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  • 1
    Online Resource
    Online Resource
    Expression of Homing Receptors on IgA1 and IgA2 Plasmablasts in Blood Reflects Differential Distribution of IgA1 and IgA2 in Various Body Fluids
    American Society for Microbiology ; 2010
    In:  Clinical and Vaccine Immunology Vol. 17, No. 3 ( 2010-03), p. 393-401
    Details
    In: Clinical and Vaccine Immunology, American Society for Microbiology, Vol. 17, No. 3 ( 2010-03), p. 393-401
    Abstract: Although secretory IgA is the most abundantly produced Ig isotype, the mechanisms underlying the differential distribution of IgA subclasses in various body fluids remain unclear. To explore these mechanisms, we examined the distribution of IgA subclasses, the influence of the nature and sites of encounters with antigens, and the correlation between IgA subclass distribution and homing potentials of circulating IgA plasmablasts. IgA1 predominated in serum, tears, nasal wash fluid, and saliva; the levels of IgA1 and IgA2 were comparable in vaginal wash fluid; and IgA2 predominated in intestinal lavage fluids. Seventy-one percent of circulating IgA plasmablasts secreted IgA1. The intestinal homing receptor (HR), α4β7, was expressed more frequently on IgA2 than on IgA1 plasmablasts, with no differences in the expression of other HRs. IgA subclass distribution among circulating antigen-specific antibody-secreting cells (ASC) was dependent on the nature of the antigen: following vaccination with Salmonella enterica serovar Typhi, unconjugated pneumococcal polysaccharide, or Haemophilus influenzae polysaccharide-diphtheria toxoid conjugate, the proportions of specific IgA1 ASC were 74%, 47%, 56%, and 80%, respectively. HR expression depended on the route of administration: expression of HRs was different after oral than after parenteral vaccination, while no difference was seen between HR expression of antigen-specific IgA1 and IgA2 ASC induced via the same route. The key factors determining IgA subclass distribution in a given secretion are the nature of the antigens encountered at a particular site and the site-specific homing instructions given to lymphocytes at that site. These two factors are reflected as differences in the homing profiles of the total populations of circulating IgA1 and IgA2 plasmablasts.
    Type of Medium: Online Resource
    ISSN: 1556-6811 , 1556-679X
    URL: Article
    DOI: 10.1128/CVI.00475-09
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2010
    detail.hit.zdb_id: 1496863-0
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  • 2
    Online Resource
    Online Resource
    Influenza Virus-Infected Epithelial Cells Present Viral Antigens to Antigen-Specific CD8 + Cytotoxic T Lymphocytes
    American Society for Microbiology ; 1998
    In:  Journal of Virology Vol. 72, No. 5 ( 1998-05), p. 4534-4536
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 72, No. 5 ( 1998-05), p. 4534-4536
    Abstract: We have investigated the mechanisms involved in the clearance of viral infection at the epithelium level by analyzing the activity of influenza virus-specific cytotoxic T lymphocytes (CTL) against virus-infected CMT-93 intestinal epithelial cells. Epithelial cells infected with live influenza virus effectively present viral antigens and were lysed by both homotypic and heterotypic influenza virus-specific CD8 + T cells. These results shed new light on the control of viral infection through the elimination of virus-infected epithelial cells by virus-specific CTL and demonstrate that CMT-93 cells furnish an appropriate model for in vitro evaluation of CTL activity against virus-infected epithelial cells.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.72.5.4534-4536.1998
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1998
    detail.hit.zdb_id: 1495529-5
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  • 3
    Online Resource
    Online Resource
    Defining HIV-1 Envelope N-Glycan Microdomains through Site-Specific Heterogeneity Profiles
    American Society for Microbiology ; 2019
    In:  Journal of Virology Vol. 93, No. 1 ( 2019-01)
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 93, No. 1 ( 2019-01)
