Adoptive transfer of protective immunity from Cryptosporidium parvum-infected interferon-γ and interleukin-12-deficient mice to naive recipients

Medical prospects of cryptosporidiosis in vivo control using biofabricated nanoparticles loaded with Cinnamomum camphora extracts by Ulva fasciata

Background and Aim

Global efforts are continuing to develop preparations against cryptosporidiosis. This study aimed to investigate the efficacy of biosynthesized Ulva fasciata loading Cinnamomum camphora oil extract on new zinc oxide nanoparticles (ZnONPs shorten to ZnNPs) and silver nanoparticles (AgNPs) as alternative treatments for Cryptosporidium parvum experimental infection in rats.

Materials and Methods

Oil extract was characterized by gas chromatography-mass spectrometry, loaded by U. fasciata on ionic-based ZnO and NPs, and then characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. Biosafety and toxicity were investigated by skin tests. A total of 105 C. parvum oocysts/rat were used (n = 81, 2-3 W, 80-120 g, 9 male rats/group). Oocysts shedding was counted for 21 d. Doses of each preparation in addition to reference drug were administered daily for 7 d, starting on post-infection (PI) day (3). Nitazoxanide (100 mg) was used as the reference drug. After 3 weeks, the rats were sacrificed for postmortem examination and histopathological examination. Two blood samples/rat/group were collected on the 21st day. Ethylenediaminetetraacetic acid blood samples were also used for analysis of biochemistry, hematology, immunology, micronucleus prevalence, and chromosomal abnormalities.

Results

C. camphora leaves yielded 28.5 ± 0.3 g/kg oil and 20 phycocompounds were identified. Spherical and rod-shaped particles were detected at 10.47-30.98 nm and 18.83-38.39 nm, respectively. ZnNPs showed the earliest anti-cryptosporidiosis effect during 7-17 d PI. Other hematological, biochemical, immunological, histological, and genotoxicity parameters were significantly fruitful; hence, normalized pathological changes induced by infestation were observed in the NPs treatments groups against the infestation-free and Nitazoxanide treated group.

Conclusion

C. camphora, U. fasciata, ZnNPs, and AgNPs have refluxed the pathological effects of infection as well as positively improved host physiological condition by its anticryptosporidial immunostimulant regenerative effects with sufficient ecofriendly properties to be proposed as an alternative to traditional drugs, especially in individuals with medical reactions against chemical commercial drugs.

A Cryptosporidium parvum vaccine candidate effect on immunohistochemical profiling of CD4+, CD8+, Caspase-3 and NF-κB in mice

BACKGROUND

Cryptosporidium parvum is a protozoan parasite of medical and veterinary importance that causes neonatal diarrhea in many vertebrate hosts. In this study, we evaluated the efficacy of an affinity-purified antigen as a C. parvum vaccine candidate using ileal and liver tissues of experimentally infected neonatal mice by immunohistochemical profiling and immune scoring of CD4+, CD8+, Caspase-3, and nuclear factor kappa B (NF-κB). This vaccine was prepared from the C. parvum oocysts antigen using immune affinity chromatography with cyanogen bromide-activated Sepharose-4B beads.

METHODS

Thirty neonatal mice were divided into three groups (10 mice/group): (1) non-immunized non-infected, (2) non-immunized infected (using gastric tubes with a single dose of 1 × 105 of C. parvum oocysts in 250 µl PBS solution 1 h before a meal) and (3) immunized (twice with 40 µg/kg of purified C. parvum antigen at 2-week intervals and then infected with 1 × 105 C. parvum oocysts simultaneously with the second group). After euthanizing the animals on the 10th day, post-infection, their ileal and liver tissues were collected and prepared for immunohistochemistry (IHC) staining to detect CD4+, CD8+, Caspase-3, and NF-κB levels, which are indicators for T helper cells, cytotoxic T cells, apoptosis, and inflammation, respectively.

