Decreased expression of cytokines that induce type 1 helper T cell/interferon-gamma responses in genetically susceptible mice infected with Mycobacterium avium.
Mycobacterium avium is an intracellular microorganism that infects and multiplies within macrophages. Cell-mediated immunity plays an important role in host defense. Two cytokines, interleukin 12 (IL-12) and interferon-gamma-inducing factor (IGIF), produced mainly by macrophages, are critical for the development of type 1 helper T (Th1) cell/interferon-gamma (IFN-gamma) responses and cell-mediated immunity. In this report, by using a mouse model of disseminated M. avium infection, we demonstrate that genetically susceptible BALB/c mice show decreased expression of IL-12 and IGIF in association with a diminished IFN-gamma/Th1 response. Conversely, resistant DBA/2 mice exhibited increased expression of IL-12, IGIF, and IFN-gamma. In both strains of infected mice, the level of IL-4/Th2 response was similar. These results suggest that decreased expression of IL-12 and IGIF leads to a diminished Th1 response without reciprocal enhanced Th2 responses in susceptible mice.
Kobayashi
K
K
Department of Host Defenses, Leprosy Research Center, National Institute of Infectious Diseases, Tokyo, Japan. kaz-koba@sa2.so-net.or.jp
Nakata
N
N
Kai
M
M
Kasama
T
T
Hanyuda
Y
Y
Hatano
Y
Y
D000818:Animals; D001483:Base Sequence; D016207:Cytokines / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D007111:Immunity, Cellular; D007369:Interferon Inducers / Q000378:metabolism; D007371:Interferon-gamma / Q000096:biosynthesis*; D018664:Interleukin-12 / Q000235:genetics; D020382:Interleukin-18; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D009162:Mycobacterium avium; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D018417:Th1 Cells / Q000276:immunology*; D014376:Tuberculosis / Q000235:genetics* / Q000276:immunology*
D016207:Cytokines; D017931:DNA Primers; D007369:Interferon Inducers; D020382:Interleukin-18; D012333:RNA, Messenger; D018664:Interleukin-12; D007371:Interferon-gamma