A quadrivalent norovirus vaccine based on a chimpanzee adenovirus vector induces potent immunity in mice.

Norovirus (NoV) infection is a major cause of gastroenteritis worldwide. The virus poses great challenges in developing vaccines with broad immune protection due to its genetic and antigenic diversity. To date, there are no approved NoV vaccines for clinical use. Here, we aimed to develop a broad-acting quadrivalent NoV vaccine based on a chimpanzee adenovirus vector, AdC68, carrying the major capsid protein (VP1) of noroviral GI and GII genotypes. Compared to intramuscular (i.m.), intranasal (i.n.), or other prime-boost immunization regimens (i.m. â€‹+ â€‹i.m., i.m. â€‹+ â€‹i.n., i.n. â€‹+ â€‹i.m.), AdC68-GI.1-GII.3 (E1)-GII.4-GII.17 (E3), administered via i.n. â€‹+ â€‹i.n. induced higher titers of serum IgG antibodies and higher IgA antibodies in bronchoalveolar lavage fluid (BALF) and saliva against the four homologous VP1s in mice. It also significantly stimulated the production of blocking antibodies against the four genotypes. In response to re-stimulation with virus-like particles (VLP)-GI.1, VLP-GII.3, VLP-GII.4, and VLP-GII.17, the quadrivalent vaccine administered according to the i.n. â€‹+ â€‹i.n. regimen effectively triggered specific cell-mediated immune responses, primarily characterized by IFN-γ secretion. Furthermore, the preparation of this novel quadrivalent NoV vaccine requires only a single recombinant adenovirus to provide broad preventive immunity against the major GI/GII epidemic strains, making it a promising vaccine candidate for further development.

Severe Immune-Related Enteritis after In Utero Exposure to Pembrolizumab.

Immune checkpoint blockade has become standard treatment for many types of cancer. Such therapy is indicated most often in patients with advanced or metastatic disease but has been increasingly used as adjuvant therapy in those with early-stage disease. Adverse events include immune-related organ inflammation resembling autoimmune diseases. We describe a case of severe immune-related gastroenterocolitis in a 4-month-old infant who presented with intractable diarrhea and failure to thrive after in utero exposure to pembrolizumab. Known causes of the symptoms were ruled out, and the diagnosis of pembrolizumab-induced immune-related gastroenterocolitis was supported by the results of histopathological assays, immunophenotyping, and analysis of the level of antibodies against programmed cell death protein 1 (PD-1). The infant's condition was successfully treated with prednisolone and infliximab.

Activation of Nod2 signaling upon norovirus infection enhances antiviral immunity and susceptibility to colitis.

Over 90% of epidemic non-bacterial gastroenteritis are caused by human noroviruses (NoVs), which persist in a substantial subset of people allowing their spread worldwide. This has led to a significant number of endemic cases and up to 70,000 children deaths in developing countries. NoVs are primarily transmitted through the fecal-oral route. To date, studies have focused on the influence of the gut microbiota on enteric viral clearance by mucosal immunity. In this study, the use of mouse norovirus S99 (MNoV_S99) and CR6 (MNoV_CR6), two persistent strains, allowed us to provide evidence that the norovirus-induced exacerbation of colitis severity relied on bacterial sensing by nucleotide-binding oligomerization domain 2 (Nod2). Consequently, Nod2-deficient mice showed reduced levels of gravity of Dextran sodium sulfate (DSS)-induced colitis with both viral strains. And MNoV_CR6 viremia was heightened in Nod2-/- mice in comparison with animals hypomorphic for Atg16l1, which are prone to aggravated inflammation under DSS. Accordingly, the infection of macrophages derived from WT mice promoted the phosphorylation of Signal Transducer and Activator of Transcription 1 (STAT1) and NOD2's expression levels. Higher secretion of Tumor Necrosis Factor alpha (TNFα) following NOD2 activation and better viral clearance were measured in these cells. By contrast, reduced levels of pSTAT1 and blunted downstream secretion of TNFα were found in Nod2-deficient macrophages infected by MNoV_S99. Hence, our results uncover a previously unidentified virus-host-bacterial interplay that may represent a novel therapeutic target for treating noroviral origin gastroenteritis that may be linked with susceptibility to several common illnesses such as Crohn's disease.

IL-17D affects the chemokines and chemokine receptors of intestinal epithelial cells under hyperoxia.

