旋毛虫新生幼虫T668重组抗原对小鼠的保护性免疫

目的研究旋毛虫新生幼虫T668重组抗原的免疫原性,制备基因工程疫苗。方法以旋毛虫新生幼虫期特异性基因T668在大肠杆菌中的表达蛋白为抗原免疫小鼠,每间隔10d免疫1次,共免疫3次。末次免疫后10d,每只小鼠攻击感染200条旋毛虫感染性肌幼虫,感染后5周用消化法检查肌幼虫(ML)负荷。结果T668重组抗原免疫组肌幼虫减虫率明显高于佐剂组和对照组。结论T668重组抗原能诱导小鼠产生一定程度的保护性免疫,且可激发特异性体液免疫。     

An antigenic recombinant serine protease from Trichinella spiralis induces protective immunity in BALB/c mice

In this study, we report the cloning and characterization of a cDNA encoding a Trichinella serine protease gene (TspSP-1.3) from GenBank. The recombinant TspSP-1.3 protein (rTspSP-1.3) was expressed in an Escherichia coli expression system and purified with Ni-affinity chromatography. Real-time quantitative PCR analysis revealed that TspSP-1.3 was expressed at significantly higher levels in muscle larvae and adult worms than in newborn larvae. TspSP-1.3 was detected in excretory–secretory proteins of Trichinella spiralis with western blotting. Immunization with the rTspSP-1.3 antigen induced humoral immune responses, which manifested as elevated specific anti-rTspSP-1.3 IgG and IgE antibodies and a mixed Th1/Th2 response. To determine whether purified rTspSP-1.3 had good antigenicity and could be a vaccine candidate for the control of T. spiralis infection, we immunized BALB/c mice with rTspSP-1.3 and subsequently challenged the mice with T. spiralis larvae. The results showed that mice vaccinated with rTspSP-1.3 exhibited an average reduction in the muscle larvae burden of 39 % relative to the control group. These results suggest that TspSP-1.3 could be a novel vaccine candidate for controlling Trichinella infection.     

Genetic factors controlling the intestinal mast cell response in mice infected with Trichinella spiralis.

Inbred strains of mice showed marked variation in their mast cell (MC) response to infection with Trichinella spiralis. Variation was under genetic control, the ability to respond to infection being inherited as a dominant trait. MHC-linked genes may influence the absolute level of response, but overall response kinetics appear to be controlled by genes which are not linked to the MHC. An enhanced MC response was transferred adoptively with immune mesenteric lymph node cells (IMLNC), but reciprocal adoptive transfers between H-2 compatible rapid (NIH) and slow (B10.G) responder strains showed that the degree of enhancement was determined by the response phenotype of the recipient, not that of the donor. Similarly, in bone marrow (BM) chimaeras, produced by reconstituting lethally irradiated F1 (B10.G x NIH) mice with parental BM, the MC response to T. spiralis was determined by the response phenotype of the BM donor, whether or not rapid responder IMLNC were transferred. The data are discussed in terms of a T lymphocyte regulated, bone marrow stem cell origin of mucosal MC and interpreted as showing that genetic regulation of the MC response is expressed at the level of stem cell or precursor response to T cell derived mastopoietic factors.     

Impaired protective immunity and T helper 2 responses in alymphoplasia (aly) mutant mice infected with Trichinella spiralis

The alymphoplasia (aly) mutation of mice prevents the development of systemic lymph nodes and Peyer's patches. The mutant homozygotes (aly/aly) are partially deficient in both humoral and cell-mediated immune functions. In the present study, we show that adult worm expulsion was slightly delayed and that T helper 2 (Th2)-type responses were partially defective in aly/aly mice after infection with Trichinella spiralis. Male aly/aly and aly/+ mice (8-weeks old) were infected with 400 muscle larvae. There was no difference in worm recovery between the two groups on day 5. However, worm recovery in aly/aly mice was significantly higher than that in aly/+ mice on day 14. Mucosal mast cells increased in number and peaked 14 days after infection in aly/+ mice. aly/aly mice were deficient in their mucosal mast cell response through out the primary infection. To examine the existence of mast cell precursors, aly/aly mice were treated with recombinant interleukin-3 (rIL-3) before infection. The mast cell response was poorly induced in aly/aly mice treated with rIL-3. An immunoglobulin E (IgE) response was not detected in aly/aly mice during the course of infection. Serum IgG1 levels in aly/aly mice were significantly lower than that of aly/+. The serum IgG2a levels increased in both strains of mice. However, IgG2a production in aly/aly mice on day 14 was half as much as that in aly/+mice. Stimulation of splenic T cells in vitro with anti-CD3 monoclonal antibody (mAb) showed that spleen cells from aly/+ mice on day 5 produced more IL-4 than spleen cells from aly/aly mice. IL-4 production from aly/aly mice on day 14 was half that from aly/+ mice. Interferon-gamma (IFN-gamma) was produced in both aly/aly and aly/+ mice on day 14. Proliferation assay showed that T cells of aly/aly mice responded poorly when cultured with antigen-presenting cells. These results suggest that aly gene is needed for the induction of protective immunity and Th2 responses in mice infected with T. spiralis.     

