Open AccessHuman serum mannose‐binding lectin (MBL)‐associated serine protease‐1 (MASP‐1): determination of levels in body fluids and identification of two forms in serum
Author(s) -
TERAI I.,
KOBAYASHI K.,
MATSUSHITA M.,
FUJITA T.
Publication year - 1997
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1111/j.1365-2249.1997.tb08334.x
Subject(s) - mannan binding lectin , lectin , serine protease , masp1 , immunology , ficolin , mannose , identification (biology) , biology , protease , virology , biochemistry , enzyme , ecology
Summary We developed an ELISA for human serum MASP‐1, a Cls‐like serine protease which is known to function in C4 and C2 activation. We then determined MASP‐1 levels in 1063 sera from normal Japanese subjects ranging in age from 3 to 100 years, as well as in certain body fluids using this assay. Individual serum MASP‐1 levels ranged from 148 to 12–83 μg/ml, with a normal frequency distribution pattern. The arithmetic mean ± s.d. of MASP‐1 levels in serum was 6–27 ± 185 μg/ml, whereas levels of MASP‐1 in cerebrospinal fluid and in urine were almost undetectable. When the mean ± s.d. of serum MASP‐1 was calculated for each age group (10 year range) and values were then compared, the age group consisting of 3–9‐year‐olds (7–54 ± l‐39;μ/ml) was found to have the highest value. When MASP‐1 was measured in cord blood, it was shown that levels were already as high as those of 3–9‐year‐olds. The serum MASP‐1 level was found to be as strongly dependent on age as is the serum MBL level. MASP‐1 and MBL are thought to play an active part in immunity in younger people. It was found that the serum level of MASP‐1 was much higher than that of MBL, and the major portion of human serum MASP‐1 appeared to exist in the circulation as a form unbound to MBL.