Mjf. Morato et al., CYTOKINE PROFILES DURING EXPERIMENTAL CHAGAS-DISEASE, Brazilian journal of medical and biological research, 31(1), 1998, pp. 123-125
People infected with Trypanosoma cruzi remain so for life, yet only 30
-40% of these individuals develop characteristic chagasic cardiomyopat
hies. Similarly, when infected with the Brazilian strain of T. cruzi,
DBA/2 mice develop severe cardiac damage while B10.D2 mice do not. To
better understand the immunological parameters that may be involved in
the disease process, we have used this murine model (DBA/2 vs B10.D2)
and compared the changes in cytokine production during the course of
infection with T. cruzi. Concanavalin A (Con A) stimulation of spleen
cells harvested during the acute phase (day 30) resulted in similarly
high levels of IFN-gamma in both mouse strains. However, the amount of
IFN-gamma in supernatants from cultures of B10.D2 spleen cells initia
ted during the chronic phase (day 72) was at subacute levels, whereas
secretion by chronic DBA/2 spleen cells remained high. In addition, Co
n A-stimulated spleen cells from acute DBA/2 mice produced approximate
ly twice as much IL-10 and significantly more IL-4 than cells from B10
.D2 mice. IL-4 secretion remained low by cells from chronic B10.D2 mic
e, but when using cells from chronic DBA/2 mice, levels continued to i
ncrease beyond the already high levels secreted by cells harvested dur
ing the acute phase. Proliferative responses to Con A stimulation by s
pleen cells from DBA/2 mice were significantly higher than those from
B10.D2 mice in both the acute and chronic phases. These data suggest t
hat enhanced responses in DBA/2 mice, which may be related to a higher
parasite burden, a lack of down-regulation, and/or the onset of autoi
mmune phenomena, correlate with the more severe cardiomyopathy seen in
pathopermissive mice.