Genetic control of immunity to Trichinella spiralis in mice: capacity of cells from slow responder mice to transfer immunity in syngeneic and F1 hybrid recipients.

Mice of the C57BL/10 (B10) strain are slow responders to infection with T. spiralis in terms of ability to expel worms from the intestine. Compared with rapid-responder NIH mice, infection stimulates a slower and reduced blast cell response in the draining mesenteric lymph node (MLN). Transfer of immune cells from the MLN (MLNC) does not accelerate worm expulsion from naive B10 recipient mice, even though MLNC from this strain effectively transfer immunity to (B10 X NIH) F1 recipients. In common with other B10 background mice C57BL/10 show an infection-dose related suppression of immunity to T. spiralis. Such suppression does not appear to determine the response to MLNC, as adoptive transfer into B10 recipients was not enhanced by reducing the level of challenge infection given, and transfer into F1 recipients was unaffected by simultaneous transfer of lymphocyte populations from donors infected at a level which would induce suppression. A hypothesis is proposed which relates slow response status to (i) the inherent capacity of the intestinal inflammatory component of worm expulsion, and (ii) the outcome of infection-dose related stimulatory and suppressive influences acting on the two interacting lymphocyte components of expulsion. The relevance of H-2-linked and non-H-2 genes to the control of the response is discussed.     

Immune responses to Trichinella spiralis and T. pseudospiralis in mice.

A comparison was made of the immunological responses of inbred NIH mice to the intestinal stage of infection with two species of the genus Trichinella, T. spiralis and T. pseudospiralis, which are known to have distinct parasitological and pathological relationships with their hosts. The parameters studied, namely antigen-specific IgG1 and IgG2a antibody responses, mucosal mastocytosis, and levels of the cytokines interferon-gamma (IFN-gamma) and interleukin-5 (IL-5) produced by concanavalin A-pulsed mesenteric node lymphocytes in vitro, were chosen to provide information about the relative activities of the Th1 and Th2 T-helper (Th) lymphocyte subsets. In this high-responder host the time-course of infections was similar, although initial levels of establishment were considerably higher for T. pseudospiralis. Both species elicited mucosal mastocytosis. Distinct differences were seen in the IgG isotype responses. Trichinella spiralis-infected mice produced a predominantly IgG2a response, whereas T. pseudospiralis elicited an IgG1 response. Cytokine release showed infection dose-related suppression of IFN-gamma and enhancement of IL-5. These effects were most marked in T. pseudospiralis-infected mice, i.e. there was an earlier shut-off of IFN-gamma and an earlier switch to IL-5. These data suggest that the two species of Trichinella show a time-related differential activity of Th subsets during the early stages of infection. The possibility that this may reflect antigenic differences between these closely related species or result from parasite-induced immunological-endocrinological changes is discussed.     

Immunity to Trichinella spiralis. II. Expression of immunity against adult worms.

Thoracic duct lymphocytes or purified T or B cells obtained from specifically immunized (Lewis x DA)F1 hybrid rats can protect normal recipients against an oral challenge infection with T. spiralis. The immune cells increase the rate of expulsion of adult worms from the small intestine. Immune TDL do not affect adult worm fecundity, as they do in other strains of rats, or the penetration and development of newborn larvae in muscle cells. Irradiated F1 rats reconstituted with either immune TDL or class-enriched populations of immune T or immune B cells also expel adult Trichinella more rapidly than do unprotected controls. However, unfractionated TDL and inocula enriched in B cells are more efficient than T cells in promoting worm expulsion. The above finding, taken in conjunction with the tissue disposition of labelled lymphocytes in the tissues of recipient rats, implies that immune T cells have a 'helper' function in promoting the formation of protective B cells.     

