Kupffer cell engraftment across the major histocompatibility barrier in mice: bone marrow origin, class II antigen...

The source of population renewal for Kupffer cells (KC), the major antigen-presenting cells of the liver, remains controversial. Using a well-described murine bone marrow transplantation (BMT) model in which the donor and recipient are disparate at the major histocompatibility complex (MHC), we have studied (a) the source of KC renewal by genotypic analysis, cell surface (class II or Ia) antigens, and immune function assays; (b) the level of KC Ia expression post-BMT in transplant recipients; and (c) the capacity of newly repopulating KC to present antigen to an Ia-restricted T cell clone of donor Ia type. Kupffer cell engraftment, as assessed by each of these three methods, was noted to be predominantly of donor marrow origin by day 21 post-BMT. Cell surface Ia expression was comparable to that of nontransplanted controls of the same strain as donor mice. Within 7 days post-BMT, KC were mature antigen-presenting cells. We conclude that KC rapidly repopulate the liver from donor bone marrow post-BMT, and these macrophages are able to interact with T lymphocytes in an immunocompetent manner.