Endotoxin antibodies in African sleeping sickness.

Antibodies to the core region of endotoxin (endotoxin core antibodies, EndoCAb), which cross-react with endotoxin from a range of Gram-negative bacteria, are maintained in relative homeostasis in health, but undergo marked changes in a number of different diseases associated directly or indirectly with endotoxaemic or septicaemic states. The levels of EndoCAb IgG in the blood and cerebrospinal fluid (CSF) of 35 late-stage sleeping sickness patients and 9 control individuals were measured by ELISA. EndoCAb levels were significantly elevated in the patient blood (mean EndoCAb value 290 MU/ml cf. control 182 MU/ml, P < 0.001), and CSF (mean EndoCAb value 254 MU/ml cf. control 150 MU/ml, P < 0.001). EndoCAb IgG levels correlated with endotoxin levels in patient blood (r = 0.78, P < 0.001), but not in the CSF and were not reduced 6 weeks following chemotherapy, unlike the endotoxin levels. It is concluded that late-stage sleeping sickness is associated with chronic exposure to endotoxins from Gram-negative bacteria.

Endotoxins in the blood and cerebrospinal fluid of patients with African sleeping sickness.

Endotoxin levels were measured in the blood and cerebrospinal fluid (CSF) of control individuals and 2 groups of patients with African sleeping sickness. Endotoxin levels were markedly elevated in the blood (infected groups mean endotoxin values 40.2 pg/ml and 53.8 pg/ml, compared to control 11.6 pg/ml, P < 0.0001 for both increases) and CSF (infected groups mean endotoxin values 45.8 pg/ml and 50.1 pg/ml compared to control 6.3 pg/ml, P < 0.0001 for both increases) of the patients. The levels were reduced 6 weeks following different drug treatments in the 2 groups (blood levels to mean 33.8 pg/ml and 28.5 pg/ml; CSF levels to 37.4 pg/ml and 27.0 pg/ml). The blood endotoxin values correlated with the CSF values before treatment (r = 0.74 and 0.57 for the 2 groups; P < 0.0001 for both) and after treatment (r = 0.57 and 0.56 for the 2 groups; P < 0.0001 for both). It is concluded that raised endotoxin equilibrates in the blood and CSF compartments, and may contribute significantly to the pathology of sleeping sickness.

Production of prostaglandins D2 and E2 by mouse fibroblasts and astrocytes in culture caused by Trypanosoma brucei brucei products and endotoxin.

A study was made to characterize the effects of living Trypanosoma brucei brucei and its products on prostaglandin D2 (PGD2) and PGE2 production by fibroblasts and astrocytes. Cultured fibroblasts were prepared from Microtus agrestis embryos and astrocyte cultures were prepared from neonatal rats. The cultures were maintained in low-endotoxin or defined media (i.e. endotoxin-free). The PG production was compared with and studied in combination with a defined lipopolysaccharide (LPS) from Escherichia coli. Living T. b. brucei were without effect on PG production. Preparations of T. b. brucei prepared by freeze-thawing and sonication produced dose- and time-dependent increases in PGD2 and PGE2 synthesis by both cell types. LPS caused a similar pattern of increases. The combination of parasite products with LPS caused synergistic production to levels higher than the maximal production by each mitogen alone. The findings have important implications for several pathological features that accompany trypanosomiasis.

Trypanosoma brucei products activate components of the reactive response in astrocytes in vitro.

A study was made of the effects of T. b. brucei and the disrupted parasite material on different components of the reactive response of astrocytes in primary cultures prepared from neonatal rats and C6 glioma cells. The effects were compared with lipopolysaccharide (LPS) and fragments of the C6 cells. The disrupted trypanosome material, LPS and C6 fragments caused dose--and time--dependent alterations in morphology of the primary cultures from flat to stellate shape, increases in levels of glial fibrillary acidic protein (GFAp) and enhanced MHC class I and II expression. Exposure to trypanosome material and C6 fragments caused marked increases in phagolysosomes and lysosomes in the primary cultures. The findings demonstrate that T. b. brucei products and astrocyte cell debris are internalized and initiate astrogliosis in vitro.

Endotoxins and the pathogenesis of Trypanosoma brucei brucei infection in mice.

The involvement of endotoxins in Trypanosoma brucei brucei infection in CD-1 mice was investigated by the Limulus amoebocyte lysate (LAL) test. At 7 days post-infection mean serum endotoxin level was elevated by 2.5 times (36.4 pg/ml cf. control 14.25 pg/ml, P < 0.001) and a similar increase was maintained throughout the infection (survival 28-35 days). Purified disrupted parasites contained significant endotoxin activity (mean value 280 pg/mg protein). The mouse infections were also associated 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 bacterial infections, other unidentified sources (e.g. from the gut), or a combination of these. It is concluded that the raised endotoxins may be important contributive factors in the pathogenesis of experimental murine trypanosomiasis.

Electrophoresis of bovine erythrocyte sialic acids: existence of additional band in trypanotolerant Ndama cattle.

Mild acid-hydrolysis of erythrocyte surface sialic acids of the trypanotolerant Ndama and the trypanosusceptible White/Fulani Zebu breeds of cattle was performed. The cleaved sialic acids from the two breeds of cattle were simultaneously subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE), along with commercial standard N-acetylneuraminic acid (MW 309.28), blank gel and plasma proteins. The cleaved sialic acids migrated in the globulin fractions, as shown by the plasma protein electrophoresis. While the Ndama and the Zebu erythrocytes had one migrating band each of which coincided with the standard N-acetylneuraminic acid, the Ndama had another trailing band of sialic acid, of an estimated molecular weight of 30 kDa, which may account for the higher erythrocyte sialic acid concentrations of the Ndama. This additional band was absent in the Zebu. All these bands were readily reproducible.