The immunomodulatory activity of human amniotic fluid can be correlated with transforming growth factor-beta 1 (TGF-beta 1) and beta 2 activity.
The role of alphafetoprotein (AFP) in the immunomodulatory activity of amniotic fluids (AF) from normally progressing human pregnancy (weeks 14-16) was investigated. A panel of 42 AF (25% v/v) reduced significantly phytohaemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMC) proliferation in serum-free cultures with a mean per cent inhibition of 68.4 +/- 5.5%. In contrast, AFP preparations, with one exception (U.AFP), failed to display inhibitory activity. Pretreatment of AF with anti-TGF-beta 1 and beta 2 antibodies used alone resulted in the mean per cent loss of inhibition of 33.1 +/- 3.9% and 52.3 +/- 7.5%, respectively. A summative loss of AF-mediated inhibition was detected when anti-TGF-beta 1 and beta 2 antibodies were used in combination, but immunomodulation was rarely abolished 100% by this treatment. Anti-TGF-beta 2 antibody treatment, unlike anti-TGF-beta 1 antibody treatment, reversed the inhibitory activity of U.AFP. The amount of TGF-beta 1 and beta 2 contained in human AF was studied by growth inhibition of Mv1 Lu cells. The mean levels of TGF-beta 1 and beta 2 in AF were 11 +/- 0.9 U/ml and 2.3 +/- 0.4 U/ml, respectively, which corresponds with a mean per cent inhibition of 49 +/- 4.7%. U.AFP also significantly inhibited Mv1 Lu cell growth. To investigate the mechanism of AF-mediated inhibition, the effect of AF and AFP on IL-2 production by concanavalin A (Con A)-stimulated PBMC blasts was determined by the CTLL-2 cell bioassay. IL-2 production was reduced 55.5% in AF-treated blasts and 61% in U.AFP-treated blasts compared with controls. Our findings indicate that the immunomodulatory activity of human AF can be correlated with TGF-beta 1 and beta 2 and not with AFP, the inhibitory activity of U.AFP preparation reflecting copurifying TGF-beta 2 activity.
Lang
A K
AK
Department of Immunology, University of Newcastle upon Tyne, UK.
Searle
R F
RF
D000653:Amniotic Fluid / Q000276:immunology* / Q000378:metabolism; D000906:Antibodies / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D009500:Neutralization Tests; D010835:Phytohemagglutinins / Q000494:pharmacology; D011247:Pregnancy; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D000509:alpha-Fetoproteins / Q000378:metabolism
D000906:Antibodies; D007376:Interleukin-2; D010835:Phytohemagglutinins; D016212:Transforming Growth Factor beta; D000509:alpha-Fetoproteins