Evaluation of Cellular and Serological Responses to Acute SARS-CoV-2 Infection Demonstrates the Functional Importance of the Receptor-Binding Domain.

The factors that control the development of an effective immune response to the recently emerged SARS-CoV-2 virus are poorly understood. In this study, we provide a cross-sectional analysis of the dynamics of B cell responses to SARS-CoV-2 infection in hospitalized COVID-19 patients. We observe changes in B cell subsets consistent with a robust humoral immune response, including significant expansion of plasmablasts and activated receptor-binding domain (RBD)-specific memory B cell populations.

Infection- and vaccine-induced antibody binding and neutralization of the B.1.351 SARS-CoV-2 variant.

The emergence of SARS-CoV-2 variants with mutations in the spike protein is raising concerns about the efficacy of infection- or vaccine-induced antibodies. We compared antibody binding and live virus neutralization of sera from naturally infected and Moderna-vaccinated individuals against two SARS-CoV-2 variants: B.1 containing the spike mutation D614G and the emerging B.

Changes in the Microbiome of -Infected Mice Correlate to Differences in Susceptibility and Infection Levels.

spp. are opportunistic protozoan parasites that infect epithelial cells of the small intestine, causing diarrheal illness in humans. Differences in severity may be due to the immunological status of the host, malnutrition or prior exposure but may also be due to differences in the host gut flora.

Inflammasome components caspase-1 and adaptor protein apoptosis-associated speck-like proteins are important in resistance to Cryptosporidium parvum.

Cryptosporidium spp. are opportunistic protozoan parasites that infect epithelial cells in the intestinal tract and cause a flu-like diarrheal illness. Innate immunity is key to limiting the expansion of parasitic stages early in infection.

The Existing Drug Vorinostat as a New Lead Against Cryptosporidiosis by Targeting the Parasite Histone Deacetylases.

Background: Cryptosporidiosis affects all human populations, but can be much more severe or life-threatening in children and individuals with weak or weakened immune systems. However, current options to treat cryptosporidiosis are limited.

Methods: An in vitro phenotypic screening assay was employed to screen 1200 existing drugs for their anticryptosporidial activity and to determine the inhibitory kinetics of top hits.

Auranofin and N-heterocyclic carbene gold-analogs are potent inhibitors of the bacteria Helicobacter pylori.

Auranofin is an FDA-approved gold-containing compound used for the treatment of rheumatoid arthritis. Recent reports of antimicrobial activity against protozoa and bacteria indicate that auranofin targets the reductive enzyme thioredoxin reductase (TrxR). We evaluated auranofin as well as five auranofin analogs containing N-heterocyclic carbenes (instead of the triethylphosphane present in auranofin) and five gold-carbene controls for their ability to inhibit or kill Helicobacter pylori in vitro Auranofin completely inhibited bacterial growth at 1.

IL-18 cytokine levels modulate innate immune responses and cryptosporidiosis in mice.

IL-18 is known to play a key role limiting Cryptosporidium parvum infection. In this study, we show that IL-18 depletion in SCID mice significantly exacerbates C. parvum infection, whereas, treatment with recombinant IL-18 (rIL-18), significantly decreases the parasite load, as compared to controls.

Validation of IMP dehydrogenase inhibitors in a mouse model of cryptosporidiosis.

Cryptosporidium parasites are a major cause of diarrhea and malnutrition in the developing world, a frequent cause of waterborne disease in the developed world, and a potential bioterrorism agent. Currently, available treatment is limited, and Cryptosporidium drug discovery remains largely unsuccessful. As a result, the pharmacokinetic properties required for in vivo efficacy have not been established.

Dendritic cells play a role in host susceptibility to Cryptosporidium parvum infection.

Our previous studies have described dendritic cells (DCs) to be important sources of Th1 cytokines such as IL-12 and IL-2 in vitro, following stimulation with Cryptosporidium parvum antigens. We further established the role of DCs during cryptosporidiosis using a diphtheria toxin promoter regulated transgenic CD11c-DTR/EGFP mouse model. In vivo depletion of CD11c(+) cells in CD11c-DTR-Tg mice significantly increased susceptibility to C.

Amelioration of Cryptosporidium parvum infection in vitro and in vivo by targeting parasite fatty acyl-coenzyme A synthetases.

