Characteristics of prion protein (PrP(Sc)) in the brains of hamsters inoculated serially with a mouse-passaged scrapie strain

Syrian hamsters were inoculated intracerebrally with a mouse-passaged scrapie strain. After serial passage, the incubation period decreased, but the vacuolar lesion profiles remained unchanged. In immunoblot analysis, accumulated prion protein (PrP) showed hamster PrP characteristics from the first passage. However, immunohistochemical examination revealed a changing pattern of accumulated PrP with each passage. In particular, there were many PrP plaques in the subpial and subependymal region at the third passage, no such plaques having been observed in the same region at the first passage. These results suggest that the species barrier influences not only the incubation period but also the pattern of accumulation of PrP in affected brains.     

Detection of PrP(Sc) in rectal biopsy and necropsy samples from sheep with experimental scrapie

Scrapie diagnosis is based on the demonstration of disease-associated prion protein (PrP(Sc)) in brain or, in the live animal, in readily accessible peripheral lymphoid tissue. Lymphatic tissues present at the rectoanal line were readily obtained from sheep without the need for anaesthesia. The presence of PrP(Sc) in such tissue was investigated in sheep infected orally with scrapie-infected brain material. The methods used consisted of immunohistochemistry and histoblotting on biopsy and post-mortem material. PrP(Sc) was detected in animals with PrP genotypes associated with high susceptibility to scrapie from 10 months after infection, i.e., from about the time of appearance of early clinical signs. In the rectal mucosa, PrP(Sc) was found in lymphoid follicles and in cells scattered in the lamina propria, often near and sometimes in the crypt epithelium. By Western blotting, PrP(Sc) was detected in rectal biopsy samples of sheep with the PrP genotype VRQ/VRQ, after electrophoresis of material equivalent to 8 mg of tissue. This study indicated that rectal biopsy samples should prove useful for the diagnosis of scrapie in sheep.     

Influence of guanidine on proteinase K resistance in vitro and infectivity of scrapie prion protein PrP(Sc)

As the scrapie prion protein PrP(Sc) is rich in beta-sheets it aggregates into prion rods, which show infectivity and proteinase K (PK) resistance. Consequently, dissociation of prion rods and breakdown of beta-sheets in PrP(Sc) by denaturation results in loss of both infectivity and PK-sensitivity. In this study, the effects of guanidine (Gdn), which solubilizes and denatures proteins by breaking down their higher structure, on the solubility, the PK-resistance in vitro and the infectivity of PrP(Sc) of scrapie strain 263K was examined. The infectivity was assayed by intracerebral inoculation into hamsters. Brain tissues of scrapie-infected hamsters were used for preparation of homogenates and crude extracts of PrP(Sc). A treatment of PrP(Sc) with Gdn enhanced its PK-sensitivity in a dose-dependent manner. The PK-resistance in vitro of PrP(Sc) denatured with lower concentrations of Gdn (<2.5 mol/l) could partially resume by renaturation. Gdn markedly reduced or, at higher concentrations, even destroyed the infectivity of PrP(Sc). On the other hand, the infectivity of PrP(Sc) inactivated by denaturation could be partially restored by renaturation. These results confirmed our assumption that all the alternations in the PK-resistance and the infectivity of PrP(Sc) caused by Gdn resulted from changes in its higher structure. However, it should be emphasized that a complete loss of PK-resistance of PrP(Sc) may not necessarily mean its full non-infectivity.     

Induction of oral tolerance to cellular immune responses in the absence of Peyer's patches

Systemic hyporesponsiveness occurs following oral administration of antigen (oral tolerance) and involves the uptake and processing of antigen by the gut-associated lymphoid tissue (GALT), which includes Peyer's patches (PP) lamina propria lymphocytes and mesenteric lymph nodes (MLN). Animals with targeted mutations of genes in the tumor necrosis factor (TNF) family have differential defects in the development of peripheral lymphoid organs including PP and MLN, and provide a unique opportunity to investigate the role of GALT structures in the induction of oral tolerance. Oral tolerance could not be induced in TNF/lymphotoxin (LT) alpha-/- mice, which are devoid of both PP and MLN, although these animals could be tolerized by intraperitoneal administration of antigen, demonstrating the requirement for GALT for oral tolerance induction. LTbeta-/- mice and LTalpha/LTbeta+/- animals do not have PP but could be orally tolerized, as measured by IFN-gamma production and delayed-type hypersensitivity responses by administration of both low or high doses of ovalbumin. To further investigate the requirement for PP, we tested the progeny of LTbeta-receptor-IgG-fusion-protein (LTbetaRigG)-treated mice, which do not form PP but have an otherwise intact immune system. Although these animals had decreased fecal IgA production, they could be orally tolerized. Our results demonstrate that PP are not an absolute requirement for the induction of either high- or low-dose oral tolerance, although oral tolerance could not be induced in animals devoid of both PP and MLN.     

