| dc.description | Platelets play a central role in hemostasis during vascular injury. Patients affected with the
hemorrhagic syndrome caused by contact with Lonomia achelous caterpillars (Lac) Lepi-
doptera distributed in various South American countries, show digestive, pulmonary and
intraperitoneal bleeding in combination with hematomas and echymosis. In the present
study, we have evaluated the effects of Lonomin V (serine protease isolated from Lac
hemolymph) on some functional properties of platelets, evaluating its importance in
primary hemostasis. Platelet adhesion to fibrinogen was reduced by 19, 20, 36, and 37%
after pre-treated with 0.2, 2, 20 and 40 nM of Lonomin V, respectively. Pre-incubation of
the platelets with 408 nM of Lonomin V, for 4 min at 37
C, resulted in complete inhibition
of the collagen-induced platelet aggregation, in contrast to 56% inhibition of the ADP -
induced platelet aggregation. Lonomin V also inhibited anti-aIIbb3 integrin binding to
platelets by 56, 57, 52 and 54% at concentrations of 0.2, 2, 20 and 40 nM respectively.
Additionally, Lonomin V inhibited anti-P-selectin binding to platelets by 28, 37, 33 and 33%
at the same concentrations. The platelets tested with Lonomin V did not modify their
viability. In summary, Lonomin V inhibited platelet aggregation, probably caused by the
degradation of collagen. The anti-platelet activity of Lonomin V has been shown to be
unique and a potentially useful tool for investigating cell-matrix and cell–cell interactions
and for the development of antithrombotic agents in terms of their anti-adhesive activities. | |
