Limits...
Leishmania mexicana infection induces IgG to parasite surface glycoinositol phospholipids that can induce IL-10 in mice and humans.

Buxbaum LU - PLoS Negl Trop Dis (2013)

Bottom Line: These changes decrease IFN-γ from T cells and nitric oxide production in infected cells, which are both required for Leishmania control.Several groups have been unsuccessful in identifying amastigote surface proteins that bind IgG.Further characterization of the target glycolipids will have important implications for drug and vaccine development and will elucidate the poorly understood role of glycolipids in the immunology of infections.

View Article: PubMed Central - PubMed

Affiliation: Philadelphia Research and Education Foundation, Philadelphia, Pennsylvania, United States of America. buxbaum17@hotmail.com

ABSTRACT
Infection with the intracellular protozoan parasite Leishmania mexicana causes chronic disease in C57BL/6 mice, in which cutaneous lesions persist for many months with high parasite burdens (10(7)-10(8) parasites). This chronic disease process requires host IL-10 and FcγRIII. When Leishmania amastigotes are released from cells, surface-bound IgG can induce IL-10 and suppress IL-12 production from macrophages. These changes decrease IFN-γ from T cells and nitric oxide production in infected cells, which are both required for Leishmania control. However, antibodies targets and the kinetics of antibody production are unknown. Several groups have been unsuccessful in identifying amastigote surface proteins that bind IgG. We now show that glycoinositol phospholipids (GIPLs) of L. mexicana are recognized by mouse IgG1 by 6 weeks of infection, with a rapid increase between 12 and 16 weeks, consistent with the timing of chronic disease in C57BL/6 mice vs. healing in FcγRIII-deficient mice. A single prominent spot on TLC is recognized by IgG, and the glycolipid is a glycosyl phosphatidylinositol containing a branched mannose structure. We show that the lipid structure of the GIPL (the sn-2 fatty acid) is required for antibody recognition. This GIPL is abundant in L. mexicana amastigotes, rare in stationary-phase promastigotes, and absent in L. major, consistent with a role for antibodies to GIPLs in chronic disease. A mouse monoclonal anti-GIPL IgG recognizes GIPLs on the parasite surface, and induces IL-10 from macrophages. The current work also extends this mouse analysis to humans, finding that L. mexicana-infected humans with localized and diffuse cutaneous leishmaniasis have antibodies that recognize GIPLs, can bind to the surface of amastigotes, and can induce IL-10 from human monocytes. Further characterization of the target glycolipids will have important implications for drug and vaccine development and will elucidate the poorly understood role of glycolipids in the immunology of infections.

Show MeSH

Related in: MedlinePlus

The immunodominant glycolipid recognized by L. mexicana-infected mouse serum is a GPI and has a branched mannose chain.L. mexicana amastigote GIPLs (lanes 1–4, 6, 8, 9) were digested with T. brucei GPI-PLC, human GPI-PLD, or jack bean α-mannosidase (JBAM), extracted with n-butanol, and separated by TLC. Then serum from L. mexicana-infected mice was used for immunoblot. In addition, Trypanosoma brucei GPI glycolipids were also analyzed by TLC immunoblot in comparison with L. mexicana amastigote GIPLs. Lane 1, 8×107 c.e. GIPL, mock GPI-PLC; lane 2, 8×107 c.e., GPI-PLC; lane 3, 8×107 c.e., mock GPI-PLD; lane 4, 8×107 c.e., GPI-PLD; lane 5, GPI-PLD without L. mex GIPL; lane 6, 2×108 c.e. GIPL; lane 7, 2×108 c.e. T. brucei GPIs; lane 8, 8×108 c.e. GIPL, mock JBAM; lane 9, 8×108 c.e., JBAM. O, origin; F, front; A, immunodominant GIPL; B, de-branched mannose product of immunodominant GIPL. Data represent at least 3 experiments with similar results.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3649955&req=5

pntd-0002224-g006: The immunodominant glycolipid recognized by L. mexicana-infected mouse serum is a GPI and has a branched mannose chain.L. mexicana amastigote GIPLs (lanes 1–4, 6, 8, 9) were digested with T. brucei GPI-PLC, human GPI-PLD, or jack bean α-mannosidase (JBAM), extracted with n-butanol, and separated by TLC. Then serum from L. mexicana-infected mice was used for immunoblot. In addition, Trypanosoma brucei GPI glycolipids were also analyzed by TLC immunoblot in comparison with L. mexicana amastigote GIPLs. Lane 1, 8×107 c.e. GIPL, mock GPI-PLC; lane 2, 8×107 c.e., GPI-PLC; lane 3, 8×107 c.e., mock GPI-PLD; lane 4, 8×107 c.e., GPI-PLD; lane 5, GPI-PLD without L. mex GIPL; lane 6, 2×108 c.e. GIPL; lane 7, 2×108 c.e. T. brucei GPIs; lane 8, 8×108 c.e. GIPL, mock JBAM; lane 9, 8×108 c.e., JBAM. O, origin; F, front; A, immunodominant GIPL; B, de-branched mannose product of immunodominant GIPL. Data represent at least 3 experiments with similar results.

Mentions: We next digested the L. mexicana glycolipids with enzymes that cleave glycosyl phosphatidylinositol (GPI) structures specifically, namely trypanosome GPI-PLC and human serum GPI-PLD, and found that binding of the immunodominant glycolipid by antibodies was abolished (Fig. 6). As these enzymes, which are GPI-specific, cleave the molecule of interest (with the glycan lost into the aqueous phase which is not run on the TLC), the molecule in question must have a GPI structure, and therefore is a GIPL. See Fig. 1 for structures and enzymatic cleavage points.