Induction of oral tolerance in rats without Peyer's patches.

The induction of oral tolerance after ingestion of antigen has been reported in several animal models. The precise mechanisms responsible for this unresponsiveness are not well understood. As some investigations have suggested a key role of Peyer's patches suppressor T cells, an animal model was developed in which the PP were surgically removed. Using this model, the influence of the PP on the induction of oral tolerance against SRBC was investigated. In order to induce tolerance, the rats were fed SRBC on four consecutive days. On Day 5 they were i.p. challenged by injection of SRBC, and 5 days later the number of immunoglobulin-secreting cells against SRBC was determined within the spleen. Using this protocol, the oral tolerance induction could be shown very clearly in control animals as well as in rats without PP. Therefore, tolerance induction is possible in the absence of PP-T cells. Other mechanisms must be responsible for the tolerance induction in this model.     

Pasteurization of milk proteins promotes allergic sensitization by enhancing uptake through Peyer's patches

Background:  The underlying mechanisms responsible for allergic sensitization to food proteins remain elusive. To investigate the intrinsic properties (as well as the effect of pasteurization) of the milk proteins α-lactalbumin, β-lactoglobulin and casein that promote the induction of milk allergy.
Methods:  Alteration of structure and immune-reactivity of native and pasteurized proteins was assessed by gel filtration and ELISA. Uptake of these proteins was compared in vitro and in vivo . The biological effect was assessed by orally sensitizing C3H/HeJ mice with milk proteins followed by a graded oral challenge. Required dose to induce anaphylaxis, symptoms and mean body temperature was recorded. Antigen-specific antibodies and cytokine production by splenocytes were analyzed.
Results:  Soluble β-lactoglobulin and α-lactalbumin but not insoluble casein were readily transcytosed through enterocytes in vitro and in vivo . Pasteurization caused aggregation of β-lactoglobulin and α-lactalbumin inhibiting uptake by intestinal epithelial cells in vitro and in vivo. Furthermore, aggregation redirected uptake to Peyer's patches, which promoted significantly higher Th2-associated antibody and cytokine production in mice than their native counterparts. Despite this only the soluble forms of β-lactoglobulin and α-lactalbumin elicited anaphylaxis (following priming) when allergens were administered orally. Aggregated β-lactoglobulin and α-lactalbumin as well as casein required systemic administration to induce anaphylaxis.
Conclusions:  These results indicate that triggering of an anaphylactic response requires two phases (1) sensitization by aggregates through Peyer's patches and (2) efficient transfer of soluble protein across the epithelial barrier. As the majority of common food allergens tend to form aggregates, this may be of clinical importance.     

Experimental bovine spongiform encephalopathy: detection of PrP(Sc) in the small intestine relative to exposure dose and age

European regulations for the control of bovine spongiform encephalopathy (BSE) decree destruction of the intestines from slaughtered cattle, therefore producers have been obliged to import beef casings from countries with a negligible BSE risk. This study applies immunohistochemical and biochemical approaches to investigate the occurrence and distribution of disease-associated prion protein (PrP(Sc)) in the duodenum, jejunum and ileum of cattle orally exposed to a 1 g or 100 g dose of a titrated BSE brainstem homogenate. Samples were derived from animals at various times post exposure. Lymphoid follicles were counted and the frequency of affected follicles recorded. No PrP(Sc) was detected in the duodenum or jejunum of animals exposed to a 1 g dose or in the duodenum of animals receiving a 100 g dose. PrP(Sc) was detected in the lymphoid tissue of the ileum of 1/98 (1.0%) animals receiving the 1 g dose and in the jejunum and ileum of 8/58 (13.8%) and 45/99 (45.5%), respectively, of animals receiving the 100 g dose. The frequency of PrP(Sc)- positive follicles was less than 1.5% per case and biochemical tests appeared less sensitive than immunohistochemistry. The probability of detecting lymphoid follicles in the ileum declined with age and for the 100 g exposure the proportion of positive follicles increased, while the proportion of positive animals decreased with age. Detection of PrP(Sc) in intestinal neural tissue was rare. The results suggest that the jejunum and duodenum of BSE-infected cattle contain considerably less BSE infectivity than the ileum, irrespective of exposure dose. In animals receiving the low exposure dose, as in most natural cases of BSE, the rarity of PrP(Sc) detection compared with high-dose exposure, suggests a very low BSE risk from food products containing the jejunum and duodenum of cattle slaughtered for human consumption.     

