The Immunology of Cutaneous Leishmaniasis: Experimental Infections and Human Disease. In: Farrell JP, editor. Leishmania. Boston: Springer US; 2002. pp. 151-68. [DOI: 10.1007/978-1-4615-0955-4_11]

Leishmania infantum: Mixed T-helper-1/T-helper-2 immune response in experimentally infected BALB/c mice

The main goal of the present study was to characterise the course of infection and immunological responses developed by Leishmania infantum infected BALB/c mice. Parasite load was determined by Real-time TaqMan PCR while cytokine and Immunoglobulin G (IgG) production were assessed by ELISA. Leishmania DNA was detected in spleen and liver as soon as day 1 post-inoculation (pi) and the parasitism was sustained until the end of the experiment. The cytokine kinetics in spleen and liver was generally associated with the oscillations of parasite load. Overall, it was not observed a distinct Th1 or Th2 pattern of cytokine production during the time of experiment. The infected mice developed a mixed immune response, with concomitant production of IFN-gamma, IL-4 and IL-10, both in spleen and liver, and both IgG isotypes. However, our results suggest that, compared to liver, the spleen is more susceptible to L. infantum infection.

Efficacy of vaccination with a combination of Leishmania amastigote antigens and the lipid A-analogue ONO-4007 for immunoprophylaxis and immunotherapy against Leishmania amazonensis infection in a murine model of New World cutaneous leishmaniasis

Activation of innate immunity using adjuvants that activate Toll-like receptor 4 pathways have great potential for improving the protection induced by parasite vaccines. We investigated protective and therapeutic effects of a vaccine against leishmaniasis containing a combination of an adjuvant synthetic lipid A-analogue, ONO-4007 and Leishmania amazonensis antigens. ONO-4007 was co-injected with soluble and membrane-enriched L. amazonensis-amastigote antigens into BALB/c mice that had either already been infected with 1 x 10(6) L. amazonensis promastigotes (immunotherapy study) or before challenge with the same infectious dose (immunoprophylaxis study). Sixty percent of mice vaccinated before infectious challenge controlled their Leishmania infections - defined by the absence of footpad-swelling and negative Leishmania cultures - compared to 0% of controls, and 40% of mice vaccinated after infection resolved their infections compared to 0% of controls. Protective immunity in both immunoprophylaxis and immunotherapy models was associated with increased protein production of IL-12 and IFN-gamma. These data suggest that vaccination with a combination of ONO-4007 and amastigote antigens of L. amazonensis may be useful for the prevention and treatment of leishmaniasis, and that the protective immunity induced is associated with the production of type-1 cytokines.