Changes in the immune response of BALB/c mice coinfected with Heligmosomoides polygyrus and Trichinella spiralis

The influence of Heligmosomoides polygyrus on infection with Trichinella spiralis was studied in BALB/c mice. Mice coinfected with T. spiralis and previously given H. polygyrus harboured both nematode species till day 34. The number of T. spiralis muscle larvae was greater in mice coinfected with H. polygyrus/T. spiralis or T. spiralis/H. polygyrus than after infection with T. spiralis alone. Infection with H. polygyrus did not enhance eosinophil and IL-5 levels induced by T. spiralis. Additionally, the production of IgG1 specific to L1 T. spiralis was inhibited by co-infection. Changes in the levels of IFN-gamma and IgG2a implicated a disturbance in Th2 cell activation during protective response and resulted in the greater number of T. spiralis muscle larvae in coinfected mice.     

Lymphocyte, antibody and cytokine responses during concurrent infections between helminths that selectively promote T-helper-1 or T-helper-2 activity

The injuence of Trichinella spiralis on infections with Trichuris murk was studied in non-responder B10. BR mice. Mice infectedonly with T. muris were unable to expel parasites and had many adult worms 35 days later. Infection with 300 larvae of T. spiralis, given seven or 14 (but not 28) days after T. muris, enabled mice to expel up to 90% of T. muris; expulsion of T. spiralis was not altered. Concurrently infected mice produced less T. murisspecijic IgG2a antibody than mice infected with T. muris only, andshowed higher proliferative responses when spleen and mesenteric lymph node cells were cultured in vitro with T. murk antigens. When T. spiralis was present mucosal mast cells were generated in T. muris-infected mice, whereas almost no mast cells were seen with only T. muris. Lymphocytes from doubly-infected mice produced significantly more interleukin 4 and 5 (IL-4, IL-5) and significantly less interferon-gamma (IFN-y) when stimulated in vitro with Concanavalin A (Con-A) than cells from mice infected with T. murk only. These data demonstrate that BI0.BR mice, which in single infections produce a Thl response to T. muris and develop no protective immunity, can mount a protective T-helper-2 (Th2) response and expel T. murk when concurrently infected with the ‘Th2 inducing’ nematode T. spiralis.     

Leishmania infantum released proteins specifically regulate cytokine expression and production patterns by CD4+ and CD8+ T cells

Specific immune responses by CD4+ and CD8+ T cells, from two infected mice strains (BALB/c and C57BL/6), induced by High, Inter and Low protein fractions released by Leishmania infantum, were assessed through the evaluation of IL-12, IFN-gamma and IL-10 mRNA by real-time PCR and respective protein production by ELISA. During infection establishment, High and Inter fractions directed both mice strains T cells subsets to increase the production of IFN-gamma, associated to IL-12 release. Later on, parasite replication augmented in BALB/c and stabilised in C57BL/6 mice. Inter fraction induced CD4+ T cells to maintain IFN-gamma production, with the simultaneous release of IL-12 by both cell subsets in BALB/c mice and by CD8+ T cells in C57BL/6 mice. These observations suggested a prophylactic potential for Inter fraction which was able to induce Th1 response with IL-12 involvement, required for the maintenance of memory cells, in mice strains with different parasitic evolution.     

NK1.1+ cell depletion in vivo fails to prevent protection against infection with the murine nematode parasite Trichuris muris

