Influence of <Emphasis Type="Italic">Echinococcus multilocularis</Emphasis> infection on immune response of mice and their offspring

Parasitic infection during pregnancy represents a serious stress factor and affects the course of pregnancy and the foeto-maternal relationship. The infection may not clinically manifest itself, however it can modulate the immune response of the offspring for a long-time. The influence of secondary Echinococcus multilocularis infection on the proportion of CD4+ and CD8+ T cells and the level of anti-Echinococcus antibodies were studied in Balb/c mice. The female mice were infected with homogenised metacestode material containing 2000 E. multilocularis protoscoleces (Group 1, 2). Group 1 was fertilised on day 60 post infection, while Group 2 remained unfertilised. Group 3 was uninfected and fertilised on the same day as Group 1. The numbers of both T cell subpopulations were higher in non-pregnant than in pregnant mice. In late pregnancy, the decline of CD4+, however, the increase of CD8+ T-cell subtypes were observed in both, infected and uninfected mothers, respectively. The strong humoral response with the high production of IgM and IgG2b antibodies in infected mice was detected. In infected mothers, IgG2b level was higher than in infected nonpregnant mice during almost whole monitored period. In Group 1, delivery caused suppression of Th2 immune response, represented by IgG1, under the level observed in uninfected mothers. The findings show the changes in helper regulatory and cytotoxic immunity mechanisms of infected mothers. In offspring of infected mothers all IgG subclasses were detected, however specific IgM were not transmitted neither transplacentary, nor transmammary.     

IgG antibody responses in mice coinfected with Toxocara canis and other helminths or protozoan parasites

The immune response expressed by IgG antibodies in BALB/c mice experimentally infected with Toxocara canis, was studied with the aim of verifying the possible in vivo cross-reactivity between antigens of T. canis and other parasites (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis and Toxoplasma gondii). Experiments included three groups of mice: one infected only by T. canis, another with one of the other species of parasites and a third concomitantly infected with T. canis and the other species in question. Animals were bled by orbital plexus at 23, 38 and 70 days post infection (p.i.). Sera were analyzed for anti-Toxocara antibodies by ELISA and Immunoblotting, using excretion-secretion antigens (ES), obtained from culture of third-stage larvae of T. canis. For all experiments a control group comprised by ten non-infected mice was used. Only in the case of A. suum infection, in these experimental conditions, the occurrence of cross-reactivity with T. canis was observed. However, in the case of co-infection of T. canis - S. mansoni, T. canis - S. venezuelensis and T. canis - T. crassiceps the production of anti-Toxocara antibodies was found at levels significantly lower than those found in mice infected with T. canis only. Co-infection with S. mansoni or S. venezuelensis showed lower mortality rates compared to what occurred in the animals with single infections. Results obtained in mice infected with T. canis and T. gondii showed significant differences between the mean levels of the optical densities of animals infected with T. canis and concomitantly infected with the protozoan only in the 23rd day p.i.     

Proinflammatory and anti-inflammatory cytokines in pregnant women chronically infected with Trypanosoma cruzi

Mother-to-child transmission of intracellular parasites could be related to the production of immunoregulatory cytokines. The levels of gamma interferon (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and lnterleukin (IL)-10 were evaluated during pregnancy in sera of women chronically infected with Trypanosoma cruzi that delivered infected or non-infected children. The levels of IL-10 increased in both, women only pregnant and only infected, compared to non-infected non-pregnant women. However, in pregnant women chronically infected with T. cruzi, IL-10 did not increase significantly, neither in the mothers of infected nor in the mothers of non-infected children. The levels of the inflammatory cytokine TNF-alpha were not affected in normal pregnancy but increased in the infected mothers of non-infected children. The levels of IFN-gamma did not increase in the groups studied, indicating that the production of this pro-inflammatory cytokine was controlled, even when the levels of IL-10 did not increase, as in pregnant women chronically infected with T. cruzi.     