Maternal to neonatal transmission of T-cell mediated immunity to Trichinella spiralis during lactation.

The potential of maternally derived cellular factors to mediate immunity to Trichinella spiralis in neonates during lactation was investigated in this study. Female FI rats, infected with T. spiralis, were able to transfer immunity to their suckling offspring, evidenced by a significant reduction in the intestinal parasite burdens of their neonates. When challenged between 2 and 3 weeks of age with 200 T. spiralis larvae, pups suckling on immune mothers harboured 28% and 26% (at 3 and 8 days post-challenge) of the worm numbers present in control neonates suckling on naive mothers. Cross-fostering experiments in which pups born of naive mothers but nursed by immune mothers showed significant immunity, demonstrated that this passage occurred through milk. The role of cell-mediated immunity in this immune transfer was analysed using T cells purified from MLN cells of syngeneic donor rats infected with T. spiralis. When 200 x 10(6) sensitized MLN T cells were adoptively transferred into lactating recipients, it led to the passive immunization of suckling neonates (26% and 13% of control values retained at 3 and 8 days post-challenge), while maternal injection of T cells primed to an irrelevant antigen (KLH) had no effect on neonatal immunity. Neonates fed per-orally with primed T lymphocytes early in lactation and prior to challenge were also rendered immune (34% and 44% of control values retained at 3 and 8 days post-challenge). A single dose of T. spiralis-primed T cells given to neonates in early lactation was sufficient to elicit a significant immune response in them at 2 weeks of age. These results support the hypothesis that cellular immunity mediated by antigen-specific T cells in milk can provide functional immune protection to the neonate against an intestinal pathogen.     

Development of cellular immune response of mice to infection with low doses of Trichinella spiralis, Trichinella britovi and Trichinella pseudospiralis larvae

The murine cellular immune response to the infection with ten larvae of encapsulating (Trichinella spiralis, Trichinella britovi) and non-encapsulating species (Trichinella pseudospiralis) was studied. Both T. spiralis and T. britovi stimulated the proliferation of splenic T and B lymphocytes during the intestinal phase of infection, but T. spiralis activated the proliferative response also at the muscle phase, particularly in B cells. Non-encapsulating T. pseudospiralis stimulated the proliferation of T and B cells only on day 10 post-infection (p.i.) and later at the muscle phase. The numbers of splenic CD4 and CD8 T cells of T. spiralis infected mice were significantly increased till day 10 p.i., i.e., at the intestinal phase, and then at the late muscle phase, on day 60 p.i. T. britovi infection increased the CD4 and CD8 T cell numbers only on day 30 p.i. Decreased numbers of CD4 and CD8 T cells after T. pseudospiralis infection suggest a suppression of cellular immunity. Both encapsulating Trichinella species induced the Th2 response (cytokines interleukin-5 (IL-5) and interleukin-10) at the intestinal phase and the Th2 dominant response at the advanced muscle phase. Interferon-γ (IFN-γ) production (Th1 type) started to increase with migrating newborn larvae from day 15 p.i. till the end of the experiment. IL-5 production was suppressed during the intestinal phase of T. pseudospiralis infection. The immune response to T. pseudospiralis was directed more to the Th1 response at the muscle phase, the high IFN-γ production was found on day 10 p.i. and it peaked on days 45 and 60 p.i.     

