Schistosoma mansoni. Anti-egg monoclonal antibodies protect against cercarial challenge in vivo.

Monoclonal antibodies that bind to surface membranes of developing schistosomula and/or cercarial tails were generated from mice immunized with living schistosome eggs or soluble egg antigen. These monoclonal antibodies detected at least three different surface epitopes. One surface antigen detected by anti-egg monoclonal antibody EG1C4B1 (E.1) persisted on the surface of developing schistosomula for 96 h posttransformation . The same or a cross-reactive antigen was also detected on the surfaces of S. japonicum and S. haematobium schistosomula and cercarial tails. Monoclonal antibody E.1 killed schistosomula in vitro as well or better than infected mouse sera and transferred immunity to naive mice when administered in vivo. The monoclonal antibody reduced the number of lung worms recoverable on day 4 postchallenge by up to 85% and reduced the adult worm burden up to 41% as compared with controls. The data also show that the molecular weights of the egg antigens detected by monoclonal antibody E.1 were different from those detected on schistosomula.

Neurochemical and neuroinflammatory perturbations in two Gulf War Illness models: Modulation by the immunotherapeutic LNFPIII.

Gulf War Illness (GWI) manifests a multitude of symptoms, including neurological and immunological, and approximately a third of the 1990-1991 Gulf War (GW) veterans suffer from it. This study sought to characterize the acute neurochemical (monoamine) and neuroinflammatory profiles of two established GWI animal models and examine the potential modulatory effects of the novel immunotherapeutic Lacto-N-fucopentaose III (LNFPIII). In Model 1, male C57BL/6 J mice were treated for 10 days with pyridostigmine bromide (PB) and permethrin (PM). In Model 2, a separate cohort of mice were treated for 14 days with PB and N,N-Diethyl-methylbenzamide (DEET), plus corticosterone (CORT) via drinking water on days 8-14 and diisopropylfluorophosphate (DFP) on day 15. LNFPIII was administered concurrently with GWI chemicals treatments. Brain and spleen monoamines and hippocampal inflammatory marker expression were examined by, respectively, HPLC-ECD and qPCR, 6 h post treatment cessation. Serotonergic (5-HT) and dopaminergic (DA) dyshomeostasis caused by GWI chemicals was apparent in multiple brain regions, primarily in the nucleus accumbens (5-HT) and hippocampus (5-HT, DA) for both models. Splenic levels of 5-HT (both models) and norepinephrine (Model 2) were also disrupted by GWI chemicals. LNFPIII treatment prevented many of the GWI chemicals induced monoamine alterations. Hippocampal inflammatory cytokines were increased in both models, but the magnitude and spread of inflammation was greater in Model 2; LNFPIII was anti-inflammatory, more so in the apparently milder Model 1. Overall, in both models, GWI chemicals led to monoamine disbalance and neuroinflammation. LNFPIII co-treatment prevented many of these disruptions in both models, which is indicative of its promise as a potential GWI therapeutic.

Schistosoma mansoni triose phosphate isomerase peptide MAP4 is able to trigger naïve donor immune response towards a type-1 cytokine profile.

We evaluated the ability of naïve monocyte-derived dendritic cells (DC) to sensitize autologous peripheral blood mononuclear cells (PBMC) to the schistosome vaccine candidate MAP4 using a priming in vitro (PIV) assay. MAP4 is a multiple antigen peptide containing B- and T-cell epitopes derived from the glycolytic enzyme triose phosphate isomerase. PBMC primed and restimulated with MAP4 first and secondary recalls (MAP4 PIV cells) were examined for cell phenotype and cytokine production. We found that after the first recall stimulation with MAP4, the major cell population was predominantly CD4(+) T-cell subsets (68.5%), CD8(+high) (16%) and CD19(+) (10%). Additionally, MAP4 PIV cells significantly expressed CD4(+)-HLA-DR(+), -CD54(+), -CD45RO(+) (P < 0.0001) and -CD25(+) (P < 0.0004) together with significant expression of CD80(+) on CD19(+) B cells (P < 0.007). Cytokine production from activated MAP4 PIV cells was predominantly Th1-like, consisting mainly of IFN-gamma. Interestingly, IFN-gamma production was suppressed when Schistosoma mansoni-soluble egg antigen (SEA) was added to a MAP4 PIV cell culture. Furthermore, addition of MAP4 to a SEA PIV cell culture significantly reduced secretion of IL-10. The present findings add to the knowledge gained from studies in the mouse model, and our results show that naïve donor DC, sensitized with MAP4, were able to prime and clonally expand MAP4-specific T cells towards a Th1-type response.