Background: Cryptosporidium is emerging as 1 of the 4 leading diarrheal pathogens in children in developing countries. Its infections in patients with AIDS can be fatal, whereas fully effective treatments are unavailable. The major goal of this study is to explore parasite fatty acyl-coenzyme A synthetase (ACS) as a novel drug target.

CD4⁺ effector and memory cell populations protect against Cryptosporidium parvum infection.

Cryptosporidium parvum is a protozoan parasite that infects the epithelial cells of the small intestine causing diarrheal illness in humans. While T cells are known to be important in resistance and recovery from infection, little has been characterized as to the phenotypic expression of surface effector and memory markers after infection. We used an acute model of infection (C57BL/6 interleukin-12p40), which develops long-standing resistance to re-infection, to characterize expression of different effector and memory cells.

Evaluation of DNA encoding acidic ribosomal protein P2 of Cryptosporidium parvum as a potential vaccine candidate for cryptosporidiosis.

The Cryptosporidium parvum acidic ribosomal protein P2 (CpP2) is an important immunodominant marker in C. parvum infection. In this study, the CpP2 antigen was evaluated as a vaccine candidate using a DNA vaccine model in adult C57BL/6 IL-12 knockout (KO) mice, which are susceptible to C.

Oral immunization with attenuated Salmonella enterica serovar Typhimurium encoding Cryptosporidium parvum Cp23 and Cp40 antigens induces a specific immune response in mice.

Attenuated Salmonella enterica serovar Typhimurium vaccine strain SL3261 was used as an antigen delivery system for the oral immunization of mice against two Cryptosporidium parvum antigens, Cp23 and Cp40. Each antigen was subcloned into the pTECH1 vector system, which allows them to be expressed as fusion proteins with highly immunogenic fragment C of tetanus toxin under the control of the anaerobically inducible nirB promoter. The recombinant vector was introduced into Salmonella Typhimurium vaccine strain SL3261, and the stable soluble expression of the chimeric protein was evaluated and confirmed by Western blotting with polyclonal C.

Modulation of gene expression of three Cryptosporidium parvum ATP-binding cassette transporters in response to drug treatment.

We studied three ATP-binding cassette (ABC) transporters (cgd1_1350, cgd7_4510, and cgd7_4520) of Cryptosporidium parvum that were identified to share a high level of homology with nucleotide binding domains of other parasitic ABC transporters and therefore could be potential candidates of efflux of drugs and/or contribute to the intrinsic resistance to chemotherapy observed of this parasite. Partial characterization and expression analysis of three C. parvum ABC transporters was determined by standard semi-quantitative real-time polymerase chain reaction.

Cryptosporidium parvum: the contribution of Th1-inducing pathways to the resolution of infection in mice.

The contribution of cytokines IL-12, IL-18, IL-23, and IFN-gamma, and Stat1 signaling molecules involved in Th1 responses associated with host resistance to Cryptosporidium parvum infection was investigated in adult IL-12p40(-/-)mice. Host resistance to C. parvum infection was assessed in different mouse strains lacking IL-12, IL-18, and IL-23 genes.

Antiparasitic activity of flavonoids and isoflavones against Cryptosporidium parvum and Encephalitozoon intestinalis.

Flavonoids, polyphenolic compounds found in plants, have demonstrated activity against several parasites and can augment the efficacy of other drugs by either increasing the uptake or decreasing the efflux of these drugs. We evaluated 11 of these compounds alone or in combination in order to test the hypothesis that flavonoids are effective against Cryptosporidium parvum and Encephalitozoon intestinalis. Using in vitro cell culture assays, HCT-8 cells or E6 cells were infected with C.

Cryptosporidium parvum: effect of multi-drug reversing agents on the expression and function of ATP-binding cassette transporters.

In the present study, the gene expression of three multidrug resistance (MDR) and resistance-associated protein (MRP) transport proteins or efflux pumps was characterized and the phenotypic evidence for such pumps was demonstrated in cultured Madin-Darby canine kidney (MDCK) cells. A gradient for the fluorescent probe calcein was established between parasite and host cell suggestive of a parasite extrusion pump at the parasite-host interface. This gradient was decreased in a glucose-free medium containing 2-deoxyglucose or 3-O-methylglucose, by probenecid, and by the isoflavonoid, narigenin, suggesting that the calcein extrusion was energy-dependent and involved an MRP-like pump.