T lymphocyte interferon-gamma production induced by Plasmodium falciparum antigen is high in recently infected non-immune and low in immune subjects.
Interferon (IFN) alpha and gamma were measured by radio-immunoassays in supernatants from cultures of peripheral blood mononuclear cells (PBMC) or purified T cell subsets incubated with either Plasmodium falciparum schizont-enriched malaria antigen (mAg), uninfected red blood cells (RBC) or pokeweed mitogen (PWM). Cell donors were 24 clinically immune, healthy African adult native residents of a P. falciparum-endemic region, Haut-Ogooué, Gabon, and seven non-immune, European temporary residents with a history of a single to a few malaria infections during the previous 1 to 9 months. When PBMC were cultured in medium alone or with RBC antigen no or low titres of IFN-gamma were detected. PBMC proliferation and IFN-gamma production observed in the presence of mAg were dose dependent and significantly correlated. When cultured with mAg, PBMC from non-immune Europeans produced significantly higher levels of IFN-gamma than did PBMC from clinically immune Africans. No such difference was found when PBMC were cultured with PWM. The mAg-induced IFN-gamma production was due mainly to CD4+ T cells and was not enhanced by CD8+ T cell depletion. No IFN-alpha was detected in culture supernatants. Thus, P. falciparum antigens are able to induce in vitro production of IFN-gamma by CD4+ T cells; however, in this sample, individuals considered to be clinically resistant to malaria were low producers of IFN-gamma.
Chizzolini
C
C
Centre International de Recherches Médicales, Fraceville, Gabon.
Grau
G E
GE
Geinoz
A
A
Schrijvers
D
D
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000953:Antigens, Protozoan / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D016827:CD8 Antigens; D002478:Cells, Cultured; D006801:Humans; D007113:Immunity, Innate; D007371:Interferon-gamma / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D008288:Malaria / Q000276:immunology*; D010963:Plasmodium falciparum / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D000945:Antigens, Differentiation, T-Lymphocyte; D000953:Antigens, Protozoan; D016827:CD8 Antigens; D007371:Interferon-gamma