Objective　　　To investigate the effect of anti-inflammatory and anticoagulant tick anticoagulant peptide (TAP)-staphylococcal superantigen like protein-5 (SSL5) fusion protein on the binding of human platelets to neutrophils.　　　 Methods　　　Cell viability was assessed by colorimetric cell counting kit-8 (CCK-8). Flow cytometry (FCM) was applied to detect the expression of CD162 (PSGL-1) on THP-1 cells as well as the inhibitory effect of TAP-SSL5 on the binding of mouse anti-human CD162 monoclonal antibody (KPL-1) to THP-1 cells. Platelets were activated by 20 μmol/L of ADP

and the binding rates of the activated platelets to THP-1 cells and neutrophils were assayed by FCM and Wright-Giemsa staining

respectively.　　　 Results　　　TAP-SSL5≤30 mg/L did not affect the viability of THP-1 cells or human neutrophils

and the TAP-SSL5 at 10 mg/L competitively inhibited KPL-1 binding to THP-1 cells. The binding rates of activated platelets (by 20 μmol/L ADP) to THP-1 cells or neutrophils were (31.3±8.4)% and (35.6±5.9)%

respectively

which decreased to (13.4±6.7)% and (10.4±6.4)% after the THP-1 cells and neutrophils were pre-incubated with 10 mg/L TAP-SSL5 (P0.01). The results of Wright-Giemsa staining showed that both TAP-SSL5 and SSL5 could inhibit the binding of activated platelets to neutrophils (P0.05).　　　 Conclusion　　　TAP-SSL5 can directly inhibit the platelet-neutrophil binding.