The efficacy of cercarial antigen loaded on nanoparticles as a potential vaccine candidate in Schistosoma mansoni-infected mice.

Schistosomiasis is one of the most common causes of morbidity and mortality from parasitic diseases. Mass treatment has proven to be insufficient because of repeated infection after treatment and the appearance of strains resistant to drug therapy. Hence, immunization is a new approach to control the disease and limit the pathological consequences of schistosomiasis. To evaluate the prophylactic effect of Cercarial antigen (CAP) loaded on chitosan nanoparticles (CSNPs) as a potential vaccine against Schistosoma mansoni-infected mice. 130 mice divided into 2 groups were used: Group I: Control groups (50 mice) subdivided into subgroup Ia (10 mice): Non-infected mice (normal control), subgroup Ib (20 mice): Schistosoma infected mice (infected control) and subgroup Ic (20 mice): Non-infected mice receiving NPs only. Group II: Vaccinated group (80 mice) subdivided equally into subgroup IIa (CAP): Received cercarial antigen and subgroup IIb (CAP + CSNP): Received cercarial antigen loaded on chitosan NPs then both vaccinated groups were infected with S. mansoni 3 weeks following the initial vaccination dose. CAP + CSNP and CAP groups showed significant reduction in adult worms count, hepatic egg count, hepatic granulomas number and size in comparison to the infected control group. Elevation of serum IgG and IgM levels, CD4+ and CD8+ T cell frequencies, IL-4, IL-10 and INF-γ levels was more significant in CAP + CSNP group than CAP group. CAP + CSNP is a promising new preparation of Schistosomal antigens that gave better results than immunization with CAP alone. CSNPs enhanced the immune and protective effect of CAP as validated by parasitological, histopathological and immunohistochemical studies.

Mefloquine loaded niosomes as a promising approach for the treatment of acute and chronic toxoplasmosis.

Toxoplasmosis is a disease with a worldwide distribution and significant morbidity and mortality. In search of effective treatment, mefloquine (MQ) was repurposed and loaded with niosomes to treat acute and chronic phases of toxoplasmosis in experimental mice. Mice were orally inoculated with 20 cysts of Toxoplasma gondii (ME 49 strain) for the acute model of infection and 10 cysts for the chronic model of infection. Infected mice were dosed with MQ solution or MQ-niosomes at 50 mg/kg/day, starting from the second day post-infection (PI) (acute model) or the fifth week PI (chronic model), and this was continued for six consecutive days. The effects of MQ solution and MQ-niosomes were compared with a pyrimethamine/sulfadiazine (PYR/SDZ) dosing combination as mortality rates, brain cyst number, inflammatory score, and immunohistochemical studies that included an estimation of apoptotic cells (TUNEL assays). In the acute infection model, MQ solution and MQ-niosomes significantly reduced the mortality rate from 45% to 25 and 10%, respectively, compared with infected untreated controls, and decreased the number of brain cysts by 51.5% and 66.9%, respectively. In the chronic infection model, cyst reduction reached 80.9% and 12.3% for MQ solution and MQ-niosomes treatments, respectively. MQ-niosomes significantly decreased inflammation induced by acute or chronic T. gondii infection. Additionally, immunohistochemical analysis revealed that MQ solution and MQ-niosomes significantly increased the number of TUNEL-positive cells in brain tissue, indicative of induction of apoptosis. Collectively, these results indicate that MQ-niosomes may provide a useful delivery strategy to treat both acute and chronic toxoplasmosis.

Oxidative stress mediated apoptotic potential of mefloquine on experimental trichinellosis.

Conventional anthelmintics such as albendazole could not achieve complete cure of trichinellosis till now. The antimalarial mefloquine mediates oxidative stress and disrupts lysosomal functions leading to cell death. Therefore, the aim of this work was to investigate the effect of mefloquine on experimental acute and chronic trichinellosis and to clarify the possible mechanisms of such effects. Mice were divided into four groups; Group I: Uninfected untreated control (20 mice); Group II: Infected untreated control (40 mice); Group III: infected and treated with albendazole (400 mg/kg) (40 mice); Group IV: infected and treated with mefloquine (300 mg/kg) (40 mice). All infected treated groups were equally subdivided into 2 subgroups; (a) treated on the 2nd day post infection (dpi) for 3 days, (b) treated on the 35th dpi for 5 days. Parasitological adults and larvae counting besides immunohistopathological examination of intestines and muscles were done. Biochemical assay of oxidant/antioxidant status, apoptotic, cytoprotective and inflammatory biomarkers in intestinal and muscle homogenates were achieved. Results showed that both albendazole and mefloquine significantly reduced adults and larvae counts with higher efficacy of albendazole in the intestinal phase and superiority of mefloquine in the muscle phase. The superiority of mefloquine was indicated by increased inflammatory immune infiltration and decreased anti-apoptotic immunohistochemical markers expression in both jejunal and muscle tissues. Biochemically, mefloquine treatment showed highly significant oxidative, apoptotic and inflammatory effects. So, our results suggest that mefloquine might be a superior treatment for chronic trichinellosis.

