Changes in Blood Lymphocyte Subpopulations and Expression of MHC-II Molecules in Wild Mares Before and After Parturition.

INTRODUCTION: Pregnancy is a physiological state in which the immune system undergoes certain changes. On the one hand, by depleting cell defence mechanisms, it favours development and maintenance of the pregnancy. At the same time cells of the immune system ensure resistance to many risk factors, including infectious agents. MATERIAL AND METHODS: The study was carried out on 24 Polish Konik breed mares which were divided into two equal groups. The first group (group I) included mares living in the reserve. The second group (group II) comprised mares maintained under conventional conditions in the stables. The blood samples were collected for the first time in the perinatal period, i.e. 2 weeks before parturition (trial 0), then within the first 24 h after delivery, and then on 7th and 21st day after foaling. Flow cytometric analysis of lymphocyte expressing TCD4+, TCD8+, CD2+, and MHC class II antigens was performed. RESULTS: Before the delivery, in group I there was a significantly higher CD4:CD8 ratio compared to group II (P ≤ 0.05). Similarly, significantly increased CD4:CD8 ratio in group I was noted within 24 h after parturition (P ≤ 0.001) and it was also observed on 7th day (P ≤ 0.03) and 21st day after foaling (P ≤ 0.02). In the first 24 h after parturition, a significant decline of lymphocytes CD8+ (P ≤ 0.02) was noted. No significant differences in terms of lymphocytes CD2+ and CD3+ were observed. Expression of MHC-II molecules before and after the parturition was higher in group I compared to group II; however, the difference between the groups was not significant. CONCLUSION: The results obtained indicate that mares living in the reserve display higher activity of cell defence mechanisms.

Levels of selected T lymphocyte subpopulations in peripheral blood of mares which experienced early embryonic death.

The objective of the present study was to analyse the immune status of mares in the early stages of pregnancy and mares which experienced early embryonic death (EED). Forty-eight fertile purebred Arabian mares were used for the study. The mares were divided into two groups. Group I was the control group composed of 32 mares in the early stages of a normal pregnancy. Group II was composed of 12 mares which had experienced EED. In both groups, subpopulations of T lymphocytes containing CD2(+), CD4(+) and CD8(+) were characterized using flow cytometry. The percentages of CD3(+) lymphocytes (adding up the cells with CD4(+) and CD8(+) phenotypes) and of NK cells (subtracting CD3(+) cells from CD2(+) lymphocytes) calculated. Due to its suppressive effects on T lymphocytes during pregnancy, TGF-beta1 was determined using ELISA. The findings revealed that in mares with EED, the percentages of lymphocytes TCD2(+), TCD4(+), NK cells at EED, i.e. between days 14 and 21, were significantly higher compared to mares without EED. The changes in the CD4(+)/CD8(+) ratio were similar. In the EED group, this ratio significantly increased between the 96th hour and the 30th day after ovulation compared to mares without EED. Otherwise, serum levels of TGF-beta1 in the EED group were significantly lower than in the control group. The results show that mares which experienced an EED develop inflammatory reactions which activate Th1 cell immune responses.

The influence of nonspecific immunostimulation of pregnant sows on the immunological value of colostrum.

The purpose of this experiment was to estimate the influence of nonspecific immunostimulation of pregnant sows on the immunological value of colostrum. The studies were done in the fall-winter season on 20 pregnant sows (Polish Landrace) divided into four groups, five animals each. The sows were clinically healthy and unvaccinated. Group I received isoprinosine, group II (TFX), group III (HMB), and group IV served a control. The immunostimulants were applicated 4-6 weeks before the expected date of delivery. The following parameters were determined in colostrum taken from sows after completed delivery: specific gravidity; total proteins, lysozyme activity, IgG level. It was found that the nonspecific immunostimulation of pregnant sows increased in colostrum the level of IgG, total protein content and lysozyme activity.