Protection against the murine nematode parasite Trichuris muris has been shown to involve interleukin 4 (IL-4). NK1.1+ T cell receptor alphabeta+ cells, designated Natural Killer T (NKT) cells, produce a large amount of IL-4 in response to anti-CD3 stimulation and numerous pieces of evidence suggest that NKT cells provide the initial source of IL-4 for T helper 2 (Th2) priming. These observations allow the hypothesis that NKT cells produce a large amount of IL-4 in response to T. muris infection and augment Th2 responses and IL-4 production, thus achieving protection against T. muris. To investigate the involvement of NKT cells in protection against T. muris infection, NK1.1+ cell-depleted B10.BR mice were prepared by anti-NK1.1 monoclonal antibody injection. Efficient expulsion of T. muris worms occurred in NK1.1+ cell-depleted infected mice, and the expulsion kinetics of T. muris worms, the levels of IL-4 production by mesenteric lymph node cells, and the kinetics of the specific IgG1 and IgG2a responses to T. muris were similar to those in mouse IgG-treated or non-treated control B10.BR mice. These observations suggest that NK1.1+ cells and NKT cells are not involved in the induction of Th2 responses and protective immunity to T. muris infection.     

Protection in lambs vaccinated with Haemonchus contortus antigens is age related, and correlates with IgE rather than IgG1 antibody

The involvement of mucosal mast cells (MMC) in protection against infection with the murine nematode parasite Trichuris muris was studied in genetically mast cell-deficient WBB6F1-W/Wv mice and their normal littermates WBB6F1-+/+ mice. Expulsion of T. muris worms occurred in infected +/+ mice, whereas no worm expulsion was observed in infected W/Wv mice where the infection persisted until at least day 46 postinfection. No MMC responses were induced in either infected W/Wv or +/+ mice. Specific IgG1and IgG2a antibodies to T. muris excretory/secretory antigens were observed in infected W/Wv and +/+ mice, and antibody production showed similar kinetics. Interleukin 4 production by concanavalin A (Con A)-stimulated mesenteric lymph node cells (MLNC) was induced preferentially in infected +/+ mice. T. muris infection increased the levels of IFN-gamma produced by Con A-stimulated MLNC of infected W/Wv and +/+ mice, with the levels of IFN-gamma in infected W/Wv mice being higher than those in infected +/+ mice. Taken together, these results indicate that W/Wv and +/+ mice are susceptible and resistant to T. muris infection, respectively, and that MMC responses are not required for protective immunity.     

The role of CD8+ cells in the establishment and maintenance of a Trichuris muris infection

Chronic infection by the caecal-dwelling intestinal murine nematode Trichuris muris occurs if given as a high-dose infection to 'susceptible' AKR mice or as a low-dose infection to the normally 'resistant' C57BL/6 mouse strain. Both regimes result in a type 1 cytokine response, i.e. high levels of IFN-gamma and IL-12. Here we show this susceptible response is associated with a large population of CD8(+) IFN-gamma(+) cells within the mesenteric lymph nodes and numerous CD8(+) cells infiltrating the caecal mucosa. Despite this, the in vivo abolition of CD8(+) cells within AKR and C57BL/6 mice, either prior to infection or once infection has become established, failed to affect chronicity, implying that CD8(+) T cells are not essential for the initiation or maintenance of the susceptible response to T. muris. Interestingly, the percentage of IFN-gamma(+) CD4(+) cells increased in treated groups, perhaps in a compensatory role. The majority of antigen-specific cytokine responses were comparable in both treated and control groups, although IL-5 was fivefold higher in animals receiving anti-CD8 mAbs and IFN-gamma was also raised in treated mice. Mastocytosis was unaltered by CD8 depletion, however, paradoxically, eosinophilia within the caecum was reduced in treated mice. Together these data clearly demonstrate that CD8(+) T cells are associated with chronic T. muris infection; however, these cells are dispensable for both the early and late phases of this response, but do appear to play a role in the regulation of certain cytokines and caecal eosinophilia.     

