Mucosal-associated invariant T cells in cancer: dual roles, complex interactions and therapeutic potential

Mucosal-associated invariant T (MAIT) cells play diverse roles in cancer, infectious diseases, and immunotherapy. This review explores their intricate involvement in cancer, from early detection to their dual functions in promoting inflammation and mediating anti-tumor responses. Within the solid tumor microenvironment (TME), MAIT cells can acquire an 'exhausted' state and secrete tumor-promoting cytokines. On the other hand, MAIT cells are highly cytotoxic, and there is evidence that they may have an anti-tumor immune response. The frequency of MAIT cells and their subsets has also been shown to have prognostic value in several cancer types. Recent innovative approaches, such as programming MAIT cells with chimeric antigen receptors (CARs), provide a novel and exciting approach to utilizing these cells in cell-based cancer immunotherapy. Because MAIT cells have a restricted T cell receptor (TCR) and recognize a common antigen, this also mitigates potential graft-versus-host disease (GVHD) and opens the possibility of using allogeneic MAIT cells as off-the-shelf cell therapies in cancer. Additionally, we outline the interactions of MAIT cells with the microbiome and their critical role in infectious diseases and how this may impact the tumor responses of these cells. Understanding these complex roles can lead to novel therapeutic strategies harnessing the targeting capabilities of MAIT cells.

Targeting SARS-CoV-2 infection through CAR-T-like bispecific T cell engagers incorporating ACE2

Objectives

Despite advances in antibody treatments and vaccines, COVID-19 caused by SARS-CoV-2 infection remains a major health problem resulting in excessive morbidity and mortality and the emergence of new variants has reduced the effectiveness of current vaccines.

Methods

Here, as a proof-of-concept, we engineered primary CD8 T cells to express SARS-CoV-2 Spike protein-specific CARs, using the extracellular region of ACE2 and demonstrated their highly specific and potent cytotoxicity towards Spike-expressing target cells. To improve on this concept as a potential therapeutic, we developed a bispecific T cell engager combining ACE2 with an anti-CD3 scFv (ACE2-Bite) to target infected cells and the virus.

Results

As in CAR-T cell approach, ACE2-Bite endowed cytotoxic cells to selectively kill Spike-expressing targets. Furthermore, ACE2-Bite neutralized the pseudoviruses of SARS-CoV, SARS-CoV-2 wild-type, and variants including Delta and Omicron, as a decoy protein. Remarkably, ACE2-Bite molecule showed a higher binding and neutralization affinity to Delta and Omicron variants compared to SARS-CoV-2 wild-type Spike proteins.

Conclusion

In conclusion, these results suggest the potential of this approach as a variant-proof, therapeutic strategy for future SARS-CoV-2 variants, employing both humoral and cellular arms of the adaptive immune response.

Engineering Human MAIT Cells with Chimeric Antigen Receptors for Cancer Immunotherapy

Engineering immune cells with chimeric Ag receptors (CARs) is a promising technology in cancer immunotherapy. Besides classical cytotoxic CD8⁺ T cells, innate cell types such as NK cells have also been used to generate CAR-T or CAR-NK cells. In this study, we devised an approach to program a nonclassical cytotoxic T cell subset called mucosal-associated invariant T (MAIT) cells into effective CAR-T cells against B cell lymphoma and breast cancer cells. Accordingly, we expressed anti-CD19 and anti-Her2 CARs in activated primary human MAIT cells and CD8⁺ T cells, expanded them in vitro, and compared their cytotoxicity against tumor cell targets. We show upon activation through CARs that CAR-MAIT cells exhibit high levels of cytotoxicity toward target cells, comparable to CD8⁺ CAR-T cells, but interestingly expressed lower levels of IFN-γ than conventional CAR CD8⁺ T cells. Additionally, in the presence of vitamin B₂ metabolite 5-ARU (5-amino-4-d-ribitylaminouracil dihydrochloride), which is a conserved compound that activates MAIT cells through MHC class I-related (MR1) protein, MAIT cells killed MR1-expressing target breast cancer and B cell lymphoma cell lines in a dose-dependent manner. Thus, MAIT cells can be genetically edited as CAR-T cells or mobilized and expanded by MR1 ligands as an off-the-shelf novel approach to cell-based cancer immunotherapy strategies while being comparable to conventional methods in effectivity.

SARS-CoV-2 specific antibody and neutralization assays reveal the wide range of the humoral immune response to virus

Development of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n = 115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.

Novel SARS-CoV-2 specific antibody and neutralization assays reveal wide range of humoral immune response during COVID-19

Development of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n=115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.

