Characterization of Japanese eel immunoglobulin M and its level in serum.
Japanese eel immunoglobulin M (IgM) was purified from the sera of Anguilla japonica immunized with Edwardsiella tarda FPU 347 and characterized. Analysis of the purified IgM on sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) under reducing and non-reducing conditions revealed that the eel IgM was a tetrameric protein with a molecular weight of 790,000; it contained an equimolar heavy chain and light chain with molecular weights of 72,000 and 25,000, respectively. While the N-terminal sequence of the heavy chain, VELTQPGSMVLKPGQSLTI, showed similarity to the variable regions of those of teleost fishes Igs, the N-terminal sequence of the light chain, DIVLTQSPAVQSVQLGDT, was similar to the variable regions of chondrostei and mammalian kappa chains. Lectin-binding assays showed that the binding of concanavalin A (Con A) to the Japanese eel IgM heavy chain was competitively inhibited by D-mannose and could be abolished by alpha-mannosidase treatment indicating the presence on the heavy chain of oligosaccharides, whose terminal were a bound mannoses. The average IgM concentration in the sera of the healthy eels was 3.4 mg ml(-1); it amounted to 10.3% of the total serum protein.
Uchida
D
D
Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
Hirose
H
H
Chang
P K
PK
Aranishi
F
F
Hirayabu
E
E
Mano
N
N
Mitsuya
T
T
Prayitno
S B
SB
Natori
M
M
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002241:Carbohydrates / Q000032:analysis; D004524:Eels / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000378:metabolism; D007075:Immunoglobulin M / Q000097:blood*; D007564:Japan; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis; D017386:Sequence Homology, Amino Acid
D002241:Carbohydrates; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007075:Immunoglobulin M; D009844:Oligosaccharides