Experimental canine leishmaniasis: evolution of infection following re-challenge with Leishmania infantum

The aim of the study was to assess the clinical, parasitological and immunological effect of a second inoculation of amastigotes in dogs previously inoculated with Leishmania infantum. Three dogs primarily inoculated with amastigotes (Group I) and four with cultured virulent stationary phase promastigotes (Group II) were afterwards re-inoculated with 2x10(9) amastigotes per kg. Three other groups of dogs were used as controls: Group III was infected only once with amastigotes, Group IV only once with promastigotes and Group V was non infected. The animals were followed up by clinical and parasitological examinations, hematological and serum protein analysis, anti-leishmanial antibody levels and proliferative assays of specific peripheral blood mononuclear cells over a period up to 50 months. Parasites were isolated from lymph node of three animals during primary amastigote infection and in five animals (Group I and II) after re-challenge. Group I dogs presented a strong increase of the humoral immune response while Group II animals displayed no significant or significantly low antileishmanial antibodies titres, after re-challenge. The detection, only after challenge, of positive specific lymphoproliferation in two animals of Group II that had the longest primary infection interval (more than 26 months), indicates the requirement of a long time interval to obtain specific lymphocyte sensitization. A previous exposure to virulent cultured L. infantum promastigotes seems to confer some degree of resistance against an amastigote infection.     

Comparison of immune responses of Schistosoma mansoni-infected mice with distinct chronic forms of the disease

BACKGROUND: Schistosoma mansoni-infected mice tend to present with either one of two different hepatic pathological patterns during chronic infection: periportal fibrosis (PF) with portal concentration of periovular granulomas and fibrosis or isolated granulomas (IG), with scattered periovular granulomas within the liver. These are models for the two clinical presentations of schistosomiasis, the severe hepatosplenic and the mild intestinal forms. In the present work, we examined the relationship between the development of these histopathological aspects and immunological markers in S. mansoni-infected mice. Although BALB/c mice with PF and IG had similar egg numbers in the liver, PF mice had higher liver collagen contents than mice with IG. Cultured spleen cells from mice with PF and IG had similar proliferation 20 and 40 weeks after S. mansoni infection upon stimulation with parasite egg antigen (SEA) or mitogen (Con A). Production of IL-4 upon SEA stimulation was higher in cell cultures from mice with PF, whereas IL-5 and IFN-gamma levels were not statistically different between PF and IG groups. Mice with IG had similar serum concentrations of total IgE and anti-SEA IgG1, IgG2a, IgG2b and IgG3 compared to sera from PF mice. Levels of IgG1 and IgG2a antibodies were the highest and the lowest detected, respectively. In conclusion, isogenic BALB/c mice infected with S. mansoni that develop periportal fibrosis or isolated granulomas have similar immunological patterns despite the two pathologic forms of schistosomal liver fibrosis.     

Modulation of cytokine production and response phenotypes in murine trichuriasis

BALB/K mice are usually resistant to infection with the intestinal nematode parasite Trichuris muris and exhibit a Th2 dominated (IL-5, IL-9) response. Conversely in B10.BR mice, which are unable to expel T. muris, Th1 type (IFN-gamma producing) cells predominate. We have manipulated the course of infection in these two strains of mice such that the period of host-parasite contact is extended in the former and curtailed in the latter. Extension of host-parasite contact in BALB/K mice beyond normal (day 21) resulted in the modulation of cytokines produced by in vitro concanavalin A (Con-A) stimulated MLNC away from IL-5 and IL-9 (Th2-type cytokines) in favour of the Th1-type cytokine IFN-gamma. Curtailment of host parasite contact in B10.BR mice to less than 21 days resulted in elevated production of IL-5 and IL-9 by MLNC in the absence of elevated IFN-gamma levels. Thus modulation of expulsion phenotype also modulates cytokine production by T-cells in the MLN draining the site of infection, with a Th2 response being associated with resistance and a Th1 type response with the inability to expel the parasite. Mechanisms by which the modulated cytokine profiles arise are discussed.     