Peripheral immune responses in pregnant cattle following Neospora caninum infection

Experimental infection of cattle with Neospora caninum in early gestation causes foetal death, but the foetus survives infection in late gestation. An immunological mechanism of abortion has been suggested; therefore changes in the maternal immune response during pregnancy could account for these differences. We have investigated the peripheral immune responses of pregnant cattle following an intravenous inoculation with 10(7) N. caninum tachyzoites in early and late gestation. Percentages of CD2+ and CD4+ T-cells in peripheral blood mononuclear cells (PBMC) increased 1-2 weeks after infection in both early (day 70) and late (day 210) gestation, and percentages of CD8+ T-cells increased 1-2 weeks after infection at day 70. Interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) mRNA expression in PBMC increased 1-2 weeks after infection at day 210 and IL-4 increased 1-2 weeks after infection at day 70. Immunomagnetic isolation of CD4+ cells from PBMC showed that they were a major source of IL-4 and IFN-gamma, and expression of both cytokines increased in CD4+ cells after infection in early and late gestation. These results suggest that CD4+ cells proliferate and express IL-4 and IFN-gamma in response to N. caninum irrespective of the stage of gestation when infection occurs.     

Immune responses to measles immunization and the impacts on HIV-infected children.

This prospective cohort study was conducted to determine the seroconversion rate and the pattern of antibody response to measles vaccine administered at age 9 months in HIV infected and non-infected children born to HIV-1 seropositive mothers. Thirty children born to HIV-1 seropositive mothers and 3 born to HIV-1 seronegative mothers were recruited. One single dose of Schwarz strain of measles virus vaccine (Rouvax) was given to every child at 9 months of age. Clinical status and measles antibody levels were evaluated at the time just before vaccination, 2 and 12 weeks post-vaccination. Antibody was measured by an enzyme immunoassay commercial kit (Enzygnost, Dade Behring Manufacturer, Germany). Children were classified into 3 groups, groups 1 and 2 were children with and without HIV infection respectively. Group 3 children were those born to HIV-1 seronegative mothers. Of the 33 enrolled children, 16, 14 and 3 were classified as groups 1, 2 and 3 respectively. Four children, 2 of each, in groups 1 and 3 did not complete the study. Group 3 was excluded due to the small number of children recruited. There was no short term complication and no measles infection noted during the course of study. None of the children had pre-existing antibodies. The median (range) of CD4 count and CD4/CD8 ratio measured at the time of vaccination were statistically different between groups 1 and 2 children. Group 2 children had better antibody response than group 1 in terms of seroconversion rate and median of antibody levels at 12 weeks post-vaccination. Only 7 of 29 children (24.1%) had detectable measles antibodies at 2 weeks post-vaccination. A decrease in antibody was noted in 2 symptomatic HIV infected children as their disease had progressed. Various potential predictors of measles vaccine responses in HIV infected children including CD4 count and CD4/CD8 ratio were not statistically different between the responders and non-responders. All 4 asymptomatic HIV infected children were responders. This study demonstrated that all of the children had already lost their maternal acquired antibodies at age 9 months. HIV infected children had a poorerantibody response to measles vaccine than the non-infected children.     

Role of gamma interferon and T cells in congenital Toxoplasma transmission

In the BALB/c mouse model, primary infection with Toxoplasma gondii during the second third of gestation leads to a high percentage of infected foetuses. However, immunity induced by infection contracted before pregnancy prevents parasites from crossing the placenta and completely protects the foetuses, as well as the pregnant women. In order to clarify the roles of CD4+, CD8+ T lymphocytes and IFN-gamma in this protection, pregnant BALB/c mice were treated with depleting monoclonal antibodies against CD4, CD8, IFN-gamma, or control antibody. Only the foetuses of the groups treated with anti-CD8 and anti-IFN-gamma antibodies developed congenital toxoplasmosis. The maternal production of IFN-gamma was depressed in the mice depleted of CD4 and CD8 cells (P < 0.001). Determination of the blood parasite load demonstrated that materno-foetal transmission of T. gondii correlates with maternal parasitaemia. Together, these results show that CD8+ T lymphocytes and IFN-gamma play an important role in protection against congenital toxoplasmosis during reinfection.     

