The identification of an eosinophil differentiation factor in culture supernatant of mononuclear cells from asthmatics.
Although peripheral eosinophilia is a common feature of bronchial asthma, the precise mechanism of its production is still unknown. It has recently been reported that murine interleukin-5 (IL-5) can cross-react with human cells and selectively stimulates the proliferation and differentiation of eosinophils. This study identified the IL-5-like activity in culture supernatants of peripheral blood mononuclear cells (MNCs) from asthmatic patients. Murine recombinant IL-5 (rIL-5) was used as a positive control; the number of eosinophils was determined by both Wright's stain and eosinophil peroxidase measurement. Time course and dose response studies showed that rIL-5 at 40 U/ml induced a maximal eosinophil differentiation after a three week incubation with cord blood MNCs. Unstimulated MNC supernatants obtained from asthmatics possessed a higher eosinophil differentiation activity (OD490, 0.09 +/- 0.02, n = 23) than those obtained from the normals (0.03 +/- 0.01) (P < 0.02). This activity in unstimulated MNC supernatant can be neutralized by anti-IL-5 antibodies. Neither Bermuda grass- nor phytohemagglutinin-stimulated MNC supernatant showed a statistical significance between these two groups. The IL-5-like activity was associated with a protein of MW around 30kD as determined by Superose-12 PG gel filtration. In conclusion, MNC culture supernatants derived from asthmatics contained an eosinophil differentiation activity, which might be important for regulation of eosinophil generation and thus contribute to the asthma-related eosinophilia.
Tsai
J J
JJ
Department of Medicine, Veterans General Hospital, Taipei, Taiwan, R.O.C.
Yu
L N
LN
Su
S N
SN
Wang
S R
SR
D001249:Asthma / Q000097:blood*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004804:Eosinophils / Q000187:drug effects*; D005260:Female; D006801:Humans; D015848:Interleukin-5 / Q000276:immunology / Q000494:pharmacology / Q000502:physiology*; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D009500:Neutralization Tests
D015848:Interleukin-5