Comparative dynamics and phenotype of the murine immune response to Trichinella spiralis and Trichinella pseudospiralis

Infection of NIH mice with Trichinella spiralis and Trichinella pseudospiralis results in qualitatively comparable immune responses. Antigen-specific proliferation by mesenteric lymph node cells was transient and temporally associated with intestinal infection, but in contrast was sustained throughout infection by splenocytes. Early cytokine production by mesenteric lymph node cells was dominated by interleukin 10, but also IL-5 and IL-4, with rapid resolution following parasite expulsion from the gut. Splenocytes showed a mixed profile of cytokine production, although again dominated by IL-10 and sustained over 60 days of infection. All antibody classes were evident, with early production of IgA and IgG1, and subsequent secretion of other subclasses including IgG2a. Granulocytic infiltration of the spleen was significantly greater in T. spiralis infection. The concentration of serum corticosterone generally remained within normal boundaries, although was raised by day 60 in T. spiralis-infected mice. We conclude that the systemic suppression of inflammation reported for T. pseudospiralis does not result from selective induction of regulatory cytokines, or a major difference in the immune response to infection with T. spiralis.     

Comparative studies on immune responses to infection in susceptible B10.BR mice infected with different strains of the murine nematode parasite Trichuris muris

A comparison of immune responses to infection between groups of B10.BR mice infected with different strains of T. muris , S strain (isolated in Sobreda, Portugal), E strain (isolated in Edinburgh), and E-J strain (originally E strain, which has been maintained in our laboratory, Japan), was performed. In mice infected with E and E-J strains, most of the worms were expelled by day 32 after infection, though the expulsion was faster in E-J strain-infected mice. In contrast, no expulsion was observed in S strain-infected mice by day 32 and egg production occurred on day 32. IL-4 production occurred in concanavalin A (Con-A)-stimulated mesenteric lymph node cells (MLNC) from B10.BR mice infected with E and E-J strains, whereas no IL-4 production was observed in S strain-infected mice. IL-4 production did not occur in normal mice. In comparison with normal mice, high levels of IFN-γ production by Con A-stimulated MLNC were detected in mice infected with every strain of  T. muris . IFN-γ production in S strain-infected mice was greater, occurred earlier and was more persistent than in mice infected with E and E-J strains. IgG1 and IgG2a antibodies to T. muris excretory/secretory antigens were observed in B10.BR mice infected with every strain of T. muris . Antibody production showed similar kinetics. These differences in the expulsion kinetics and IL-4 production in B10.BR mice infected with S, E, and E-J strains suggest the involvement of IL-4 in protection against T. muris infection, and confirm the previous conclusion by Else et al . (1994).     

Giardiasis in mice: analysis of humoral and cellular immune responses to Giardia muris

Summary Humoral and cellular immune responses have been evaluated in two inbred strains of mice which differ markedly in their susceptibility to infection with Giardia muris. Serum IgG and IgA antibody levels and IgA levels in intestinal washes were determined by a solid-phase radioimmunoassay using G. muris antigen prepared by sonication of trophozoites, while cell-mediated immunity was assessed by a radiometric ear-assay for delayed-type hypersensitivity. Following infection of BALB/c mice (resistant) and C3H/He mice (susceptible), the IgG and IgA antibody levels in serum progressively increased over the period of study with C3H/He mice having significantly higher titres of IgA antibodies than BALB/c late in the infection. Systemic immunization with G. muris trophozoites resulted in high titres of IgG antibodies in the serum. IgA antibodies were detected in intestinal washes 2 weeks after infection with a subsequent fall in levels in BALB/c mice but a progressive increase in levels in C3H/He mice. Prior immunization resulted in IgA antibodies being detected earlier in the intestinal washings after a challenge infection. Delayed-type hypersensitivity to G. muris antigens could not be detected during an infection but a positive response was elicited following antigen priming in mice pretreated with cyclophosphamide. The immune responses evaluated in this study were assessed using a whole G. muris trophozoite sonicate and variations in the quantitative aspects of the responses did not account for observed differences in the course of infection in the two strains of mice.     

