7. Persistent viruses

2018 ◽  
pp. 75-91
Author(s):  
Dorothy H. Crawford
Keyword(s):  
Hepatitis Viruses ◽  
Immune Mechanisms ◽  
Persistent Viruses ◽  
Immune Attack ◽  
Life Threatening ◽  
Asymptomatic Infections ◽  
Immune Defences ◽  
Hiv 1

‘Persistent viruses’ explains how some viruses have evolved strategies for overcoming immune mechanisms and survive inside their host for prolonged periods, even for a lifetime. Evasion strategies encompass three basic manoeuvres: finding a niche in which to hide from immune attack, manipulating immune processes to benefit the virus, and outwitting immune defences by mutating rapidly. Most persistent viruses have evolved to cause mild or even asymptomatic infections, since a life-threatening disease would not only be detrimental to the host, but would also deprive the virus of its home. The herpesvirus family, retrovirus family, HIV-1, and hepatitis viruses are described in detail.

scholarly journals Kill and cure: dietary augmentation of immune defences against colon cancer

2000 ◽  
Vol 59 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Fiona Armstrong ◽  
J. C. Mathers
Keyword(s):  
Colon Cancer ◽  
Immune System ◽  
Genetic Disease ◽  
Selective Pressure ◽  
Transformed Cells ◽  
Tumour Suppressor Genes ◽  
Food Components ◽  
Immune Attack ◽  
Dietary Components ◽  
Immune Defences

At its most fundamental, cancer is a genetic disease resulting from inherited or acquired mutations in tumour suppressor genes and proto-oncogenes. Environmental factors, including ingested food components, interact with genetic inheritance to determine individual cancer risk. There is growing evidence that the immune system exerts selective pressure during neoplastic development. Tumour cells that evade this immunosurveillance because they are non-antigenic or because they defend themselves successfully against immune attack have a survival advantage. Effective chemopreventative agents will include dietary components that enhance the immune system’s ability to identify transformed cells and to target them for apoptosis.

scholarly journals HIV-1-Specific IgA Monoclonal Antibodies from an HIV-1 Vaccinee Mediate Galactosylceramide Blocking and Phagocytosis

2018 ◽  
Vol 92 (7) ◽  
Author(s):  
Saintedym Wills ◽  
Kwan-Ki Hwang ◽  
Pinghuang Liu ◽  
S. Moses Dennison ◽  
Matthew Zirui Tay ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Functional Properties ◽  
Mononuclear Cells ◽  
Immunoglobulin A ◽  
Systemic Circulation ◽  
Peripheral Blood Mononuclear ◽  
Immune Mechanisms ◽  
Clonal Cell Lines ◽  
Hiv 1

ABSTRACTVaccine-elicited humoral immune responses comprise an array of antibody forms and specificities, with only a fraction contributing to protective host immunity. Elucidation of antibody effector functions responsible for protective immunity against human immunodeficiency virus type 1 (HIV-1) acquisition is a major goal for the HIV-1 vaccine field. Immunoglobulin A (IgA) is an important part of the host defense against pathogens; however, little is known about the role of vaccine-elicited IgA and its capacity to mediate antiviral functions. To identify the antiviral functions of HIV-1-specific IgA elicited by vaccination, we cloned HIV-1 envelope-specific IgA monoclonal antibodies (MAbs) by memory B cell cultures from peripheral blood mononuclear cells from an RV144 vaccinee and produced two IgA clonal cell lines (HG129 and HG130) producing native, nonrecombinant IgA MAbs. The HG129 and HG130 MAbs mediated phagocytosis by monocytes, and HG129 blocked HIV-1 Env glycoprotein binding to galactosylceramide, an alternative HIV-1 receptor. These findings elucidate potential antiviral functions of vaccine-elicited HIV-1 envelope-specific IgA that may act to block HIV-1 acquisition at the portal of entry by preventing HIV-1 binding to galactosylceramide and mediating antibody Fc receptor-mediated virion phagocytosis. Furthermore, these findings highlight the complex and diverse interactions of vaccine-elicited IgA with pathogens that depend on IgA fine specificity and form (e.g., multimeric or monomeric) in the systemic circulation and mucosal compartments.IMPORTANCEHost-pathogen interactionsin vivoinvolve numerous immune mechanisms that can lead to pathogen clearance. Understanding the nature of antiviral immune mechanisms can inform the design of efficacious HIV-1 vaccine strategies. Evidence suggests that both neutralizing and nonneutralizing antibodies can mediate some protection against HIV in animal models. Although numerous studies have characterized the functional properties of HIV-1-specific IgG, more studies are needed on the functional attributes of HIV-1-specific IgA, specifically for vaccine-elicited IgA. Characterization of the functional properties of HIV-1 Env-specific IgA monoclonal antibodies from human vaccine clinical trials are critical toward understanding the capacity of the host immune response to block HIV-1 acquisition.

