Human and rodent interferon-gamma as a growth factor for Trypanosoma brucei.
An example for the bidirectional exchange of activating signals between a pathogen and immunocompetent cells in the host is presented. Trypanosoma brucei, which include subspecies that cause African sleeping sickness, secrete a molecule that triggers lymphocytes to produce interferon (IFN)-gamma. We now report that proliferation of T. brucei is stimulated in axenic cultures by IFN-gamma. The growth-enhancing effect on the pathogen is inhibited by anti-IFN-gamma receptor (R) antibodies and does not occur after exposure to other cytokines, i.e. IFN-alpha, IFN-beta and tumor necrosis factor (TNF)-alpha. While rodent-pathogenic T. brucei strains are stimulated by rat IFN-gamma, human pathogenic strains are more potently stimulated by human IFN-gamma. Rat and human IFN-gamma can partially block each others effects. Mice with disrupted IFN-gamma genes have reduced parasitemia and prolonged survival, while the outcome is reversed in mice that lack the IFN-gamma R gene.
Bakhiet
M
M
Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Olsson
T
T
Mhlanga
J
J
Büscher
P
P
Lycke
N
N
van der Meide
P H
PH
Kristensson
K
K
D000818:Animals; D005260:Female; D006133:Growth Substances; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D011994:Recombinant Proteins; D013045:Species Specificity; D014346:Trypanosoma brucei brucei / Q000254:growth & development*; D014352:Trypanosomiasis / Q000276:immunology / Q000469:parasitology
D006133:Growth Substances; D011994:Recombinant Proteins; D007371:Interferon-gamma