The influence of the procedure of excretory-secretory L1 trichinella spiralis antigen preparation on the efficiency of an ELISA test in pigs

BACKGROUND: Trichinellosis is a parasitic zoonosis transmitted to humans by consumption of raw or undercooked meat from animals infected by worms of the Trichinella genus. Every year seropositive cases are found among the human population and thus trichinellosis still remains an epidemiologically important disease in Poland. The usefulness of ELISA for anti-T. spiralis IgG detection in pigs is still limited by the nature of antigen. The objective in the present study was to compare the usefulness of excretory-secretory antigens of L1 T. spiralis for the serological detection of IgG antibodies in pigs. MATERIAL AND METHODS: The antigens were prepared in different laboratories: Ag ES L1 T. spiralis (N) in Germany, Ag ES L1 T. spiralis (W) in Italy and Ag ES L1 T. spiralis in Poland. Conventional, Iberian pigs were infected with 200, 1000 and 20 000 muscle larvae of T. spiralis. Serum samples were obtained at 5 and 1 dbi (day before infection), and 5, 10, 15, 20, 25, 30, 40, 50, 60 dpi (day post infection) and screened for specific IgG antibodies to excretory-secretory L1 T. spiralis antigens. Serum samples were obtained from the EU project TRICHIPORSE. The cut-off value of ELISA was determined on serum samples from 248 Trichinella-free pigs from Poznaii and Boza Wola, that were examined by artificial digestion. RESULTS: In pigs infected with 200 L1 T. spiralis larvae, specific IgG were detectable from 50 dpi, when the Ag ES L1 T. spiralis (N) was used, whereas when Ag ES L1 T. spiralis (W) and Ag ES L1 T. spiralis were used, the specific IgG were detectable from 40 dpi. In pigs infected with 1000 LI T. spiralis larvae, specific IgG was observed from 30 dpi when Ag ES L1 T. spiralis (W) and Ag ES L1 T. spiralis were used, but when Ag ES L1 T. spiralis (N) was used specific IgG were detectable from 40 dpi. In the group infected with the highest dose of T. spiralis larvae, specific IgG were detectable from 30 dpi when Ag ES L1 T. spiralis (N) and Ag ES L1 T. spiralis (W) were used, whereas when Ag ES L1 T. spiralis was used specific IgG were detectable from 20 dpi. The results strongly indicated that in the examined pigs, the specific IgG response against T. spiralis infection is dose dependent. Furthermore, it was shown that the high infectious dose induced earlier increasing of specific IgG response. Statistical analysis revealed a significant positive correlation between OD values obtained in procedures based on the three antigens. The results were statistically repeatable for procedures and for single pigs (P<0.01).     

Specific lgG1 and lgG2 antibody responses of dogs to Leishmania infantum and other parasites

Sera from dogs naturally infected with Leishmania infantum were analysed for the IgG subclass specificity of their antibody response by ELISA. Dogs infected with L. infantum produced both IgGl and IgG2 antibodies with IgG2 being associated with asymptomatic infections and IgGl being associated with disease (symptomatic dogs, non- or low-responsive to chemotherapy). The differential responses of IgG] and IgGl serum antibodies in asymptomatic and symptomatic dogs may indicate a dichotomous immune response to infection with L. infantum. To confirm this, on a broader scale, sera from dogs naturally exposed to an asymptomatic protozoan infection, Toxoplasma gondii, were also analysed as were sera from dogs exposed to the helminths, Dirofilaria immitis and Toxocara canis. Antibodies specific for T. gondii antigen detected in sera from 17 dogs were of the IgG2 subclass only. Both IgGl and IgG2 antibodies to D. immitis andl. canis were present in the sera of naturally infected dogs but IgGl appeared to be the predominant subclass. Furthermore, in dogs experimentally infected with T. canis, selective regulation ofIgG2 and IgGl responses was apparent since production of the two subclasses occurred at different times following infection, with IgGl levels declining as IgGl levels rose. Thus, the analysis of IgG subsets in parasitized dogs provides evidence of a dichotomous response to infection: IgGl is associated with asymptomatic protozoan infections and IgGl is associated with helminth infections and disease caused by protozoan infection.     

