Leishmania major: secreted antigens of Leishmania major promastigotes shift the immune response of the C57BL/6 mice toward Th2 in vitro.
BALB/c mice are sensitive to Leishmaniamajor infection, while C57BL/6 mice are resistant and able to mount an effective immune response against the parasite. Since the secreted antigens of L. major suppress the proliferation of BALB/c mice lymphocytes in vitro, we analyzed their effects on the immune system of resistant C57BL/6 mice. Secreted antigens were semi-purified and two fractions with immunosuppressive activity were isolated. 15 μg/ml of fraction could suppress 60% of lymphocyte proliferation and prevent the stimulated lymphocytes entering from G1 phase into the S phase of the cell cycle. These fractions decreased the production of IFN-γ, increased IL-4 level in the lymphocyte culture and down-regulated the nitric oxide production by activated macrophages. These results may suggest that L. major parasite by secreting immunosuppressive factors could down-regulate the immune system of both sensitive and resistant mice for own survival advantage.
Tabatabaee
Parisa-Alsadat
PA
Dept of Immunology, Pasteur Institute of Iran, Hybridoma Lab, Tehran 13164, Iran.
Abolhassani
Mohsen
M
Mahdavi
Mehdi
M
Nahrevanian
Hossein
H
Azadmanesh
Kayhan
K
D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology* / Q000302:isolation & purification; D002453:Cell Cycle / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D007371:Interferon-gamma / Q000032:analysis / Q000096:biosynthesis; D015847:Interleukin-4 / Q000032:analysis / Q000096:biosynthesis; D018320:Leishmania major / Q000276:immunology*; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000032:analysis / Q000096:biosynthesis; D013154:Spleen / Q000166:cytology / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*
D000953:Antigens, Protozoan; D015847:Interleukin-4; D009569:Nitric Oxide; D007371:Interferon-gamma