The Influence of Mechanical Recycling on Properties in Injection Molding of Fiber-Reinforced Polypropylene

Due to higher mechanical demands on technical parts, the application of short fiber reinforced thermoplastics for injection molding is strongly increasing. Therefore, more attention needs to be paid to the optimization of their recycling processes. Mechanical shredding of thermoplastics into granules is a common recycling method within polymer industries. The breaking of polymer chains and reinforcing fibers during this process may affect the material properties. This study presents the effect of ten recycling sequences on four different materials: polypropylene, glass fiber filled polypropylene, carbon fiber filled polypropylene and flax fiber filled polypropylene. Tests indicate that recycling has a negative influence on most of the mechanical properties. Polypropylene without fibers forms an exception as it does not exhibit any significant change in material properties. Glass fiber and carbon fiber reinforced polypropylene show a decrease in stiffness and tensile strength during the recycling steps. The impact strength of carbon and flax fiber reinforced polypropylene increases whereas that of glass fiber reinforced polypropylene decreases.

Posterior Reversible Encephalopathy Syndrome in the Emergency Service

Posterior reversible encephalopathy syndrome (PRES) is an entity characterized by headache, altered mental status, seizures, visual disturbances, and focal neurological signs. The most common etiologies of PRES are hypertension and renal failure, and the most frequent pathophysiology is hyperperfusion. PRES is generally symmetrical, often in the occipital and parietal lobes, and is typically characterized by vasogenic edema in the subcortical white matter. This study involves a 38-year-old female patient who had hypertension, used immunosuppressive drugs and was also found to have nephropathy. After 3 months of treatment for PRES, the patient's symptoms had declined.

Usefulness of C1 esterase inhibitor protein concentrate in the management of hereditary angioedema of oropharyngeal tissue

Hereditary angioedema is an autosomal-dominant disorder caused by mutation of the gene encoding the C1 esterase inhibitor (C1-INH). It manifests as painless, nonpruritic, nonpitting episodic swelling of the subcutaneous tissues, gastrointestinal, and upper respiratory tracts in the absence of urticaria. An attack typically takes 24 h to peak and resolves over 48-72 h. The most serious manifestation is a laryngeal attack associated with upper airway swelling. The aim of this case report is to describe the lifesaving use of a novel C1-INH protein concentrate in a patient with mild-to-moderate dyspnea caused by swelling of the upper airway (larynx) and tongue.

Keeping an Open Mind about Acute Flank Pain in Emergency Department: Acute Kidney Infarction

Differential diagnosis of the acute flank pain in a patient without nephrolithiasis is challenging in emergency department. Renal infarction should be suspected if accompanying cardiac arrhythmia, heart failure or valvular disease is present. Activated protein C resistance is the most common thrombophilia that triggers venous-obstructive conditions and rarely arterial thromboembolism. We described a young male with a history of non-ischemic dilated cardiomyopathy and coexisting activated protein C resistance presented with new onset acute flank pain due to acute renal infarction.

The efficiency of Levofloxacin Containing Sequential Therapy with or without Bismuth, in Helicobacter Pylori Eradication, in Non-ulcer Dyspepsia

INTRODUCTION

The aim of this study is to determine the efficiency of levofloxacin containing sequential therapy with or without bismuth in Helicobacter pylori (Hp) eradication in nonulcer dyspepsia.

MATERIALS AND METHODS

One hundred and ninety Hp-positive patients with the pre-diagnosis of nonulcer dyspepsia were included in this study. Patients were randomized into 2 groups and 95 individuals were included in each group. The first group was administered levofloxacin containing sequential therapy with bismuth, whereas the second group was administered only levofloxacin containing sequential therapy. Rates of therapy discontinuation and eradication success were compared between the 2 groups. Furthermore, symptomatic healing rates were com-pared between patients in whom Hp eradication was achieved and in whom it was not achieved.

RESULTS

Ninety-one patients from each group applied for follow-up after treatment. It was found that 7/91(7.6%) patients from the first group and 5/91(5.4%) patients from the second group did not complete the therapy (p >0.05). In patients who completed therapy, Hp eradication was achieved in 72 out of the 84 patients (85.2%) from the first group and 71 out of 86 patients (82.6%) from the second group (p > 0.05). In addition, symptomatic healing occurred in 125 out of 143 patients (87.4%) in whom Hp was eradicated and 12 out of 27 (44.4%) patients in whom Hp was not eradicated (p < 0.001).

CONCLUSION

Levofloxacin containing sequential therapy for 14 days is quite effective and well-tolerated choice for Hp eradication. However, adding bismuth to sequential therapy does not significantly improve Hp eradication success rates. Therefore, Hp eradication is beneficial and necessary in patients with nonulcer dyspepsia.