Selective induction of Th2 cells in murine Peyer's patches by oral immunization.

We have used three different methods to determine the T helper (Th) cell response, including Th1 and Th2 types, in murine Peyer's patches (PP) following oral immunization with sheep red blood cells (SRBC). These include: (i) use of cytokine-specific (IFN-gamma and IL-5), single cell assays to estimate the frequencies of Th1 and Th2 cells respectively, (ii) cytokine-specific mRNA--cDNA dot blot and Northern gel hybridizations to detect levels of specific mRNA, and (iii) T cell cloning techniques to determine the frequency of Th1 and Th2 clones. Mice were immunized with SRBC by either the oral or i.p. route. The PP and splenic (SP) CD3+ and CD3+ CD4+ T cell subsets were isolated and cultured with antigen, feeder cells, and IL-2, and were assessed at various intervals (days 0, 1, 3, and 6) for numbers of T cells producing either IFN-gamma or IL-5 by use of an enzyme-linked immunospot (ELISPOT) procedure. Cultures of T cells from PP or SP of mice given SRBC by the oral route had a high frequency of IL-5 spot forming cells (SFC), with lower numbers of IFN-gamma SFC. However, cultures of CD3+ T cells and CD3+ CD4+ Th cells from spleens of i.p. immunized mice exhibited predominantly IFN-gamma SFC, with smaller but significant numbers of IL-5 SFC. This distinct pattern of cytokine production was supported by mRNA analysis where high IL-5 specific mRNA levels were noted in PP T cell cultures of orally primed mice, while IFN-gamma mRNA was predominant in the SP CD3+ T cell and CD3+ CD4+ Th cell cultures from i.p. immunized mice. When the frequencies of IFN-gamma or IL-5 SFC were assessed among cloned Th cells from orally- or systemically-immunized mice, 74% of Th cell clones from PP of mice orally immunized with SRBC were IL-5 producers (Th2 type), while 67% of Th cell clones from SP of mice immunized by the i.p. route were IFN-gamma producers (Th1 type). Our studies show that higher frequencies of IFN-gamma producing Th1-type cells occur in SP of mice given antigen by the systemic route, while oral immunization results in predominantly IL-5 producing, Th2-type cells in PP.     

Pathological PrP is abundant in sympathetic and sensory ganglia of hamsters fed with scrapie.

Although the ultimate target of infection is the CNS, there is evidence that the peripheral nervous system (PNS) is involved in the pathogenesis of Transmissible Spongiform Encephalopathies (TSEs). We used immunocytochemistry to identify the presence of pathological accumulations of a host protein, PrP, in the CNS and PNS (sensory and autonomic ganglia) of hamsters orally infected with 263K scrapie. All hamsters showed pathological deposition of PrP in most brain areas, along the length of the spinal cord, in nodose (NG) and dorsal root (DRG) ganglia and in the coeliac mesenteric ganglion complex (CMGC). In one case, scant deposition was observed along a few axons of the vagus nerve. This finding suggests that, after oral challenge, TSE infectious agent uses neural pathways and ganglia of the peripheral nervous system to reach target sites in the CNS.     

