title: Diffusion of Immunoglobulin G in Shed Vaginal Epithelial Cells and in Cell-Free Regions of Human Cervicovaginal Mucus.
abstract: Human cervicovaginal mucus (CVM) is a viscoelastic gel containing a complex mixture of mucins, shed epithelial cells, microbes and macromolecules, such as antibodies, that together serve as the first line of defense against invading pathogens. Here, to investigate the affinity between IgG and different mucus constituents, we used Fluorescence Recovery After Photobleaching (FRAP) to measure the diffusion of IgG in fresh, minimally modified CVM. We found that CVM exhibits substantial spatial variations that necessitate careful selection of the regions in which to perform FRAP. In portions of CVM devoid of cells, FRAP measurements using different IgG antibodies and labeling methods consistently demonstrate that both exogenous and endogenous IgG undergo rapid diffusion, almost as fast as in saline, in good agreement with the rapid diffusion of IgG in mid-cycle endocervical mucus that is largely devoid of cells. This rapid diffusion indicates the interactions between secreted mucins and IgG must be very weak and transient. IgG also accumulated in cellular debris and shed epithelial cells that had become permeable to IgG, which may allow shed epithelial cells to serve as reservoirs of secreted IgG. Interestingly, in contrast to cell-free regions of CVM, the diffusion of cell-associated IgG was markedly slowed, suggesting greater affinity between IgG and cellular constituents. Our findings contribute to an improved understanding of the role of IgG in mucosal protection against infectious diseases, and may also provide a framework for using FRAP to study molecular interactions in mucus and other complex biological environments.
authors.affiliation: Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Wang
authors.affiliation: Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Holly A
authors.initials: HA
authors.lastname: Schroeder
authors.affiliation: UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Kenetta L
authors.initials: KL
authors.lastname: Nunn
authors.affiliation: Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Karen
authors.initials: K
authors.lastname: Woods
authors.affiliation: Departments of Obstetrics/Gynecology, Microbiology and Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Anderson
authors.affiliation: Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, United States of America.|UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, United States of America.|Department of Microbiology & Immunology, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Samuel K
authors.identifier: http://orcid.org/0000-0003-4721-528X
authors.initials: SK
authors.lastname: Lai
authors.affiliation: Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Cone
mesh_terms: D001692:Biological Transport; D002474:Cell-Free System; D002582:Cervix Mucus / Q000166:cytology / Q000276:immunology*; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology*; D005260:Female; D036681:Fluorescence Recovery After Photobleaching; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D014621:Vagina / Q000166:cytology / Q000276:immunology
chemical_list: D007074:Immunoglobulin G