule presently satisfies these properties and thus should be considered the major mediator of resistance to infection. Study of naturally occurring infection is needed for determining the duration and specificity of secretory IgA in nasal and lower respiratory secretions so as to establish its relative importance as a mediator of immunity. However, the described duration, specificity, and consistent relationship to immunity suggest that IgG antibody in respiratory secretions, derived entirely or partly from serum, is the most likely mediator of resistance to natural influenza.
449 citations
TL;DR: The ability to produce human antibodies of exceptional affinity and broad neutralizing ability has implications for the therapeutic and prophylactic application of antibodies for human immunodeficiency virus type 1 infection.
Abstract: A method is described that allows for the improvement of antibody affinity. This method, termed complementary-determining region (CDR) walking, does not require structural information on either antibody or antigen. Complementary-determining regions are targeted for random mutagenesis followed by selection for fitness, in this case increased binding affinity, by the phage-display approach. The current study targets a human CD4-binding-site anti-gp120 antibody that is potently and broadly neutralizing. Evolution of affinity of this antibody demonstrates in this case that affinity can be increased while reactivity to variants of human immunodeficiency virus type 1 is broadened. The neutralizing ability of this antibody is improved, as assayed with laboratory and primary clinical isolates of human immunodeficiency virus type 1. The ability to produce human antibodies of exceptional affinity and broad neutralizing ability has implications for the therapeutic and prophylactic application of antibodies for human immunodeficiency virus type 1 infection.
449 citations
TL;DR: It is shown that although Vpr has no effect on the initial cytopathic effect of HIV-1, viruses that contain an intact vPR gene are unable to establish a chronic infection of T cells, however, virus with a mutated vpr gene can readily establish such long-term cultures.
Abstract: Human immunodeficiency virus type 1 (HIV-1) is a retrovirus that can cause extensive cytopathicity in T cells. However, long-term productive infection of T-cell lines has been described. Here we show that although Vpr has no effect on the initial cytopathic effect of HIV-1, viruses that contain an intact vpr gene are unable to establish a chronic infection of T cells. However, virus with a mutated vpr gene can readily establish such long-term cultures. The effect of Vpr is independent of the env gene and the nef gene. Furthermore, expression of Vpr alone affects the progression of cells in the cell cycle. These results suggest that HIV-1 has evolved a viral gene to prevent chronic infection of T cells.
449 citations
TL;DR: This review focuses on recent advances in understanding of the roles of intrinsic antiviral factors that restrict infection by human immunodeficiency virus and influenza virus.
Abstract: Intrinsic antiviral immunity refers to a form of innate immunity that directly restricts viral replication and assembly, thereby rendering a cell nonpermissive to a specific class or species of viruses. Intrinsic immunity is conferred by restriction factors that are mostly preexistent in certain cell types, although these factors can be further induced by viral infection. Intrinsic virus-restriction factors recognize specific viral components, but unlike other pattern-recognition receptors that inhibit viral infection indirectly by inducing interferons and other antiviral molecules, intrinsic antiviral factors block viral replication immediately and directly. This review focuses on recent advances in understanding of the roles of intrinsic antiviral factors that restrict infection by human immunodeficiency virus and influenza virus.
448 citations
TL;DR: Concentrations of soluble CD4 in the nanomolar range, like certain anti-CD4 monoclonal antibodies, inhibit syncytium formation and HIV infection by binding gp120-expressing cells, and class II specific T-cell interactions are uninhibited by solubleCD4 protein, whereas they are virtually abrogated by equivalent amounts of anti-T4 antibody.
Abstract: The CD4 (T4) molecule is expressed on a subset of T lymphocytes involved in class II MHC recognition1,2, and is probably the physiological receptor for one or more monomorphic regions of class II MHC (refs 1–3). CD4 also functions as a receptor for the human immunodeficiency virus (HIV) exterior envelope glycoprotein (gp120) (refs 4–9), being essential for virus entry into the host cell and for membrane fusion, which contributes to cell-to-cell transmission of the virus and to its cytopathic effects10,11. We have used a baculovirus expression system to generate mg quantities of a hydrophilic extracellular segment of CD4. Concentrations of soluble CD4 in the nanomolar range, like certain anti-CD4 monoclonal antibodies, inhibit syncytium formation and HIV infection by binding gp120-expressing cells. Perhaps more importantly, class II specific T-cell interactions are uninhibited by soluble CD4 protein, whereas they are virtually abrogated by equivalent amounts of anti-T4 antibody. This may reflect substantial differences in CD4 affinity for gp120 and class II MHC.
448 citations