育成猪对猪链球菌的免疫应答

取 7周龄长大杂交猪 12头 ,随机均分为试验组和对照组。试验组按每公斤体重 4.5亿个菌腹部皮下接种猪链球菌 C551 2 6复制猪链球菌病 ,接种后 0、7、14、2 1、2 8d,自前腔静脉采血 ,计数红、白细胞总数和白细胞分类 ,用硝基蓝四氮唑 (NBT)还原试验定量检测嗜中性粒细胞吞噬功能 ,噻唑蓝 (MTT)比色法检测外周血中淋巴细胞转化 ,单向免疫扩散法测定血清 Ig G浓度 ,5 0 %溶血试验测定血清中补体总活性 ,同时 ,用植物血凝素 (PHA)皮肤试验检测迟发型超敏(DTH)反应。结果表明 ,接种后 7d开始 ,试验组白细胞总数升高 ,接种后 14d嗜中性粒细胞百分含量低于对照组 ,淋巴细胞百分含量则升高 ;嗜中性粒细胞还原硝基蓝四氮唑 (NBT)能力均极显著高于对照组 (P<0 .0 1) ,PHA诱导的淋巴细胞转化则极显著降低 (P<0 .0 1) ,DTH只在接种后 2 1d显著低于对照组 (P<0 .0 5 ) ,血清中 Ig G总量接种后 7d降低 (P<0 .0 5 ) ,14d却极显著升高 (P<0 .0 1) ,此后恢复正常 ,血清补体总活性只在接种后 7d降低 (P<0 .0 5 )。可见 ,猪对猪链球菌的免疫应答除了常见的抗原抗体反应外 ,还表现在免疫细胞数及其功能的变化 ,以及补体活性的改变。

Immune Response of Growing Pigs to Streptococcus suis

In order to study the effect of Streptococcus suis on immune response of growing pigs,twelve 7-week-old hybrid healthy pigs were randomly allotted to two groups:the control and the test group.Pigs in the test group were developed a typical subacute Streptococcosis suum by inoculating subcutaneously 0.45 billion of pure living Streptococcus suis (type C 55126) per 1.0 kg body weight.Some immunity parameters were tested on days 0,7,14,21 and 28 after inoculation.Leukocytes were counted with microscope and differential leukocyte counts performed on Giemsa-stained blood smears.The effect on the nitroblue tetrazolium(NBT) reduction of neutrophil was used to determin its phagocytic ability.Lymphocyte proliferation was determined by using the mitogens PHA.The total serum IgG concentration was measured by radial single immunodiffusion.A 50% hemolytic test was used to investigate the complement activity in serum.Whereas,a phytohemagglutinin(PHA) skin test was used to investigate in vivo immunity.The results indicated that the mean leukocyte counts on day 7 after inoculation was higher than that in the control group.Inaddition,compared with the control group,the mean percent of neutrophil in the test group was lower,whereas the percent of lymphocytes was higher on day 14,21,28 after inoculation.The nitroblue tetrazolium(NBT) reduction by neutrophil was significantly higher(P<0.01) than that in the control group on day 7,14,21,28 after inoculation.In vivo proliferation to phytohemagglutinin(PHA) of lymphocytes was significantly lower than that in the control group on day 7,14,21,28 after inoculation.But delayed-type hypersensitivity(DTH) to PHA was lower(P<0.05) only on the 21 st day after inoculation.The IgG level in serum was lower(P<0.05) on day 7,but was significantly higher(P<0.01) on the 14 th day after inoculation,and reached the standard level on day 21,28.The complement activity in serum was lower(P<0.05) than the control group.