Naïve donor responses to Schistosoma mansoni soluble egg antigens.

Schistosome infection induces profound Th-biasing and immune suppression. Although much has been examined in mice, few studies have examined responses of naïve humans to schistosome antigens. In this study, we examined the response of naïve human peripheral blood mononuclear cells (nPBMC) to stimulation with Schistosoma mansoni soluble egg antigen (SEA) using a priming in vitro (PIV) assay. We found that SEA induced a pronounced CD4+ T-helper cell response based on cytokine secretion and phenotyping markers. SEA-stimulated nPBMC (SEA cells) at day 7 post-priming and after the first recall consisted predominantly of Th0-like CD4+ T cells. Following the second recall, the majority of donor (10/12) responses were Th2-like. The cell population consisted of approximately 64% CD4+, 17% CD8(+high), 12% CD19+, and 7% CD23+ cells. The CD4+ population also expressed HLA-DR+, CD54+, CD45RO+ and CD25+ whereas the CD19+ cells expressed CD80 and CD86. Following priming, we detected high levels of IL-6, IFN-gamma, IL-12p40, IL-10 and IL-5. Upon restimulation, SEA cells secreted IL-5 and high levels of IL-10, typical of a Th2-like response. The data presented herein shows that the majority of naïve donor dendritic cells, following stimulation with SEA, prime and clonally expand SEA-specific T cells towards a Th2-type response. However, two donors responded with an atypical response, producing IFN-gamma coincident with low levels of IL-10. Whether this differential response was due to HLA or other genes was not determined but is currently under investigation.

[Protective effects of co-immunization with SjCTPI-Hsp70 and interleukin-12 DNA vaccines against Schistosoma japonicum challenge infection in water buffalo].

OBJECTIVE: To induce protective effect of co-immunization with S. japonicum triose-phosphate isomerase fused to heat shock protein 70 (SjCTPI-Hsp70) plasmid and interleukin-12 (IL-12) DNA vaccines against Schistosoma japonicum (Chinese strain) infection in water buffalo. METHODS: Forty-five 8-10 months-old water buffalo from a nonendemic area were divided into three treatment groups each with fifteen buffalo: experimental group A (SjCTPI-Hsp70+IL-12, 300 microg), experimental group B (SjCTPI+IL-12, 300 microg), and control group C (pVAX+IL-12, 300 microg). All buffalo were immunized with a series of 3 intramuscular injections administered once every four weeks. Twenty-eight days postvaccination, water buffalo were percutaneously challenged with 1000 S. japonicum cercariae. Fecal examinations were conducted two days prior, one day prior, and on perfusion day, and the number of hatching miracidia and eggs per gram feces were recorded. Fifty-six days post-infection, the buffalo were sacrificed and perfused via the descending aorta. The recovered adult worms and eggs in liver tissue were counted. RESULTS: Groups A and B showed a worm reduction rate of 51.2% and 41.5% (chi2=1.89, P>0.05)), female worm reduction of 48.9% and 44.7% (chi2=0.35,P>0.05), fecal egg reduction of 52.1% and 38.3% (chi2=3.84,P<0.05), a reduction of miracidia-hatching rate by 52.1% and 33.2% (chi2=7.30, P<0.01), and liver egg reduction of 61.5% and 42.0% (chi2=7.61 , P<0.01), respectively. CONCLUSION: Co-immunization with SjCTPI-Hsp70 and IL-12 DNA vaccines induces protective immunity against S. japonicum in water buffalo.

Neurochemical and electrophysiological deficits in the ventral hippocampus and selective behavioral alterations caused by high-fat diet in female C57BL/6 mice.

