A novel Leishmania infantum recombinant antigen which elicits interleukin 10 production by peripheral blood mononuclear cells of patients with visceral leishmaniasis.
We report here the characterization of a novel Leishmania infantum protein termed papLe22 (22-kDa potentially aggravating protein of Leishmania). A positive clone from a cDNA library was identified by serum of a visceral leishmaniasis (VL) patient. Full-length cDNA obtained using rapid amplification of cDNA ends-PCR codes for a 22-kDa protein. In L. infantum promastigotes an endogenous nuclear protein of 14-kDa electrophoretic mobility was found by using an antiserum prepared against the fusion protein glutathione S-transferase-papLe22. Its expression was also shown in L. infantum amastigotes and in Leishmania major and Leishmania guyanensis promastigotes. VL patients' sera showed anti-papLe22 immunoglobulin M (IgM) and IgG reactivities, indicating that a primary response against the leishmanial protein papLe22 accompanied acute VL manifestations. Specific IgG levels were correlated with patients' clinical status. The presence of IgG1, IgG2, and IgG3 subclasses suggested a mixed Th1- and Th2-type response; there was no correlation between subclass reactivity and the disease course. The recombinant papLe22 specifically activated interleukin-10 production by VL patients' peripheral blood mononuclear cells collected at diagnosis and after treatment-induced cure, indicating its contribution to VL pathogenesis and concomitant immunosuppression and its potential role in the reactivation of latent parasites. As a dominant immunogen, papLe22 might be used as a vaccine component, provided that the vaccination protocol directs the response toward the Th1 pattern.
Suffia
I
I
Groupe de Recherche en Immunopathologie de la Leishmaniose, Laboratoire de Parasitologie, Faculté de Médecine, 06107 Nice Cedex 2, France.
Ferrua
B
B
Stien
X
X
Mograbi
B
B
Marty
P
P
Rousseau
D
D
Fragaki
K
K
Kubar
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D003001:Cloning, Molecular; D005260:Female; D007106:Immune Sera / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis*; D018314:Leishmania infantum / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008969:Molecular Sequence Data; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007106:Immune Sera; D011994:Recombinant Proteins; D016753:Interleukin-10