旋毛虫对不同肠炎模型小鼠脾脏淋巴细胞Th1/Th2水平的影响

目的：研究旋毛虫（T.spiralis）对肠炎小鼠［三硝基苯磺酸（TNBS）或唑酮（OXZ）诱导］脾脏淋巴细胞中Th1/Th2水平的影响。方法：雌性BALB/c小鼠,随机分为50%乙醇对照组、TNBS(OXZ)诱导肠炎模型组、预先感染T.spiralis后诱导TNBS(OXZ)模型组,每组小鼠取材时保证6只以上。对各组小鼠脾脏淋巴细胞进行分离,采用流式细胞术观察TNBS（OXZ）诱导肠炎模型组和预先感染T.spiralis后诱导TNBS（OXZ）模型组。造模后3 d和7 d脾脏淋巴细胞中Th1/Th2水平的变化。结果：与模型组相比,预先感染T.spiralis后诱导TNBS肠炎第3天脾脏Th1/Th2比值未见明显下降（P>0.05）,于第7天明显降低（P<0.05）。诱导OXZ肠炎模型后第3天及第7天小鼠脾脏Th1/Th2比值均明显低于T.spiralis干预组（P<0.05）。结论：针对TNBS 肠炎模型,T.spiralis可能是通过诱导Th2及Tr1型免疫反应抑制模型小鼠过度的Th1型免疫而起到良好的干预作用。在T.spiralis对OXZ模型小鼠的干预性研究中,并无T.spiralis感染诱发的Th2型炎症反应加重同样以Th2升高为主的OXZ模型小鼠的病情。     

Cellular immunity in Peyer''s patches of rats infected with Trichinella spiralis.

A rat model of Trichinella spiralis gut infection was used to observe the sequence of developing cellular immunity in Peyer's patches and other lymphoid tissues. Whereas cellular reactivity (lymphocyte blastogenesis) for worm antigens was evident in mesenteric lymph nodes draining the gastrointestinal tract within 3 days after infection, Peyer's patch lymphocytes developed maximal reactivity 2 to 3 weeks later at the same time as the spleen and other lymphoid tissues. Furthermore, the immune reactivity found in Peyer's patches was only transient. Thus, in this parasitic gut infection, the Peyer's patch lymphoid tissue does not appear to be the first site of cellular responsiveness but rather to acquire cellular reactivity only when other lymphoid elements in the infected host have also acquired similar antigen-induced reactivity.     

Differential modulation of lymphocyte proliferative responses and lymphokine secretion in mice during development of immunity to Chlamydia psittaci.

A murine model was utilized to study immune responses occurring during the period of acquisition of immunity to chlamydial infection. C3H (H-2k) mice were immunized by intramuscular injection of 5 x 10(3) viable Chlamydia psittaci elementary bodies (EBs) by a protocol which permits animals to survive an otherwise lethal intraperitoneal challenge 10 days later with the homologous chlamydial strain. Spleen cells assayed during the 10-day period of development to immunity showed depressed proliferative responses in vitro to the T-cell mitogen, concanavalin A, and also exhibited suppressor cell activity. Spleen cell mitogen responses returned to normal levels by 30 days postimmunization, concomitant with the detectable development in vitro of responses to chlamydia-specific antigen. In marked contrast to the reduced proliferative responses, mitogen-stimulated production of the T-cell-derived lymphokines interleukin-2 and gamma interferon by spleen cells from immunized animals was within the normal range at 10 days postimmunization, and supernatant fluids containing these products had both microbicidal and microbistatic effects on chlamydial organisms in vitro. These results demonstrate that independent regulation of T-cell proliferation and lymphokine production occurs in vivo as part of the development of an antigen-specific protective immune response. These results also suggest that such differential modulation of T-cell responses may contribute to the development of protective immunity to chlamydiae in mice, perhaps through limited T-cell clonal expansion coupled with early or preferential maturation of cytokine-secreting helper T cells.     

A comparative study of the immunohistological and serological response of intact and T cell-deprived mice to Trichinella spiralis.

Thymectomized, lethally irradiated CBA mice reconstituted with anti-theta-serum-treated bone-marrow cells (TxB) were infected with T. spiralis at the age of 11 weeks. Intact, age-matched T. spiralis infected and non-infected CBA mice served as controls. Sera were collected up to 26 days after infection and examined for the presence of total and class-specific antibodies by indirect immunoflourescence. Mesenteric lymph nodes, spleen and axillary lymph nodes were examined by conventional histopathology for the presence of pyroninophilic blast cells, plasma blasts and plasma cells. Immunoflourescence was applied to examine cells containing immunoglobulins of various classes. Antibodies against T. siralis were demonstrated both in intact and TxB mice from day 10 after infection onwards. The amount of antibodies was lower in the TxB than in the intact mice. This might indicate that besides thymus-dependent, also thymus-independent antibodies against Trichinella are formed. No difference was observed in the thymus-independent areas of the lymphoid tissues from both intact and TxB mice, with the exception of a lower increase in number of IgM-containing cells in T cell-deprived mice. A marked increase in pyroninophilic blast cells was found in the thymus-dependent areas of the intact mice after infection, whereas only a very limited increase was observed in the T cell-deprived mice. The data were interpreted as supporting the thymus dependency of host response against Trichinella.     

