Protein-coated nanoparticles are internalized by the epithelial cells of the female reproductive tract and induce systemic and mucosal immune responses

PLoS One. 2014 Dec 9;9(12):e114601. doi: 10.1371/journal.pone.0114601. eCollection 2014.

Abstract

The female reproductive tract (FRT) includes the oviducts (fallopian tubes), uterus, cervix and vagina. A layer of columnar epithelium separates the endocervix and uterus from the outside environment, while the vagina is lined with stratified squamous epithelium. The mucosa of the FRT is exposed to antigens originating from microflora, and occasionally from infectious microorganisms. Whether epithelial cells (ECs) of the FRT take up (sample) the lumen antigens is not known. To address this question, we examined the uptake of 20-40 nm nanoparticles (NPs) applied vaginally to mice which were not treated with hormones, epithelial disruptors, or adjuvants. We found that 20 and 40 nm NPs are quickly internalized by ECs of the upper FRT and within one hour could be observed in the lymphatic ducts that drain the FRT, as well as in the ileac lymph nodes (ILNs) and the mesenteric lymph nodes (MLNs). Chicken ovalbumin (Ova) conjugated to 20 nm NPs (NP-Ova) when administered vaginally reaches the internal milieu in an immunologically relevant form; thus vaginal immunization of mice with NP-Ova induces systemic IgG to Ova antigen. Most importantly, vaginal immunization primes the intestinal mucosa for secretion of sIgA. Sub-cutaneous (s.c) boosting immunization with Ova in complete Freund's adjuvant (CFA) further elevates the systemic (IgG1 and IgG2c) as well as mucosal (IgG1 and sIgA) antibody titers. These findings suggest that the modes of antigen uptake at mucosal surfaces and pathways of antigen transport are more complex than previously appreciated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens / immunology
  • Antigens / metabolism*
  • Biological Transport
  • Epithelial Cells / immunology
  • Epithelial Cells / metabolism*
  • Female
  • Immunity, Mucosal
  • Immunization / methods
  • Immunoglobulin G / blood
  • Lymph Nodes / immunology
  • Lymph Nodes / physiology
  • Mice
  • Mice, Inbred C57BL
  • Nanoparticles / analysis*
  • Ovalbumin / immunology
  • Vaginal Absorption*

Substances

  • Antigens
  • Immunoglobulin G
  • Ovalbumin

Grants and funding

This work was supported by the start up funds provided to Vjollca Konjufca by Southern Illinois University. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.