Isolation of immunologically active uterine luminal proteins associated with follicular and luteal phases of the ovary in buffalo (Bubalus bubalus)

Abstract

Uterine luminal proteins (ULP) collected from the genital tract of buffalo during the follicular (Group F) and luteal (Group L) phases of the estrous cycle were chromatographed using sephacryl S-200 gel. Five peaks were detected in each group. Different protein concentrations (10 to 200 μg) from Peaks I and V in each group were examined for immunological activity on polymorph nuclear leukocytic cells (PMNL) in vitro. All concentrations except 10 μg of ULP Peak I (≥ 250 kDa) in Group F enhanced phagocytic activity of PMNL. Peak V (56 kDa) in the same group enhanced phagocytic activity of PMNL only at low protein concentrations (10, 20 and 40 μg protein), while at greater concentrations (80, 150 and 200 μg protein) PMNL activity was suppressed. On the other hand, all protein concentrations from Peak I (≥ 250 kDa) in Group L suppressed PMNL activity in a dose-dependent manner. Proteins from Peak V (31 kDa) in Group L suppressed PMNL phagocytic activity at all concentrations but not to the same extent as in Peak I. Electrophoretic analysis of Peaks I and V in both groups revealed only 3 detectable protein bands (subunits) in Peak I and 1 detectable subunit in Peak V. Several additional proteins were probably not detected. The molecular weights of the detected subunits in Peaks I and V in Group F were greater than those in Group L as indicated by SDS-PAGE analysis. The results of this study show that ULP collected from buffalo possessed proteins that modulated phagocytic activity of PMNL in vitro. Proteins collected during the follicular phase, especially Peak I, enhanced phagocytic activity of the PMNL, whereas those collected during the luteal phase (Peaks I and V) suppressed activity. Changes in the molecular weights of ULP detected in this experiment may be related to the changes in phagocytic activity of PMNL tested in vitro.