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Vitamin A in liposomes. Inhibition of complement binding and alteration of membrane structure.

Publication ,  Journal Article
Alving, CR; Conrad, DH; Gockerman, JP; Gibbs, MB; Wirtz, GH
Published in: Biochim Biophys Acta
June 25, 1975

Incorporation of vitamin A aldehyde (retinal) into liposomes had an inhibitory effect on the amount of human complement protein bound in the presence of specific antiserum. The total membrane-bound protein was directly measured on liposomes which were washed after incubation in antiserum and fresh human serum (complement). At every concentration of complement, decreased protein binding was found with liposomes which contained retinal. Binding of the third component of complement (C3) was also measured directly on washed liposomes and was found to be decreased in the presence of retinal. The diminution in protein binding due to retinal was not caused by differences in the amount of antibody bound and this was shown by two experiments. First, specific antibody protein binding to liposomes was directly measured and was essentially unaffected by retinal. Second, liposomes were prepared from lipid extracts of sheep erythrocytes. These liposomes were used as as immunoadsorbants to remove antisheep erythrocyte antibodies. The immunoadsorbant capacity was the same in both the presence and the absence of retinal. A further conclusion from these experiments was that retinal did not change the number of liposomal glycolipid antigen molecules available for antibody binding and thus presumably did not change the total number of lipid molecules present on the outer surface of the liposomes. Retinal did have an effect on the geometric structure of the liposomes. Size distribution measurements were performed in the diameter range of 1-6.35 mum by using an electronic particle size analyzer (Coulter Counter). Liposomes containing retinal were shifted toward smaller sizes and had less total surface area and volume. It was suggested that retinal-containing liposomes may have had a tighter packing of the molecules in the phospholipid bilayer. This effect of retinal on liposomal structure may have been responsible for the observed decreased binding of C3 and total complement protein.

Duke Scholars

Published In

Biochim Biophys Acta

DOI

ISSN

0006-3002

Publication Date

June 25, 1975

Volume

394

Issue

2

Start / End Page

157 / 165

Location

Netherlands

Related Subject Headings

  • Vitamin A
  • Sheep
  • Rabbits
  • Protein Conformation
  • Protein Binding
  • Phospholipids
  • Phosphatidylcholines
  • Molecular Conformation
  • Liposomes
  • Humans
 

Citation

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Alving, C. R., Conrad, D. H., Gockerman, J. P., Gibbs, M. B., & Wirtz, G. H. (1975). Vitamin A in liposomes. Inhibition of complement binding and alteration of membrane structure. Biochim Biophys Acta, 394(2), 157–165. https://doi.org/10.1016/0005-2736(75)90253-9
Alving, C. R., D. H. Conrad, J. P. Gockerman, M. B. Gibbs, and G. H. Wirtz. “Vitamin A in liposomes. Inhibition of complement binding and alteration of membrane structure.Biochim Biophys Acta 394, no. 2 (June 25, 1975): 157–65. https://doi.org/10.1016/0005-2736(75)90253-9.
Alving CR, Conrad DH, Gockerman JP, Gibbs MB, Wirtz GH. Vitamin A in liposomes. Inhibition of complement binding and alteration of membrane structure. Biochim Biophys Acta. 1975 Jun 25;394(2):157–65.
Alving, C. R., et al. “Vitamin A in liposomes. Inhibition of complement binding and alteration of membrane structure.Biochim Biophys Acta, vol. 394, no. 2, June 1975, pp. 157–65. Pubmed, doi:10.1016/0005-2736(75)90253-9.
Alving CR, Conrad DH, Gockerman JP, Gibbs MB, Wirtz GH. Vitamin A in liposomes. Inhibition of complement binding and alteration of membrane structure. Biochim Biophys Acta. 1975 Jun 25;394(2):157–165.

Published In

Biochim Biophys Acta

DOI

ISSN

0006-3002

Publication Date

June 25, 1975

Volume

394

Issue

2

Start / End Page

157 / 165

Location

Netherlands

Related Subject Headings

  • Vitamin A
  • Sheep
  • Rabbits
  • Protein Conformation
  • Protein Binding
  • Phospholipids
  • Phosphatidylcholines
  • Molecular Conformation
  • Liposomes
  • Humans