Mounting experimental evidence, predominantly from male rodents, demonstrates that high-fat diet (HFD) consumption and ensuing obesity are detrimental to the brain. To shed additional light on the neurological consequences of HFD consumption in female rodents and to determine the relatively early impact of HFD in the likely continuum of neurological dysfunction in the context of chronic HFD intake, this study investigated effects of HFD feeding for up to 12weeks on selected behavioral, neurochemical, and electrophysiological parameters in adult female C57BL/6 mice; particular focus was placed on the ventral hippocampus (vHIP). Selected locomotor, emotional and cognitive functions were evaluated using behavioral tests after 5weeks on HFD or control (low-fat diet) diets. One week later, mice were sacrificed and brain regional neurochemical (monoamine) analysis was performed. Behaviorally naïve mice were maintained on their respective diets for an additional 5-6weeks at which time synaptic plasticity was determined in ex vivo slices from the vHIP. HFD-fed female mice exhibited increased: (i) locomotor activity in the open field testing, (ii) mean turn time on the pole test, (iii) swimming time in the forced swim test, and (iv) number of marbles buried in the marble burying test. In contrast, the novel object recognition memory was unaffected. Mice on HFD also had decreased norepinephrine and dopamine turnover, respectively, in the prefrontal cortex and the vHIP. HFD consumption for a total of 11-12weeks altered vHIP synaptic plasticity, evidenced by significant reductions in the paired-pulse ratio and long-term potentiation (LTP) magnitude. In summary, in female mice, HFD intake for several weeks induced multiple behavioral alterations of mainly anxiety-like nature and impaired monoamine pathways in a brain region-specific manner, suggesting that in the female, certain behavioral domains (anxiety) and associated brain regions, i.e., the vHIP, are preferentially targeted by HFD.

Purification and immunochemical characterization of a 22 kilodalton surface antigen from Schistosoma mansoni.

A 22 kDa antigen (Sm22) was purified from schistosomula membrane extracts by immunoaffinity chromatography with monoclonal antibody M.2. Western blotting suggested that the epitope bound by M.2 required a specific conformational folding of the molecule, which was sensitive to reducing agents. Two-dimensional electrophoresis of purified Sm22 demonstrated that the single 22 kDa protein recognized by M.2 on one-dimensional gel analysis was composed of at least two isomorphs. Additional Western blotting showed that Sm2 was one of the major antigens recognized by mouse anti-irradiated cercariae serum, and that this same serum recognized at least one epitope which was not sensitive to reducing agents. The mice vaccinated with irradiated cercariae were shown to be 75% protected from cercarial challenge. Sera from a rabbit immunized with Sm22 contained antibodies which bound to the surface of schistosomula and detected a single protein at 22 kDa by immunoprecipitation or Western blot. The rabbit anti-Sm22 sera also immunoprecipitated a 22 kDa in vitro translation product, indicating that at least one epitope on Sm22 is not dependent on glycosylation.

Identification by monoclonal antibody of a major (28 kDa) surface membrane antigen of Schistosoma mansoni.

Monoclonal antibody M.1 was generated from mice immunized with membrane enriched extracts of mechanically transformed schistosomula. M.1 bound to the surface membranes of cercariae and young (0-24 h post-transformation) schistosomula but did not bind to older schistosomula or cultured worms. M.1 immunoprecipitated an antigen of approximate molecular weight 27-28 kDa from schistosomula. Experiments using metabolic labeling showed that the antigen was actively synthesized by developing schistosomula. Further M.1 immunoprecipitated a similar 27-28 kDa antigen from membrane-enriched extracts of miracidia, lung and adult worms as well as from schistosomula.

Lewis(x)-containing oligosaccharide attenuates schistosome egg antigen-induced immune depression in human schistosomiasis.

The proliferative and interleukin (IL)-10 responses to Lacto-n-fucopentaose III (LNFPIII) that contains Lewis(x)(Le(x))-trisaccharide was assessed in PBMC from humans infected with Schistosoma mansoni. All patient groups with low, medium, and high egg counts in their feces responded to polyvalent LNFPIII-HSA (where HSA = human serum albumin) conjugate. PBMC of all subjects showed a significant proliferative response to this sugar conjugate. However, the levels of interleukin (IL)-10 induced by LNFPIII-HSA were higher in groups with low and medium egg counts than those with high egg. Soluble egg antigens (SEA) also induced IL-10 production by PBMC from infected patients. Interestingly, the SEA-induced IL-10 production was remarkably inhibited by pretreatment of PBMC with free ligands of LNFPIII (monovalent form). These LNFPIII-pretreated PBMC displayed appreciable increase in the level of proliferation to SEA stimulation. We propose that the observed bystander immune potentiation rendered by free LNFPIII is due to the reduced IL-10 level which, presumably, up-regulate expression of co-stimulatory molecules on APC. The ensemble of results indicates that the Le(x)-containing LNFPIII is a potent immunoreactive epitope in SEA that negatively influences PBMC response against this parasite antigens via IL-10.

Failure of schistosomiasis to significantly decrease testosterone levels in Brazilian men.

