title: [The mechanism of inhibition of the activation of the complement first component by polyanions and polycations ].
abstract: Polyethyleneimine (PEI, 50 kDa) and polymethacrylic acid (PMA, 200 kDa) were shown to inhibit the lysis of sheep erythrocytes induced by the guinea pig complement. They twofold suppress the hemolysis at the concentrations of 0.47 and 0.89 microgram/ml, respectively. The inhibitory effect on the binding of the C1q subunit of human complement to the sensitized sheep erythrocytes (EA) was found to depend on the component of the reaction with which the inhibitors were preliminarily incubated. When an inhibitor, C1q, and EA were simultaneously incubated, the inhibition constants for PEI and PMA were 17 +/- 6 and 8.1 +/- 0.1 micrograms/ml, respectively. The preincubation of EA with PEI and the subsequent washing out of the inhibitor resulted in the inhibition constant of 22 +/- 3 micrograms/ml. No inhibitory effect was observed after a similar preincubation of EA with PMA. No inhibition was also detected when the inhibitors were added after the formation of the C1q complex with antibodies. These observations suggest that the binding of antibodies to cationic PEI prevents the C1q-antibody complex formation, while the binding of anionic PMA to the active site of C1q impedes the interaction of this subunit with immunoglobulins. Moreover, within the range of concentrations studied, the studied inhibitors did not affect the subsequent C1q binding to the C1r and C1s enzymes.
authors.affiliation: Lomonosov State Academy of Fine Chemical Technology, pr. Vernadskogo 86, Moscow, 119571 Russia.
authors.forename: O O
authors.initials: OO
authors.lastname: Burdelev
authors.forename: A P
authors.initials: AP
authors.lastname: Kaplun
authors.forename: L V
authors.initials: LV
authors.lastname: Kozlov
authors.forename: S V
authors.initials: SV
authors.lastname: Lysakova
authors.forename: V L
authors.initials: VL
authors.lastname: D'iakov
authors.forename: V I
authors.initials: VI
authors.lastname: Shvets
mesh_terms: D000818:Animals; D000838:Anions / Q000494:pharmacology; D000906:Antibodies / Q000378:metabolism; D001671:Biochemistry / Q000379:methods; D002412:Cations / Q000494:pharmacology; D002478:Cells, Cultured; D003167:Complement Activation; D003174:Complement C1 Inactivator Proteins / Q000737:chemistry / Q000494:pharmacology*; D015922:Complement C1q / Q000187:drug effects / Q000378:metabolism*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D006168:Guinea Pigs; D006801:Humans; D011094:Polyethyleneimine / Q000737:chemistry / Q000494:pharmacology*; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D013329:Structure-Activity Relationship
chemical_list: D000838:Anions; D000906:Antibodies; D002412:Cations; D003174:Complement C1 Inactivator Proteins; D011109:Polymethacrylic Acids; C030613:polymethacrylic acid; D015922:Complement C1q; D011094:Polyethyleneimine
vernacular_title: Mekhanizm ingibirovaniia polianionami i polikationami aktivatsii pervogo komponenta komplementa.