A study of cutaneous lesions caused by Leishmania mexicana in plasminogen-deficient mice

The role of plasminogen, the zymogenic form of the serine protease plasmin, was investigated in the infection of Leishmania mexicana in plasminogen-deficient (plg−/−) and Plg wild-type (plg+/+) mice. Differences in the lesion size were observed between male plg+/+ and plg−/− mice. However, these differences were not observed in female mice. In both genders, examination of the lesion tissues at 8 weeks post-infection showed differences in the immunoreactivity pattern with anti-Leishmania antibodies. The parasites were limited to isolated foci in the plg−/− mice lesion, in contrast to the scattered pattern observed in plg+/+ mice. These results support the hypothesis that the interaction of the parasite with the host plasminogen–plasmin system might contribute to the virulence of L. mexicana.