not-yet-known not-yet-known not-yet-known unknown Introduction: Evidence from multiple data sources indicates that toxocariasis might play a role in the allergic asthma in children. This case-control study investigated the connection between Toxocara seropositivity and allergic asthma. It also sought to identify the conventional risk factors associated with both asthma and Toxocara infection. Methods: In this case-control study, 200 allergic asthma children, and 208 children with no history of allergic asthma were included as the healthy group. Sera samples were examined for specific anti-Toxocara IgG antibodies using a serological assay. Results: The overall prevalence of toxocariasis was 6.9% among children. The seroprevalence of toxocariasis in asthmatic children and healthy children was 8% and 5.8% respectively, with no significant difference (P-value= 0.373). In subgroup analyses based on sociodemographic, Toxocara infection seropositivity was significantly associated with two independent variables, including the father’s occupation (P-value = 0.017) and soil contact in asthmatic children (P-value = 0.033). Conclusions: Our results showed a higher prevalence of Toxocara infection in asthmatic children compared to healthy controls, but this difference was not statistically significant. To gain a clearer understanding and comparison of Toxocara infection rates between asthmatic and healthy children, additional comprehensive studies with larger sample sizes and diverse detection methods using different antigenic sources are required.

As an effort towards vaccine development against African trypanosomiasis, we studied key parasite molecules that mediate VSG functions, specifically the major surface protease-B of Trypanosoma brucei that catalyzes proteolytic removal of old VSGs for expression of new ones, an important stage-specific function that allows the parasite to survive in its host, thus making it an attractive candidate for vaccine development. Herein, Tbmsp-b gene was cloned into a pVAX-1 plasmid to produce pVAX-1-Tbmsp-b construct for DNA vaccine trials. BALB/c mice were immunized by intradermal injection with 100 µg dose of the construct thrice on days 0, 21 and 42, then inoculated with 2000 parasites on day 56. Anti-trypanosomes specific antibody (IgG) and cytokine (γ-IFN) were monitored by ELISA from sera of immunized and unimmunized mice. Immunized mice showed significantly (p < 0.05) higher IgG and γ-IFN responses, lower parasitaemia (by 75% and 51.2% of parasitaemic scores on first and fifth week of infection) and longevity by up to 22 days compared to unimmunized mice. These results showed that the construct provided partial protection to virulent T. b. brucei (Federe strain) infection in susceptible BALB/c mice suggesting the potentials for using MSP-B as an antigen in DNA vaccine development against African trypanosomiasis.

To study on the proteome and to investigate the immune response mechanisms in P. skrjabini infection. Serum samples were randomly collected from patients with P. skrjabini infection and healthy individuals in Guizhou Province. ITRAQ (Isobaric Tags for Relative and Absolute Quantitation) assays were utilized for the analysis of protein catalogs in serum samples. Bioinformatics analysis on the differed proteins was performed. River crabs were sampled from the patients’ habitats, Paragonimus metacercariae were isolated for subsequent rat experimental infection. White blood cells and serum were collected at 42 days post-infection, changes in the expression of IL-4 were assessed. In result, a total of 50 proteins were identified. Typically, increased expression neutrophil defensin 3, protein S100-A9 (S100A9) and serum amyloid A-1 protein (SAA1) were found. S100A9 and SAA1 were involved in the main network but DEFA3 was not. The interaction networks were constituted with the core of Apolipoproteins family and the interactions with the fibrinogen and fibrinolytic system. Through subsequent experimental infections in rats, the expression of Th2 cytokines IL-4 remains unaltered. In conclusion, neutrophils may play a pivotal role in the elimination of parasites, whereas host Th2 cell immune response is suppressed in eliminating worms.

One of the types of external human parasites is a follicular scab called Demodex. Demodicosis is a skin disease in human and canine. Demodex mites feed on the epithelial cells of the hair follicle or sebaceous gland which found on and around the face. The host body immune system is responsible for controlling the population of parasites and Disruption of the cutaneous barrier causes stimulation of Toll-like receptors (TLRs) Consequently, Demodex chitin detect by keratinocyte TLRs. According to the results, association between Demodicosis and the HLA gene showed that individuals with the gene HLACW2 are five times more likely to develop Demodicosis than others because Nk2 and T1 cells of the adaptive immune response are reduced. In human Demodicosis, factors such as carbohydrate-like Tn antigen (expressed by Demodex) and secretion of pro-inflammatory mediators may play a role in the innate immune response. Additionally, the expression level of TLR2 was increased and TLR4, TLR6 expression was decreased. Flow cytometry analysis of blood samples collected from individuals with human Demodicosis and healthy individuals showed that in the patient group, there were more T9 and T reg cells in the blood samples and in skin homing T cell populations compared to the control group. Studies of canine Demodicosis have reported that lymphocyte populations are composed mostly of CD3+ and CD8+ T cells. The importance of the humoral immune response during primary Demodicosis has not yet been determined because no significant differences in circulatory immune were seen. It seems that the host immune system appears to recognize and tolerate the presence of these mites, although the physiological role of human Demodex mites in healthy skin remains unclear, especially the way in which they escape the innate immune system is very important.

