Biochemical and biological characterization of the protective Leishmania pifanoi amastigote antigen P-8.
The Leishmania pifanoi amastigote antigen P-8 has been previously shown to induce protective immunity in a murine model of cutaneous leishmaniasis (L. Soong, S. M. Duboise, P. Kima, and D. McMahon-Pratt, Infect. Immun. 63:3559-3566, 1995). As this antigen is of interest for further vaccine studies, the biochemical characterization of P-8 was undertaken. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western-blot analysis, and gel filtration chromatography revealed that P-8 antigen consisted of two proteoglycolipid complexes. The P-8 epitope is associated with the L. pifanoi amastigote-specific glycolipid components found in the two complexes. The P-8 complex 1 (P-8c1) consists of a 56-kDa serine metalloproteinase, apolipoprotein E (derived from fetal bovine serum), and amastigote-specific glycolipids. The P-8 complex 2 (P-8c2) consists of a 31-kDa cysteine proteinase associated with amastigote glycolipids. Biochemical analyses suggest that the P-8 antigenic glycolipids may be distinct from previously described Leishmania glycolipids (glycosylinositol-phospholipids and sphingoglycolipids). Protective immunity studies revealed that P-8c1 (serine metalloproteinase-glycolipid complex) confers comparable protection against infection as immunopurified P-8. The isolated P-8c2 (cysteine proteinase-glycolipid complex) does not provide significant protection, nor does stimulation with P-8c2 result in significant T-cell activation in P-8- or P-8c2-vaccinated mice. Consequently, the P-8c1 complex appears to be the immunodominant component of P-8.
Colmenares
M
M
Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, USA.
Tiemeyer
M
M
Kima
P
P
McMahon-Pratt
D
D
D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis* / Q000276:immunology; D005260:Female; D006017:Glycolipids / Q000032:analysis / Q000276:immunology; D007891:Leishmania / Q000276:immunology*; D008565:Membrane Proteins / Q000032:analysis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011510:Proteolipids / Q000032:analysis / Q000276:immunology; D015800:Protozoan Proteins / Q000032:analysis* / Q000276:immunology; D016052:Protozoan Vaccines / Q000276:immunology
D000953:Antigens, Protozoan; D006017:Glycolipids; D008565:Membrane Proteins; D011510:Proteolipids; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; C024374:proteoglycolipids