Lateral hapten mobility and immunochemistry of model membranes.

AUTOR(ES)

Brûlet, P

RESUMO

A study has been made of the interaction of specific anti-nitroxide (anti-spin label) IgG antibodies, Fab fragments, complement, and liposomes containing dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, and dipalmitoylphosphatidylcholine plus 0-50 mole % cholesterol, together with various concentrations of a head group spin-labeled phospholipid (0.5-0.01 mole % in the plane of the membrane). The spin-labeled lipid is the amide formed from the reaction of an iodoacetamide spin label, N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)iodoacetamide, with dipalmitoylphosphatidylethanolamine. We have reached two conclusions: (i) complement fixation depends on the lateral mobility of the lipid hapten at low hapten concentrations in the plane of the membrane (less than or equal 0.1 mole %) and does not depend strongly on this mobility at high hapten concentrations; (ii) cholesterol may have two distinct effects on complement fixation, one arising from an enhancement of hapten exposure to antibody binding sites and a second due to a modulation of membrane fluidity.

Documentos Relacionados

• Use of a fluorescent cholesterol derivative to measure lateral mobility of cholesterol in membranes.
• Mobility of cholera toxin receptors on rat lymphocyte membranes.
• Lateral diffusion of lipids in complex biological membranes.
• Interaction of polynucleotides with natural and model membranes.
• Phase separation dynamics and lateral organization of two-component lipid membranes.