Bidirectional signalling between Trypanosoma brucei brucei and CD8+
T cells involves reciprocal action of the parasite-derived trypanosome derived lymphocyte triggering factor (TLTF) and lymphocyte-derived IFN-γ. Herein we further
characterize this relationship and report quantitation of TLTF secretion into culture supernatants using a newly developed
ELISA. Secretion is induced by IFN-γ in a dose–response manner, with 100 U/ml giving maximal yields of bioactive
TLTF as assessed by ELISA and ELISPOT. This is a constitutive and active secretion. Furthermore, IFN-γ-induced
secretion was dependent on tyrosine protein kinase activity. Specific blockers of this signalling system resulted in lower
yields of TLTF in the culture supernatants.
