Ubiquitous interleukin-1 alpha in fetal bovine serum may mislead the experimental results in vitro.
Fetal bovine sera (FBS) from several commercial suppliers were fractionated by gel filtration. Interleukin-1 (IL-1) activity was bioassayed using the IL-1-specific murine T cell line D10(N4)M. All the sera examined contained IL-1-like activity, with molecular weights (M(r)) of 30 kDa and 15-10 kDa. Under isoelectric focusing (IEF), the majority of IL-1 activity in either 30 kDa or 15-10 kDa fractions was focused into a position of pl 5. The activity recovered from either IEF or gel filtration was inhibited by either recombinant human IL-1 receptor antagonist (rhlL-1ra) or by the antibody against human IL-1 alpha. These biological and physicochemical properties strongly suggest that the active molecules were bovine IL-1 alpha and its precursor. There was no correlation between the amount of endotoxin and IL-1 activity. Quantification of the fractionated IL-1 indicated its presence in concentrations of 200-5000 pg/ml equivalent to human IL-1. However, high levels of IL-1 were not apparent in unfractionated FBS. Proliferation of T cells in the presence of FBS absorbed with protein A-Sepharose was greater than that of cells in original FBS. Therefore, the activity in FBS as a whole appeared to result from the balance between IL-1 and the inhibitory molecule(s). These results suggest that data obtained from experiments conducted in the presence of FBS may be influenced by the effect of bovine IL-1.
Hida
S
S
Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
Takeuchi
A
A
Hayashi
H
H
Yano
T
T
Hopkins
S J
SJ
Onozaki
K
K
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001681:Biological Assay; D002417:Cattle; D002460:Cell Line; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005312:Fetal Blood / Q000276:immunology*; D005333:Fetus; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000097:blood* / Q000302:isolation & purification / Q000494:pharmacology; D007525:Isoelectric Focusing; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000494:pharmacology; D012680:Sensitivity and Specificity; D012795:Sialoglycoproteins / Q000494:pharmacology; D013601:T-Lymphocytes
D000906:Antibodies; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins