Biocompatible metal-organic frameworks as promising platforms to eradicate HIV reservoirs ex vivo in people living with HIV.

The HIV attacks the immune system provoking an infection that is considered a global health challenge. Despite antiretroviral treatments being effective in reducing the plasma viral load in the blood to undetectable levels in people living with HIV (PLWH), the disease is not cured and has become chronic. This happens because of the existence of anatomical and cellular viral reservoirs, mainly located in the lymph nodes and gastrointestinal tract, which are composed of infected CD4+ T cells with a resting memory phenotype and inaccessible to antiretroviral therapy. Herein, a new therapeutic strategy based on nanotechnology is presented. Different combinations of antiretroviral drugs (bictegravir/tenofovir/emtricitabine and nevirapine/tenofovir/emtricitabine) and toll-like receptor agonists were encapsulated into metal-organic frameworks (MOFs) PCN-224 and ZIF-8. The encapsulation efficiencies of all the drugs, as well as their release rate from the carriers, were measured. In vitro studies about the cell viability, the hemocompatibility, and the platelet aggregation of the MOFs were carried out. Epifluorescence microscopy assays confirmed the ability of ZIF-8 to target a carboxyfluorescein probe inside HeLa cell lines and PBMCs. These results pave the way for the use of these structures to eliminate latent HIV reservoirs from anatomical compartments through the activation of innate immune cells, and a higher efficacy of the triplet combinations of antiretroviral drugs.

Type-A Gelatin-Based Hydrogel Infiltration and Degradation in Titanium Foams as a Potential Method for Localised Drug Delivery.

A gelatin-based hydrogel was infiltrated and degraded-released in two different titanium foams with porosities of 30 and 60 vol.% (Ti30 and Ti60 foams) and fabricated by the space holder technique to evaluate its potential to act as an innovative, alternative, and localised method to introduce both active pharmaceutical ingredients, such as antibiotics and non-steroidal anti-inflammatory drugs, and growth factors, such as morphogens, required after bone-tissue replacement surgeries. In addition, the kinetic behaviour was studied for both infiltration and degradation-release processes. A higher infiltration rate was observed in the Ti60 foam. The maximum infiltration hydrogel was achieved for the Ti30 and Ti60 foams after 120 min and 75 min, respectively. Further, both processes followed a Lucas-Washburn theoretical behaviour, typical for the infiltration of a fluid by capillarity in porous channels. Regarding the subsequent degradation-release process, both systems showed similar exponential degradation performance, with the full release from Ti60 foam (80 min), versus 45 min for Ti30, due to the greater interconnected porosity open to the surface of the Ti60 foam in comparison with the Ti30 foam. In addition, the optimal biocompatibility of the hydrogel was confirmed, with the total absence of cytotoxicity and the promotion of cell growth in the fibroblast cells evaluated.

Immune defects associated with lower SARS-CoV-2 BNT162b2 mRNA vaccine response in aged people.

The immune factors associated with impaired SARS-CoV-2 vaccine response in elderly people are mostly unknown. We studied individuals older than 60 and younger than 60 years, who had been vaccinated with SARS-CoV-2 BNT162b2 mRNA, before and after the first and second dose. Aging was associated with a lower anti-RBD IgG levels and a decreased magnitude and polyfunctionality of SARS-CoV-2-specific T cell response. The dramatic decrease in thymic function in people > 60 years, which fueled alteration in T cell homeostasis, and their lower CD161+ T cell levels were associated with decreased T cell response 2 months after vaccination. Additionally, deficient DC homing, activation, and TLR-mediated function, along with a proinflammatory functional profile in monocytes, were observed in the > 60-year-old group, which was also related to lower specific T cell response after vaccination. These findings might be relevant for the improvement of the current vaccination strategies and for the development of new vaccine prototypes.

Deciphering the quality of SARS-CoV-2 specific T-cell response associated with disease severity, immune memory and heterologous response.

SARS-CoV-2 specific T-cell response has been associated with disease severity, immune memory and heterologous response to endemic coronaviruses. However, an integrative approach combining a comprehensive analysis of the quality of SARS-CoV-2 specific T-cell response with antibody levels in these three scenarios is needed. In the present study, we found that, in acute infection, while mild disease was associated with high T-cell polyfunctionality biased to IL-2 production and inversely correlated with anti-S IgG levels, combinations only including IFN-γ with the absence of perforin production predominated in severe disease. Seven months after infection, both non-hospitalised and previously hospitalised patients presented robust anti-S IgG levels and SARS-CoV-2 specific T-cell response. In addition, only previously hospitalised patients showed a T-cell exhaustion profile. Finally, combinations including IL-2 in response to S protein of endemic coronaviruses were the ones associated with SARS-CoV-2 S-specific T-cell response in pre-COVID-19 healthy donors' samples. These results could have implications for protective immunity against SARS-CoV-2 and recurrent COVID-19 and may help for the design of new prototypes and boosting vaccine strategies.

Biocompatible and Thermoresistant Hydrogels Based on Collagen and Chitosan.

Hydrogels are considered good biomaterials for soft tissue regeneration. In this sense, collagen is the most used raw material to develop hydrogels, due to its high biocompatibility. However, its low mechanical resistance, thermal stability and pH instability have generated the need to look for alternatives to its use. In this sense, the combination of collagen with another raw material (i.e., polysaccharides) can improve the final properties of hydrogels. For this reason, the main objective of this work was the development of hydrogels based on collagen and chitosan. The mechanical, thermal and microstructural properties of the hydrogels formed with different ratios of collagen/chitosan (100/0, 75/25, 50/50, 25/75 and 0/100) were evaluated after being processed by two variants of a protocol consisting in two stages: a pH change towards pH 7 and a temperature drop towards 4 °C. The main results showed that depending on the protocol, the physicochemical and microstructural properties of the hybrid hydrogels were similar to the unitary system depending on the stage carried out in first place, obtaining FTIR peaks with similar intensity or a more porous structure when chitosan was first gelled, instead of collagen. As a conclusion, the synergy between collagen and chitosan improved the properties of the hydrogels, showing good thermomechanical properties and cell viability to be used as potential biomaterials for Tissue Engineering.

