title: Ex vivo host and parasite response to antileishmanial drugs and immunomodulators.
abstract: BACKGROUND
  Therapeutic response in infectious disease involves host as well as microbial determinants. Because the immune and inflammatory response to Leishmania (Viannia) species defines the outcome of infection and efficacy of treatment, immunomodulation is considered a promising therapeutic strategy. However, since Leishmania infection and antileishmanial drugs can themselves modulate drug transport, metabolism and/or immune responses, immunotherapeutic approaches require integrated assessment of host and parasite responses.
  
  
  METHODS
  To achieve an integrated assessment of current and innovative therapeutic strategies, we determined host and parasite responses to miltefosine and meglumine antimoniate alone and in combination with pentoxifylline or CpG 2006 in peripheral blood mononuclear cells (PBMCs) of cutaneous leishmaniasis patients. Parasite survival and secretion of TNF-α, IFN-γ, IL-10 and IL-13 were evaluated concomitantly in PBMCs infected with Luc-L. (V.) panamensis exposed to meglumine antimoniate (4, 8, 16, 32 and 64 μg SbV/mL) or miltefosine (2, 4, 8, 16 and 32 μM HePC). Concentrations of 4 μM of miltefosine and 8 μg SbV/mL were selected for evaluation in combination with immunomodulators based on the high but partial reduction of parasite burden by these antileishmanial concentrations without affecting cytokine secretion of infected PBMCs. Intracellular parasite survival was determined by luminometry and cytokine secretion measured by ELISA and multiplex assays.
  
  
  RESULTS
  Anti- and pro-inflammatory cytokines characteristic of L. (V.) panamensis infection were evaluable concomitantly with viability of Leishmania within monocyte-derived macrophages present in PBMC cultures. Both antileishmanial drugs reduced the parasite load of macrophages; miltefosine also suppressed IL-10 and IL-13 secretion in a dose dependent manner. Pentoxifylline did not affect parasite survival or alter antileishmanial effects of miltefosine or meglumine antimoniate. However, pentoxifylline diminished secretion of TNF-α, IFN-γ and IL-13, cytokines associated with the outcome of infection by species of the Viannia subgenus. Exposure to CpG diminished the leishmanicidal effect of meglumine antimoniate, but not miltefosine, and significantly reduced secretion of IL-10, alone and in combination with either antileishmanial drug. IL-13 increased in response to CpG plus miltefosine.
  
  
  CONCLUSIONS
  Human PBMCs allow integrated ex vivo assessment of antileishmanial treatments, providing information on host and parasite determinants of therapeutic response that may be used to tailor therapeutic strategies to optimize clinical resolution.
authors.affiliation: Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia.
authors.forename: Laura
authors.initials: L
authors.lastname: Gonzalez-Fajardo
authors.affiliation: Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia.
authors.forename: Olga Lucía
authors.initials: OL
authors.lastname: Fernández
authors.affiliation: Yale University School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Diane
authors.initials: D
authors.lastname: McMahon-Pratt
authors.affiliation: Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia.
authors.forename: Nancy Gore
authors.initials: NG
authors.lastname: Saravia
mesh_terms: D000293:Adolescent; D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology* / Q000627:therapeutic use; D016898:Interferon-alpha / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D018793:Interleukin-13 / Q000378:metabolism; D007891:Leishmania / Q000187:drug effects*; D007896:Leishmaniasis / Q000188:drug therapy*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008264:Macrophages / Q000469:parasitology; D008297:Male; D008536:Meglumine / Q000494:pharmacology* / Q000627:therapeutic use; D000077485:Meglumine Antimoniate; D009942:Organometallic Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D055815:Young Adult
chemical_list: D000981:Antiprotozoal Agents; C508609:IL10 protein, human; C578095:IL13 protein, human; D007155:Immunologic Factors; D016898:Interferon-alpha; D018793:Interleukin-13; D009942:Organometallic Compounds; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D010767:Phosphorylcholine; D016753:Interleukin-10; C039128:miltefosine; D008536:Meglumine; D000077485:Meglumine Antimoniate