Leishmania mexicana infection induces IgG to parasite surface glycoinositol phospholipids that can induce IL-10 in mice and humans.

Buxbaum LU - PLoS Negl Trop Dis (2013)

The immunodominant glycolipid recognized by L. mexicana-infected mouse serum is a GPI and has a branched mannose chain.L. mexicana amastigote GIPLs (lanes 1–4, 6, 8, 9) were digested with T. brucei GPI-PLC, human GPI-PLD, or jack bean α-mannosidase (JBAM), extracted with n-butanol, and separated by TLC. Then serum from L. mexicana-infected mice was used for immunoblot. In addition, Trypanosoma brucei GPI glycolipids were also analyzed by TLC immunoblot in comparison with L. mexicana amastigote GIPLs. Lane 1, 8×107 c.e. GIPL, mock GPI-PLC; lane 2, 8×107 c.e., GPI-PLC; lane 3, 8×107 c.e., mock GPI-PLD; lane 4, 8×107 c.e., GPI-PLD; lane 5, GPI-PLD without L. mex GIPL; lane 6, 2×108 c.e. GIPL; lane 7, 2×108 c.e. T. brucei GPIs; lane 8, 8×108 c.e. GIPL, mock JBAM; lane 9, 8×108 c.e., JBAM. O, origin; F, front; A, immunodominant GIPL; B, de-branched mannose product of immunodominant GIPL. Data represent at least 3 experiments with similar results.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3649955&req=5

pntd-0002224-g006: The immunodominant glycolipid recognized by L. mexicana-infected mouse serum is a GPI and has a branched mannose chain.L. mexicana amastigote GIPLs (lanes 1–4, 6, 8, 9) were digested with T. brucei GPI-PLC, human GPI-PLD, or jack bean α-mannosidase (JBAM), extracted with n-butanol, and separated by TLC. Then serum from L. mexicana-infected mice was used for immunoblot. In addition, Trypanosoma brucei GPI glycolipids were also analyzed by TLC immunoblot in comparison with L. mexicana amastigote GIPLs. Lane 1, 8×107 c.e. GIPL, mock GPI-PLC; lane 2, 8×107 c.e., GPI-PLC; lane 3, 8×107 c.e., mock GPI-PLD; lane 4, 8×107 c.e., GPI-PLD; lane 5, GPI-PLD without L. mex GIPL; lane 6, 2×108 c.e. GIPL; lane 7, 2×108 c.e. T. brucei GPIs; lane 8, 8×108 c.e. GIPL, mock JBAM; lane 9, 8×108 c.e., JBAM. O, origin; F, front; A, immunodominant GIPL; B, de-branched mannose product of immunodominant GIPL. Data represent at least 3 experiments with similar results.
Mentions: We next digested the L. mexicana glycolipids with enzymes that cleave glycosyl phosphatidylinositol (GPI) structures specifically, namely trypanosome GPI-PLC and human serum GPI-PLD, and found that binding of the immunodominant glycolipid by antibodies was abolished (Fig. 6). As these enzymes, which are GPI-specific, cleave the molecule of interest (with the glycan lost into the aqueous phase which is not run on the TLC), the molecule in question must have a GPI structure, and therefore is a GIPL. See Fig. 1 for structures and enzymatic cleavage points.

Bottom Line: These changes decrease IFN-γ from T cells and nitric oxide production in infected cells, which are both required for Leishmania control.Several groups have been unsuccessful in identifying amastigote surface proteins that bind IgG.Further characterization of the target glycolipids will have important implications for drug and vaccine development and will elucidate the poorly understood role of glycolipids in the immunology of infections.

View Article: PubMed Central - PubMed

Affiliation: Philadelphia Research and Education Foundation, Philadelphia, Pennsylvania, United States of America. buxbaum17@hotmail.com

ABSTRACT
Infection with the intracellular protozoan parasite Leishmania mexicana causes chronic disease in C57BL/6 mice, in which cutaneous lesions persist for many months with high parasite burdens (10(7)-10(8) parasites). This chronic disease process requires host IL-10 and FcγRIII. When Leishmania amastigotes are released from cells, surface-bound IgG can induce IL-10 and suppress IL-12 production from macrophages. These changes decrease IFN-γ from T cells and nitric oxide production in infected cells, which are both required for Leishmania control. However, antibodies targets and the kinetics of antibody production are unknown. Several groups have been unsuccessful in identifying amastigote surface proteins that bind IgG. We now show that glycoinositol phospholipids (GIPLs) of L. mexicana are recognized by mouse IgG1 by 6 weeks of infection, with a rapid increase between 12 and 16 weeks, consistent with the timing of chronic disease in C57BL/6 mice vs. healing in FcγRIII-deficient mice. A single prominent spot on TLC is recognized by IgG, and the glycolipid is a glycosyl phosphatidylinositol containing a branched mannose structure. We show that the lipid structure of the GIPL (the sn-2 fatty acid) is required for antibody recognition. This GIPL is abundant in L. mexicana amastigotes, rare in stationary-phase promastigotes, and absent in L. major, consistent with a role for antibodies to GIPLs in chronic disease. A mouse monoclonal anti-GIPL IgG recognizes GIPLs on the parasite surface, and induces IL-10 from macrophages. The current work also extends this mouse analysis to humans, finding that L. mexicana-infected humans with localized and diffuse cutaneous leishmaniasis have antibodies that recognize GIPLs, can bind to the surface of amastigotes, and can induce IL-10 from human monocytes. Further characterization of the target glycolipids will have important implications for drug and vaccine development and will elucidate the poorly understood role of glycolipids in the immunology of infections.

Show MeSH
Related in: MedlinePlus