Hereditary subtypic patterns detected in the Ba fragment of complement factor B: occurrence of four common alleles in Japanese.
A procedure which can detect subtype-specific minor bands of factor B (BF) by polyacrylamide gel isoelectric focusing is presented. After zymosan-mediated fragmentation of BF in serum via alternative pathway for complement activation, serum samples are subjected to isoelectric focusing in a narrow pH range (4.2-4.9). The Ba fragments are detected by using immunoblotting. In addition to the previously reported minor bands with subtypic specificities, heterogeneities are observed in other minor band group, where a single minor band corresponds exclusively to a subtype in a regular combination with the previously announced subtypic patterns. A one-to-one correspondence of a single band to each subtype provides an unambiguous determination for three subtypic phenotypes deduced from the two divided BF*F alleles, BF*FA and BF*FB. An autosomal codominant heredity is confirmed through segregation analysis. A population survey reveals that four common alleles, BF*S, BF*FA, BF*FB, BF*Fb1, occur in a Japanese population and the former three alleles, except BF*Fb1, occur in a Cambodian population. The presence or absence of a single anodal minor band was found to be the only difference after neuraminidase treatment of FA and FB, implying that an amino acid substitution responsible for the FA-FB subtypic difference is involved in an additional acquisition in FA of an oligosaccharide unit with a charged sialic acid.
Suzuki
K
K
Department of Legal Medicine, Osaka Medical College, Japan.
Ito
S
S
Tamura
A
A
Fujita
K
K
Matsumoto
H
H
D000483:Alleles; D003167:Complement Activation; D011415:Complement Factor B / Q000235:genetics*; D005787:Gene Frequency; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D007564:Japan; D009439:Neuraminidase; D010446:Peptide Fragments / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic
D010446:Peptide Fragments; D009439:Neuraminidase; D011415:Complement Factor B