Figure 1. Passive systemic anaphylaxis (PSA) depends on mast cells and histamine.

PSA was induced by i.v. sensitization with 10 µg of anti-DNP IgE and challenge 24hrs later with 500 µg of DNP-HSA (black symbols) or PBS as control (white symbols) in MC-deficient mice homozygotes mutants (W/W^v Ho) (circles), heterozygotes (W/W^v He) (triangles) and their WT littermates (+/+) (squares) (A) and in Histamine receptor-1-deficient (HR1^°/°) (triangles) and WT B6 mice (squares) mice (B). Body temperature was measured at various time points after challenge. Data are presented as mean (± SEM) of body temperature (n= 5 mice/group).