Studies of macrophage function during Trichinella spiralis infection in mice.

Studies were made to investigate the quantitative and functional changes which occur in peritoneal macrophage populations obtained from mice infected orally with Trichinella spiralis larvae. C57BL/6 mice infected with T. spiralis larvae became parasitized with adult worms which were rejected from the intestine from 14 to 20 days after infection. Infected mice developed a striking increase in peritoneal exudate cells, composed largely of macrophages, which was maximal at from 16 to 18 days after infection. T. spiralis larvae and eosinophils were not seen in the peritoneal exudates. Macrophages from mice infected more than 11 days earlier inhibited DNA synthesis of syngeneic and allogeneic tumour cells, a property atributed to activated macrophages. In addition, macrophages from T. spiralis-infected mice had the functional ability to kill EL-4 tumour cells as measured by 51Cr release. Unlike activated macrophages, however, macrophages from infected mice did not develop the ability to inhibit multiplication of the intracellular pathogen Toxoplasma gondii. These studies demonstrate that T. spiralis infection in mice induces changes in macrophage function that differ from changes associated with infections by intracellular pathogens.     

L3T4-positive T lymphoblasts are responsible for transfer of immunity to Trichinella spiralis in mice

The characteristics of lymphocyte subpopulations involved in mediating immunity to the intestinal nematode Trichinella spiralis in vivo have been examined using adoptive transfer in conjunction with accurate cell-sorting and cell-depletion techniques. Positive selection of cell subsets, using FACS sorting and velocity sedimentation at unit gravity, confirm that rapidly dividing T blasts are the major population that mediates expulsion of the worm from the gut. Furthermore, cell-depletion studies demonstrated that the T-cell subset involved is of the L3T4 + ve Lyt 2-ve phenotype. This phenotype suggests class II MHC restriction in recognition of T. spiralis antigens by T cells in vivo. The roles that such T cells play in immunity to T. spiralis are discussed in terms of lymphokine release.     

旋毛虫成虫抗原和肌幼虫抗原保护性免疫的比较研究

目的:比较旋毛虫成虫抗原和肌幼虫抗原诱导小鼠产生保护性免疫效果的异同.方法:制备旋毛虫成虫抗原和肌幼虫抗原,分组免疫小鼠,并于末次免疫后10 d用旋毛虫感染性幼虫对各组小鼠实施攻击感染,检测攻击感染后各组小鼠肠道成虫和肌肉幼虫数并计算减虫率,同时采用ELISA法检测各组小鼠血清IgG抗体水平.结果:成虫抗原免疫组小鼠和肌幼虫抗原免疫组小鼠检获的肠道成虫数和肌幼虫数均显著少于对照组(P＜0.05),其中以成虫抗原免疫组小鼠减虫率最高(P＜0.01).成虫抗原免疫组和肌幼虫抗原免疫组小鼠于实施旋毛虫感染性幼虫进行攻击感染的当日所检测的血清IgG抗体水平与其免疫前相比均升高(P＜0.01,P＜0.05),与对照组相比亦升高(P＜0.01,P＜0.05),其中也以成虫抗原免疫组小鼠血清IgG抗体升高最为显著(P＜0.01).结论:旋毛虫成虫抗原和肌幼虫抗原均能激发小鼠产生保护性免疫,其中成虫抗原免疫组小鼠显示出更好的抗感染保护性.     

Genetic control of eosinophilia. Analysis of production and response to eosinophil-differentiating factor in strains of mice infected with Trichinella spiralis.

