Research Article

New Insights on the Adjuvant Properties of the Leishmania infantum Eukaryotic Initiation Factor

Figure 3

In vivo effect of recombinant LieIF protein on the response of innate immune cells. (a) Schematic representation of the experimental protocol. Female BALB/c mice were i.p. injected in the right quadrant with 500 μL of LieIF suspension (10 μg/mouse) in sterile PBS containing equal quantity of OVA protein (10 μg/mouse) (OVA-LieIF) or with 500 μL of OVA suspension (10 μg/mouse) in sterile PBS. Mice of the positive control received the known adjuvant alum (10 mg/mouse) in combination with OVA (10 μg/mouse) (OVA-alum). Mice receiving only PBS were also included. Six and 24 h after injection, the peritoneal exudate cells (PEC) were harvested with 5 mL of ice-cold PBS. (b) Recombinant LieIF protein recruits innate immune cells to the peritoneal cavity. Six and 24 h after immunization, the peritoneal lavage was harvested and the percentages of neutrophils (Ly6G+-CD11b+), monocytes (Ly6C+-CD11b+), and macrophages (F4/80+-CD11b+) were determined by FACS. Results are presented in 2D line charts and in representative contour plots. indicates statistical difference compared with the PBS-immunized mice (negative control group), and indicates statistical difference compared to OVA-immunized mice. (c) The immunopotentiating effect of LieIF does not depend on the production of uric acid. The levels of uric acid (mg/dL) were measured in serum of immunized mice using the enzymatic colorimetric uricase PAP method. The results are presented as the , and data shown are representative of three independent experiments. indicates statistically significant differences as compared to the negative control.