Partial characterization of ovine intrauterine suppressor cells.

Ovine uterine cells that represented Day 14 cyclic and pregnant endometrium were fractionated with Percoll and evaluated for suppression of cocultured phytohemagglutinin (PHA)-induced peripheral blood lymphocyte (PBL) proliferation and for the presence of T-lymphocyte markers. Uterine cells were then evaluated for suppressor activity following the depletion of conventional lymphocyte classes (i.e., T-, B-, and NK-like) with complement + antibody treatment. In addition, supernatant (derived from cultured uterine cells) was tested for transforming growth factor beta (TGFbeta) activity using neutralization antibodies to TGFbeta. Fractionated uterine cells (density range of 1.002-1.056 g/ml) from cyclic and pregnant ewes suppressed PHA-induced proliferation of PBL, and the majority (69.5%) of these cells were < or = 5.2 microm in diameter. Percentages of CD5+, CD4+, and CD8+ lymphocytes recovered from endometrial curettage were less for cells in this density range than for cells with greater densities. Uterine cells released suppressor factor(s) into the culture medium (supernatant); however, suppressor activity was unaffected by either anti-TGFbeta or complement + antibody treatment. In conclusion, low-density uterine cells from Day 14 cyclic and pregnant ewes suppressed the proliferation of cocultured PBL and released a suppressor factor(s) into the medium that did not exhibit TGFbeta activity. It is unlikely that the suppressor cells comprise conventional T-, B-, or NK-like lymphocyte lineages.

Estradiol-17 beta and progesterone increase ovine uterine suppressor cell activity.

We evaluated the regulation of ovine uterine (UT) suppressor cell activity by progesterone (P4), estradiol-17 beta (E2), and P4 + E2 in ovariectomized (OVX) ewes. Following 14 d of steroid injections, endometrial cells (designated as UT cells) were recovered postmortem, and unfractionated and fractionated cells were assessed for suppression of autologous phytohemagglutinin (PHA)-treated peripheral blood lymphocytes (PBL). Supernatants from cultured UT cells were also assessed for suppressor activity. In other experiments, UT cells recovered from nontreated OVX ewes were cocultured with PHA-treated PBL and varying concentrations (1 x 10(-11) to 1 x 10(-5) M) of each steroid preparation. Supernatants from separate cultures that contained UT cells and steroids were evaluated for suppressor activity. Uterine cells from control and steroid-treated ewes suppressed proliferative responses of PHA-treated PBL; however, suppressor activity of UT cells was greater (P < .05) for E2-treated than for control and P4-treated ewes. Uterine suppressor cells from steroid-treated ewes sedimented in Percoll within a density range of 1.002 to 1.056 g/mL. Uterine cells from all ewes released suppressor factor(s) into the culture medium; however, the activity of the supernatant from the cultured cells was not increased for the steroid-treated ewes. For cocultures that contained steroids and cultures that contained supernatant, suppressor activity of the UT cells was increased by specific concentrations of each steroid preparation. These findings demonstrate that reproductive steroids augment ovine UT suppressor cell activity.

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 (> or = 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 > or = 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 PHA-treated PBL, the > or = 4 MDa component and neutralization antibodies to either TGF-beta 1 or -beta 2. In Exp. 1, the > or = 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 > or = 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 > or = 4 MDa component recovered from gilts on d 15 of pregnancy. In conclusion, a temporal pattern of TGF-beta activity was associated with a > or = 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.

Economic viability of crosses of Bos taurus and Bos indicus for dairying in warm climates.

Countries in the warm climatic zones need greater domestic supplies of milk. To increase yields, the option that is least expensive and most widely used is to cross dairy breed sires with local cattle. First generation crosses have more vigor than other crosses under stressful environmental conditions; growth rate, milk yield, and reproduction rate exceed those of local breeds and other crossbred combinations. On average, lactating first generation crosses are fed energy at 45 to 60% below their potential response, which limits their capabilities. Other crosses with local breeds fall short of first generation crosses as do some of the present synthetic breeds with 5/8 to 3/4 dairy breeding. Well-fed (> 2.5 maintenance needs) Holstein or Jersey crosses containing 1/4, 1/2, or 3/4 Bos indicus (Zebu) tend to follow projections of parental means for milk yield, reproduction rate, and tolerance to heat stress; however, for crosses, losses exceed predictions for lactation length, persistency of milk yield, feed efficiency, and rate of milking. Size of thoracic and abdominal organs, size of endocrine glands, stomach weight, and intestine length are lower than expected compared with values for purebreds. The smaller digestive system affects feeding intake of B. indicus crosses, and the smaller endocrine glands appear to limit responses to high energy diets. Possible directional dominance of B. indicus needs further investigation. The first generation crosses could support their use for dairy purposes if feeding rate and management were optimal, but prospects for other crosses remain questionable.