Preconception helminth infection alters offspring microbiota and immune subsets in a mouse model

Both maternal microbiota and helminth infection may alter offspring immunity but the relationship between these is underexplored. We hypothesized that maternal helminth exposure prior to pregnancy has lasting consequences on offspring intestinal microbiota and consequent immunity. Female BALB/c adult mice were infected with 500L3 Nippostrongylus brasiliensis (N brasiliensis). Infection was cleared by ivermectin treatment, and mice were mated 3 weeks post-infection (NbM). Control mice were not infected but were exposed to ivermectin (NvM). We analysed maternal gut microbiota during pregnancy, breastmilk microbiota and offspring faecal microbiota and immunity 2 weeks after delivery. During pregnancy, NbM (Mothers previously infected with Nippostrongylus brasiliensis) displayed significantly altered stool bacterial communities (R² = .242; P = .001), with increased abundance of Enterococcaceae versus NvM (Naive mothers). Similarly, we observed a profound impact on breastmilk microbiota in NbM vs NvM. Moreover, NbM pups showed significantly altered gut microbial communities at 14 days of age versus those born to NvM with increased relative abundance of Coriobacteriaceae and Micrococcaceae. These changes were associated with alterations in pup immunity including increased frequencies and numbers of activated CD4 T cells (CD4 + CD44hi) in NbM offspring spleens. Taken together, we show that preconception helminth infections impact offspring immunity possibly through alteration of maternal and offspring microbiota.     

Seroprevalence and risk factors for canine toxocariasis by detection of specific IgG as a marker of infection in dogs from Salvador, Brazil

Toxocara canis is a highly prevalent worldwide canine nematode responsible for enzootic and zoonotic infections. It is considered to be one of the main agents of human visceral and ocular larva migrans. False negative diagnosis may occur because adult infected dogs with "dormant" larvae may have negative fecal test results since they usually do not shed parasite eggs in their stools. During pregnancy, the larvae become active and infect the offspring through the placenta. A serological test can distinguish infected animals, thus increasing the accuracy of the diagnosis for epidemiological studies and prophylactic purposes. In the present work a serological investigation was carried out to study the risk factors for the acquisition of this infection in 301 dogs inhabiting the city of Salvador, northeast Brazil. A validated questionnaire was applied to the donors and caretakers to assess animal management practices. All dogs were submitted to clinical evaluation and blood collection. Serum samples were analyzed for IgG antibodies against excretory-secretory products of T. canis larvae, used as antigens, by indirect ELISA. The overall seroprevalence of anti-T. canis IgG antibodies was 82.7%. Risk factors for T. canis infection included sex, area of origin within the city, homemade leftover food intake, failure to receive regular vaccination against infectious diseases and lack of preventive anti-helminthic treatment. Most of these risk factors suggest a lack of veterinary care and poverty. The high frequency of seropositivity found for toxocariasis in dogs suggests that results based on parasitological fecal examination could underestimate the actual prevalence of the infection.     

先天性感染日本血吸虫家兔攻击感染后血清抗体动态的进一步研究

目的运用日本血吸虫成虫抗原和虫卵抗原检测日本血吸虫先天性感染仔兔攻击感染后的血清特异性IgG、IgM抗体并观察其动态变化,探讨仔兔先天性感染后的体液免疫应答.方法10只怀孕晚期母兔分为三组:4只孕兔人工感染700条日本血吸虫尾蚴/只,所产仔兔为先天性感染组(G1);3只孕兔人工感染700条日本血吸虫尾蚴/只,所产仔兔于出生后第55天攻击感染20条尾蚴/只,该组仔兔为先天性感染且攻击感染组(G2);3只孕兔不感染,正常分娩的健康同龄仔兔感染20条尾蚴/只作对照C组.三组仔兔分别于出生后第53、67、81、95天采血收集血清,分别运用AWA-ELISA及SEA-ELISA法检测血清特异性IgG、IgM抗体,观察动态变化.结果仔兔先天性感染率为66.7%(10/15);G2组和G1组10只先天性感染仔兔相比较,血清特异性IgG、IgM抗体动态规律均比较接近,无论是AWA-ELISA还是SEA-ELISA检测,出生后第95天仔兔IgG、IgM抗体0D均值在两组间差异均没有显著性(P＞0.05);对照组仔兔血清IgG、IgM出生后第95天检测几乎全部呈阳性,抗体阳性仔兔数明显多于同期G1、G2组,且0D均值也显著高于同期G1、G2组(P＜0.05).结论先天性感染日本血吸虫的仔兔血清抗体呈低免疫反应状态(hypo-responsiveness),可能存在免疫耐受,攻击性感染不能诱导仔兔免疫系统产生明显的保护性免疫.     

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.     