IMPACT OF IMMUNE SUPPRESSION ON HISTOPATHOLOGICAL AND IMMUNOLOGICAL PARAMETERS OF MICE EXPERIMENTALLY INFECTED WITH GIARDIA LAMBLIA.

Giardiasis is one of the most frequent entero-parasites worldwide; its prevalence is more common in developing countries. Giardia lamblia is considered one of the opportunistic parasites and aits clinical manifestations represent the expression of host resistance and parasite viri lence. As of chronic giardiasis cases were expected to worsen in immunosuppressed patients with development of various complications. This work assessed the histolopathological and the possible immunological effects of infection with G. lamblia in an immunosuppressed experimental animal model in comparison to immunocompetent one. Mice were divided into 4 groups;. group I: simmunocompetent (IC) mice infected with G. lamblia cysts, group II: immunosup pressed (S) mice infected with cysts, group III: uninfected immunocompetent mice and group. IV: uninfected immunosuppressed mice. From each group, small intestine was. removed for histopathological and molecular studies. Also, cyst counting in the stool of infected mice was estimated. We found that the number of G. lamblia cysts in the stool of IS mice was significantly higher than that from IC ones. Shortening of the villi was more pronounced in the IS than in IC group. Furthermore, intraepithelial lymphocytic count, goblet cell count and mast cell count were significantly decreased in the IS infected group as compared to IC ones. Expression of interleukin.6 mRNA showed high expression in IC infected mice while it was weak in IS mice. In conclusicn, the present study revealed the importance of the innate immunity presented by goblet cells, mast cells and other adaptive immunity responses; in the clearance of Giardia.

IMMUNOTHERAPEUTIC EFFECT OF SPIRAMYCIN IN EXPERIMENTAL GIARDIASIS.

Giardiasis is a major global cause of water borne diarrheal disease, which contributes greatly to the burden of malnutrition and malabsorption especially in children. There is a great demand for a new effective therapeutic agent against giardiasis that can be used safely during pregnancy, lactation and in infants. In the present study, the therapeutic effect of spiramycin as well as its immunomodulatory mechanism of action in giardiasis had been investigated. 90 Swiss albino mice were used in this study and classified into 3 groups: GI: 40 mice infected with Giardia lamblia cysts, GII: 40 infected mice that received spiramycin treatment in a daily oral dose of 1000 IU/gm body weight for one week starting one week post infection and GIII: 10 control uninfected untreated mice. 20 mice from each infected group were sacrificed 2 weeks post infection (p.i.) and the remaining mice were sacrificed 4 weeks p.i. Mice of the control groups were sacrificed at one time. The antigiardial therapeutic efficacy of spiramycin was assessed 2 and 4 weeks p.i. by counting of Giardia cysts in stool of mice and studying the histopathological changes and disaccharidase activity in small intestine of mice of different groups. Significant reduction in cysts number shedded in stool of treated animals reached 95.73%. The histopathological changes were mild in all infected groups 2 weeks p.i., while 4 weeks p.i. There was also a significant increase in the number of IELs in treated groups denoting the stimulatory effect of spiramycin on lymphocytic proliferation. On studying the disaccharidase activity, there was significant increase in both sucrase and maltase activities in the treated groups as compared with the nontreated groups. The possible immunomodulatory mechanism of action of spiramycin was studied by measuring the local IgA deposition in small intestinal mucosa by PAP technique 4 weeks p.i. The levels of IgA in small intestine were higher in SP-treated group as compared with the non-treated group. The present results suggested that spiramycin has high efficacy as anti-giardial agent possibly by stimulation of local IgA production.

HISTOCHEMICAL EFFECTS OF SOME BIOLOGICAL AGENTS ON CULEX PIPIENS LARVAE.

The histochemical effects of the lethal concentration that kills 50% of larvae (LC50) of three biological agents, abamectin, Bacillus thuringiensis and spinosad on the carbohydrates (polysaccharides), proteins, nucleic acids and lipids content of the midgut and fat bodies of Culex pipiens 2nd instar larvae were studied. The results showed that the three tested compounds reduced the carbohydrates (polysaccharides), proteins, RNA synthesis and lipids content after 72 hours of treatment where abamectin was the most effective followed by Bacillus thuringiensis then spinosad.