Immunovirological Efficacy of Once-Daily Maraviroc Plus Ritonavir-Boosted Atazanavir After 48 Weeks in Naive HIV-Infected Patients.

Toxicities related to the use of nucleoside analogues have increased the interest in developing nucleoside-sparing regimens, mainly combining protease inhibitors with raltegravir. However, data regarding the use of CCR5-antagonists in this setting and in the naive scenario are scarce. The main objective was to analyze the immunovirological efficacy and tolerability of a low-dose, once-daily, maraviroc (MVC)-containing, nucleoside reverse transcriptase inhibitor-sparing dual therapy compared with standard triple therapy after 48 weeks for naive HIV-infected patients in the routine clinical practice setting. All naive HIV-infected patients with stable clinical condition that started antiretroviral treatment since February 1, 2008 to May 30,h 2012 were included. MVC clinical test was used to select candidate subjects to MVC therapy. Thirty-two subjects with MVC + atazanavir/ritonavir (ATV/r) and 66 with standard triple therapy were analyzed. A comparable virological efficacy between groups was found after 48 weeks (87.5% vs. 80.3% of HIV undetectability, p = 0.37, MVC + ATV/r and triple therapy groups, respectively). The CD4 recovery after 48 weeks was similar and more than 200 cells/mm3 in both groups. No need of therapy changes or treatment discontinuations was observed in the MVC + ATV/r group. Effect on lipid profile, high-sensitivity C reactive protein, and ß2-microglobulin was similar for both groups. Noteworthy, a significant increase of erythrocyte mean corpuscular volume was observed only in the triple therapy group. A nucleoside-sparing MVC-containing dual therapy showed similar immunovirological efficacy and tolerability than standard triple therapy in naive HIV-infected patients.

Monocyte Phenotype and Polyfunctionality Are Associated With Elevated Soluble Inflammatory Markers, Cytomegalovirus Infection, and Functional and Cognitive Decline in Elderly Adults.

Monocytes are mediators of the inflammatory response and include three subsets: classical, intermediate, and nonclassical. Little is known about the phenotypical and functional age-related changes in monocytes and their association with soluble inflammatory biomarkers, cytomegalovirus infection, and functional and mental decline. We assayed the activation ex vivo and the responsiveness to TLR2 and TLR4 agonists in vitro in the three subsets and assessed the intracellular production of IL1-alpha (α), IL1-beta (ß), IL-6, IL-8, TNF-α, and IL-10 of elderly adults (median 83 [67-90] years old;n= 20) compared with young controls (median 35 [27-40] years old;n= 20). Ex vivo, the elderly adults showed a higher percentage of classical monocytes that expressed intracellular IL1-α (p= .001), IL1-ß (p= .001), IL-6 (p= .002), and IL-8 (p= .007). Similar results were obtained both for the intermediate and nonclassical subsets and in vitro. Polyfunctionality was higher in the elderly adults. The functionality ex vivo was strongly associated with soluble inflammatory markers. The activation phenotype was independently associated with the anti-cytomegalovirus IgG levels and with functional and cognitive decline. These data demonstrate that monocytes are key cell candidates for the source of the high soluble inflammatory levels. Our findings suggest that cytomegalovirus infection might be a driving force in the activation of monocytes and is associated with the functional and cognitive decline.

B cell-specific expression of B7-2 is required for follicular Th cell function in response to vaccinia virus.

Follicular Th (T(FH)) cells are specialized in provision of help to B cells that is essential for promoting protective Ab responses. CD28/B7 (B7-1 and B7-2) interactions are required for germinal center (GC) formation, but it is not clear if they simply support activation of naive CD4 T cells during initiation of responses by dendritic cells or if they directly control T(FH) cells and/or directly influence follicular B cell differentiation. Using a model of vaccinia virus infection, we show that B7-2 but not B7-1 deficiency profoundly impaired T(FH) cell development but did not affect CD4 T cell priming and Th1 differentiation. Consistent with this, B7-2 but not B7-1 was required for acquisition of GC B cell phenotype, plasma cell generation, and virus-specific neutralizing Ab responses. Mixed adoptive transfer experiments indicated that bidirectional interactions between CD28 expressed on activated T cells and B7-2 expressed on follicular B cells were essential for maintenance of the T(FH) phenotype and GC B cell development. Our data provide new insight into the source and nature of molecules required for T(FH) cells to direct GC B cell responses.

Selective CD4+ T cell help for antibody responses to a large viral pathogen: deterministic linkage of specificities.

Antibody responses are critical components of protective immune responses to many pathogens, but parameters determining which proteins are targeted remain unclear. Vaccination with individual MHC-II-restricted vaccinia virus (VACV, smallpox vaccine) epitopes revealed that CD4(+) T cell help to B cells was surprisingly nontransferable to other virion protein specificities. Many VACV CD4(+) T cell responses identified in an unbiased screen targeted antibody virion protein targets, consistent with deterministic linkage between specificities. We tested the deterministic linkage model by efficiently predicting new vaccinia MHC II epitopes (830% improved efficiency). Finally, we showed CD4(+) T cell help was limiting for neutralizing antibody development and protective immunity in vivo. In contrast to the standard model, these data indicate individual proteins are the unit of B cell-T cell recognition for a large virus. Therefore, MHC restriction is a key selective event for the antiviral antibody response and is probably important for vaccine development to large pathogens.