In vivo inhibition of inducible nitric oxide synthase decreases lung injury induced by Toxocara canis in experimentally infected rats

The direct effect of nitric oxide (NO) on the viability of Toxocara canis larvae was studied. We observed that the nitric oxide donors, SIN-1 and SNOG, exert no cytotoxic effect on the in vitro viability of T. canis larvae. In addition, we developed a model in rats to elucidate the role of NO during T. canis infection. We evaluated different indicators in four experimental groups: morphological parameters, the total number cells and cell types recovered, nitrite and protein concentration, lactate dehydrogenase and alkaline phosphatase enzymatic activity in the bronchoalveolar lavage fluid, lung index and detection of anti-T. canis specific antibodies. We observed significant differences between non-infected and infected groups. The infected animals treated with the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine were less damaged than infected, non-treated animals. Our results suggest that the in vivo inhibition of the synthesis of NO triggered by iNOS diminishes the deleterious effects of the parasite upon the host, especially the vascular alterations in the lungs. We could show that in vivo production of NO induced by infection with T. canis results in direct host damage. Thus, this induction may constitute an evasion/adaptation mechanism of the parasite.     

Immunological study of condylomata acuminata in men infected with the human immunodeficiency virus

As condylomata acuminata often persist in individuals infected with the human immunodeficiency virus (HIV), an immunohistological study of warts from infected men was undertaken to further knowledge about human papillomavirus persistence in this group. Using an indirect immunoperoxidase method and a panel of monoclonal antibodies, the phenotypes of cells were studied in cryostat sections of perianal or anal warts removed from 14 HIV-infected men (10 homosexual and 4 heterosexual) and from 16 non-infected men (10 homosexual and 6 heterosexual). Although the median numbers of CD1+, CD3+ and CD4+ cells per unit area were similar in each group of individuals, the number of CD8+ cells was significantly higher in HIV-infected homosexual men when compared with non-infected individuals and HIV-infected heterosexual men. The median CD4+ cell count in the peripheral blood was significantly higher in HIV-infected heterosexual men than in HIV-infected homosexual men (P less than 0.05). These findings may reflect differences in duration of HIV infection between the two groups. There was no significant difference in the proportion of cells expressing interleukin-2 receptors between HIV-infected and non-infected individuals. Natural killer (CD16+) cells were not identified in any of the condylomata.     

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.     

Maternal Immunity and Vaccination Influence Disease Severity in Progeny in a Novel Mast Cell-Deficient Mouse Model of Severe Dengue

Sub-neutralizing concentrations of antibodies in dengue infected patients is a major risk factor for the development of dengue hemorrhagic fever and dengue shock syndrome. Here, we describe a mouse model with a deficiency in mast cells (MCs) in addition to a deficiency in Type-I and II IFN receptors for studying dengue virus (DENV) infection. We used this model to understand the influence of MCs in a maternal antibody-dependent model of severe dengue, where offspring born to DENV-immune mothers are challenged with a heterologous DENV serotype. Mice lacking both MCs and IFN receptors were found susceptible to primary DENV infection and showed morbidity and mortality. When these mice were immunized, pups born to DENV-immune mothers were found to be protected for a longer duration from a heterologous DENV challenge. In the absence of MCs and type-I interferon signaling, IFN-γ was found to protect pups born to naïve mothers but had the opposite effect on pups born to DENV-immune mothers. Our results highlight the complex interactions between MCs and IFN-signaling in influencing the role of maternal antibodies in DENV-induced disease severity.     

Influence of Echinococcus multilocularis infection on reproduction and cellular immune response of mice

The influence of secondary Echinococcus multilocularis infection on reproduction and cellular immune response of mice was studied in BALB/c mice infected with 2000 E. multilocularis protoscoleces. Of the total infected mothers, 11·7% did not give birth and 10% of uninfected ones did not deliver. Both, healthy and infected mothers, produced on average 6–7 offspring per litter. The changes in production of seral IFN‐γ, TNF and IL‐10 did not significantly influence the course of gravidity. On the other hand, more intensive metacestode growth was observed after the delivery. This study confirmed the ability of host organism to adapt to severe damage caused by E. multilocularis, not only in normal conditions, but also during pregnancy.     