    Abstract: The HIV-1 envelope (Env) glycans shield the surface of Env from the immune system and form integral interactions important for a functional Env. To understand how individual N-glycosylation sites (NGS) coordinate to form a dynamic shield and evade the immune system through mutations, we tracked 20 NGS in Env from HIV-transmitted/founder (T/F) and immune escape variants and their mutants involving the N262 glycan. NGS were profiled in a site-specific manner using a high-resolution mass spectrometry (MS)-based workflow. Using this site-specific quantitative heterogeneity profiling, we empirically characterized the interdependent NGS of a microdomain in the high-mannose patch (HMP). The changes (shifts) in NGS heterogeneity between the T/F and immune escape variants defined a range of NGS that we further probed for exclusive combinations of sequons in the HMP microdomain using the Los Alamos National Laboratory HIV sequence database. The resultant sequon combinations, including the highly conserved NGS N262, N448, and N301, created an immune escape map of the conserved and variable sequons in the HMP microdomain. This report provides details on how some clustered NGS form microdomains that can be identified and tracked across Env variants. These microdomains have a limited number of N-glycan-sequon combinations that may allow the anticipation of immune escape variants. IMPORTANCE The Env protein of HIV is highly glycosylated, and the sites of glycosylation can change as the virus mutates during immune evasion. Due to these changes, the glycan location and heterogeneity of surrounding N-glycosylation sites can be altered, resulting in exposure of different glycan or proteoglycan surfaces while still producing a viable HIV variant. These changes present a need for vaccine developers to identify Env variants with epitopes most likely to induce durable protective responses. Here we describe a means of anticipating HIV-1 immune evasion by dividing Env into N-glycan microdomains that have a limited number of N-glycan sequon combinations.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.01177-18
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2019
    detail.hit.zdb_id: 1495529-5
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  • 4
    Online Resource
    Online Resource
    Induction of Susceptibility to Disseminated Infection with IgA1 Protease-Producing Encapsulated Pathogens Streptococcus pneumoniae, Haemophilus influenzae Type b, and Neisseria meningitidis
    American Society for Microbiology ; 2022
    In:  mBio Vol. 13, No. 3 ( 2022-06-28)
    Details
    In: mBio, American Society for Microbiology, Vol. 13, No. 3 ( 2022-06-28)
    Abstract: Streptococcus pneumoniae , Neisseria meningitidis , and Haemophilus influenzae are the principal causes of bacterial meningitis. It is unexplained why only occasional individuals develop invasive infection, while the vast majority remain healthy and develop immunity when encountering these pathogens. A capsular polysaccharide and an IgA1 protease are common to these pathogens. We tested the hypothesis that patients are primed to susceptibility to invasive infection by other bacteria that express the same capsular polysaccharide but no IgA1 protease. Thereby, the subsequently colonizing pathogen may protect its surface with IgA1 protease-generated Fab fragments of IgA1 devoid of Fc-mediated effector functions. Military recruits who remained healthy when acquiring meningococci showed a significant response of inhibitory antibodies against the IgA1 protease of the colonizing clone concurrent with serum antibodies against its capsular polysaccharide. At hospitalization, 70.8% of meningitis patients carried fecal bacteria cross-reactive with the capsule of the actual pathogen, in contrast to 6% of controls ( P   〈  0.0001). These were Escherichia coli K100, K1, and K92 in patients with infection caused by H. influenzae type b and N. meningitidis groups B and C, respectively. This concurred with a significant IgA1 response to the capsule but not to the IgA1 protease of the pathogen. The demonstrated multitude of relationships between capsular types and distinct IgA1 proteases in pneumococci suggests an alternative route of immunological priming associated with recombining bacteria. The findings support the model and offer an explanation for the rare occurrence of invasive diseases in spite of the comprehensive occurrence of the pathogens. IMPORTANCE Why some individuals develop invasive infection, including meningitis, with Streptococcus pneumoniae , Neisseria meningitidis , and Haemophilus influenzae type b is unexplained. The vast majority of humans are colonized with the three pathogens but remain healthy and develop immunity. The findings of this study support the hypothesis that patients are primed for disease by time-shifted acquisition of two different bacteria, an immunogenic commensal followed by the pathogen, but both expressing the same capsular polysaccharide. The IgA1 protease common to the three pathogens cleaves the preexisting IgA1 antibodies induced by the commensal. This eliminates Fc-mediated protective mechanisms and releases capsule-binding monomeric Fab fragments that enhance bacterial adherence and block access of other isotypes of antibody molecules. This concept provides new insight into the pathogenesis of bacterial meningitis and potential new strategies for prevention.
    Type of Medium: Online Resource
    ISSN: 2150-7511
    URL: Article
    DOI: 10.1128/mbio.00550-22
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2022
    detail.hit.zdb_id: 2557172-2
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