Antigen transport into Peyer's patches: increased uptake by constant numbers of M cells

Membranous (M) cells are specialized epithelial cells of the Peyer's patches that sample antigens from the gut lumen, thereby enabling the host to respond immunologically. Recent studies suggest that this transport can be up-regulated within hours by de novo formation of M cells from enterocytes. To test this hypothesis, we used an in vivo model and induced the transcytosis of tracers in Peyer's patches by application of Streptococcus pneumoniae R36a into the gut lumen. Using cell-type-specific markers, we quantified M cells in the Peyer's patch domes, lymphocytes associated with M cells, and the transport rate for experimentally applied microbeads after 3 hours of exposure to R36a. The transport of latex microbeads was significantly increased by +131% in the R36a-treated patches as compared to buffer controls (P < 0.001). While in controls, each M cell was associated with 2.05 +/- 0.64 lymphocytes, a significant increase (+55.1%; P < 0.001) was determined in the R36a-treated patches. However, no statistical difference was detected in the percentage of M cells in the dome epithelia (46.0 +/- 4.6% versus 45.5 +/- 3.8%). It is concluded that bacteria-induced up-regulation of particle transport in Peyer's patch domes is due to an increased transport rate of the M cells, but not to a de novo formation of M cells. The data support the hypothesis that M cells represent a separate cell lineage that does not derive from enterocytes on the domes.     

Chitosan microparticles for oral vaccination: preparation, characterization and preliminary in vivo uptake studies in murine Peyer's patches

Although oral vaccination has numerous advantages over parenteral injection, degradation of the vaccine in the gut and low uptake in the lymphoid tissue of the gastrointestinal tract still complicate the development of oral vaccines. In this study chitosan microparticles were prepared and characterized with respect to size, zeta potential, morphology and ovalbumin-loading and -release. Furthermore, the in vivo uptake of chitosan microparticles by murine Peyer's patches was studied using confocal laser scanning microscopy (CLSM). Chitosan microparticles were made according to a precipitation/coacervation method, which was found to be reproducible for different batches of chitosan. The chitosan microparticles were 4.3+/-0.7 microm in size and positively charged (20+/-1 mV). Since only microparticles smaller than 10 microm can be taken up by M-cells of Peyer's patches, these microparticles are suitable to serve as vaccination systems. CLSM visualization studies showed that the model antigen ovalbumin was entrapped within the chitosan microparticles and not only associated to their outer surface. These results were verified using field emission scanning electron microscopy, which demonstrated the porous structure of the chitosan microparticles, thus facilitating the entrapment of ovalbumin in the microparticles. Loading studies of the chitosan microparticles with the model compound ovalbumin resulted in loading capacities of about 40%. Subsequent release studies showed only a very low release of ovalbumin within 4 h and most of the ovalbumin (about 90%) remained entrapped in the microparticles. Because the prepared chitosan microparticles are biodegradable, this entrapped ovalbumin will be released after intracellular digestion in the Peyer's patches. Initial in vivo studies demonstrated that fluorescently labeled chitosan microparticles can be taken up by the epithelium of the murine Peyer's patches. Since uptake by Peyer's patches is an essential step in oral vaccination, these results show that the presently developed porous chitosan microparticles are a very promising vaccine delivery system.     

A morphological study of the lymphocyte traffic in Peyer's patches after an in vivo antigenic stimulation

Background: Lymphoid cells have often been observed in the intestinal lumen and it has been hypothesized that M cells could represent one of the most important migration routes for the immunocompetent cells from the lymphoid follicle to the lumen. However, a direct evidence of the passage was lacking. In this study we describe a morphological analysis of the lymphocyte traffic in rabbit Peyer's patches after an in vivo stimulation with an antigen normally not present in the intestine. Methods: The antigenic stimulation of a large number of Peyer's patches was carried out using the isolated ileal loop technique and then the samples from stimulated and control Peyer's patches were analysed by light and transmission electron microscopy. Results: We have been able to describe details of lymphocyte migration through M cells, from the follicle to the intestinal lumen, and a marked increase of intraluminal lymphocytes by counting the immunocompetent cells after periods of antigenic stimulation of varying lengths. Conclusions: Our finding is that the passage of lymphocytes to the lumen is an antigen-dependent event and we also provide direct evidence that M cells are one of the migration routes. Our observations also indicate that lymphoid cells in the intestinal lumen may play an immunologic role in mucosal immunity. © 1994 Wiley-Liss, Inc.     

