Chemokines exert their actions through G-proteinlinked
receptors, which are expressed to variable extents by different
cell types. In accordance with the chemokine classification,
these receptors are designated as CXC, CC, XC, and
CX3C, followed by R and a number. The
purpose of this investigation was to evaluate CCR1 expression in
human peripheral blood-derived macrophages and the human
monocytic U-937 cell line. Cells in
vitro were infected with live Leishmania infantum promastigotes
(zymodeme MON1); cell lysates were then subjected to SDS-PAGE
and immunoblotting, by using an anti-CCR1 affinity purified
polyclonal antibody. The expression of the CCR1 gene was
analyzed by RT-PCR, using specific human primers. The results of
both immunoblotting and RT-PCR showed that CCR1 expression in
Leishmania-infected cells was
lower than in uninfected control cells. These results indicate
that Leishmania infantum
infection causes a down-regulation of the CCR1 gene and protein
expression, suggesting that reduced phagocyte recruitment at the
inflammation sites could favor parasite progression and the
spread of Leishmania
infection.