scholarly journals Evidence for high density lipoproteins as the major apolipoprotein A-IV-containing fraction in normal human serum.

1989 ◽  
Vol 30 (10) ◽  
pp. 1525-1534 ◽  
Author(s):  
L Lagrost ◽  
P Gambert ◽  
M Boquillon ◽  
C Lallemant
Keyword(s):  
Human Serum ◽  
High Density ◽  
Normal Human Serum ◽  
High Density Lipoproteins ◽  
Apolipoprotein A ◽  
Normal Human

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 Detection of chymase-digested C-terminally truncated apolipoprotein A-I in normal human serum

2011 ◽  
Vol 369 (1-2) ◽  
pp. 51-58 ◽  
Author(s):  
Yoko Usami ◽  
Kazuyuki Matsuda ◽  
Mitsutoshi Sugano ◽  
Nau Ishimine ◽  
Yuriko Kurihara ◽  
...  
Keyword(s):  
Human Serum ◽  
Normal Human Serum ◽  
Apolipoprotein A ◽  
Normal Human

scholarly journals Lipopolysaccharide-Binding Protein and Phospholipid Transfer Protein Release Lipopolysaccharides from Gram-Negative Bacterial Membranes

2000 ◽  
Vol 68 (5) ◽  
pp. 2410-2417 ◽  
Author(s):  
C. J. Vesy ◽  
R. L. Kitchens ◽  
G. Wolfbauer ◽  
J. J. Albers ◽  
R. S. Munford
Keyword(s):  
Human Serum ◽  
Binding Protein ◽  
Normal Human Serum ◽  
High Density Lipoproteins ◽  
Phospholipid Transfer Protein ◽  
Gram Negative ◽  
Bacterial Membranes ◽  
Transfer Protein ◽  
Phospholipid Transfer ◽  
Normal Human

ABSTRACT Although animals mobilize their innate defenses against gram-negative bacteria when they sense the lipid A moiety of bacterial lipopolysaccharide (LPS), excessive responses to this conserved bacterial molecule can be harmful. Of the known ways for decreasing the stimulatory potency of LPS in blood, the binding and neutralization of LPS by plasma lipoproteins is most prominent. The mechanisms by which host lipoproteins take up the native LPS that is found in bacterial membranes are poorly understood, however, since almost all studies of host-LPS interactions have used purified LPS aggregates. Using nativeSalmonella enterica serovar Typhimurium outer membrane fragments (blebs) that contained 3H-labeled lipopolysaccharide (LPS) and 35S-labeled protein, we found that two human plasma proteins, LPS-binding protein (LBP) and phospholipid transfer protein (PLTP), can extract [3H]LPS from bacterial membranes and transfer it to human high-density lipoproteins (HDL). Soluble CD14 (sCD14) did not release LPS from blebs yet could facilitate LBP-mediated LPS transfer to HDL. LBP, but not PLTP, also promoted the activation of human monocytes by bleb-derived LPS. Whereas depleting or neutralizing LBP significantly reduced LPS transfer from blebs to lipoproteins in normal human serum, neutralizing serum PLTP had no demonstrable effect. Of the known lipid transfer proteins, LBP is thus most able to transfer LPS from bacterial membranes to the lipoproteins in normal human serum.

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