Evaluation of follow-up of therapy with fenbendazole incorporated into stabilized liposomes and immunomodulator glucan in mice infected with Toxocara canis larvae

Anthelmintic activity of benzimidazole carbamate anthelmintics is low against dormant Toxocara canis larvae during late infections in paratenic hosts. The present study was conducted to examine the efficacy of pure fenbendazole, or drug incorporated into sterically stabilized liposomes (SL-FBZ) administered to T. canis-infected mice alone and after its co-administration with the immunomodulator (1-->3)-beta-D-glucan against larvae localized in muscles and brains. Therapy with either drug forms (in total 250 mg/kg in 10 doses) commenced on day 28 post-infection (p.i.) and the efficacy of treatment, examined on day 30 after the last dose of drug, was the highest in groups of mice treated with SL-FBZ in combination with glucan (89.5+/-5.8% in the muscles, 66.1+/-8.1% in brains). During 56 days of follow-up after termination of therapy, serum levels of anti-TES IgG antibodies, circulating IgG-TES immune complexes (CIC) as well as IgG antibodies to the most immunogenic part of recombinant myosin antigen of T. canis larvae were investigated. In contrast to anti-TES IgG antibodies, levels of CIC and anti-myosin antibodies were in the linear correlation with the efficacy of treatments beginning from day 38 post-therapy. We also showed that the serum levels of CIC as well as anti-myosin IgG antibodies seem to be the suitable serological markers for the monitoring of progress in larval destruction and TES resorption from the tissues.     

Transplacental transfer of schistosomal circulating anodic antigens in cows

The present work investigated the transplacental passage of circulating anodic schistosome antigens (CAA) and the production of foetal antibodies in response to antigenic stimulation in Schistosoma mattheei infected cows. Three groups were available: six calves born to non-infected cows received colostrum from a pool from non-infected cows (group 1), six calves born to non-infected cows (group 2) and six calves born to infected cows (group 3) received colostrum from a pool from infected cows. Schistosoma-specific IgG1 antibody and CAA levels were measured in the colostrum pools, the sera collected from the cows, and the sera collected from the calves at birth, after intake of colostrum and at day 30. The specific IgG1 antibody levels were significantly higher in the sera from cows of group 3. In four cows of group 3 high CAA levels were detected. The specific IgG1 antibody levels were 0.646 and 0.176 OD for the infected and non-infected colostrum pool, respectively, and the CAA levels were 5667 and 2557 pg CAA/mL, respectively. At birth high levels of specific IgG1 antibody and CAA were detected in 4 calves of group 3; levels in the other two calves were negligible. After intake of colostrum, specific IgG1 antibody levels of group 1 increased slightly at day 1 to become again insignificant at day 30. In group 2 specific IgG1 antibody levels increased significantly between days 0 and 1, to decrease, although not significantly, at day 30. Finally, in group 3 the delta OD values increased at day 1 and remained high until day 30. After intake of colostrum the CAA level increased very slightly for groups 1 and 2 to become again undetectable at day 30. In group 3 a nonsignificant decrease in CAA levels was observed at day 1 followed by a further significant decrease to reach low levels at day 30. The suggested intrauterine antigenic stimulation may be important not only for generating immune responses to natural early infections, but also for enhancing the immunogenicity and efficacy of vaccines administered to newborns.     

Investigations of the development of immunity in the course of experimental murine toxocariasis

Mice were infected with Toxocara canis by an oral administration of embryonated eggs of the parasite, then they were killed between 1st and 8th week after infection to obtain sera and splenic lymphocytes. The lymphocytes were kept in culture medium for 3 to 6 days with either concanavalin A or excretory-secretory antigen of T. canis and assayed for proliferative responses. The obtained sera were examined for the presence of specific IgG and IgM antibodies. It was found that cell-mediated immunity was depressed for 3 weeks after infection and the first signs of the developing immunity were detected only at the 4th week of infection. Subsequently, the blastogenic responses increased reaching a level significantly higher when compared with those of the control cultures at 8th week of infection. Specific toxocaral IgG and IgM antibodies were first detected in the samples collected at the 4th week.     