Schistosomes can decrease the reproductive potential or castrate both invertebrate (snail) hosts as well as vertebrate (mouse, rat, and hamster) hosts. To determine if host castration occurs in human males, we examined testosterone levels in the sera of 38 Brazilian males, 16-35 years of age, who had Schistosoma mansoni infections. We found that individuals with intestinal schistosomiasis exhibited serum testosterone levels similar to those of noninfected controls. Four subjects with severe hepatosplenic disease also exhibited testosterone levels within the normal range. We did observe a negative correlation between parasite load (as predicted by fecal egg count) and testosterone levels but could not dissociate this relationship from the effect of age on either parameter. Therefore, in contrast to rodent models, host castration does not appear to be a usual side effect of human schistosomiasis.

Protective immunity induced with 23 kDa membrane protein dna vaccine of Schistosoma japonicum Chinese strain in infected C57BL/6 mice.

A 23 kDa membrane protein DNA vaccine for Schistosoma japonicum Chinese strain was developed and tested for its protective efficacy and immune responses in infected C57BL/6 mice. The cDNA encoding SjC23 amplified from pUC19-SjC23 were subcloned into an eukaryotic expression vector (pcDNA3.1). Forty-eight female C57BL/6 mice were divided into three groups. Each mouse of group A (control group) was immunized intramuscularly (i.m.) with 100 microg of pcDNA3.1; of group B (SjC23 group) was immunized (i.m.) with 100 microg of pcDNA3.1-SjC23; of group C (SjC23+IL-12) was immunized (i.m.) with a mixture of 100 microg of pcDNA3.1-SjC23, 100 microg of pcDNA3.1-p35 and 100 microg of pcDNA-p40. These were followed by two boosts of the same DNA once every two weeks. All mice were challenged with 45 cercariae of Schistosoma japonicum Chinese strain at week 8, and were killed and perfused at week 14. The numbers of recovered worms and hepatic eggs were counted. The expression of SjC23 and p35, p40 in muscle tissue was determined by immunohistochemical method. By culture of spleen cells, the production of IL-2, IL-4, IL-10 and IFN-gamma with the stimulation of specific antigen of the recombinant hydrophilic domain of SjC23 (rSjC23-HD) was determined after the last immunization (before challenge). Sera were collected from each group before immunization and two weeks before and after challenge. Anti-SjC23 antibodies were tested by Western blot. The results showed that SjC23 and p35, p40 of mouse IL-12 were expressed on the membrane and in the plasma of the muscle cells of immunized C57BL/6 mice. A rise of IL-2 and IFN-gamma in the SjC23 group and SjC23+IL-12 group was observed; No changes were found in IL-4 and IL-10. Detection of anti-SjC23 antibody with Western blot showed that after the third immunization (before challenge) all the serum samples from the control group were negative; 8 of 10 sera from the SjC23 group and 9 of 10 sera from the SjC23+IL-12 group were positive. The worm reduction rates in the SjC23 group and SjC23+IL-12 group were 26.9% and 35.4% respectively; the liver eggs reduction rates were 22.2% and 28.4%, respectively in comparison to the control group. This indicates that the pcDNA3.1-SjC23 DNA vaccine can induce partial protection against Schistosoma japonicum infection in C57BL/6 mice.

The protective immunity of a DNA vaccine encoding Schistosoma japonicum Chinese strain triose-phosphate isomerase in infected BALB/C mice.

The development of a DNA vaccine for schistosomiasis japonica and testing the protective efficacy after challenge in BALB/c mice were performed. Thirty-nine female BALB/c mice were divided into three groups. Each mouse of the control group was injected intramuscularly with 100 microg of pcDNA3.1 DNA. In the TPI group, each mouse was injected with 100 microg of pcDNA3.1-SjCTPI DNA. The TPI+IL-12 group was injected with 100 microg of pcDNA3.1-SjCTPI DNA and 100 microg of the mixture of pcDNA3.1-P35 and pcDNA3.1-P40 DNA. Each mouse was immunized three times at two-week intervals and challenged with 45 cercariae of Schistosoma japonicum Chinese strain four weeks post-immunization. Then the mice were sacrificed and perfused at 45 days after challenge; the recovered worms and hepatic eggs were counted. Cytotoxic T lymphocyte (CTL) activity mediated by SjCTPI was detected with the 51Cr release assay. ELISA was performed for the detection of anti-rTPI antibodies. Anti-rTPI antibody detection with ELISA after immunization showed ten serum samples from the control group were negative, five of ten serum samples from the TPI group were weakly positive, six of ten from the TPI+IL-12 group were also weakly positive. The CTL activity of the control group was 9.1%, while CTL activities of the TPI group and the TPI+IL-12 group were 27.6% and 54.4%, respectively. The worm and egg reduction rates of TPI group and the TPI+IL-12 group were 30.2%, 52.9%, 32.7%, and 47.0%, respectively in comparison with the control group. This study further proved the possibility of the SjCTPI DNA vaccine as a potential DNA vaccine for schistosomiasis.

