A NEW PROTOCOL FOR THE PROPAGATION OF DENDRITIC CELLS FROM RAT BONE-MARROW USING RECOMBINANT GM-CSF, AND THEIR QUANTIFICATION USING THE MABOX-62

Bone marrow (BM)-derived dendritic cells (DC) are the most potent know n antigen (Ag) presenting cell in vivo and in vitro. Detailed analysis of their properties and mechanisms of action requires an ability to p roduce large numbers of DC. Although DC have been isolated from severa l rat tissues, including BM, the yield is uniformly low. We describe a simple method for the propagation of large numbers of DC from rat BM and document cell yield with the rat DC marker, OX-62. After depletion of plastic-adherent and Fc(+) cells by panning on dishes coated with normal serum, residual BM cells were cultured in gelatin coated flasks using murine rGM-CSF supplemented medium. Prior to analysis, non-adhe rent cells were re-depleted of contaminating Fc(+) cells. Propagation of DC was monitored by double staining for FAGS analysis (major histoc ompatibility complex (MHC) class II+/OX-62(+), OX-19(-)). Functional a ssay, morphological analysis and evaluation of homing patterns of cult ured cells revealed typical DC characteristics. MHC class II and OX-62 antigen expression increased with lime in culture and correlated with allostimulatory ability. DC yield increased until day 7, when 3.3 x 1 0(6) DC were obtained from an initial 3 x 10(8) unfractionated BM cell s. Significant numbers of DC can be generated from rat BM using these simple methods. This should permit analysis and manipulation of rat DC functions in vivo and in vitro.