TM11 inhibits HL60 adhesion to P-selectin.
Monomeric and tetrameric TM11 were tested for their capacity to inhibit P-selectin–mediated cell adhesion. HL60 cells, expressing PSGL-1, were labeled with calcein and allowed to adhere to P-selectin–transfected CHO cells (CHO-P) in the presence or absence of TM11 and (TM11)4. (A) HL60 cells did not adhere to control CHO cells. (B) Specific adhesion of HL60 cells to CHO-P was observed in the absence of peptides. (C) HL60 cell adhesion to CHO-P could be completely blocked by 12.5 μM TM11, or (D) by 45 nM (TM11)4. HL60 cells were visualized by calcein fluorescence detection. Original magnification, × 100 (A-D). (E) TM11 (▪) and (TM11)4 (▴) inhibit HL60 adhesion to CHO-P at concentrations comparable to ELISA IC50 values (Figure 4). EC50 values are 2.2 μM and 11 nM for TM11 and (TM11)4, respectively. Values represent means of quadruplicate experiments ± variation.