Characterization of isoelectric point (pI) fractions of soluble egg antigen of Schistosoma japonicum.

The soluble egg antigen of Schistosoma japonicum was fractionated into 20 individual isoelectric point (pI) fractions with different pIs ranging from 1.86-11.40 by isoelectric focusing (IEF). The fractions were tested for humoral and cellular responses, as well as in vitro granuloma formations. The results indicated that the fractions in the acidic region (pI 3.78-5.54) may play an important role in granuloma elicitation in schistosomiasis japonica, and antibodies are also involved in the regulation of granuloma formation especially at the early stage (5 week postinfection).

[Generation and immunochemical characterization of an anti-egg monoclonal antibody specific to Schistosoma japonicum].

Monoclonal antibodies (McAbs) were generated from mice immunized with soluble egg antigen (SEA) of Schistosoma japonicum. Five of which were specific to SEA of S. japonicum. The isotype of these McAbs was IgG1. Immunoblotting showed that the approximate molecule weight of the antigens recognized by the McAbs were 22 kDa, 116 kDa and greater than 200 kDa respectively. At least 3 isomorphs of the 22 kDa antigen recognized by 1E1 were found at pI 4.6-6 with 2-D Western blot. Moreover, immunoprecipitation using 125I-labeled S. japonicum SEA demonstrated that only one band corresponding to 30 kDa was recognized by 1E1.

[Protective immunity induced by 23 kDa membrane protein DNA vaccine of Schistosoma japonicum Chinese strain in mice].

OBJECTIVE: To develop 23 kDa membrane protein DNA vaccine of Schistosoma japonicum Chinese strain and test its protective efficacy in infected C57BL/6 mice. METHODS: The full length cDNA encoding SjC23 amplified from pUC19-SjC23 subcloned into pcDNA3.1. 48 female mice were divided into three groups: A, B and C. Group A (control group) was each immunized i.m. with 100 micrograms of pcDNA3.1; group B (SjC23 group) was each immunized i.m. with 100 micrograms of pcDNA3.1-SjC23; group C (SjC23 + IL-12) was each immunized i.m. with a mixture of 100 micrograms of pcDNA3.1-SjC23, 100 micrograms of pcDNA3.1-p35 and 100 micrograms of pcDNA-p40, followed by two boosts of the same DNA once every two weeks. All the mice were challenged with 45 cercariae at week 8, killed and perfused for worms at week 14. The expression of SjC23 and p35, p40 in muscle tissue was determined by immuno-histochemical method. By the culture of spleen cells, the production of IL-2, IL-4, IL-10 and IFN-gamma after the stimulation of rSjC23-HD was determined two weeks before and after challenge. Anti-SjC23 antibodies were tested by Western blotting. RESULTS: SjC23 and p35, p40 were all expressed on the membrane and in the plasma of muscle cells of the infected mice. Significant increase of IL-2 and IFN-gamma in SjC23 and SjC23 + IL-12 groups was observed before and after challenge. Western blotting showed that after the third immunization (before challenge) 8 out of 10 sera from SjC23 group and 9 out of 10 sera from SjC23 + IL-12 group were positive. The worm reduction rate in SjC23 group and SjC23 + IL-12 group was 26.9% and 35.4%, respectively; the number of eggs in liver tissue was reduced by 22.2% and 28.4%, respectively. CONCLUSION: pcDNA3.1-SjC23 DNA vaccine could induce partial protection against Schistosoma japonicum in C57BL/6 mice.

Schistosoma japonicum triose-phosphate isomerase plasmid DNA vaccine protects pigs against challenge infection.