小鼠实验感染不同种旋毛虫后血清IgG抗体水平的变化

目的观察小鼠感染不同种旋毛虫后血清IgG抗体水平的变化。方法将50只小鼠随机分成5组（每组10只），分别感染旋毛虫（T1）、乡土旋毛虫（T2）、布氏旋毛虫（T3）、伪旋毛虫（T4）及纳氏旋毛虫（T7），每只感染300条幼虫，感染后1～6周每周尾部静脉采血，6周后每2周尾部静脉采血，至感染后20周，用旋毛虫肌幼虫ES抗原ELISA检测血清中抗旋毛虫IgG抗体水平。结果小鼠感染旋毛虫、乡土旋毛虫、布氏旋毛虫及纳氏旋毛虫后3～5周，血清IgG抗体水平快速升高，至感染后第8周达高峰，此后旋毛虫和乡土旋毛虫感染小鼠的血清IgG抗体水平缓慢下降，布氏旋毛虫及纳氏旋毛虫感染小鼠的血清IgG抗体水平迅速下降；小鼠感染伪旋毛虫后3～5周血清IgG抗体水平快速升高，至第16周达高峰，之后缓慢下降。5种旋毛虫感染小鼠的血清IgG抗体水平差异具有显著性（P〈0．05）。结论5种旋毛虫感染小鼠的血清IgG抗体水平和动态变化不同；旋毛虫肌幼虫ES抗原可用于其他4种旋毛虫（乡土旋毛虫、布氏旋毛虫、伪旋毛虫、纳氏旋毛虫）感染的血清学诊断及流行病学调查。     

The role of TNF-alpha in Trichuris muris infection I: influence of TNF-alpha receptor usage, gender and IL-13

Th1 and Th2 responses to the gut-dwelling nematode Trichuris muris have been well established in mouse models of infection, with Th2 responses clearly playing an important role in resistance. TNF-alpha has previously been shown to play an undefined role in resistance, although it is not a typical Th2 cytokine. However, the relative importance of the two TNF-alpha receptors, p55 and p75, has not previously been investigated. We demonstrate that p55 is the dominant TNF-alpha receptor during T. muris infection as p55-/- mice are more susceptible to infection than p75-/- mice. Moreover, p75 clearly plays a role in negatively regulating TNF-alpha. We also demonstrate that a gender difference influences the immune response of p55-/- and p75-/- mice in response to T. muris infection, with female mice fully expelling by day 35 post-infection (p.i.) and male mice harbouring chronic infections. Further, this gender difference can be reversed with recombinant IL-13 (rIL-13) in male gene-deficient mice or IL-13R2.Fc treatment in female gene-deficient mice.     

Antigenic cross-reactivity between the human whipworm, Trichuris trichiura, and the mouse trichuroids Trichuris muris and Trichinella spiralis

Cross-reactivity was demonstrated between circulating antibodies from Trichuris trichiura-infected humans and T. muris-infected mice for heterologous antigen preparations. Mouse immune sera raised against excretory/secretory (E/S) products and anterior end homogenate from adult T. muris showed marked affinity for T. trichiura adult homogenate in ELISA, and 35S-methionine-labelled adult T. muris E/S products were precipitated by T. trichiura infection sera. Monoclonal antibodies recognizing a 48 kD Trichinella spiralis muscle larval beta-stichocyte granule antigen also showed avidity for T. trichiura adult homogenate in ELISA, as did serum from mice with patent T. muris worm burdens. This cross-reactivity is thought to result from shared stichocyte antigens and the relevance of this observation is discussed.     

