Isolation and characterization of a human alternative complement pathway-inhibiting protein from larval hemolymph of the silkworm, Bombyx mori.
An alternative complement pathway-inhibiting protein (ACPIP), which inhibits the activation of the alternative complement pathway (ACP) of the human serum, was isolated from larval hemolymph of the silkworm, Bombyx mori, by using ammonium sulfate fractionation and column chromatographies to homogeneity. About 400microg of ACPIP was routinely obtained from 20ml hemolymph. The purified ACPIP preparation consisted of two distinct polypeptides (34 and 32kDa) on SDS-PAGE. The amino acid compositions of the two polypeptides were nearly identical; 21% of the amino acid residues were acidic. The amino terminal amino acid sequences up to 20 residues in these two polypeptides were also identical. Addition of the ACPIP to human serum resulted in a dose-dependent inhibition of the hemolysis of intact rabbit erythrocytes via the ACP, whereas in no inhibition of hemolysis of sensitized-sheep erythrocytes (EA) via the classical pathway.
Sekijima
Y
Y
Department of Immunology, Saitama Prefectural University Junior College, 343-8540, Koshigaya, Japan. sekijima-yasutaka@spu.ac.jp
Fujikura
Y
Y
Hiyama
T
T
Maenaka
T
T
Uda
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001482:Base Composition; D012831:Bombyx / Q000737:chemistry*; D003169:Complement Inactivator Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D003170:Complement Pathway, Alternative / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000187:drug effects / Q000276:immunology; D006458:Hemolymph / Q000737:chemistry*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D007814:Larva / Q000737:chemistry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011817:Rabbits; D012756:Sheep
C419106:ACPIP protein, Bombyx mori; D003169:Complement Inactivator Proteins; D019476:Insect Proteins