Novel functions and cellular interaction of human lymphoid stromal cells with lymphoid cell lines in vitro.

Lymphoid stromal (SG) cells have been isolated from the lymph node of a patient with malignant lymphoma, and characterized by positive reaction with a monoclonal antibody against the T-zone stromal cells in human lymph nodes. B-acute lymphoblastic leukemia (BALL) cells showed prominent emperipolesis toward SG cells when they were cocultured, whereas T-acute lymphoblastic leukemia (TALL) cells attached firmly to the surface of SG cells. Autologous peripheral B and T cells behaved, respectively, in the same way as BALL and TALL cells. Both BALL and TALL cells while directly interacting with the SG cells were completely inhibited from incorporating [3H]thymidine, although radioactive grains were observed in 16.4%-12.4% of supernatant BALL and 13.8%-13.0% of supernatant TALL cells in each coculture. Furthermore the media conditioned by SG cells significantly increased the incorporation of [3H]thymidine into the TALL cells as much as 190% of the control. These results indicate that SG cells undergo tissue-specific cellular interactions with B- and T-lymphoid cell lines but not with a myeloid cell line, and they can modify their growth by two distinct mechanisms. SG cells proved to be very useful in studying the effect of the lymphoid microenvironment on the proliferation of lymphocytes in vivo.