KINETICS OF INTERFERON-γ (IFN-γ) RELEASE IN THE PERIPHERAL BLOOD OF CALVES VACCINATED WITH BCG

ABSTRACT

A study was conducted on 13 Friesian-Zebu crossbred calves, the ages of which lie between 6 and 18 months, to investigate the kinetics of IFN-γ release in the peripheral blood following Bacille Calmete Guerine (BCG) vaccination. After being screened for bovine tuberculosis (BTB), the calves were vaccinated with 1 mL inoculums containing 6 × 10⁶ CFU of BCG. The level of IFN-γ in the peripheral blood was measured two times before vaccination and seven times after vaccination, using a sandwich ELISA. The kinetics of IFN-γ post vaccination presented itself in three phases: rising, falling, and steady phases. The concentration of IFN-γ, before and after vaccination, both in stimulated and non-stimulated samples, was statistically significant (P<0.01). Strong positive correlation (r = 0.86) was recorded between the levels of IFN-γ release in avian PPD- and bovine PPD-stimulated samples. Of the total 13 calves, 11 (84.6%) reacted positively to tuberculin inoculation 15 weeks post vaccination. It is concluded that the IFN-γ rises immediately after BCG vaccination, reaching its peak two weeks post vaccination, and then declines gradually in the following weeks. The strong positive reaction of calves to tuberculin inoculation 15 weeks post vaccination showed the capability of BCG in causing the release of IFN-γ in the peripheral blood, indicating its role in protection against infection with Mycobacterium bovis in calves.     

dt_2-cAMP,IFN-γ和PMA对U937胞浆Ca~(2 )和酪氨酸激酶的影响

目的探讨dt2 cAMP ,PMA和IFN γ对U937细胞C5aR表达的影响 ,以及rhC5a刺激受dt2 cAMP ,PMA和IFN γ分化的U937细胞后 ,其胞浆Ca2 浓度的变化情况。方法用流式细胞仪分析胞膜C5aR和胞浆蛋白酪氨酸激酶的表达 ;荧光发光法测定胞浆Ca2 浓度的变化。结果dt2 cAMP ,PMA和IFN γ等可不同程度地上调C5aR表达。用0.5mmol/L的dt2 cAMP就足以上调U937细胞C5aR分子 ,10～20nmol/L浓度范围的PMA对C5aR表达的上调没有明显差异 ,IFN γ也可上调U937细胞上C5aR的表达。此外 ,rhC5a刺激受dt2 cAMP ,PMA和IFN γ分化的U937细胞 ,可使其细胞浆Ca2 浓度上升。蛋白酪氨酸激酶(PTK)抑制剂Genistein可明显抑制rhC5a所致U937细胞胞浆Ca2 浓度升高。结论PTK可能参与了C5a C5aR相互作用过程中的信号转导。     

THE EFFECT OF INTRACEREBRAL IMMUNIZATION OF C57BL/6 MICE FOLLOWING CHALLENGE WITH T.GONDII ON IFN-γ AND TNF-α PRODUCTION IN BRAIN

脑传统上被认为是一个免疫学上特殊的器官。我们观察到用丝裂霉素处理过的弓形虫脑内免疫小鼠，可防止弓形虫感染后引起的小鼠的死亡，未接受免疫的小鼠，弓形虫感染后，敏感性小鼠与抵抗性小鼠相比，敏感性小鼠脑内有高水平的ＩＦＮ－γ、ＴＮＦ－α及ＩＬ－６。本研究观察了脑内免疫的小鼠，经几种不同途径的弓形虫负荷后，脑内及脾脏内淋巴介素的变化情况。与腹腔内或肠道内免疫途径相比，脑内免疫可引起弓形虫负荷后，脑内ＩＦＮ－γ和ＴＮＦ－α水平明显升高；而在脾脏，弓形虫负荷后ＩＦＮ－γ和ＴＮＦ－α产生，经肠道免疫的比经腹腔内和脑内免疫的要显著的高。这种淋巴介素产生的不同可能产生于不同的免疫途径诱导不同的Ｔｈ淋巴介素类型。以上结果也提示了脑本身具有内在性的抵抗微生物感染的免疫功能。