Life-threatening reaction after first ever dose of abacavir in an HIV-1-infected patient

AIDS ◽  
2004 ◽  
Vol 18 (3) ◽  
pp. 578-579 ◽  
Author(s):  
Rafael de la Rosa ◽  
Marianne Harris ◽  
Linda Uyeda ◽  
Karin Goodison ◽  
Paul Keown ◽  
...  
Keyword(s):  
Infected Patient ◽  
Life Threatening ◽  
Hiv 1

Collaboration with China

2014 ◽  
Vol 9 (5) ◽  
pp. 793-800
Author(s):  
Aikichi Iwamoto ◽  
◽  
Zene Matsuda ◽  
Yoshihiro Kitamura ◽  
Takaomi Ishida ◽  
...  
Keyword(s):  
Medical Science ◽  
Hepatitis Viruses ◽  
Highly Pathogenic ◽  
Chinese Academy Of Sciences ◽  
Working Together ◽  
The University ◽  
Academy Of Sciences ◽  
Joint Laboratory ◽  
Hiv 1 ◽  
Japan And China

In Japanese fiscal 2005, the Institute of Medical Science of the University of Tokyo (IMSUT) launched joint laboratory in each Institute of Biophysics (IBP) and Institute of Microbiology (IM) of Chinese Academy of Sciences in Beijing. Japanese investigators have resided in Beijing and been working together with young Chinese scientists. As the principal investigator of the joint laboratory in IBP, Dr. Zene Matsuda have focused on the membrane fusion process in HIV-1 infection and invented a remarkable assay systemto be used for the analysis of themembrane fusion. Dr. Yoshihiro Kitamura started the joint laboratory in IM and handed to Dr. Takaomi Ishida. The research in IM has focus on the epidemiology and molecular biology of HIV-1 and hepatitis viruses. The research in Beijing has been supervised by Dr. Tadashi Yamamoto and then by Dr. Junichiro Inoue. Highly productive collaboration between Dr. Yoshihiro Kawaoka and Dr. Hualan Chen has been producing cutting edge outcomes in the research on highly pathogenic avian viruses and their molecular epidemiology in China. The whole schema of the collaboration between Japan and China has been led by Dr. Aikichi Iwamoto.

scholarly journals HIV-1 Vpu Interference with Innate Cell-mediated Immune Mechanisms

2012 ◽  
Vol 10 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Johan K. Sandberg ◽  
Sofia K. Andersson ◽  
Susanna M. Bachle ◽  
Douglas F. Nixon ◽  
Markus Moll
Keyword(s):  
Immune Mechanisms ◽  
Hiv 1

scholarly journals Standardized Method of MeasuringAcanthamoeba Antibodies in Sera from Healthy Human Subjects

2001 ◽  
Vol 8 (4) ◽  
pp. 724-730 ◽  
Author(s):  
Cynthia L. Chappell ◽  
John A. Wright ◽  
Michael Coletta ◽  
Anthony L. Newsome
Keyword(s):  
Human Subjects ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Healthy Human ◽  
Serological Studies ◽  
Life Threatening ◽  
Assay Methods ◽  
Asymptomatic Infections ◽  
Acanthamoeba Culbertsoni ◽  
Positive Results