IL-17D is a new member of the IL-17 family. Currently, it is believed that IL-17D can directly act on immune cells or may indirectly modulate immune responses by regulating cytokine expression. Herein, we hypothesized that IL-17D regulates the expression of chemokines in intestinal epithelial cells, in turn modulating the immune response within intestinal mucosa under hyperoxia. To explore this notion, newborn rats were divided into a hyperoxia group (85 % O2) and control group (21 % O2). Small intestinal tissues were obtained from neonatal rats at 3, 7, 10, and 14 days. Similarly, intestinal epithelial cells were treated by hyperoxia (85 % O2) as the hyperoxia group or were incubated under normal oxygen (21 % O2) as the control group. Finally, intestinal epithelial cells subjected to hyperoxia were treated with recombinant IL-17D and IL-17D antibodies for 24, 48, and 72 h. Immunohistochemistry, western blot, and reverse transcription-quantitative polymerase chain reaction were used to detect the expression levels of chemokines and chemokine receptors in intestinal tissues of newborn rats and intestinal epithelial cells. We found that hyperoxia affected chemokine expression both in vivo and in vitro. Under hyperoxia, IL-17D promoted the expression of CCL2, CCL25, CCL28, and CCR9 in intestinal epithelial cells while downregulating CCR2, CCR5, CCL5, and CCL20. Our findings provide a basis for further study on the effects of hyperoxia-induced intestinal inflammation and intestinal injury.

Obesity in Humans Is Characterized by Gut Inflammation as Shown by Pro-Inflammatory Intestinal Macrophage Accumulation.

Chronic low-grade inflammation is a hallmark of obesity and associated with cardiovascular complications. However, it remains unclear where this inflammation starts. As the gut is constantly exposed to food, gut microbiota, and metabolites, we hypothesized that mucosal immunity triggers an innate inflammatory response in obesity. We characterized five distinct macrophage subpopulations (P1-P5) along the gastrointestinal tract and blood monocyte subpopulations (classical, non-classical, intermediate), which replenish intestinal macrophages, in non-obese (BMI<27kg/m2) and obese individuals (BMI>32kg/m2). To elucidate factors that potentially trigger gut inflammation, we correlated these subpopulations with cardiovascular risk factors and lifestyle behaviors. In obese individuals, we found higher pro-inflammatory macrophages in the stomach, duodenum, and colon. Intermediate blood monocytes were also increased in obesity, suggesting enhanced recruitment to the gut. We identified unhealthy lifestyle habits as potential triggers of gut and systemic inflammation (i.e., low vegetable intake, high processed meat consumption, sedentary lifestyle). Cardiovascular risk factors other than body weight did not affect the innate immune response. Thus, obesity in humans is characterized by gut inflammation as shown by accumulation of pro-inflammatory intestinal macrophages, potentially via recruited blood monocytes. Understanding gut innate immunity in human obesity might open up new targets for immune-modulatory treatments in metabolic disease.

Novel Models for Chronic Intestinal Inflammation in Chickens: Intestinal Inflammation Pattern and Biomarkers.

For poultry producers, chronic low-grade intestinal inflammation has a negative impact on productivity by impairing nutrient absorption and allocation of nutrients for growth. Understanding the triggers of chronic intestinal inflammation and developing a non-invasive measurement is crucial to managing gut health in poultry. In this study, we developed two novel models of low-grade chronic intestinal inflammation in broiler chickens: a chemical model using dextran sodium sulfate (DSS) and a dietary model using a high non-starch polysaccharide diet (NSP). Further, we evaluated the potential of several proteins as biomarkers of gut inflammation. For these experiments, the chemical induction of inflammation consisted of two 5-day cycles of oral gavage of either 0.25mg DSS/ml or 0.35mg DSS/ml; whereas the NSP diet (30% rice bran) was fed throughout the experiment. At four times (14, 22, 28 and 36-d post-hatch), necropsies were performed to collect intestinal samples for histology, and feces and serum for biomarkers quantification. Neither DSS nor NSP treatments affected feed intake or livability. NSP-fed birds exhibited intestinal inflammation through 14-d, which stabilized by 36-d. On the other hand, the cyclic DSS-treatment produced inflammation throughout the entire experimental period. Histological examination of the intestine revealed that the inflammation induced by both models exhibited similar spatial and temporal patterns with the duodenum and jejunum affected early (at 14-d) whereas the ileum was compromised by 28-d. Calprotectin (CALP) was the only serum protein found to be increased due to inflammation. However, fecal CALP and Lipocalin-2 (LCN-2) concentrations were significantly greater in the induced inflammation groups at 28-d. This experiment demonstrated for the first time, two in vivo models of chronic gut inflammation in chickens, a DSS and a nutritional NSP protocols. Based on these models we observed that intestinal inflammation begins in the upper segments of small intestine and moved to the lower region over time. In the searching for a fecal biomarker for intestinal inflammation, LCN-2 showed promising results. More importantly, calprotectin has a great potential as a novel biomarker for poultry measured both in serum and feces.

