Transforming growth factor-beta(2) activity is temporally associated with a porcine high-molecular-weight uterine component recovered during early pregnancy

A high-molecular-weight component (greater than or equal to 4 MDa, eluted at void volume of a Sepharose CL-6B column) was recovered postmortem from uterine luminal secretions from crossbred gilts (4/d) on d 9, 12, 15, and 18 of pregnancy and d 15 of the cycle. It was tested for suppression of peripheral blood lymphocyte (PBL) proliferation and for transforming growth factor-beta (TGF-beta) activity. In Exp. 1, the greater than or equal to 4 MDa component was cultured with phytohemagglutinin (PHA)-treated PBL. Parallel cultures received a pan-specific neutralization antibody to TGF-beta. In Exp. 2, cultures contained PKA-treated PBL, the greater than or equal to 4 MDa component and neutralization antibodies to either TGF-beta(1) or -beta(2). In Exp. 1, the greater than or equal to 4 MDa component recovered from uterine secretions for d-12 to d-18 pregnant gilts and d-15 cyclic gilts suppressed (P < .001) the proliferation of PHA-treated PBL; however, suppressor responses were reversed (P < .001) by anti-TGF-beta only for the greater than or equal to 4 MDa component recovered from gilts on d 15 and 18 of pregnancy. In Exp. 2, anti-TGF-beta(2) reversed (P < .05) the suppressor activity of the greater than or equal to 4 MDa component recovered from gilts on d 15 of pregnancy. In conclusion, a temporal pattern of TGF-beta activity was associated with a greater than or equal to 4 MDa carrier recovered from porcine uterine luminal secretions during early pregnancy. For uterine secretions recovered on d 15, suppressor activity was at least partly attributed to TGF-beta(2).