细粒棘球蚴感染中国美利奴羊免疫指标的动态变化

目的检测分析绵羊感染细粒棘球蚴免疫指标的变化。方法用细粒棘球蚴对14只健康的中国美利奴羊在相同的条件下进行人工感染,在感染前7d(-7d)、感染当天(0d)、感染后7d、21d、30d、60d用流式细胞仪分析外周血中CD4+T、CD8+T、B淋巴细胞亚群的动态变化,同时检测血清中IgG、IgM、IgE、IFN-γ水平和粒细胞数量。结果进行人工感染的14只绵羊中有8只感染(感染组),6只未感染(未感染组);CD4+T细胞在攻虫后第7d、30d未感染组显著高于感染组(P<0.05)。CD8+T细胞和B淋巴细胞两组之间差异不显著(P>0.05);IgG和IgE水平在攻虫后第30d未感染组显著高于感染组(P<0.05)。IFN-γ水平在攻虫后第21d、30d未感染组显著高于感染组(P<0.05);淋巴细胞在攻虫后第21d(P<0.01)、30d(P<0.05)未感染组显著高于感染组。嗜中性粒细胞在攻虫后第21d感染组极显著高于未感染组(P<0.01)。结论中国美利奴羊感染细粒棘球绦蚴过程中,CD4+T细胞、IgG、IgE、IFN-γ和淋巴细胞水平升高可增强机体对细粒棘球蚴的抵抗力。     

Effects of Maternal Ethanol Consumption on the Subsequent Development of Immunity to Trichinella spiralis in Rat Neonates

The immune response of rat pups to the intestinal parasite Trichinella spiralis was studied to determine if maternal pre-and/or postnatal ethanol consumption affected neonatal immune responses. Female rats were fed ethanol-containing (36% of calories) or pair-fed control liquid diets and include groups that were maintained on ethanol as follows: group 1, from day 1 of pregnancy through weaning and whose pups were then placed on ethanol to sacrifice; group 2, from day 1 of pregnancy through lactation; group 3, from day 1 of pregnancy through pup delivery; and group 4, from day 1 of lactation through weaning. A parallel group of animals was pair-fed isocaloric control diet until sacrifice. The pups of all litters were immunized orally with 500 L₁ (T. spiralis) larva 5 days after weaning. To examine the effects of maternal ethanol on primary immune responses, one-fourth of the pups from each litter were sacrificed on days 10 and 20 after immunization. To examine the effects on neonatal secondary immune responses, the remaining pups were challenged with 1,000 larva 30 days after the initial immunization and sacrificed either 3 or 8 days after challenge. At the time of sacrifice, blood samples were collected, the intestine removed to determine T. spiralis worm burdens, and suspensions of mesenteric lymph node (MLN) cells prepared. Intestinal worm counts and serum levels of anti-T. spiralis IgM and IgG antibodies, interleukin-2 (IL-2), and tumor necrosis factor (TNF) were determined. In vitro proliferation responses of MLN cells to T. spiralis antigen and to the mitogen concanavalin A (Con A) were also examined. Pups from groups 1 to 3 demonstrated significantly higher intestinal worm counts (decreased immunity) than the pair-fed controls at the day 20 primary immune response sacrifice, and pups from group 1 had significantly higher worm counts at day 3 after a secondary immune challenge. Pups of dams from groups 1, 3, and 4 had significantly lower IgM antibody titers at the day 20 primary immune response sacrifice. All experimental ethanol groups (1 to 4) demonstrated significantly lower IgG antibody titers than that observed in pair-fed control pups at the 20-day sacrifice. IgM antibody titers showed significant reductions for ethanol-treated groups at 3 and 8 days after T. spiralis secondary challenge. In addition, IgG antibody titers were also significantly reduced for all alcohol groups at 3 and 8 days during the secondary immune response. Serum IL-2 and TNF levels were significantly lower in all experimental ethanol groups (1 to 4) relative to pair-fed controls at day 20 during a primary immune response, and IL-2 levels at 3 days postchallenge were lower in groups 2 to 4 after a secondary immune challenge. MLN proliferation responses to antigen and Con A were significantly reduced in ethanol groups 1 to 3 and to Con A in group 4 at day 10 after a primary immune challenge. Ethanol group 3 pups also demonstrated a reduced response to antigen at day 20. For animals undergoing a secondary immune response, ethanol group 2 demonstrated a reduced response to antigen at day 3, whereas groups 2 and 4 showed increased reactivity to antigen at days 3 and 8 postchallenge. These results show that maternal ethanol consumption diminishes the capacity of neonates to respond to T. spiralis antigen and that the depressed immune response involves T-and B-cell–mediated reactions and also affects the production of certain cytokines. These results also suggest that the diminished immune responses are increased with longer periods of maternal and neonatal exposure to ethanol.