Reduction of protein kinase MARK4 in the brains of experimental scrapie rodents and human prion disease correlates with deposits of PrP(Sc)

Microtubule affinity-regulating kinase 4 (MARK4) belongs to a family of kinases that are able to actively phosphorylate the neuronal microtubule-associate proteins (MAPs), such as tau, MAP2 and the ubiquitous MAP4. Abnormal changes in tubulin and the profiles of tau have been previously reported in the human brain and animal transmissible spongiform encephalopathies (TSEs), which may be associated with abnormal alterations of various cellular kinases. To elucidate the possible role of MARK4 in TSE pathogenesis, the MARK4 levels in the brain tissues of scrapie-infected rodents and human prion diseases were evaluated using western blotting and immunohistochemical assays. The results revealed that at terminal stages of the diseases, MARK4 levels in the brain tissues of the scrapie 263K-infected hamsters, 139A-infected mice and a case of Creutzfeldt-Jakob disease (CJD, G114V gCJD) correlated with amounts of PrP(Sc) deposits that were almost undetectable. On the other hand MARK4 signals were noticeable in the brain tissues of a fatal familial insomnia (FFI) patient without PrP(Sc). The reduction of MARK4 was closely related to the prolonged incubation times. These results could be reproduced in SK-N-SH and PC12 cell lines after being exposed to the synthetic peptide PrP106-126. Accordingly, the levels of phosphorylated tau at Ser262 (p-tau262) in cultured cells exposed to PrP106-126, or the ratios of p-tau262/total tau in the brain tissues of 263K-infected hamsters were also significantly decreased. According to our data there is a correlation between a TSE pathological-associated decline of MARK4 in the brain tissues with the deposits of PrP(Sc). Reduction of MARK4 will result in abnormalities of tau phosphorylation, and possibly induce further detachment of microtubules and hinder microtubule transportation.     

Generation of gamma interferon responses in murine Peyer's patches following oral immunization.

To date, oral immunizations have been shown to generate only Th2 responses in murine Peyer's patches (PP), raising the possibility that T cells present in PP may be capable of mounting only Th2 responses or that the microenvironment of PP does not favor the generation of Th1 cells. However, it is also possible that antigens that can generate Th1 responses have not yet been used for oral immunizations. This study shows that T cells in PP of mice immunized orally with live Salmonella typhimurium secrete large amounts of gamma interferon (IFN-gamma) when they are stimulated with bacterial sonicate in vitro. Moreover, oral challenge of mice with live bacteria 4 months after immunization elicits a secondary IFN-gamma response in PP and mesenteric lymph nodes. Parenteral immunization does not generate an IFN-gamma T-cell response in PP, and parenteral challenge of orally immunized mice does not elicit a secondary response in PP. However, oral challenge of intraperitoneally immunized mice elicits a secondary IFN-gamma response in PP and mesenteric lymph nodes, and intraperitoneal challenge of orally immunized mice elicits a secondary response in the spleen. The data suggest that memory T cells recirculate between mucosal and nonmucosal compartments and that they may be recruited to the site of antigenic challenge.     

Adaptation of the agent of scrapie to hamsters

The agent of scrapie (Compton strain) can be transmitted from mice to hamsters; the incubation period of the disease is 5–6 months. Passage of the agent of scrapie through suspensions of brain tissue was repeated 10 times. The scrapie agent was found in the spinal cord and spleen but it could not be found in the liver, kidneys, adrenals, and lungs of the infected animals in the last stage of the disease.Division of General Epidemiology, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR O. V. Baroyan.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 199–201, February, 1976.     

Peyer's patches are precocious to the appendix in human development

PP are first visible at approximately 15.5 wk gestation after which there is a rapid spurt in the development and maturation of lymphoid follicles so that at any given point of time new foci of PP development are continuously formed at a rapid rate. Addition of rows of follicles results in the formation of a PP. Immature PP of younger fetuses have a spongy structure in contrast with the compact lymphoid follicles of mature PP of older fetuses. Immunocytochemical studies reveal that there is a subtle gradation in the expression of lymphocyte surface markers with increasing fetal age. Expression of antigenic markers occurs in an ordered sequence viz. HLA - DR, CD19 (B cell population), CD9 (pre-B cells), CD3 T lymphocytes, CD4 helper / inducer lymphocytes, the CD8 suppressor / cytotoxic cells and lastly, the CD57 Natural Killer cells. The antigens are expressed first on lymphocytes of PP and thereafter in those of the appendix. Our findings clearly demonstrate that the approximately 5 wk fetal period from 17.5 wk to 22 wk represents a major growth phase in the development of surface markers of lymphocytes in the mucosal immune system of the gut.     

