Infection with Leishmania major induces interleukin-12 production in vivo.
Experimental infections of mice with the protozoan parasite Leishmania major provide an excellent model for defining the conditions required for generation of CD4+ Th1 and Th2 cells in vivo. Since interleukin-12 (IL-12) has been implicated in the development of Th1 cells, we investigated whether L. major stimulates IL-12 production in vitro or in vivo. Surprisingly, macrophages cultured in vitro failed to produce IL-12 following L. major infection. In contrast, lymph node cells from C3H mice infected for 2 days with L. major produced elevated levels of IL-12. In order to determine if the inability to stimulate IL-12 production was limited to in vitro infections, we infected macrophages in vivo by inoculating L. major into the peritoneal cavity. Peritoneal cells isolated 24 h later exhibited a significant increase in the number of cells producing IL-12. In addition, supernatants harvested from these cells following culture contained elevated levels of IL-12. These data indicate that L. major infection induces increased IL-12 production in mice.
Vieira
L Q
LQ
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104.
Hondowicz
B D
BD
Afonso
L C
LC
Wysocka
M
M
Trinchieri
G
G
Scott
P
P
D000818:Animals; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018664:Interleukin-12; D007378:Interleukins / Q000096:biosynthesis*; D018320:Leishmania major / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology*; D008198:Lymph Nodes / Q000166:cytology; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology; D017737:Macrophages, Peritoneal / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H
D007378:Interleukins; D018664:Interleukin-12