Differential mechanisms of neutrophil and monocyte adhesion on neuroblastoma cells: CD18 and VLA-4 integrins mediate adhesion to SK-N-SH, but not to SK-N-MC cell line

We examined the adhesion of monocytes and polymorphonuclear leukocytes (PMN Ls) to the neuroblastoma (NB) cell lines SK-N-SH and SK-N-MC, which have so me distinct differentiation characteristics. Monocytes adhered to SK-N-SH a nd SK-N-MC to the same extent (20 +/- 1.4% and 24 +/- 0.8% of monocytes add ed). Monocyte adhesion to SK-N-SH but not SK-N-MC was partially inhibited b y treating monocytes with a mAb to the CD18 (beta 2) integrin chain. The ad hesion was further inhibited when monocytes were treated with a combination of mAb to CD18 and VLA-4. Treatment of both NE cell lines with interleukin -1 alpha (0.5 ng/ml), tumor necrosis factor alpha (100 U/ml), interferon ga mma (200 U/ml), or their combinations increased monocyte adhesion to SK-N-S H and SK-N-MC. With each condition, monocyte adhesion to SK-N-SH was partia lly blocked by mAb to CD18. The inhibition of adhesion to IL-1 alpha- or TN F alpha-treated SK-N-SH cells was greater when the monocytes were treated w ith mAb to both CD18 and VL4-4. In contrast, monocyte adhesion to IL-1 alph a or IFN gamma treated SK-N-MC was only slightly inhibited with a combinati on of mAb to CD18 + VLA-4 and there was no inhibition at all to TNF alpha-t reated SK-N-MC. Spontaneous PMNL adhesion to SK-N-SH was almost negligible but increased by treating the cell line with IL-1 alpha, TNF alpha, IFN gam ma or their combinations. A mAb to CD18 blocked this increase in each case. The pattern of adhesion of PMNLs to SK-N-MC was totally different. PMNL ad hesion to unstimulated SK-N-MC was very high (24 +/- 1.3%), was not inhibit ed by mAb to CD18, and did not increase by stimulating the cell line with I L-1 alpha, TNF alpha, IFN gamma or their combinations. Overall, these resul ts suggest two distinct patterns of monocyte and PMNL interaction with neur al cells, such as the SK-N-SH and MC cell lines. While monocyte and PMNL ad hesion to SK-N-SH is mainly via CD18/VLA-4 or the CD18 mechanisms, respecti vely, leukocyte adhesion to SK-N-MC is CD18- and VLA-4-independent. Thus, l eukocyte-neural cell interactions share some mechanisms common also to leuk ocyte-endothelium interaction, but there are also unique mechanisms which m ay be neural cell and differentiation specific. (C) 2000 Wiley-Liss, Inc.