Analysis on the expression of protection to Listeria monocytogenes by MCF derived from T cells with a low thymus dependency

所谓的细胞介导免疫被认为是胸腺依赖免疫，然而，有各种免疫反应可以很容易地在新生胸腺切除（NTx）小鼠（裸鼠）中进行，而不是。对单核增生李斯特菌的保护性免疫是胸腺依赖性低的这种免疫的一个例子。本研究对胸腺依赖性较低的单核增生l.s的保护性T细胞进行了鉴定。在李斯特菌免疫T细胞产生的各种淋巴因子中，MCF是本研究的特别关注对象，因为该淋巴因子在保护表达中的生物学意义尚未阐明。从活的单核增生l.s免疫的NTx小鼠获得的T细胞显示为Lytl^+，L3T4^+和Lyt2^-细胞。效应T细胞受特异性抗原刺激后可释放多种淋巴因子；然而，它们表现出IL-2释放和抗原特异性增殖受损。结果表明，低胸腺依赖性的T细胞的特点可能是对克隆扩增的要求较低。利用李斯特免疫T细胞加抗原培养上清，采用凝胶层析法对MCF进行部分纯化。可以得到显示MCF活性但没有污染MAF活性的组分。将该MCF组分注射到小鼠体内，在注射后10小时观察到巨噬细胞的明显积聚。mcf诱导的巨噬细胞积累对相对小剂量的强毒菌株甚至高剂量的低毒株单核细胞增生l.s的攻击都有效。在给予MCF的足部观察到最显著的保护水平，可能是因为MCF在该部位的定位。当在体内使用IFN-< γ >作为MAF时，通过使用额外的MCF获得最高水平的保护。这些结果表明MCF是由胸腺依赖性较低的T细胞产生的，它本身在保护性免疫的表达中起重要作用，并且能够与MAF/IFN-< γ >表现出协同作用。少

So-called cell-mediated immunity has been regarded as a thymus-dependent immunity, however, there are various immune responses which can be easily mounted in neonatally thymectomized (NTx) mice but not in nude mice. Protective immunity to Listeria monocytogenes is an example of such an immunity with a low thymus dependency.In the present study, the characterization of protective T cells against L.monocytogenes, which are of low thymus dependency, was done. Among various lymphokins produced by Listeria-immune T cells, MCF was of the special interest in this study, since the biological significance of this lymphokine in the expression of protection has not yet been elucidated. T cells obtained from NTx mice immunized with viable L.monocytogenes was shown to be Lytl^+,L3T4^+ and Lyt2^- cells. The effector T cells could release several lymphokines upon stimulation with specific antigen; however, they showed an impaired release of IL-2 and antigen-specific proliferation. It was suggested th … More at the characetristics of T cells with a low thymus dependency may be a low requirement for clonal expansion. Using the culture supernatant of Listeriaimmune T cells plus antigen, a partial purification of MCF was carried out by a gel chromatography. Fractions showing MCF activity but no contaminating MAF activity could be obtained. When this MCF fraction was injected into mice, a marked accumulation of macrphages was observed 10 h after injection. MCF-induced accumulation of macrophages was effective against challenge with relatively small dose of virulent strain and with even a high dose of low virulent strain of L.monocytogenes. The most significant level of protection was observed in the footpad given MCF, probably because of the localization of MCF at this site. When IFN-<gamma> was used as MAF in vivo, the highest level of protection was obtained by the use of an additional administration of MCF. These results suggested that MCF, which is produced by T cells with a low thymus dependency, plays an important role by itself in the expression of protective immunity and also is capable of showing the synergistic effect with MAF/IFN-<gamma>. Less