The protective efficacy of a Schistosoma japonicum, Chinese strain, triose-phosphate isomerase (TPI) plasmid DNA vaccine was examined in naïve pigs. Pigs were vaccinated with the TPI DNA-plasmid alone, or in conjunction with IL-12 as pcDNA3.1-P35, pcDNA3.1-P40 plasmids via intramuscular injection. Control pigs were immunized with equivalent amounts of pcDNA3.1. Pigs were immunized 3 times at 21-day intervals and challenged 30 days after the final boost. Forty-five days post-challenge, pigs were sacrificed and perfused to compare adult worm burdens, female worm burdens, liver egg burdens and granuloma size. We found that pigs vaccinated with SjCTPI DNA alone had adult worm burdens reduced by 48.3% and that a further decrease in adult worm burdens was not seen in the group vaccinated with SjCTPI DNA in conjunction with IL-12 (46.2% reduction). The SjCTPI DNA vaccines had a more pronounced effect on reducing female worm burdens i.e. 53.6% SjCTPI alone and 59.6% for SjCTPI+IL-12. Vaccination with SjCTPI-DNA reduced liver eggs by 49.4% and this response was significantly enhanced by the addition of IL-12 (65.8% reduction in liver eggs). In addition to the dramatic protective effects seen in vaccinated pigs, we also noted that granuloma size was reduced by 42% in both groups. Thus, vaccination of pigs and other large animals in China with SjCTPI DNA vaccine will likely reduce transmission by reducing adult worm burdens and worm egg output and simultaneously reduce hepatic egg-associated pathology.

Comparison of Schistosoma mansoni irradiated cercariae and Sm23 DNA vaccines.

Immunization with defined antigens is generally less effective at inducing host protection against experimental infection with Schistosoma mansoni than vaccination with attenuated infective cercariae. We predicted that quantitative and/or qualitative differences existed between the immune responses generated to attenuated cercariae and those induced by defined antigens. Thus, we compared immune responses typically associated with protection in the murine model between animals vaccinated with attenuated cercariae and mice immunized with DNA encoding Sm23, a schistosome integral membrane protein that has previously been shown to confer protection. Mice vaccinated three times with attenuated cercariae demonstrated higher levels of protection than Sm23-vaccinated animals but spleen cells from Sm23 DNA vaccinated mice produced significantly higher levels of schistosome antigen-specific IFN-gamma. Both vaccines induced similar levels of Sm23-specific antibody and post-challenge dermal inflammation. However, the pulmonary inflammatory responses following challenge were much less pronounced in DNA immunized animals compared to those receiving irradiated cercariae. Thus, although Sm23 DNA vaccination effectively induced parasite-specific IFN-gamma and antibody responses, it failed to evoke other critical responses needed for optimal vaccine efficacy.

Characterization of protective and non-protective surface membrane carbohydrate epitopes of Schistosoma mansoni.

We have produced a number of monoclonal antibodies, protective and non-protective, which recognize a complex of schistosomula antigens, including the 38 kDa antigen. Eight different protective and non-protective monoclonal antibodies, varying in isotypes, were used in the binding assays. Lectin inhibition studies suggested that the monoclonal antibodies probably recognized carbohydrate epitopes on the antigen(s). Immunoprecipitation studies showed that at least two of the monoclonal antibodies recognized different epitopes on the same molecule. Additionally, we tested for monoclonal antibody binding after the antigens were treated with; 1) proteases, 2) periodate, 3) various exo- and endoglycosidases, 4) mild acid hydrolysis. We also tested for binding of the antibodies to keyhole limpet hemocyanin (KLH). Using the 8 monoclonal antibodies as probes, we were able to define at least 4 different carbohydrate epitopes related to the protective monoclonal antibodies, and at least one epitope which is seen by the non-protective antibodies. The epitope seen by the non-protective antibodies was shown to be cross-reactive with epitopes on KLH. These results demonstrate the importance of epitope mapping studies for any defined vaccine.

Monoclonal anti-idiotypic and anti-anti-idiotypic antibodies from mice immunized with a protective monoclonal antibody against Schistosoma mansoni.

To study the role of idiotypic anti-idiotypic interactions in schistosomiasis, mice were immunized with a mAb, E.1, which bound to soluble egg and larval stage Ag and also passively transferred resistance to cercarial challenge in mice. Subsequently, hybridomas were produced from E.1 immunized mice and tested for the ability to inhibit E.1 binding to soluble egg Ag. The results showed that anti-idiotypic mAb (Ab2) were produced. The range of inhibitory activity was from 33 to 100%. By using a direct Ab2 binding assay, the Ab2 were shown to be idiotypic specific, not isotype specific. It was also found that six of the hybridomas bound to soluble egg Ag and were therefore anti-anti-idiotypic antibodies (Ab3). Ab3 were shown to be inhibited from binding to soluble egg Ag by Ab2. To the authors' knowledge, this is the first time that an in vivo network relevant to an infectious organism has been reproduced in vitro such that both Ab2 and Ab3 were produced from the same animals independent of exposure to parasite Ag.