Endoscopic features and clinical outcomes of cytomegalovirus gastroenterocolitis in immunocompetent patients.

We aimed to investigate the endoscopic features and clinical course of CMV gastroenterocolitis in immunocompetent patients. We reviewed the medical records and endoscopic images of 86 immunocompetent patients with CMV gastroenterocolitis. Immunocompetent patients were defined as those without congenital or acquired immunodeficiency syndrome, use of anti-cancer chemotherapeutic and immunosuppressive agents, and inflammatory bowel diseases. The mean age was 65.5 ± 11.8 years and 53 (61.6%) were male. Sixty-eight (79.1%) patients had comorbidities. Upper gastrointestinal-dominant, small bowel-dominant, and colon-dominant types were observed in 19, 7, and 60 patients, respectively. Endoscopic features could be classified into discrete ulcerative type with/without exudate and diffuse erythematous type with/without exudate. Antiviral treatment with ganciclovir was initiated in 51 patients (59.3%), 40 of whom improved and 1 improved after changing ganciclovir to foscarnet. Thirty-three patients (38.4%) improved without antiviral treatment. Surgery was necessary in two patients because of colon perforation before antiviral treatment. Another two patients underwent surgery because of sigmoid stricture and cecal perforation during antiviral treatment. Endoscopic type was not associated with clinical outcomes, such as surgery and death. CMV gastroenterocolitis in immunocompetent patients mostly occur in older patients with comorbidities, and the endoscopic features vary with no association with clinical outcomes.

Virus-Host Interactions Between Nonsecretors and Human Norovirus.

BACKGROUND & AIMS: Human norovirus infection is the leading cause of acute gastroenteritis. Genetic polymorphisms, mediated by the FUT2 gene (secretor enzyme), define strain susceptibility. Secretors express a diverse set of fucosylated histoblood group antigen carbohydrates (HBGA) on mucosal cells; nonsecretors (FUT2-/-) express a limited array of HBGAs. Thus, nonsecretors have less diverse norovirus strain infections, including resistance to the epidemiologically dominant GII.4 strains. Because future human norovirus vaccines will comprise GII.4 antigen and because secretor phenotype impacts GII.4 infection and immunity, nonsecretors may mimic young children immunologically in response to GII.4 vaccination, providing a needed model to study cross-protection in the context of limited pre-exposure. METHODS: By using specimens collected from the first characterized nonsecretor cohort naturally infected with GII.2 human norovirus, we evaluated the breadth of serologic immunity by surrogate neutralization assays, and cellular activation and cytokine production by flow cytometry. RESULTS: GII.2 infection resulted in broad antibody and cellular immunity activation that persisted for at least 30 days for T cells, monocytes, and dendritic cells, and for 180 days for blocking antibody. Multiple cellular lineages expressing interferon-γ and tumor necrosis factor-α dominated the response. Both T-cell and B-cell responses were cross-reactive with other GII strains, but not GI strains. To promote entry mechanisms, inclusion of bile acids was essential for GII.2 binding to nonsecretor HBGAs. CONCLUSIONS: These data support development of within-genogroup, cross-reactive antibody and T-cell immunity, key outcomes that may provide the foundation for eliciting broad immune responses after GII.4 vaccination in individuals with limited GII.4 immunity, including young children.

Eosinophils, a Jack of All Trades in Immunity: Therapeutic Approaches for Correcting Their Functional Disorders.