ABSTRACT Acanthamoeba species can cause serious, debilitating, and sometimes life-threatening infections. Three groups have been identified using morphological and immunological comparisons. Previous serological studies have utilized a variety of antigen preparations and assay methods and reported disparate (3 to 100%) results. This study was designed to (i) optimize an enzyme-linked immunosorbent assay for detecting serum antibodies to each of the Acanthamoebaserogroups and (ii) test 55 healthy individuals for specific immunoglobulin G reactivity. The highest signal-to-background ratio was found when 3,000 fixed, intact trophozoites per well were used with a 1:10 serum dilution. Sera yielding optical densities of <0.25 against all three Acanthamoeba serogroups were used to define the cutoff for positive results. The highest background reactivity with these sera was seen with Acanthamoeba polyphaga (serogroup 2), followed by Acanthamoeba culbertsoni (serogroup 3) andAcanthamoeba astronyxis (serogroup 1). Of 55 subjects tested, the highest number of positive results was seen with A. polyphaga (81.8%), followed by A. astronyxis(52.8%) and A. culbertsoni (40%). Seven serum samples (12.7%) were negative for all three Acanthamoebaserogroups, 16 (29.1%) were positive for one serogroup only, 16 were positive for two serogroups, and 16 reacted to all three serogroups. Further analysis showed no significant associations between serogroup reactivity and age or gender. However, some ethnic differences were noted, especially with A. polyphaga antigens. In that case, serum samples from Hispanic subjects were 14.5 times less likely to be positive (P = 0.0025) and had lower mean absorbance values (P = 0.047) than those from Caucasian subjects. Overall, these data suggest that Acanthamoeba colonization or infection is more common than previously thought. Mild or asymptomatic infections may contribute to the observed serum reactivities.

scholarly journals Underestimated Amoebic Appendicitis among HIV-1-Infected Individuals in Japan

2016 ◽  
Vol 55 (1) ◽  
pp. 313-320 ◽  
Author(s):  
Taiichiro Kobayashi ◽  
Koji Watanabe ◽  
Hideaki Yano ◽  
Yukinori Murata ◽  
Toru Igari ◽  
...  
Keyword(s):  
Acute Appendicitis ◽  
Clinical Features ◽  
Periodic Acid ◽  
Periodic Acid Schiff ◽  
Content Type ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Life Threatening ◽  
Pas Staining ◽  
Hiv 1

ABSTRACT Entamoeba histolytica is not a common causative agent of acute appendicitis. However, amoebic appendicitis can sometimes be severe and life threatening, mainly due to a lack of awareness. Also, its frequency, clinical features, and pathogenesis remain unclear. The study subjects were HIV-1-infected individuals who presented with acute appendicitis and later underwent appendectomy at our hospital between 1996 and 2014. Formalin-fixed paraffin-embedded preserved appendix specimens were reexamined by periodic acid-Schiff (PAS) staining and PCR to identify undiagnosed amoebic appendicitis. Appendectomies were performed in 57 patients with acute appendicitis. The seroprevalence of E. histolytica was 33% (14/43) from the available stored sera. Based on the medical records, only 3 cases were clinically diagnosed as amoebic appendicitis, including 2 diagnosed at the time of appendectomy and 1 case diagnosed by rereview of the appendix after the development of postoperative complications. Retrospective analyses using PAS staining and PCR identified 3 and 3 more cases, respectively. Thus, E. histolytica infection was confirmed in 9 cases (15.8%) in the present study. Apart from a significantly higher leukocyte count in E. histolytica -positive patients than in negative patients (median, 13,760 versus 10,385 cells/μl, respectively, P = 0.02), there were no other differences in the clinical features of the PCR-positive and -negative groups. In conclusion, E. histolytica infection was confirmed in 9 (15.8%) of the appendicitis cases. However, only 3, including one diagnosed after intestinal perforation, were diagnosed before the present analyses. These results strongly suggest there is frequently a failure to detect trophozoites in routine examination, resulting in an underestimation of the incidence of amoebic appendicitis.

scholarly journals Risk surveillance and mitigation: autoantibodies as triggers and inhibitors of severe reactions to SARS-CoV-2 infection

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Catherine Chen ◽  
Aisah Amelia ◽  
George W. Ashdown ◽  
Ivo Mueller ◽  
Anna K. Coussens ◽  
...  
Keyword(s):  
Severe Disease ◽  
Surface Proteins ◽  
Prognostic Indicators ◽  
Individual Risk ◽  
Long Term Effects ◽  
Complement Components ◽  
Screening Strategies ◽  
Life Threatening ◽  
Asymptomatic Infections