Cytokines and antibody responses during Trypanosoma congolense infections in two inbred mouse strains that differ in resistance

We studied IL-4, IL-10 and IFN-gamma secretion by splenocytes and the plasma levels of different isotypes of antibodies against various antigens of Trypanosoma congolense in highly susceptible BALB/c and relatively resistant C57BL/6 mice during the early course of infection with T. congolense. The patterns of appearance of cytokine spotforming cells in the spleens were essentially similar in the two mouse strains although higher numbers were detected in the spleens of BALB/c than C57BL/6 mice on some days post-infection. However, the amount of IL-4, IL-10 and IFN-gamma secreted into the culture fluids was dramatically different. From day 4 forward, splenocytes from BALB/c mice secreted very high levels of these cytokines. In contrast, splenocytes from infected C57BL/6 mice did not secrete detectable levels of IL-4 throughout the period tested. The secretion of IL-10 and IFN-gamma by C57BL/6 splenocytes only became appreciable on day 6 and was down-regulated by day 8, when the first wave of parasitaemia was being controlled. At days 6-8, splenocytes from infected C57BL/6 mice secreted two-fold higher amounts of IL-12 p40 than those from BALB/c mice. Infected BALB/c mice mounted an earlier IgM antibody response to variant surface glycoprotein (VSG), formalin-fixed T. congolense and whole T. congolense lysates than did infected C57BL/6 mice. However, they failed to make any detectable IgG3 and IgG2a antibody responses to these antigens whereas infected C57BL/6 mice made strong IgG3 and IgG2a responses. We speculate that enhanced resistance against T. congolense infections in mice may be mediated by IL-12 dependent synthesis of IgG2 antibodies to VSG and possibly also common trypanosomal antigens.     

旋毛虫感染小鼠IgG、IL-2和T淋巴细胞亚群动态变化的观察

目的　了解小鼠感染旋毛虫后 Ig G抗体水平、IL - 2分泌量和 T淋巴细胞亚群的动态变化。方法　分别于旋毛虫感染后第 7、14、2 1、2 8和 35天 ,采用 EL ISA方法检测血清特异性 Ig G抗体水平和 IL- 2含量 ,采用流式细胞仪检测 CD4+、CD8+T细胞百分率。结果　 Ig G抗体水平在感染后逐渐上升 ,感杂后 35天达最高值 ;T淋巴细胞的变化表现为 CD4+T细胞减少、CD8+T细胞增多 ,CD4+/ CD8+细胞比值下降 ,以感染后第 14天最为显著 ,直到感染后第 35天仍未见恢复。IL - 2分泌量以感染后第 7天达高峰 ,然后迅速下降 ,到感染后第 35天低于正常组。讨论　旋毛虫感染的急性期 ,小鼠出现免疫抑制现象。抗旋毛虫感染的保护性免疫是由细胞免疫与体液免疫协同完成的。     

Nutrition, immunity and helminth infection: effect of dietary protein on the dynamics of the primary antibody response to Trichuris muris (Nematoda) in CBA/Ca mice

The effect of dietary protein on the specific antibody responses (total immunoglobulins, IgG1 and IgA) to the intestinal nematode Trichuris muris was studied in CBA/Ca mice fed isocaloric diets containing 16% or 4% protein. Mice fed the 16% diet and given a high infection dose of 650 eggs expelled almost their entire primary infection by day 21 post infection. In similarly infected animals fed the 4% protein diet, there was prolonged survival of adult worms. At a low infection dose of 10 eggs, there was no evidence of an expulsion response in either dietary group. The primary antibody response to parasite excretory/secretory (E/S) antigen was time-dependent, regardless of dietary protein or infection dose, and was predominantly an IgG1 response. Within each dietary group, antibody production and antigen recognition occurred earlier and the antibody responses were more intense in mice given the higher infection dose. The principal finding was that the specific antibody response was more vigorous, both quantitatively (serum titres) and qualitatively (antigen recognition by IgG1), in mice on a low protein diet, even though worm expulsion did not occur in these hosts. This result suggests that serum antibody level or antigen recognition is not related simply to protective immunity against T. muris in CBA/Ca mice.