BACKGROUND AND OBJECTIVE: Eosinophils are primitive myeloid cells derived from bonemarrow precursors and require the intervention of interleukin (IL)-5 for their survival and persistence in blood and tissues. Under steady-state conditions, they contribute to immune regulation and homeostasis. Under pathological circumstances, eosinophils are involved in host protection against parasites and participate in allergy and inflammation. DISCUSSION: Mostly, in asthma, eosinophils provoke airway damage via the release of granule contents and IL-13 with mucus hypersecretion and differentiation of goblet cells. Then, tissue remodeling follows with the secretion of transforming growth factor-ß. Eosinophils are able to kill helminth larvae acting as antigen-presenting cells with the involvement of T helper (h)-2 cells and subsequent antibody response. However, they also exert pro-worm activity with the production of suppressive cytokine (IL- 10 and IL-4) and inhibition of nitric oxide. Eosinophils may play a pathogenic role in the course of chronic and autoimmune disease, e.g., inflammatory bowel disease and eosinophilic gastroenteritis, regulating Th2 responses and promoting a profibrotic effect. In atopic dermatitis, eosinophils are commonly detected and may be associated with disease severity. In cutaneous spontaneous urticaria, eosinophils participate in the formation of wheals, tissue remodeling and modifications of vascular permeability. With regard to tumor growth, it seems that IgE can exert anti-neoplastic surveillance via mast cell and eosinophil-mediated cytotoxicity, the so-called allergo-oncology. From a therapeutic point of view, monoclonal antibodies directed against IL-5 or the IL-5 receptors have been shown to be very effective in patients with severe asthma. Finally, as an alternative treatment, polyphenols for their anti-inflammatory and anti-allergic activities seem to be effective in reducing serum IgE and eosinophil count in bronchoalveolar lavage in murine asthma. CONCLUSION: Eosinophils are cells endowed with multiple functions and their modulation with monoclonal antibodies and nutraceuticals may be effective in the treatment of chronic disease.

A 72-Year-Old Man With a Violaceous Rash and Sepsis.

CASE PRESENTATION: A 72-year-old man presented to our ED less than 24 hours following the acute onset of nausea, vomiting, and diarrhea. Within 12 hours of symptom onset, he noted bilateral lower extremity pain and swelling. His pain was associated with a new violaceous irregular rash on the anterior aspect of both feet and legs. There was no history of inciting trauma or recent wounds. In addition, there was no history of consumption of raw or undercooked food (including seafood) or recent change in food source. There was accompanying fever and chills for the same duration and painful swelling of his left thumb. His comorbidities included stage IIIb classical Hodgkin lymphoma diagnosed 4 months prior. His last dose of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy was 4 days before presentation. He had previously failed anti-CD30 monoclonal therapy resulting from attributed pancolitis.

Systemic BK Virus Infection in a Pediatric Patient With Severe Combined Immunodeficiency.

Human BK virus (BKV) infection is known to occur mostly during childhood with the establishment of latent infection with no tissue damage or clinical manifestations. However, conditions causing immunosuppression can lead to increased virus replication and tissue damage. Although the tissues most commonly involved are the kidneys, bladder, ureters and, to some extent, brain tissue, there are some reports that suggest that BKV may cause multisystemic infections. In this case, a 12-month-old child was seen to suffer from multiple gastrointestinal infections. This prompted a search for immunodeficiencies, which revealed the presence of severe combined immunodeficiency. The child was eventually hospitalized and continued showing recurrent bouts of gastroenteritis as well as lower respiratory infection. After multiple antibiotic courses, he developed acute kidney injury, a hemophagocytic syndrome, and eventually respiratory failure, which led to his death a year later. Autopsy findings revealed the presence of a disseminated BKV infection involving the kidneys, ureters, leptomeninges, and pancreas. Analysis of the literature failed to show any previous case of BKV pancreatitis. The present case suggests that BKV can damage more tissues than previously reported and may be responsible for systemic infections in immunosuppressed patients.

GI inflammation Increases Sodium-Glucose Cotransporter Sglt1.

A correlation between gastrointestinal (GI) inflammation and gut hormones has reported that inflammatory stimuli including bacterial endotoxins, lipopolysaccharides (LPS), TNFα, IL-1ß, and IL-6 induces high levels of incretin hormone leading to glucose dysregulation. Although incretin hormones are immediately secreted in response to environmental stimuli, such as nutrients, cytokines, and LPS, but studies of glucose-induced incretin secretion in an inflamed state are limited. We hypothesized that GI inflammatory conditions induce over-stimulated incretin secretion via an increase of glucose-sensing receptors. To confirm our hypothesis, we observed the alteration of glucose-induced incretin secretion and glucose-sensing receptors in a GI inflammatory mouse model, and we treated a conditioned media (Mϕ 30%) containing inflammatory cytokines in intestinal epithelium cells and enteroendocrine L-like NCI-H716 cells. In GI-inflamed mice, we observed that over-stimulated incretin secretion and insulin release in response to glucose and sodium glucose cotransporter (Sglt1) was increased. Incubation with Mϕ 30% increases Sglt1 and induces glucose-induced GLP-1 secretion with increasing intracellular calcium influx. Phloridzin, an sglt1 inhibitor, inhibits glucose-induced GLP-1 secretion, ERK activation, and calcium influx. These findings suggest that the abnormalities of incretin secretion leading to metabolic disturbances in GI inflammatory disease by an increase of Sglt1.

