Characterization of the bone marrow cell population expressing an AKR murine leukaemia-virus gp71-like antigen

The murine bone marrow population mainly responsible for the unique competing activity of this lymphoid organ in the competition radioimmunoassay (cRIA) for AKR murine leukaemia viruses gp71 has been partially purified and characterized. That population could be distinguished by the following properties: (i)gp71+ cells (cell population expressing the AKR MuLV gp71 antigen) are mainly medium density cells, according to their distribution in the layers of a discontinuous bovine serum albumin (BSA) gradient; (ii) The gp71 positive cells are not mature lymphocytes; (iii) This cell population is found both in the FcR+ and FcR- compartments and is not included in the complement (C') receptor-positive population; and finally, (iv) the gp71+ cells are phagocytic cells and an adherent cell population according to its capacity to adhere to plastic surfaces, nylon wool and Sephadex G-10.