Co-evolutionary adaptation of hookworms with their mammalian hosts has selected for immunoregulatory excretory/secretory (E/S) products. However, it is not known whether, or if so, how host immunological status impacts the secreted profile of hematophagous adult worms. This study interrogated the impact of host Signal and transducer of activator of transcription 6 (STAT6) expression during experimental evolution of hookworms through sequential passage of the life-cycle in either STAT6 deficient or WT C57BL/6 mice. Proteomic analysis of E/S products by LC-MS showed increased abundance of 15 proteins, including myosin-3, related to muscle function, and aconitate hydratase, related to iron homeostasis. However, most E/S proteins (174 of 337 unique identities) were decreased, including those in the Ancylostoma-secreted protein (ASP) category, and metallopeptidases. Several identified proteins are established immune-modulators such as fatty acid-binding protein homolog, cystatin, and acetylcholinesterase. Enrichment analysis of InterPro functional categories showed down-regulation of Cysteine-rich secretory proteins, Antigen 5, and Pathogenesis-related 1 proteins (CAP), Astacin-like metallopeptidase, Glycoside hydrolase, and Transthyretin-like protein groups in STAT6 KO adapted worms. Taken together, these data indicate that in an environment lacking Type 2 immunity, hookworms alter their secretome by reducing immune evasion proteins- and increasing locomotor- and feeding-associated proteins.

Aim: Natural transmission of Trypanosoma cruzi occurs when infected hematophagous deposit feces contaminated with metacyclic trypomastigotes on injured skin or mucosa. To study the inflammatory response at the inoculation site, dissemination of parasites, Th cell subtypes at the local lymph nodes and myocarditis mice were exposed to Triatoma dimidiata naturally contaminated with Trypanosoma cruzi. Methods and results: Mice were intradermal inoculated with T. dimidiata feces containing metacyclic trypomastigotes or were previously immunized with feces without metacyclic trypomastigotes and analyzed from 15 minutes to 3 months after inoculation. Parasites remained at the inoculation site until 20 days after inoculation but disappeared early in pre-immunized mice that presented with edema and collagen fragmentation as early as 15 minutes after being challenged with metacyclic trypomastigotes. The Th2 subpopulation dominated in the first week in mice infected with feces containing metacyclic trypomastigotes, whereas Th1 and Th17 populations dominated in the challenged mice population. Similarly in heart tissue, intense myocarditis and remodeling, with faster clearance of amastigotes was observed in mice previously immunized with Triatoma dimidiata feces. Furthermore, immune cell-types, Th1 and Th17, predominated after 20 days post-infection in all experimental groups. Conclusions: Previous exposure with Triatoma dimidiata feces prior to infection with metacyclic trypomastigotes favors parasitic dissemination and early induction of Th1 and Th17 subpopulations with lower parasitism in heart tissue but does not ameliorate inflammation and tissue damage which is accompanied with Th1/Th17 and Treg profile.

Introduction: The T-cell subset (CD4+Tregs) play a significant role in immunoregulation, by active suppression of the immune system, through cell-to-cell contact and the secretion of IL10. The frequencies of these cell subpopulations were investigated in the mother. Methods: The study recruited 61 mothers out of this number, 31 mothers with plasmodium parasitized placentas and 30 mothers without plasmodium infection. Placental malaria positivity was determined by PCR and microscopy. Peripheral mononuclear cells (PBMCs) were isolated from peripheral blood, cultured in the presence of VAR2CSA antigen, and stained with antibodies (CD3, CD4, CD25, and IL-10), before cytometry analysis. Results: The CD4+CD25+ T cell frequencies were significantly higher in all the participants (p<0.0001), and comparable across gravida. These cell populations were similar when compared between primigravid and secumgravida mothers (p=0.77), and between multigravida and secumgravida mothers (p=0.84). Primigravid mothers with placental malaria had significantly higher frequencies of CD4+CD25+ T cell population (p=0.04). The frequencies of CD4+IL10 were significantly high in both primigravid and multigravid mothers who were placental malaria positive (p=0.03) and (p=0.04) respectively. Conclusion: Induced Tregs (CD4+IL10) cells could play a role in placental malaria susceptibility due to an increase in their populations in mothers with plasmodium-infected placentas.