RESULTS

The IHC results showed that CD4+, CD8+, Caspase-3, and NF-κB expression varied significantly (P < 0.001) in both organs in all the groups. We also recorded high CD4+ levels and low CD8+ expression in the non-immunized non-infected mice tissues, while the opposite was observed in the non-immunized infected mice tissues. In the immunized infected mice, the CD4+ level was higher than CD8 + in both organs. While the Caspase-3 levels were higher in the ileal tissue of non-immunized infected than immunized infected mice ileal tissues, the reverse was seen in the liver tissues of both groups. Furthermore, NF-κB expression was higher in the liver tissues of non-immunized infected mice than in immunized infected mice tissues. Therefore, the IHC results and immune-scoring program revealed a significant difference (P < 0.001) in the CD4+, CD8+, Caspase-3, and NF-κB expression levels in both ileal and liver tissues of all mice groups, which might be necessary for immunomodulation in these tissues.

CONCLUSIONS

The improvement observed in the immunized infected mice suggests that this vaccine candidate might protect against cryptosporidiosis.

Cytotoxic innate intraepithelial lymphocytes control early stages of Cryptosporidium infection

Background

Intraepithelial lymphocytes (IELs) are the first immune cells to contact and fight intestinal pathogens such as Cryptosporidium, a widespread parasite which infects the gut epithelium. IFN-γ producing CD4+ T IELs provide an efficient and a long-term protection against cryptosporidiosis while intraepithelial type 1 innate lymphoid cells limits pathogen spreading during early stages of infection in immunodeficient individuals. Yet, the role of T-cell like innate IELs, the most frequent subset of innate lymphocytes in the gut, remains unknown.

Methods

To better define functions of innate IELs in cryptosporidiosis, we developed a co-culture model with innate IELs isolated from Rag2-/- mice and 3D intestinal organoids infected with C. parvum using microinjection.

Results

Thanks to this original model, we demonstrated that innate IELs control parasite proliferation. We further showed that although innate IELs secrete IFN-γ in response to C. parvum, the cytokine was not sufficient to inhibit parasite proliferation at early stages of the infection. The rapid protective effect of innate IELs was in fact mediated by a cytotoxic, granzyme-dependent mechanism. Moreover, transcriptomic analysis of the Cryptosporidium-infected organoids revealed that epithelial cells down regulated Serpinb9b, a granzyme inhibitor, which may increase their sensitivity to cytolytic attack by innate IELs.

Conclusion

Based on these data we conclude that innate IELs, most likely T-cell-like innate IELs, provide a rapid protection against C. parvum infection through a perforin/granzymes-dependent mechanism. C. parvum infection. The infection may also increase the sensitivity of intestinal epithelial cells to the innate IEL-mediated cytotoxic attack by decreasing the expression of Serpin genes.

Enterocyte-innate lymphoid cell crosstalk drives early IFN-γ-mediated control of Cryptosporidium

The intestinal parasite, Cryptosporidium, is a major contributor to global child mortality and causes opportunistic infection in immune deficient individuals. Innate resistance to Cryptosporidium, which specifically invades enterocytes, is dependent on the production of IFN-γ, yet whether enterocytes contribute to parasite control is poorly understood. In this study, utilizing a mouse-adapted strain of C. parvum, we show that epithelial-derived IL-18 synergized with IL-12 to stimulate innate lymphoid cell (ILC) production of IFN-γ required for early parasite control. The loss of IFN-γ-mediated STAT1 signaling in enterocytes, but not dendritic cells or macrophages, antagonized early parasite control. Transcriptional profiling of enterocytes from infected mice identified an IFN-γ signature and enrichment of the anti-microbial effectors IDO, GBP, and IRG. Deletion experiments identified a role for Irgm1/m3 in parasite control. Thus, enterocytes promote ILC production of IFN-γ that acts on enterocytes to restrict the growth of Cryptosporidium.

