Tsetse fly saliva biases the immune response to Th2 and induces anti-vector antibodies that are a useful tool for exposure assessment.
Tsetse flies (Glossina sp.) are blood-feeding dipteran insects that transmit African trypanosomes, parasites that are responsible for human sleeping sickness and veterinary infections. Increasing attention is being paid to the effects of tsetse fly saliva deposited at the feeding site, which enables the blood-feeding process and putatively promotes parasite transmission. Here we demonstrate that saliva induces strong humoral responses against the major 43-45 kDa protein fraction (tsetse salivary gland proteins 1 and 2 - Tsal1 and Tsal2) in mice and humans and suppresses murine T and B cell responses to heterologous antigen. The saliva-induced immune response is associated with a Th2-biased cytokine profile and the production of mainly IgG1 and IgE antibody isotypes. Functionally, the antibodies raised in mice exposed to tsetse fly bites or induced after experimental saliva immunisation do not affect the fly's blood-feeding efficiency nor its survival. We propose that anti-saliva as well as anti-Tsal1/2 antibody responses can be used in epidemiological studies as a tool to analyze human exposure to tsetse flies.
Caljon
Guy
G
Unit of Cellular and Molecular Immunology, Flanders Interuniversity Institute for Biotechnology (VIB), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium. gucaljon@vub.ac.be
Van Den Abbeele
Jan
J
Sternberg
Jeremy M
JM
Coosemans
Marc
M
De Baetselier
Patrick
P
Magez
Stefan
S
D000818:Animals; D001733:Bites and Stings / Q000453:epidemiology / Q000276:immunology; D005247:Feeding Behavior; D005260:Female; D007111:Immunity, Cellular; D007114:Immunization; D007073:Immunoglobulin E / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D019476:Insect Proteins / Q000276:immunology; D007303:Insect Vectors / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D012463:Saliva / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D014370:Tsetse Flies / Q000276:immunology*; D014454:Uganda / Q000453:epidemiology
D007074:Immunoglobulin G; D019476:Insect Proteins; C428613:Tsal1 protein, Glossina morsitans morsitans; C428610:Tsal2 protein, Glossina morsitans morsitans; D007073:Immunoglobulin E; D010047:Ovalbumin