B cell: T cell interactions occur within hepatic granulomas during experimental visceral leishmaniasis

PLoS One. 2012;7(3):e34143. doi: 10.1371/journal.pone.0034143. Epub 2012 Mar 30.

Abstract

Hepatic resistance to Leishmania donovani infection in mice is associated with the development of granulomas, in which a variety of lymphoid and non-lymphoid populations accumulate. Although previous studies have identified B cells in hepatic granulomas and functional studies in B cell-deficient mice have suggested a role for B cells in the control of experimental visceral leishmaniasis, little is known about the behaviour of B cells in the granuloma microenvironment. Here, we first compared the hepatic B cell population in infected mice, where ≈60% of B cells are located within granulomas, with that of naïve mice. In infected mice, there was a small increase in mIgM(lo)mIgD(+) mature B2 cells, but no enrichment of B cells with regulatory phenotype or function compared to the naïve hepatic B cell population, as assessed by CD1d and CD5 expression and by IL-10 production. Using 2-photon microscopy to quantify the entire intra-granuloma B cell population, in conjunction with the adoptive transfer of polyclonal and HEL-specific BCR-transgenic B cells isolated from L. donovani-infected mice, we demonstrated that B cells accumulate in granulomas over time in an antigen-independent manner. Intra-vital dynamic imaging was used to demonstrate that within the polyclonal B cell population obtained from L. donovani-infected mice, the frequency of B cells that made multiple long contacts with endogenous T cells was greater than that observed using HEL-specific B cells obtained from the same inflammatory environment. These data indicate, therefore, that a subset of this polyclonal B cell population is capable of making cognate interactions with T cells within this unique environment, and provide the first insights into the dynamics of B cells within an inflammatory site.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer
  • Animals
  • Antigens, CD1d / biosynthesis
  • B-Lymphocytes / cytology*
  • CD5 Antigens / biosynthesis
  • Disease Models, Animal
  • Female
  • Granuloma / parasitology*
  • Granuloma / pathology
  • Interleukin-10 / biosynthesis
  • Leishmania donovani / metabolism
  • Leishmaniasis, Visceral / metabolism*
  • Liver / parasitology*
  • Liver / pathology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Phenotype
  • T-Lymphocytes / cytology*

Substances

  • Antigens, CD1d
  • CD5 Antigens
  • Interleukin-10