Estrada A, van Kessel A, Laarveld B
Animal Biotechnology Centre, Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon.
Can J Vet Res. 1999 Oct;63(4):261-8.
In order to assess the effect of oat beta-glucan (ObetaG) administration on immune parameters of beef steers, 3 experiments were carried out. In experiment 1, the in vitro effect of ObetaG on the proliferation of blood lymphocytes, with or without the presence of dexamethasone (DXM), was evaluated. In experiment 2, groups of 12 healthy steers were administered ObetaG or saline solution and immunized with ovalbumin (OVA). Immune parameters studied included IgG antibody levels to OVA, proliferation responses of blood lymphocytes to OVA, and blood leukocyte differential cell counts. For experiment 3, groups of 10 steers were treated with ObetaG and DXM, DXM only, or saline solution, and immunized with OVA and keyhole limpet hemocyanin (KLH). Serum antibody responses to OVA and KLH, serum IgG concentration levels, blastogenic responses of blood lymphocytes to OVA and KLH, differential blood leukocyte numbers, and iron and zinc concentration in serum were tested to evaluate the effect of ObetaG to overcome immunosuppression. The in vitro treatment of naive blood lymphocytes with ObetaG did not increase their ability to proliferate; however, when ObetaG was added to cultures of DXM-treated lymphocytes, a significant (P < 0.05 to P < 0.001) reversion of the immunosuppressive effect of DXM occurred. Administration of ObetaG to clinically healthy steers did not induce significant changes on any of the immune parameters studied. The administration of ObetaG to DXM-treated steers provoked, on Day 25, a significant increase in IgG anti-OVA (P < 0.01) and anti-KLH (P < 0.05) responses vs the DXM only group. On Day 25, the specific proliferation responses of lymphocytes, to both OVA and KLH, were significantly increased (P < 0.05) in ObetaG+DXM group compared to DXM group. On Day 4, a significant increase in the number of leukocytes (P < 0.01) and neutrophils (P < 0.001), and a significant decrease in the number of monocytes (P < 0.05) were observed in the group treated with DXM only compared to ObetaG+DXM group. No significant differences were observed in iron and zinc concentration between ObetaG+DXM and DXM groups. These results indicated that ObetaG did not influence immune responses of naive cells in vitro or of healthy steers in vivo; however, when cells or animals were treated with DXM, ObetaG significantly restored some of the specific and non-specific immune parameters studied.
为了评估燕麦β-葡聚糖（ObetaG）给药对肉牛免疫参数的影响，进行了3项实验。在实验1中，评估了ObetaG在有或没有地塞米松（DXM）存在的情况下对血液淋巴细胞增殖的体外作用。在实验2中，将12头健康的肉牛分为几组，分别给予ObetaG或盐溶液，并用卵清蛋白（OVA）进行免疫。研究的免疫参数包括针对OVA的IgG抗体水平、血液淋巴细胞对OVA的增殖反应以及血液白细胞分类计数。在实验3中，将10头肉牛分为几组，分别用ObetaG和DXM、仅用DXM或盐溶液进行处理，并用OVA和钥孔戚血蓝蛋白（KLH）进行免疫。检测血清对OVA和KLH的抗体反应、血清IgG浓度水平、血液淋巴细胞对OVA和KLH的增殖反应、血液白细胞分类数量以及血清中铁和锌的浓度，以评估ObetaG克服免疫抑制的效果。用ObetaG对未接触过抗原的血液淋巴细胞进行体外处理，并未增加其增殖能力；然而，当将ObetaG添加到经DXM处理的淋巴细胞培养物中时，DXM的免疫抑制作用出现了显著（P < 0.05至P < 0.001）的逆转。对临床健康的肉牛给予ObetaG，在所研究的任何免疫参数上均未引起显著变化。与仅用DXM处理的组相比，在第25天，对经DXM处理的肉牛给予ObetaG后，IgG抗OVA（P < 0.01）和抗KLH（P < 0.05）反应显著增加。在第25天，与DXM组相比，ObetaG + DXM组中淋巴细胞对OVA和KLH的特异性增殖反应均显著增加（P < 0.05）。在第4天，与ObetaG + DXM组相比，仅用DXM处理的组中白细胞数量（P < 0.01）和中性粒细胞数量（P < 0.001）显著增加，单核细胞数量显著减少（P < 0.05）。ObetaG + DXM组和DXM组之间在铁和锌浓度方面未观察到显著差异。这些结果表明，ObetaG在体外对未接触过抗原的细胞或体内健康肉牛的免疫反应没有影响；然而，当细胞或动物用DXM处理时，ObetaG显著恢复了一些所研究的特异性和非特异性免疫参数。
