Alpha 1-microglobulin is mitogenic to human peripheral blood lymphocytes. Regulation by both enhancing and suppressive serum factors
Författare
Summary, in English
Human alpha 1-microglobulin (alpha 1-m), a 26 kilodalton serum glycoprotein, was found to exert mitogenic effects on human peripheral blood lymphocytes (PBL) in serum-free medium. Purified T cells, but not B cells, responded with proliferation to alpha 1-m, but only in the presence of monocytes. The mitogenic activity could be partially neutralized by a mouse monoclonal antibody against alpha 1-m. The mitogenicity was species-specific, since alpha 1-m homologues from rats, guinea pigs and rabbits had no effect on human PBL. In a previous study, no effect of alpha 1-m was seen on PBL in the presence of 20% serum, and, therefore, we studied the influence of different concentrations of serum on the alpha 1-m-induced mitogenicity. Thus, human serum enhanced the mitogenic effects of alpha 1-m on human PBL at 1% concentration (v/v) and suppressed the effects at 10%. The suppressing effect of serum at 10%, but not the enhancing effect at 1%, seemed to be conserved among several species. To test the effect of serum proteins of different molecular sizes, human autologous serum was separated by gel chromatography on Sephadex G-200 into four fractions. Fractions 1 and 2 (roughly containing proteins larger than 100 kilodaltons) suppressed the mitogenic effects of alpha 1-m, while fractions 3 and 4 enhanced the stimulation by alpha 1-m, at 0.5% and concentrations above. It is concluded that the mitogenic effect of alpha 1-m on lymphocytes is regulated by several serum factors, both enhancing and suppressive, that does not have any proliferative effect of their own. It can be speculated that the balance between enhancing and suppressing co-factors in the blood determines the degree of the stimulation of lymphocytes by alpha 1-m. This is compatible with an immunomodulatory role for alpha 1-m, in spite of its relatively constant plasma levels in health and disease.
Avdelning/ar
- Avdelningen för hematologi och transfusionsmedicin
- Drug Target Discovery
- Infektionsmedicin
- Transfusionsmedicin
Publiceringsår
1990
Språk
Engelska
Sidor
221-234
Publikation/Tidskrift/Serie
Immunobiology
Volym
180
Issue
2-3
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Pharmacology and Toxicology
- Infectious Medicine
- Hematology
Status
Published
Forskningsgrupp
- Drug Target Discovery
- Transfusion Medicine
ISBN/ISSN/Övrigt
- ISSN: 1878-3279