Colon perforation due to antigenemia-negative cytomegalovirus gastroenteritis after liver transplantation: A case report and review of literature.

BACKGROUND: Cytomegalovirus (CMV) remains a critical complication after solid-organ transplantation. The CMV antigenemia (AG) test is useful for monitoring CMV infection. Although the AG-positivity rate in CMV gastroenteritis is known to be low at onset, almost all cases become positive during the disease course. We treated a patient with transverse colon perforation due to AG-negative CMV gastroenteritis, following a living donor liver transplantation (LDLT). CASE SUMMARY: The patient was a 52-year-old woman with decompensated liver cirrhosis as a result of autoimmune hepatitis who underwent a blood-type compatible LDLT with her second son as the donor. On day 20 after surgery, upper and lower gastrointestinal endoscopy (GE) revealed multiple gastric ulcers and transverse colon ulcers. The biopsy tissue immunostaining confirmed a diagnosis of CMV gastroenteritis. On day 28 after surgery, an abdominal computed tomography revealed transverse colon perforation, and simple lavage and drainage were performed along with an urgent ileostomy. Although the repeated remission and aggravation of CMV gastroenteritis and acute cellular rejection made the control of immunosuppression difficult, the upper GE eventually revealed an improvement in the gastric ulcers, and the biopsy samples were negative for CMV. The CMV-AG test remained negative, therefore, we had to evaluate the status of the CMV infection on the basis of the clinical symptoms and GE. CONCLUSION: This case report suggests a monitoring method that could be useful for AG-negative CMV gastroenteritis after a solid-organ transplantation.

IL-22 Preserves Gut Epithelial Integrity and Promotes Disease Remission during Chronic Salmonella Infection.

The cytokine IL-22 is rapidly induced at barrier surfaces where it regulates host-protective antimicrobial immunity and tissue repair but can also enhance disease severity in some chronic inflammatory settings. Using the chronic Salmonella gastroenteritis model, Ab-mediated neutralization of IL-22 impaired intestinal epithelial barrier integrity and, consequently, exaggerated expression of proinflammatory cytokines. As disease normally resolved, neutralization of IL-22 caused luminal narrowing of the cecum-a feature reminiscent of fibrotic strictures seen in Crohn disease patients. Corresponding to the exaggerated immunopathology caused by IL-22 suppression, Salmonella burdens in the gut were reduced. This enhanced inflammation and pathogen clearance was associated with alterations in gut microbiome composition, including the overgrowth of Bacteroides acidifaciens Our findings thus indicate that IL-22 plays a protective role by limiting infection-induced gut immunopathology but can also lead to persistent pathogen colonization.

ATP released by intestinal bacteria limits the generation of protective IgA against enteropathogens.

T cell dependent secretory IgA (SIgA) generated in the Peyer's patches (PPs) of the small intestine shapes a broadly diverse microbiota that is crucial for host physiology. The mutualistic co-evolution of host and microbes led to the relative tolerance of host's immune system towards commensal microorganisms. The ATP-gated ionotropic P2X7 receptor limits T follicular helper (Tfh) cells expansion and germinal center (GC) reaction in the PPs. Here we show that transient depletion of intestinal ATP can dramatically improve high-affinity IgA response against both live and inactivated oral vaccines. Ectopic expression of Shigella flexneri periplasmic ATP-diphosphohydrolase (apyrase) abolishes ATP release by bacteria and improves the specific IgA response against live oral vaccines. Antibody responses primed in the absence of intestinal extracellular ATP (eATP) also provide superior protection from enteropathogenic infection. Thus, modulation of eATP in the small intestine can affect high-affinity IgA response against gut colonizing bacteria.

Progress on norovirus vaccine research: public health considerations and future directions.

