scholarly journals The main lytic factor of Trypanosoma brucei brucei in normal human serum is not high density lipoprotein.

1996 ◽  
Vol 183 (3) ◽  
pp. 1023-1029 ◽  
Author(s):  
J Raper ◽  
V Nussenzweig ◽  
S Tomlinson
Keyword(s):  
High Density Lipoprotein ◽  
Human Serum ◽  
Trypanosoma Brucei ◽  
Gel Filtration ◽  
Density Lipoprotein ◽  
High Density ◽  
Lytic Activity ◽  
Normal Human Serum ◽  
Trypanosoma Brucei Brucei ◽  
Normal Human

Natural immunity of humans to the cattle pathogen Trypanosoma brucei brucei has been attributed to the presence in normal human serum (NHS) of lytic factors for the parasites. We and others have shown that NHS contains two trypanolytic factors (herein termed TLF1 and TLF2) that can be separated by gel filtration. TLF1 copurifies with a subclass of high density lipoprotein (HDL), whereas TLF2 has a much higher molecular weight and does not appear to be a lipoprotein. We find that the trypanolytic activity of purified TLF1 is totally inhibited by exogenous haptoglobin (Hp) at concentrations (0.1 mg/ml) lower than those present in NHS (0.2-2 mg/ml). In contrast, exogenous Hp (up to 2.5 mg/ml) has no effect on the lytic activity of either NHS or isolated TLF2. Hp-depleted sera from patients with intravascular hemolysis is severalfold more trypanolytic than NHS. These sera contain only TLF1, and their lytic activity is totally abolished upon the addition of Hp (0.1 mg/ml). When NHS containing different Hp allotypes is fractionated by gel filtration, TLF1 activity is either revealed or remains masked, depending on whether it coelutes with Hp. Masked TLF1 activity in the column fractions is revealed if Hp is removed by density gradient ultracentrifugation. We conclude that endogenous Hp inhibits TLF1 activity, and that TLF2 is the main trypanolytic factor in NHS.

scholarly journals In Vitro Generation of Human High-Density-Lipoprotein-Resistant Trypanosoma brucei brucei

2006 ◽  
Vol 5 (8) ◽  
pp. 1276-1286 ◽  
Author(s):  
Sara D. Faulkner ◽  
Monika W. Oli ◽  
Rudo Kieft ◽  
Laura Cotlin ◽  
Justin Widener ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Trypanosoma Brucei ◽  
Density Lipoprotein ◽  
High Density ◽  
Surface Glycoprotein ◽  
Trypanosoma Brucei Brucei ◽  
African Trypanosomes ◽  
Expression Site ◽  
Human High Density Lipoprotein

ABSTRACT The host range of African trypanosomes is influenced by innate protective molecules in the blood of primates. A subfraction of human high-density lipoprotein (HDL) containing apolipoprotein A-I, apolipoprotein L-I, and haptoglobin-related protein is toxic to Trypanosoma brucei brucei but not the human sleeping sickness parasite Trypanosoma brucei rhodesiense. It is thought that T. b. rhodesiense evolved from a T. b. brucei-like ancestor and expresses a defense protein that ablates the antitrypanosomal activity of human HDL. To directly investigate this possibility, we developed an in vitro selection to generate human HDL-resistant T. b. brucei. Here we show that conversion of T. b. brucei from human HDL sensitive to resistant correlates with changes in the expression of the variant surface glycoprotein (VSG) and abolished uptake of the cytotoxic human HDLs. Complete transcriptome analysis of the HDL-susceptible and -resistant trypanosomes confirmed that VSG switching had occurred but failed to reveal the expression of other genes specifically associated with human HDL resistance, including the serum resistance-associated gene (SRA) of T. b. rhodesiense. In addition, we found that while the original active expression site was still utilized, expression of three expression site-associated genes (ESAG) was altered in the HDL-resistant trypanosomes. These findings demonstrate that resistance to human HDLs can be acquired by T. b. brucei.

Identification of a trypanocidal factor againstTrypanosoma equiperdumin normal human serum

Parasitology ◽  
1989 ◽  
Vol 98 (3) ◽  
pp. 401-407 ◽  
Author(s):  
G. Verducci ◽  
S. Perito ◽  
R. Rossi ◽  
E. Mannarino ◽  
F. Bistoni ◽  
...  
Keyword(s):  
Human Serum ◽  
Gel Filtration ◽  
Density Lipoprotein ◽  
Natural Antibodies ◽  
Normal Human Serum ◽  
Mouse Serum ◽  
Trypanocidal Activity ◽  
Normal Human

SUMMARYNormal human serum (HS) contains trypanolytic activity and agglutinins toTrypanosoma equiperdum, while such activities are not found in sera from a range of animals susceptible to infection. HS given toT. equiperdum-infected mice caused a rapid decrease in the number of circulating trypanosomes and protection from lethal infection. Trypanolytic activity of human serum was found to be associated, after DEAE chromatography and Sephadex G-200 gel filtration, with the fraction containing 19S antibodies. Immunofluorescence assays confirmed a binding of human IgM and C1qcomplement component onto the surface ofT. equiperdum. Anti-T. equiperdumactivity of HS was specifically directed toT. equiperdumsurface components and not to some mouse serum components adsorbed on parasites during the growth in the host, because HS adsorbedin vivoin CD-1 mice retained full protective and agglutinating properties. Trypanocidal activity appears in human serum about the 7th month after birth and persists until late in life. On the contrary, human purified high-density lipoprotein had no significantin vitroorin vivotrypanocidal activity. In conclusion, strong natural anti-T. equiperdumactivity in human serum was mainly mediated by natural antibodies of the IgM class. The presence of natural IgM active againstT. equiperdumin HS could represent one of the natural mechanisms of resistance of refractory hosts against trypanosome infections. This phenomenon provides further evidence that host specificity of trypanosomes may be partly conditioned by the presence of natural antibodies.

High-density-lipoprotein-independent killing of Trypanosoma brucei by human serum

1995 ◽  
Vol 70 (1-2) ◽  
pp. 131-138 ◽  
Author(s):  
Stephen Tomlinson ◽  
Ana-Maria Jansen ◽  
Alexei Koudinov ◽  
Jorge A. Ghiso ◽  
Nam-Ho Choi-Miura ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Human Serum ◽  
Trypanosoma Brucei ◽  
Density Lipoprotein ◽  
High Density

The Binding of Lithium Carmine to a2-Macroglobulin

1969 ◽  
Vol 24 (11) ◽  
pp. 1442-1447 ◽  
Author(s):  
J. J. Picard ◽  
J. F. Heremans
Keyword(s):  
Human Serum ◽  
Density Gradient ◽  
Protein Complex ◽  
Gel Filtration ◽  
Heavy Fraction ◽  
Normal Human Serum ◽  
Density Gradient Ultracentrifugation ◽  
Γ Globulins ◽  
Normal Human

The colloidal dye lithium carmine was added in vitro to normal human serum. Electrophoretic experiments showed that the dye was associated mainly with α2-globulins, small amounts with the albumin and only traces with the γ-globulins. The main complex was eluted with the macroglobulin peak obtained by gel filtration on Sephadex G-200 and sedimented in the heavy fraction on density gradient ultracentrifugation. The dye-protein complex could be precipitated with an antiserum specific for a2-macroglobulin. Gel filtration of a solution of pure a2-macroglobulin, to which lithium carmine was added, demonstrated that the dye was bound to this protein.

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