The host–parasite neuroimmunoendocrine network in schistosomiasis: consequences to the host and the parasite

Characterization of Schistosoma japonicum estrogen-related receptor beta like 1 and immunogenicity analysis of the recombinant protein

The estrogen-related receptor beta like 1 (EsRRBL1) is a sex hormone receptor. Here, we describe the cloning and expression of the EsRRBL1 gene from Schistosoma japonicum (SjEsRRBL1). Quantitative real time PCR (qPCR) and Western blot analysis revealed that SjEsRRBL1 was highly expressed in 14-, 18-, 23- and 28-days-old schistosomes at the transcriptional and protein levels, when the schistosomes were undergoing early development of reproductive organs, male and female coupling, and egg-laying. qPCR also showed that schistosomula isolated from a S. japonicum-susceptible mouse host had 3- to 4-fold higher expression of SjEsRRBL1 than that from the S. japonicum non-permissive Microtus fortis host or the non-susceptible rat host. Moreover, SjEsRRBL1 expression was 2-fold higher in schistosomula from female mice than that from male mice. Western blot analysis revealed that rSjEsRRBL1 had good antigenicity. After immunization of BALB/c mice with recombinant (r)SjEsRRBL1, partial and significantly protective efficacy was observed in two independent trials (30.84% and 30.70% worm reduction; 35.39% and 35.61% liver eggs reduction), as compared with the blank control group. An enzyme-linked immunosorbent assay (ELISA) showed that mice vaccinated with rSjEsRRBL1 produced increased levels of specific IgG, IFN-γ and IL-4, but a reduced IgG1/IgG2a ratio, as compared to the adjuvant control group and the blank control group, suggesting that rSjEsRRBL1 vaccination could induce a mixed Th1/Th2 response. The results suggested that SjEsRRBL1 might be a critical regulator of schistosome development and represent a promising vaccine target for schistosomiasis.

Schistosoma genomics: new perspectives on schistosome biology and host-parasite interaction

Schistosomiasis, caused mainly by Schistosoma japonicum, S. mansoni, and S. hematobium, remains one of the most prevalent and serious parasitic diseases worldwide. The blood flukes have a complex life cycle requiring adaptation for survival in fresh water as free-living forms and as parasites in snail intermediate and vertebrate definitive hosts. Functional genomics analyses, including transcriptomic and proteomic approaches, have been performed on schistosomes, in particular S. mansoni and S. japonicum, using powerful high-throughput methodologies. These investigations have not only chartered gene expression profiles across genders and developmental stages within mammalian and snail hosts, but have also characterized the features of the surface tegument, the eggshell and excretory-secretory proteomes of schistosomes. The integration of the genomic, transcriptomic, and proteomic information, together with genetic manipulation on individual genes, will provide a global insight into the molecular architecture of the biology, pathogenesis, and host-parasite interactions of the human blood flukes. Importantly, these functional genomics analyses lay a foundation on which to develop new antischistosome vaccines as well as drug targets and diagnostic markers for treatment and control of schistosomiasis.

Plasmodium falciparum biology: analysis of in vitro versus in vivo growth conditions

Recent studies of Plasmodium falciparum isolated directly from infected patients indicate that alternative parasite biological states occur in the natural host that are not observed with in vitro cultivated parasites. Variation in host substrates, immune responses and other factors probably induce modifications in parasite biology. These biological states could have important implications for pathogenesis, transmission and therapy. We review the differences between P. falciparum in vitro culture systems and in vivo host environments, as well as evidence that host conditions can alter pathogen biology. For select biological questions, the incorporation of naturally occurring conditions into in vitro experimental manipulation of microbes may provide novel insight into pathogen biology.

Schistosoma mansoni: Microarray analysis of gene expression induced by host sex

Schistosoma mansoni is a digenetic trematode and a human parasite responsible for high social and economic impact. Although some authors have studied the effect of host hormones on parasites, not much is known about the effects of host sex on gene expression in Schistosomes. In order to study gene transcripts associated with the host sex, we compared the gene expression profiles of both male and female unisexual adult S. mansoni parasites raised on either male or female hosts, using DNA microarrays. Our results show that host sex caused differential expression of at least 11 genes in female parasites and of 134 in male parasites. Of the differentially expressed genes in female worms, 10 were preferentially expressed in female worms from male mice, while of the 134 differentially expressed genes in male parasites, 79 (59%) were preferentially expressed in worms from female mice. Further investigation of the role of each of those genes will help understand better their importance in the pathogenesis of Schistosomiasis.

Mexican immunoparasitology: what is done and has to be done

In this special issue of Parasite Immunology, the reader will find reviewed some of the hottest topics in immunoparasitology, with emphasis on the most studied parasite species in Mexico. For instance, the immunological conditions that appear favorable for the survival or destruction of the parasite in the intermediate and definitive hosts in cysticercosis, as well as the use of immunodiagnostic tests in epidemiological/intervention studies are discussed in two different articles. The role that alternatively activated macrophages plays in modulating host immunity is also discussed, while in the field of Leishmaniasis, the reader will find reviewed the role that CD8+ T cells play in the host defense during the human infection. The role that antibodies may play as biomarkers of protective or pathological cellular immune events in Toxoplasma gondii infections, as well as the new insights about the regulation of the inflammatory immune response by the cytokine/chemokine network in amebiasis, are topics reviewed. The use that TSL-1 antigens may have in the development of more sensitive and specific diagnosis of human and animal trichinellosis as well as the role that the neuroimmunoendocrine network plays during schistosomiasis are also presented. We hope that our readers will find fascinating and enticing, the first ever Special Issue devoted to Mexican Immunoparasitology.