Antiparasitic and immunomodulating effects of nitazoxanide, ivermectin and selenium on Cryptosporidium infection in diabetic mice

The present work aims to investigate the antiparasitic and the immunomodulating effects of nitazoxanide (NTZ) and ivermectin (IVC) alone or combined together or combined with selenium (Se), on Cryptosporidium infection in diabetic mice. The results revealed that the combined NTZ and IVC therapy achieved the highest reduction of fecal oocysts (92%), whereas single NTZ showed the lowest reduction (63%). Also, adding Se to either NTZ or IVC resulted in elevation of oocyst reduction from 63% to 71% and from 82% to 84% respectively. All treatment regimens, with the exception of NTZ monotherapy, showed a significant improvement in the intestinal histopathology, the highest score was in combined NTZ and IVC therapy. The unique results of immunohistochemistry in this study showed reversal of the normal CD4/CD8 T cell ratio in the infected untreated mice, however, following therapy it reverts back to a normal balanced ratio. The combined (NTZ+ IVC) treatment demonstrated the highest level of CD4 T cell expression. Taken together, NTZ and IVC combined therapy showed remarkable anti-parasitic and immunostimulatory effects, specifically towards the CD4 population that seem to be promising in controlling cryptosporidiosis in diabetic individuals. Further research is required to explore other effective treatment strategies for those comorbid patients.

Host-directed therapies for parasitic diseases

Parasitic infections are responsible for significant morbidity and mortality throughout the world. Management strategies rely primarily on antiparasitic drugs that have side effects and risk of drug resistance. Therefore, novel strategies are needed for treatment of parasitic infections. Host-directed therapy (HDT) is a viable alternative, which targets host pathways responsible for parasite invasion/survival/pathogenicity. Recent innovative combinations of genomics, proteomics and computational biology approaches have led to discovery of several host pathways that could be promising targets for HDT for treating parasitic infections. Herein, we review major advances in HDT for parasitic disease with regard to core regulatory pathways and their interactions.

Delivery of SA35 and SA40 peptides in mice enhances humoral and cellular immune responses and confers protection against Cryptosporidium parvum infection

BACKGROUND

Cryptosporidium parvum is a major cause of diarrhea in children and ruminants at the earliest stages of life. Maternal antibodies represent the main shield of neonate mammals for most of the infections. Two recombinant antigens (SA35 and SA40), portions of two C. parvum proteins, were tested for their ability to induce immune responses in adult mice and for protection on neonate BALB/c mice born from females immunised by mucosal delivery of both peptides.

METHODS

Adult BALB/c mice were intraperitoneally immunised with SA35 and SA40, separately or mixed, and their immune response was characterised. Furthermore, BALB/c pregnant mice were immunised by mucosal delivery with an SA35/40 mix, before and during pregnancy. Soon after birth, their offspring were infected with two doses (1 × 105 and 5 × 103) of C. parvum oocysts and the parasitic burden was determined at 5 and 9 days post-infection.

RESULTS

Intraperitoneal immunisation with SA35 and SA40 induced specific IgG and IgG1 in serum, specific IgA in the intestinal mucosa, increase of CD3+/CD4+ and CD30+ cells in splenocytes, which produced IFN-γ. Neonates born from immunised mice and infected with 1 × 105 oocysts showed a significant reduction of oocysts and intestinal forms (23 and 42%, respectively). A reduction of all parasitic forms (96%; P < 0.05) was observed when neonates were infected with 5 × 103 oocysts.

CONCLUSIONS

SA35 and SA40 peptides induce specific humoral and cell-mediated immune responses to C. parvum in adult mice. Moreover, mucosal administration of the SA35/40 mix in pregnant mice reduces C. parvum burden in their litters.

Cryptosporidiosis: host immune responses and the prospects for effective immunotherapies

Cryptosporidium spp. that develop in intestinal epithelial cells are responsible for the diarrhoeal disease cryptosporidiosis, which is common in humans of all ages and in neonatal livestock. Following infection, parasite reproduction increases for a number of days before it is blunted and then impeded by innate and adaptive immune responses. Immunocompromised hosts often cannot establish strong immunity and develop chronic infections that can lead to death. Few drugs consistently inhibit parasite reproduction in the host, and chemotherapy might be ineffective in immunodeficient hosts. Future options for prevention or treatment of cryptosporidiosis might include vaccines or recombinant immunological molecules, but this will probably require a better understanding of both the mucosal immune system and intestinal immune responses to the parasite.

