Kinetoplastid membrane protein-11 (KMP-11), a protein present in all kinetoplastid protozoa, is considered a potential candidate for
a leishmaniasis vaccine. A suitable leishmaniasis vaccine candidate molecule must be expressed in amastigotes, the infective stage for
mammals. However, the expression of KMP-11 in
Leishmania
amastigotes has been a subject of controversy. We evaluated the expression
of this molecule in logarithmic and stationary growth phase promastigotes, as well as in amastigotes, of
Leishmania amazonensis
by immunoblotting,
flow cytometry and immunocytochemistry, using a monoclonal antibody against KMP-11. We found that KMP-11 is present in promastigotes
and amastigotes. In both stages, the protein was found in association with membrane structures (at the cell surface, flagellar pocket and
intracellular vesicles). More importantly, its surface expression is higher in amastigotes than in promastigotes and increases during
metacyclogenesis. The increased expression of KMP-11 in metacyclic promastigotes, and especially in amastigotes, indicates a role for
this molecule in the parasite relationship with the mammalian host. The presence of this molecule in amastigotes is consistent with the
previously demonstrated immunoprotective capacity of vaccine prototypes based on the KMP-11-coding gene and the presence of humoral
and cellular immune responses to KMP-11 in
Leishmania-infected humans and animals.
