Browsing by Subject "Enzyme-linked immunosorbent assay"

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    Antibody Profiles to P. falciparum Antigens Over Time Characterize Acute and Long-Term Malaria Exposure in an Area of Low and Unstable Transmission
    (American Society of Tropical Medicine and Hygiene, 2020-12) Ondigo, Bartholomew N.; Hamre, Karen E.S.; Frosch, Anne E.P.; Ayodo, George; White, Michael T.; John, Chandy C.; Pediatrics, School of Medicine
    Prevalence and levels of antibodies to multiple Plasmodium falciparum antigens show promise as tools for estimating malaria exposure. In a highland area of Kenya with unstable transmission, we assessed the presence and levels of antibodies to 12 pre-erythrocytic and blood-stage P. falciparum antigens by multiplex cytometric bead assay or ELISA in 604 individuals in August 2007, with follow-up testing in this cohort in April 2008, April 2009, and May 2010. Four hundred individuals were tested at all four time points. During this period, the only substantial malaria incidence occurred from April to August 2009. Antibody prevalence in adults was high at all time points (> 70%) for apical membrane antigen 1, erythrocyte-binding antigen 175, erythrocyte-binding protein-2, glutamate rich protein (GLURP)-R2, merozoite surface protein (MSP) 1 (19), MSP-1 (42), and liver-stage antigen-1; moderate (30-70%) for GLURP-R0, MSP-3, and thrombospondin-related adhesive protein; and low (< 30%) for SE and circumsporozoite protein (CSP). Changes in community-wide malaria exposure were best reflected in decreasing antibody levels overtime for highly immunogenic antigens, and in antibody seroprevalence overtime for the less-immunogenic antigens. Over the 3 years, antibody levels to all antigens except CSP and schizont extract (SE) decreased in an age-dependent manner. Prevalence and levels of antibodies to all antigens except CSP and SE increased with age. Increases in antibody prevalence and levels to CSP and SE coincided with increases in community-wide malaria incidence. Antibody levels to multiple P. falciparum antigens decrease in the absence of consistent transmission. Multiplex assays that assess both the presence and level of antibodies to multiple pre-erythrocytic and blood-stage P. falciparum antigens may provide the most useful estimates of past and recent malaria transmission in areas of unstable transmission and could be useful tools in malaria control and elimination campaigns.
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    Improved Reproducibility and Quality of GVHD Biomarker Assay- Application of Multiplex Microfluidic Channel System
    (Springer Nature, 2016) Anandi, Prathima; Tian, Xin; Chinian, Fariba; Cantilena, Caroline R.; Dunavin, Neil; Hensel, Nancy; Draper, Debbie; Koklanaris, Eleftheria; Maxwell, Sandra; Superata, Jeanine; Muranski, Pawel; Battiwalla, Minoo; Paczesny, Sophie; Barrett, A. John; Ito, Sawa; Pediatrics, School of Medicine
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    LAMP-2C inhibits MHC class II presentation of cytoplasmic antigens by disrupting chaperone-mediated autophagy
    (American Association of Immunologists, 2016-03-15) Pérez, Liliana; McLetchie, Shawna; Gardiner, Gail J.; Deffit, Sarah N.; Zhou, Delu; Blum, Janice S.; Department of Microbiology & Immunology, IU School of Medicine
    Cells use multiple autophagy pathways to sequester macromolecules, senescent organelles, and pathogens. Several conserved isoforms of the lysosome-associated membrane protein-2 (LAMP-2) regulate these pathways influencing immune recognition and responses. LAMP-2A is required for chaperone-mediated autophagy (CMA), which promotes Ag capture and MHC class II (MHCII) presentation in B cells and signaling in T cells. LAMP-2B regulates lysosome maturation to impact macroautophagy and phagocytosis. Yet, far less is known about LAMP-2C function. Whereas LAMP2A and LAMP2B mRNA were broadly detected in human tissues, LAMP2C expression was more limited. Transcripts for the three LAMP2 isoforms increased with B cell activation, although specific gene induction varied depending on TLR versus BCR engagement. To examine LAMP-2C function in human B cells and specifically its role in Ag presentation, we used ectopic gene expression. Increased LAMP-2C expression in B cells did not alter MHCII expression or invariant chain processing, but did perturb cytoplasmic Ag presentation via CMA. MHCII presentation of epitopes from exogenous and membrane Ags was not affected by LAMP-2C expression in B cells. Similarly, changes in B cell LAMP-2C expression did not impact macroautophagy. The gene expression of other LAMP2 isoforms and proteasome and lysosomal proteases activities were unperturbed by LAMP-2C ectopic expression. LAMP-2C levels modulated the steady-state expression of several cytoplasmic proteins that are targeted for degradation by CMA and diminished peptide translocation via this pathway. Thus, LAMP-2C serves as a natural inhibitor of CMA that can selectively skew MHCII presentation of cytoplasmic Ags.