ENDOTOXINS AND THE PATHOGENESIS OF TRYPANOSOMA-BRUCEI-BRUCEI INFECTION IN MICE

The involvement of endotoxins in Trypanosoma brucei brucei infection i n CD-1 mice was investigated by the Limulus amoebocyte lysate (LAL) te st. At 7 days post-infection mean serum endotoxin level was elevated b y 2.5 times (36.4 pg/ml cf. control 14.25 pg/ml, P < 0.001) and a simi lar increase was maintained throughout the infection (survival 28-35 d ays). Purified disrupted parasites contained significant endotoxin act ivity (mean value 280 pg/mg protein). The mouse infections were also a ssociated with progressive Gram-negative bacteraemia (present in 4 out of 5 infected animals by day 28 p.i.). The increased endotoxin levels may be due to parasite products, the products of intercurrent bacteri al infections, other unidentified sources (e.g. from the gut), or a co mbination of these. It is concluded that the raised endotoxins may be important contributive factors in the pathogenesis of experimental mur ine trypanosomiasis.