Suppression of T-cell proliferation by CD8+ T cells induced in the presence of protoscolices of Echinococcus multilocularis in vitro.
Immunoregulatory influences of protoscolices (PSC) of Echinococcus multilocularis on murine T-lymphocyte functions have been examined in an in vitro system. Proliferative responses of spleen cells stimulated with concanavalin A (ConA) or anti-CD3 monoclonal antibodies were depressed by the addition of PSC. In the presence of PSC, both interleukin-2 (IL-2) production and IL-2 receptor (IL-2R) expression by lymphocytes stimulated with ConA were significantly reduced. However, exogenous IL-2 reconstituted both the ConA-stimulated proliferative responses and IL-2R expression. These findings suggest that PSC of E. multilocularis can suppress lymphoid cell responses via influences on IL-2 production. Indeed, addition of CD(8+)-enriched cells from cultures stimulated with ConA plus PSC to fresh spleen cells showed marked suppression of the ConA responses. IL-2 production as well as IL-2R expression on the spleen cells so treated were suppressed. These findings reveal a suppressive immunologic function induced by E. multilocularis PSC that involves inhibition of IL-2 production and reduction of IL-2R expression. The PSC-induced CD8+ cells appear to play a key role in the suppressive regulation of host immune responses against E. multilocularis.
Kizaki
T
T
Hokkaido Institute of Public Health, Japan.
Ishige
M
M
Kobayashi
S
S
Bingyan
W
W
Kumagai
M
M
Day
N K
NK
Good
R A
RA
Onoé
K
K
D000818:Animals; D017252:CD3 Complex / Q000276:immunology; D016827:CD8 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D003208:Concanavalin A; D004446:Echinococcus / Q000276:immunology*; D005260:Female; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D017252:CD3 Complex; D016827:CD8 Antigens; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D003208:Concanavalin A