AbstractCOVID-19 clinical presentation differs considerably between individuals, ranging from asymptomatic, mild/moderate and severe disease which in some cases are fatal or result in long-term effects. Identifying immune mechanisms behind severe disease development informs screening strategies to predict who are at greater risk of developing life-threatening complications. However, to date clear prognostic indicators of individual risk of severe or long COVID remain elusive. Autoantibodies recognize a range of self-antigens and upon antigen recognition and binding, important processes involved in inflammation, pathogen defence and coagulation are modified. Recent studies report a significantly higher prevalence of autoantibodies that target immunomodulatory proteins including cytokines, chemokines, complement components, and cell surface proteins in COVID-19 patients experiencing severe disease compared to those who experience mild or asymptomatic infections. Here we discuss the diverse impacts of autoantibodies on immune processes and associations with severe COVID-19 disease.

scholarly journals Association of human cytomegalovirus (HCMV) neutralizing antibodies with antibodies to the HCMV glycoprotein complexes

2020 ◽  
Author(s):  
Miho Shibamura ◽  
Tomoki Yoshikawa ◽  
Souichi Yamada ◽  
Takuya Inagaki ◽  
Phu Hoang Anh Nguyen ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Immunofluorescence Assay ◽  
Plaque Reduction Assay ◽  
Glycoprotein Complex ◽  
Life Threatening ◽  
Antibody Titers ◽  
Asymptomatic Infections ◽  
Adult Volunteers

Abstract Background: Human cytomegalovirus (HCMV) causes asymptomatic infections, but also causes congenital infections when women were infected with HCMV during pregnancy, and life-threatening diseases in immunocompromised patients. To better understand the mechanism of the neutralization activity against HCMV, the association of HCMV NT antibody titers was assessed with the antibody titers against each glycoprotein complex (gc) of HCMV. Methods: Sera collected from 78 healthy adult volunteers were used. HCMV Merlin strain and HCMV clinical isolate strain 1612 were used in the NT assay with the plaque reduction assay, in which both the MRC-5 fibroblasts cells and the RPE-1 epithelial cells were used. Glycoprotein complex of gB, gH/gL complexes (gH/gL/gO and gH/gL/UL128-131A [PC]) and gM/gN were selected as target glycoproteins. 293FT cells expressed with gB, gM/gN, gH/gL/gO, or PC, were prepared and used for the measurement of the antibody titers against each gc in an indirect immunofluorescence assay (IIFA). The correlation between the IIFA titers to each gc and the HCMV-NT titers was evaluated.Results: There were no significant correlations between gB-specific IIFA titers and the HCMV-NT titers in epithelial cells or between gM/gN complex-specific IIFA titers and the HCMV-NT titers. On the other hand, there was a statistically significant positive correlation between the IIFA titers to gH/gL complexes and HCMV-NT titers.Conclusions: The data suggest that the gH/gL complexes might be the major target to induce NT activity against HCMV.

scholarly journals The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives

2020 ◽  
Author(s):  
Christophe d'Enfert ◽  
Ann-Kristin Kaune ◽  
Leovigildo-Rey Alaban ◽  
Sayoni Chakraborty ◽  
Nathaniel Cole ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Current Knowledge ◽  
Fungal Host ◽  
Susceptibility To Infection ◽  
Life Threatening ◽  
Antifungal Immunity ◽  
Epithelial Barriers ◽  
Systemic Infections ◽  
Immune Defences ◽  
The Impact

Abstract Candida albicans is a major fungal pathogen of humans. It exists as a commensal in the oral cavity, gut or genital tract of most individuals, constrained by the local microbiota, epithelial barriers and immune defences. Their perturbation can lead to fungal outgrowth and the development of mucosal infections such as oropharyngeal or vulvovaginal candidiasis, and patients with compromised immunity are susceptible to life-threatening systemic infections. The importance of the interplay between fungus, host and microbiota in driving the transition from C. albicans commensalism to pathogenicity is widely appreciated. However, the complexity of these interactions, and the significant impact of fungal, host and microbiota variability upon disease severity and outcome, are less well understood. Therefore, we summarise the features of the fungus that promote infection, and how genetic variation between clinical isolates influences pathogenicity. We discuss antifungal immunity, how this differs between mucosae, and how individual variation influences a person's susceptibility to infection. Also, we describe factors that influence the composition of gut, oral and vaginal microbiotas, and how these affect fungal colonisation and antifungal immunity. We argue that a detailed understanding of these variables, which underlie fungal-host-microbiota interactions, will present opportunities for directed antifungal therapies that benefit vulnerable patients.

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