Expression of ICAM-1 enhances in vivo lymphocyte adhesion in a murine fibrosarcoma

Background and Objectives ICAM‐1 is essential for lymphocyte‐endothelial cell interactions. We have demonstrated that increased expression of ICAM‐1 in tumors results in an enhanced response to adoptive immunotherapy. We undertook this study to determine whether increased expression of ICAM‐1 results in increased lymphocyte adhesion in vivo. Methods Parental MCA‐105 tumor cells were cotransfected with ICAM‐1 and the NeoR plasmid. A neomycin resistant clone (Cl149) was selected and increased expression of ICAM‐1 confirmed by FACS analysis. Tumor fragments (MCA‐105 or Cl149) were placed in a dorsal skinfold chamber on day 0 in C57BL/6 mice. Lymphocytes were fluorescently labeled using 0.5% acridine orange and activity recorded on videotape at 700× magnification. Lymphocyte activity was quantitated over 30 second intervals in postcapillary venules as either passing or rolling/sticking (R/S). The % R/S was calculated for each category and evaluated using χ2 analysis. Results Whereas 38% of lymphocytes were classified as R/S in normal tissue, 32% were classified as R/S (P > .05) in the MCA‐105 tumor. However, in the ICAM‐1 transfected CL149, there was significantly greater R/S at 53% (P < .05). Conclusions These data demonstrate increased lymphocyte adhesion in tumors with enhanced expression of ICAM‐1 by direct in vivo observations and may partially explain the salutary effect of increased ICAM‐1 expression on adoptive immunotherapy. This suggests the possible application of adhesion molecule expression in the cellular therapy of cancer. J. Surg. Oncol. 1977;66:39–44. © 1997 Wiley‐Liss, Inc.