INTRODUCTION: Noroviruses are the leading cause of foodborne illness worldwide, account for approximately one-fifth of acute gastroenteritis (AGE) cases globally, and cause a substantial economic burden. Candidate norovirus vaccines are in development, but there is currently no licensed vaccine. AREAS COVERED: Noroviruses cause approximately 684 million cases and 212,000 deaths per year across all age groups, though burden estimates vary by study and region. Challenges to vaccine research include substantial and rapidly evolving genetic diversity, short-term and homotypic immunity to infection, and the absence of a single, well-established correlate of protection. Nonetheless, several norovirus vaccine candidates are currently in development, utilizing virus-like particles (VLPs), P particles, and recombinant adenoviruses. Of these, a bivalent GI.1/GII.4 VLP-based intramuscular vaccine (Phase IIb) and GI.1 oral vaccine (Phase I) are in clinical trials. EXPERT COMMENTARY: A norovirus vaccine should target high-risk populations, including the young and the elderly, and protect them against the most common circulating norovirus strains. A norovirus vaccine would be a powerful tool in the prevention and control of norovirus while lessening the burden of AGE worldwide. However, more robust burden and cost estimates are needed to justify investments in and guide norovirus vaccine development.

Routine Hematoxylin and Eosin Stain Is Specific for the Diagnosis of Cytomegalovirus Infection in Gastrointestinal Biopsy Specimens.

BACKGROUND: Gastrointestinal cytomegalovirus (CMV) infection is a serious complication in immunocompromised patients; clinicians often expect expedited results for biopsy specimens. Our goal is to determine the accuracy of identification of CMV on hematoxylin and eosin (H&E) stain. METHODS AND RESULTS: A total of 361 biopsy specimens from 273 patients with suspicion for CMV infection were retrieved. CMV was detected by immunohistochemistry (IHC) in 37 specimens acquired from 33 individual patients (average age = 54 years). Among the CMV-positive patients, 29 (88%) were reported to be immunosuppressed. Colon was the most common affected location. Of 37 CMV-positive specimens by IHC, 28 were positive by H&E (76%), 6 were negative (16%), and 3 were suspicious (8%). Of the 29 positive specimens on H&E, 28 were confirmed by IHC (97%) and 1 was indeterminate (3%). The sensitivity and specificity of H&E were 84% and 94%, respectively; the positive predictive value was 97%, and the negative predictive value was 93% ( P < .00001). CONCLUSION: Our results show that a preliminary diagnosis of CMV infection, based on H&E stains, can be reported with high specificity and low risk for false-positive results. Suspicious cases should be deferred pending the result of IHC stains.

A nano silicon adjuvant enhances inactivated transmissible gastroenteritis vaccine through activation the Toll-like receptors and promotes humoral and cellular immune responses.

Inactivated transmissible gastroenteritis virus (TGEV) vaccines are widely used in swine herds in China. These are limited, however, by the need to elicit both humoral and cellular immunity, as well as the efficiency of adjuvants. In this study, a 70-nm nano silicon particle was applied with inactivated TGEV vaccine in mice, and its immune-enhancing effects and mechanism of action investigated. We found that nano silicon applied with inactivated TGEV vaccine induced high antibody titers, increase IL-6, TNF-α and IFN-γ expression, and stimulate CD3+ T cell proliferation with a high CD4+/CD8+ T lymphocyte ratio. Nano silicon could quickly activate innate and adaptive immunity by stimulating Toll-like receptor signaling pathways, indicating that the nano silicon adjuvant enhanced long-term humoral and early cellular immune responses when combined with inactivated TGEV vaccine. Nano silicon could be considered for use as an antigen- carrier and adjuvant for veterinary vaccines.

Natural killer cell activity irreversibly decreases after Cryptosporidium gastroenteritis in neonatal mice.

Cryptosporidiosis causes persistent diarrhoea in infants, immunocompromised patients and elderly persons. Long-term consequences of the disease include increased risk of malignancy, cardiomyopathy and gastrointestinal inflammation. This study aimed to investigate prolonged effects of cryptosporidiosis on innate immunity and growth in neonatal C3HA mice. The disease was challenged by Cryptosporidium parvum oocyst inoculation into 7-day-old animals. The mice whose intestine smears contained 3-5 or 6 and more oocysts per microscopic field at the day 5 after infection were considered as mildly or severely infected, correspondingly. To determine natural killer cell (NK) activity, we applied 3 H-uridine cytotoxic assay to the animals at 5-68 days after infection using K562 cells as targets. At severe infection, there was a statistically significant 1.5-2.0 fold decline of body mass, spleen mass and spleen cellularity that persisted in animals of all ages. Accordingly, NK cytotoxicity showed even more drastic drop reaching 2.7-3.0 folds that was statistically significant in all animals. At mild infection, the discovered effects were less pronounced and reached significance only in some age groups. Thus, our study provides evidence that NK cells show long-term cytotoxic activity decrease following Cryptosporidium infection in neonatal mice, particularly in severe disease.