Effects of selected blood-derived factors on innate immunity in the human body louse.

Our findings demonstrate that the immune system of body lice can be affected by factors present in the blood of their human hosts and suggest potential conservation of the function of some immune molecules from human host to ectoparasite. Further, the discord between the effects of neopterin on immunity-related gene expression and B. quintana load highlights the complexity of the regulation of pathogen infection in the louse vector.