Bone marrow cultures were established from mice undergoing parasitic eosinophilia after infection with Trichinella spiralis. In the presence of eosinophil-differentiation factor (EDF/IL-5) eosinophil precursor cells differentiated and could be identified and counted after a 7-day in vitro culture period. The EDF-bone marrow assay system was used to determine differences in bone marrow eosinophil precursor capacity between a number of inbred strains of mice. Bone marrow cultures from high peripheral eosinophil-response phenotype strains of mice (NIH, SWR & SJL) contained significantly greater numbers of eosinophil precursor cells than the low response strain C57BL/10. All congenic strains of mice with the B10 background, i.e. C57BL/10, B10.S, B10.BR and B10.G were found to have low eosinophil precursor capacity. Bone marrow cultures obtained from F1 hybrids (NIH x C57/BL10, SJL x C57/BL10 and SWR x C57BL/10) demonstrated high precursor numbers, indicating that low responsiveness is inherited as a recessive characteristic. When spleen cells from T. spiralis-infected, high and low responder strains of mice were stimulated in vitro with concanavalin A (Con A) or with parasite antigen, it was found that low responder phenotype strains produced quantities of two eosinophilopoietic lymphokines EDF and IL3, which were similar to, if not greater than high responder strains. This suggests that bone marrow precursor capacity and not T cell lymphokine release is an important limiting factor in determining strain-dependent eosinophilia.     

Depression of cell-mediated immunity following inoculation of Trichinella spiralis extract in the mouse.

Mice pretreated with Trichinella spiralis extract (TsE), or infected with the parasite, rejected primary skin allografts in 18-23 days and secondary allografts in 12-16 days. Mice pretreated with saline or with bovine serum albumin (BSA) rejected the primary allografts in 12-18 days and did not accept the secondary grafts. Inoculation of increasing doses of parental spleen cells from mice pretreated with saline or with BSA in F1 hybrids produced proportionately stronger graft-versus-host reactions (GvHR) whereas increasing doses of cells from TsE pretreated mice reduced proportionately the capacity of the inoculum to induce a GvHR. Immunodepression of the parental cells was obtained with 7 and with 4, but not with 2, daily injections of TsE. The depression waned rapidly after the treatment with TsE but a significant degree still remained after 3 days. Immunodepression by TsE cannot be solely explained by antigenic competition and although our results are consistent with the induction of suppressor cells, it is probable that other mechanisms are also involved.     

A single gene determines rapid expulsion of Trichinella spiralis in mice.

In rats and some inbred mouse strains, one immune response, rapid expulsion, confers up to 95% protection against a challenge infection with Trichinella spiralis. Strain analysis in mice has shown that only three inbred strains, all originating from Swiss-line mice at the National Institutes of Health, Bethesda, Md., express rapid expulsion. Crosses between responder strain mice (NFR/N) and nonresponders (C3H/HeJ or B10 X BR) have indicated that rapid expulsion is dominant and autosomal (Bell et al., Exp. Parasitol. 53:301-314, 1982). In this study a segregation analysis of rapid expulsion in the F2 and backcross conformed to the Mendelian ratios expected of a single gene. This gene was not linked to the major histocompatibility complex (MHC) (chromosome 17) or the gene for albinism (c/c locus on chromosome 7). This locus has not previously been identified as conferring resistance to any infectious agent, and we have therefore designated the gene Ihe-1 (intestinal helminth expulsion 1).     

Effect of Trichinella spiralis infection on passive cutaneous anaphylaxis in mice.

Infection of CFW mice with Trichinella spiralis induced a state of relative unresponsiveness to passive cutaneous anaphylaxis (PCA) induced with hen egg albumin and its corresponding antibodies. The unresponsiveness was to PCA produced either with immunoglobulin G1 (IgG1) or IgE type of antibodies, but was more pronounced with the latter. As few as 25 larvae given by stomach tube 20 days before induced this resistance, although 400 larvae induced a greater resistance. When 400 to 600 larvae were fed to mice, the refractoriness of these mice to PCA was noticed 15 days later. The sera of infected mice had the ability to inhibit mainly PCA induced by IgE. This inhibitory property of sera from infected mice was more pronounced 35 days after infection than 10 months later, when only weak inhibitory activity was detected. Purified rat IgE inhibited the PCA reactions induced in both mice and rats with mouse IgE-type antibody. At high concentrations, evidence of inhibition of the IgG1-induced PCA in mice was also obtained. We believe that the relative unresponsiveness of infected mice is due to an increase in production of IgE which competitively blocks the mast cell sites for other IgE molecules.