List of primer sequences.

<div><p>In canine leishmaniosis endemic areas, <i>Leishmania infantum</i> may occur in sympatry with the non-pathogenic <i>Leishmania tarentolae</i>, which is associated to reptiles. The potential infectivity of <i>L</i>. <i>tarentolae</i> for mammals raises questions about the interactions between the two <i>Leishmania</i> species, and the potential cross-immune protection in dogs. This study aimed to assess the outcome of experimental <i>L</i>. <i>tarentolae</i> infection in dogs, determining: i) the anti-<i>L</i>. <i>tarentolae</i> antibody production, ii) the duration of the immunity and cytokine expression, and iii) the possible pathogenic effect in the canine host. Twelve purpose-bred beagle dogs were randomly allocated to three groups (intravenous inoculation, G1; intradermal inoculation, G2; negative control, G3). G1 and G2 dogs were inoculated twice (day 0, day 28) with 10<sup>8</sup> promastigotes of <i>L</i>. <i>tarentolae</i> strain (RTAR/IT/21/RI-325) isolated from a <i>Tarentola mauritanica</i> gecko. The animals were followed until day 206. Blood, serum, conjunctival swabs and lymph node aspirate samples were collected monthly and bone marrow, liver and spleen biopsies on day 91. Hematological and biochemical parameters were assessed monthly, as well as serology (IFAT and ELISA) and molecular identification of <i>L</i>. <i>tarentolae</i>. Mononuclear cells (PBMC) were obtained to assess the cytokine expression through <i>in vitro</i> stimulation or (re-) infection. Data from this study demonstrated that DNA from <i>L</i>. <i>tarentolae</i> is detectable up to 3 months post-infection, with seroconversion after day 28. Moreover, the non-pathogenic nature of <i>L</i>. <i>tarentolae</i> was confirmed, with a neutral Th1/Th2 polarization, and a possible shift to Th1 phenotype after derived macrophages (re-) infection, as demonstrated by the expression of IFN-gamma. Therefore, <i>L</i>. <i>tarentolae</i> demonstrated a great potential as a surrogate pathogen and/or immune-prophylaxis/immune-therapy against <i>Leishmania</i> infections in dogs and humans.</p></div>