Immunity to sand fly salivary protein LJM11 modulates host response to vector-transmitted leishmania conferring ulcer-free protection

J Invest Dermatol. 2012 Dec;132(12):2735-43. doi: 10.1038/jid.2012.205. Epub 2012 Jun 28.


Leishmania vaccines that protect against needle challenge fail against the potency of a Leishmania-infected sand fly transmission. Here, we demonstrate that intradermal immunization of mice with 500 ng of the sand fly salivary recombinant protein LJM11 (rLJM11) from Lutzomyia longipalpis, in the absence of adjuvant, induces long-lasting immunity that results in ulcer-free protection against Leishmania major delivered by vector bites. This protection is antibody independent and abrogated by depletion of CD4(+) T cells. Two weeks after challenge, early induction of IFN-γ specifically to rLJM11 correlates to diminished parasite replication in protected animals. At this time point, Leishmania-specific induction of IFN-γ in these mice is low in comparison with its high level in non-protected controls. We hypothesize that early control of parasites in a T-cell helper type 1 environment induced by immunity to LJM11 permits the slow development of Leishmania-specific immunity in the absence of open ulcers. Leishmania-specific immunity observed 5 weeks after infection in rLJM11-immunized mice shows a twofold increase over controls in the percentage of IFN-γ-producing CD4(+) T cells. We propose LJM11 as an immunomodulator that drives an efficient and controlled protective immune response to a sand fly-transmitted Leishmania somewhat mimicking "leishmanization"-induced protective immunity but without its associated lesions.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Bites and Stings / immunology
  • Bites and Stings / parasitology
  • Disease Models, Animal
  • Ear, External / immunology
  • Ear, External / parasitology
  • HEK293 Cells
  • Humans
  • Insect Proteins / immunology
  • Insect Proteins / pharmacology
  • Leishmania major / growth & development
  • Leishmania major / immunology*
  • Leishmaniasis Vaccines / immunology*
  • Leishmaniasis Vaccines / pharmacology
  • Leishmaniasis, Cutaneous / immunology*
  • Leishmaniasis, Cutaneous / prevention & control*
  • Leishmaniasis, Cutaneous / transmission
  • Lymph Nodes / immunology
  • Lymph Nodes / parasitology
  • Lymphocyte Depletion
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Psychodidae / immunology*
  • Psychodidae / parasitology
  • Saliva / immunology
  • Saliva / parasitology
  • Salivary Proteins and Peptides / immunology*
  • Skin Ulcer / immunology
  • Skin Ulcer / parasitology
  • Skin Ulcer / prevention & control
  • Spleen / cytology
  • Spleen / immunology
  • Th1 Cells / immunology
  • Th1 Cells / parasitology
  • Vaccines, Synthetic / immunology
  • Vaccines, Synthetic / pharmacology


  • Insect Proteins
  • Leishmaniasis Vaccines
  • Salivary Proteins and Peptides
  • Vaccines, Synthetic