Nanoparticle-delivered TLR4 and RIG-I agonists enhance immune response to SARS-CoV-2 subunit vaccine.

Despite success in vaccinating populations against SARS-CoV-2, concerns about immunity duration, continued efficacy against emerging variants, protection from infection and transmission, and worldwide vaccine availability remain. Molecular adjuvants targeting pattern recognition receptors (PRRs) on antigen-presenting cells (APCs) could improve and broaden the efficacy and durability of vaccine responses. Native SARS-CoV-2 infection stimulates various PRRs, including toll-like receptors (TLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors. We hypothesized that targeting PRRs using molecular adjuvants on nanoparticles (NPs) along with a stabilized spike protein antigen could stimulate broad and efficient immune responses. Adjuvants targeting TLR4 (MPLA), TLR7/8 (R848), TLR9 (CpG), and RIG-I (PUUC) delivered on degradable polymer NPs were combined with the S1 subunit of spike protein and assessed in vitro with isogeneic mixed lymphocyte reactions (isoMLRs). For in vivo studies, the adjuvant-NPs were combined with stabilized spike protein or spike-conjugated NPs and assessed using a two-dose intranasal or intramuscular vaccination model in mice. Combination adjuvant-NPs simultaneously targeting TLR and RIG-I receptors (MPLA+PUUC, CpG+PUUC, and R848+PUUC) differentially induced T cell proliferation and increased proinflammatory cytokine secretion by APCs in vitro. When delivered intranasally, MPLA+PUUC NPs enhanced CD4+CD44+ activated memory T cell responses against spike protein in the lungs while MPLA NPs increased anti-spike IgA in the bronchoalveolar (BAL) fluid and IgG in the blood. Following intramuscular delivery, PUUC NPs induced strong humoral immune responses, characterized by increases in anti-spike IgG in the blood and germinal center B cell populations (GL7+ and BCL6+ B cells) in the draining lymph nodes (dLNs). MPLA+PUUC NPs further boosted spike protein-neutralizing antibody titers and T follicular helper cell populations in the dLNs. These results suggest that protein subunit vaccines with particle-delivered molecular adjuvants targeting TLR4 and RIG-I could lead to robust and unique route-specific adaptive immune responses against SARS-CoV-2.

Can the intestine perform some functions of the kidney?

The majority of patients in countries like India and Pakistan with end-stage renal disease (ESRD) die without renal replacement therapy due to lack of adequate resources. The use of the intestinal mucosa as a semipermeable membrane for removal of urea and creatinine from the body has been previously studied using various types of intestinal lavage for gut dialysis. This study was undertaken in an animal model to assess the applicability, cost of therapy, and acceptability of the method for potential application in humans. Renal failure was induced in six dogs by bilateral ureteric ligation along with six healthy controls. Dialysis fluid was introduced per rectum as an enema, which was repeatedly administered. Clearances of serum creatinine and urea were assessed. Mean recovery of creatinine and urea in dialysate in the present study was around 8.925 mmol/l and around 207.74 micromol//l, respectively. The mean clearances of serum creatinine and urea were, respectively, 0.0683 and 0.0633 ml/sec. Enteral dialysis was effective and, considering its minimal cost (monthly cost will be around US$35-40) vis a vis available methods, it holds promise for the treatment of patients with ESRD. The creation of an appendicostomy for repeated introduction of antegrade enemas would be a consideration.

Comparative evaluation of heating ability and biocompatibility of different ferrite-based magnetic fluids for hyperthermia application.

In this study, lauric acid-coated, superparamagnetic, nanoparticle-based magnetic fluids of different ferrites (Fe(3)O(4), MnFe(2)O(4), and CoFe(2)O(4)) were prepared and compared in terms of heating ability and biocompatibility to evaluate the feasibility of use in hyperthermia treatment of cancer. All the magnetic fluids prepared had particles of average sizes 9-11 nm. Heating ability of these magnetic fluids was evaluated by calorimetric measurement of specific absorption rate (SAR) at 300 kHz frequency and 15 kA/m field. Fe(3)O(4) and MnFe(2)O(4) showed higher SAR (120 and 97 W/g of ferrite, respectively) than CoFe(2)O(4) (37 W/g of ferrite). In vitro study on BHK 21 cell lines showed dose-dependent cell viability for all the magnetic fluids. Threshold-biocompatible ferrite concentration for all the magnetic fluids was 0.1 mg/mL. Above 0.2 mg/mL, CoFe(2)O(4) was more toxic than the other magnetic fluids. On intravenous injection of different doses (50, 200, and 400 mg/kg body weight) of magnetic fluids in mice, no significant changes in hematological and biochemical parameters were observed for Fe(3)O(4) and MnFe(2)O(4). With CoFe(2)O(4), an increase in SGPT levels at a dose rate of 400 mg/kg body weight was observed, indicating its mild hepatotoxic effect. However, histology of different vital organs showed no pathological changes for all the three magnetic fluids. Further, long term in vivo evaluation of biocompatibility of the lauric acid-coated ferrites is warranted. This study shows that lauric acid-coated, superparamagnetic Fe(3)O(4) and MnFe(2)O(4) may be used for hyperthermia treatment and are to be preferred over CoFe(2)O(4).