Interleukin-6 secreted from human myxoma reduces murine viral myocarditis.
The effect of interleukin-6 (IL-6) secreted by a human atrial myxoma in vitro was investigated in C3H female mice with acute viral myocarditis. A culture medium containing IL-6 (100 ng/ml) and IL-8 (250 ng/ml), was prepared; viral myocarditis was induced by exposure to the encephalomyocarditis virus. Mice were assigned to four groups: 1) intraperitoneal (i.p.) injection of supernatant with IL-6 and IL-8 (0.2 ml/mice) given simultaneously with virus, 500 pfu for 4 days (Group 1); 2) i.p. injection of supernatant with IL-6 starting on Day 4 for 4 days in the same manner (Group 2); 3) i.p. injection of culture medium simultaneously with the virus (Group 3); and 4) i.p. injection of PBS in the same manner (Group 4). Uninfected control mice were administered medium only (Group 5) or supernatant with IL-6 and IL-8 (Group 6) for 4 days without virus. The survival rate on Day 14 in Group 1 was 90% significantly (p < 0.01) prolonged. The ratio of heart weight-to-day weight in the Group 1 was significantly (p < 0.01) lower. Histopathological examination revealed that cardiac necrosis and cellular infiltration in Group 1 was reduced compared with Group 3. Moreover, the radio of spleen weight/body weight in Group 1 was significantly (p < 0.01) higher than that of Group 3 and of Group 4. To confirm the effect of IL-6 or IL-8, mice were treated with recombinant IL-6 to IL-8 simultaneously with virus for 4 days. IL-6 treated mice survived significantly compared with IL-8 treated mice and untreated mice. The viral titer on day 4 of IL-6 treated mice was significantly lower than IL-8 treated or untreated mice. Thus, IL-6 derived from human myxoma improved the survival of murime viral myocarditis and reduced myocardial necrosis when the myxoma-derived IL-6 was administered simultaneously with the virus, due to eliciting cellular immunity in the spleen.
Kanda
T
T
Department of Laboratory Medicine, Gunma University School of Medicine, Japan.
Sakamoto
H
H
McManus
B M
BM
Sakamaki
T
T
Nagai
R
R
Suzuki
T
T
Kobayashi
I
I
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006338:Heart Neoplasms / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism* / Q000627:therapeutic use; D051379:Mice; D008809:Mice, Inbred C3H; D009205:Myocarditis / Q000401:mortality / Q000628:therapy / Q000821:virology; D009232:Myxoma / Q000378:metabolism*; D009929:Organ Size; D015996:Survival Rate
D015850:Interleukin-6