M-Cells Contribute to the Entry of an Oral Vaccine but Are Not Essential for the Subsequent Induction of Protective Immunity against Francisella tularensis

PLoS One. 2016 Apr 21;11(4):e0153402. doi: 10.1371/journal.pone.0153402. eCollection 2016.

Abstract

M-cells (microfold cells) are thought to be a primary conduit of intestinal antigen trafficking. Using an established neutralizing anti-RANKL (Receptor Activator of NF-κB Ligand) antibody treatment to transiently deplete M-cells in vivo, we sought to determine whether intestinal M-cells were required for the effective induction of protective immunity following oral vaccination with ΔiglB (a defined live attenuated Francisella novicida mutant). M-cell depleted, ΔiglB-vaccinated mice exhibited increased (but not significant) morbidity and mortality following a subsequent homotypic or heterotypic pulmonary F. tularensis challenge. No significant differences in splenic IFN-γ, IL-2, or IL-17 or serum antibody (IgG1, IgG2a, IgA) production were observed compared to non-depleted, ΔiglB-vaccinated animals suggesting complementary mechanisms for ΔiglB entry. Thus, we examined other possible routes of gastrointestinal antigen sampling following oral vaccination and found that ΔiglB co-localized to villus goblet cells and enterocytes. These results provide insight into the role of M-cells and complementary pathways in intestinal antigen trafficking that may be involved in the generation of optimal immunity following oral vaccination.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bacterial Vaccines / immunology*
  • Female
  • Francisella tularensis / immunology*
  • Immunity
  • Interferon-gamma / immunology
  • Interleukin-17 / immunology
  • Interleukin-2 / immunology
  • Intestines / cytology*
  • Intestines / immunology*
  • Intestines / microbiology
  • Mice
  • Mice, Inbred BALB C
  • Spleen / immunology
  • Spleen / microbiology
  • Tularemia / immunology*
  • Tularemia / prevention & control*
  • Vaccines, Attenuated / immunology*

Substances

  • Bacterial Vaccines
  • Interleukin-17
  • Interleukin-2
  • Vaccines, Attenuated
  • Interferon-gamma