Cryptosporidiosis-an overview

Apicomplexan protozoan parasites of the genus Cryptosporidium infect the gastrointestinal tract and lungs of a wide variety of animals, including humans. The majority of human infections are due to either Cryptosporidium hominis (C. hominis) and/or Cryptosporidium parvum (C. parvum). The parasite has a complex life cycle that includes both asexual and sexual stages. While there are invasive free living stages, proliferation and differentiation take place within a unique parasitrophorous vacuole under the host cell brush border but outside the host cell cytoplasm. Infection is spread by environmentally resistant spores that primarily contaminate drinking water and occasionally food sources, which may cause significant outbreaks of diarrhea that generally lasts less than 2 w in immunocompetent individuals. In immunodeficient or immunosuppressed individuals, diarrhea may be copious and can result in significant morbidity and mortality, particularly in AIDS patients. Although diagnosis is relatively simple, effective drug treatment, particulary for infections in immunodeficient patients, has not been uniformly successful. This overview summarizes the species known to infect humans, aspects of the parasite life cycle, sources of infection, the pathophysiology of cryptosporidiosis, the immune response to infection, diagnosis, treatment and some aspects of cryptosporidiosis in China.

Prevalence and clinical significance of Cryptosporidium infection in patients with hepatitis B virus-associated acute-on-chronic liver failure

BACKGROUND

Patients with acute-on-chronic liver failure (ACLF) are often highly susceptible to microbial infection due to a depressed immune system. This study was carried out to investigate the prevalence and clinical significance of Cryptosporidium infection in patients with hepatitis B virus (HBV)-associated ACLF in Hunan Province, China.

METHODS

Fecal samples from 218 patients with HBV-associated ACLF, 122 patients with chronic hepatitis B (CHB), and 140 children with diarrhea were collected; Cryptosporidium infection was detected by auramine-phenol staining, modified acid-fast staining, and the polymerase chain reaction. The clinical characteristics of this parasitic infection in Cryptosporidium-positive ACLF patients were further evaluated.

RESULTS

The prevalence of Cryptosporidium infection in the HBV-associated ACLF patients was 6.0% (13/218), which was markedly higher than that found in CHB patients (0.8%, 1/122) and in children with diarrhea (1.4%, 2/140). Although watery diarrhea was not seen in the 13 Cryptosporidium-positive ACLF patients, eight (61.5%) of them had diarrhea. Moreover, our investigation showed that Cryptosporidium infection was not associated with the severity of the disease in ACLF patients.

CONCLUSIONS

The prevalence of Cryptosporidium infection is high among patients with HBV-associated ACLF and might be a significant cause of diarrhea in this population.

Immunogenicity of orally administrated recombinant Lactobacillus casei Zhang expressing Cryptosporidium parvum surface adhesion protein P23 in mice

Cryptosporidium parvum, an intestinal apicomplexan parasite, is a significant cause of diarrheal diseases in both humans and animals. What is more, there is no promising strategy for controlling cryptosporidiosis. In this study, the P23 immunodominant surface protein of C. parvum sporozoites was stably expressed in the Lactobacillus casei Zhang strain and its immunogenicity was evaluated in a mouse model. The molecular weight (23 kDa) and immunogenicity of p23 gene expressed by L. casei Zhang were similar to that of the native P23 protein. Oral immunization with control L. casei Zhang and recombinant L. casei Zhang-p23 activated the mucosal immune system to elicit serum immunoglobulin G (IgG) and mucosal IgA in mice. Furthermore, the expression of cytokines such as IL-4, IL-6, and IFN-γ in splenocytes of mice was detected by real-time PCR after oral immunization. P23-specific immunocyte activation was also verified. These findings indicate that the live L. casei Zhang vector may be a new tool for the production of mucosal vaccines against cryptosporidiosis in animals.