Interaction between dendritic cells and nerve fibres in lymphoid organs after oral scrapie exposure

In transmissible spongiform encephalopathies (TSEs), the infectious agent, called PrPsc, an abnormal isoform of the cellular prion protein, accumulates and replicates in lymphoid organs before affecting the nervous system. To clarify the cellular requirements for the neuroinvasion of the scrapie agent from the lymphoid organs to the central nervous system, we have studied, by confocal microscopy, the innervations within Peyer’s patches, mesenteric lymph nodes and the spleen of mice in physiological conditions and after oral exposure to prion. Contacts between nerve fibres and PrPsc-associated cells, dendritic cells (DCs) and follicular dendritic cells (FDCs), were evaluated in preclinical prion-infected mice. Using a double immunolabelling strategy, we demonstrated the lack of innervation of PrPsc-accumulating cells (FDCs). Contacts between nerve fibers and PrPsc-propagating cells (DCs) were detected in T-cell zones and cell-trafficking areas. This supports, for the first time, the possible implication of dendritic cells in the prion neuroinvasion process.     

Early accumulation of pathological PrP in the enteric nervous system and gut-associated lymphoid tissue of hamsters orally infected with scrapie

Previous research revealed the existence of coupling mechanisms (e.g. iso-directionality) at the level of perception and action. The present experiment investigated how the strength of the perception-action coupling affected synchronization performance. Arm movements were to be synchronized with a moving light that traveled back and forth from the left to the right side of a runway. Four experimental conditions were administered representing the orthogonal combination of two viewing conditions (intermittent vs. continuous) and two synchronization modes (in-phase, i.e. arm moving in the same direction as the light vs. anti-phase, i.e. arm moving in the opposite direction). Performance outcome measures, movement kinematics, and relative phase were used to examine the data. The results revealed a better synchronization performance when the arm and light traveled in the same direction (iso-directionality) during the continuous viewing condition. Apparently, the strength of the perception–action coupling has a severe impact on the quality of the synchronization of an arm movement to an external event.     

口服Ⅱ型胶原蛋白对血清抗体和派氏集结细胞因子表达的影响

目的:探讨口服Ⅱ型胶原蛋白(cⅡ)对派[伊尔]氏集结(PP结)的形态学、细胞因子表达水平和血清特异性IgG、IgA、IgM含量的影响.方法:连续10 d给小鼠口服不同剂量的CⅡ,第11天和第21天用佐剂或CⅡ进行免疫,分别于第11天、第21天和第31天采集血液和PP结.PP结经HE染色后,镜下观察其增生的情况.用荧光实时定量RT-PCR法,检测PP结中IL-17、TNF-α、IFN-γ和TGF-β1 mRNA 的水平.采用ELISA法检测血清抗CⅡIgG、IgA、IgM的水平.结果:口服CⅡ10 d后,PP结增生活跃,高剂量组可见清晰的帽状结构;血清中出现IgA,未见IgG和IgM水平增加;IL-17、TNF-α、IFN-γ mRNA的表达受到抑制.以CⅡ初次免疫后,实验组IgA、IgM、IL-17的水平均低于对照组(P＜0.05或P＜0.01),TGF-β1的水平显著增加(P＜0.05).以C Ⅱ加强免疫后,高剂量组IgA的水平显著增加(P＜0.05),实验组IgM的水平仍受到抑制(P＜0.05或P＜0.01),TGF-β1的水平高于对照组(P＜0.05).以佐剂免疫时PP结中细胞因子的表达与CⅡ免疫时相似,未见血清抗CⅡ IgG、IgA、IgM 水平的变化.结论:口服CⅡ能使血清中产生特异性IgA,抑制PP结IL-17、TNF-α、IFN-γ的基因表达,对CⅡ免疫后IgA、IgM的产生和IL-17 mRNA的表达具有一定的抑制作用.以上结果表明,血清特异性抗体的水平和细胞因子表达的变化在口服CⅡ诱导免疫耐受对类风湿性关节炎的治疗作用方面发挥着重要的作用.