Antibody-secreting cells in respiratory tract tissues in the absence of eosinophils as supportive partners

Impaired Circulating Antibody-Secreting Cells Generation Predicts the Dismal Outcome in the Elderly Septic Shock Patients

Purpose

Sepsis is a condition that derives from a dysregulated host response to infection. Although B lymphocytes play a pivotal role in immune response, little is known about status of their terminally differentiated cells, antibody-secreting cells (ASCs) during immunosuppressive phase of sepsis, especially in elderly patients. Our aim was to extensively characterize the immune functions of ASCs in elderly septic patients.

Patients and Methods

Clinical and laboratory data were collected on days 1, 3, and 7 of hospitalization. Circulating ASCs were evaluated by flow cytometry from fresh whole blood in elderly septic patients at the onset of disease. RNA sequencing analyzed ASCs gene expression profile. Receiver operating characteristic (ROC) curve analysis and logistic regression predicted the survival rate of 28-day mortality.

Results

A total of 103 septic patients were enrolled. The number and proportion of ASCs among total lymphocytes dramatically increased in septic patients, and RNA sequencing analysis showed that ASCs from septic patients exhibited a different gene expression profile. Furthermore, we found these ASCs could promote the function of T cells. Logistic regression analysis showed ASCs population was an independent outcome predictor in septic shock patients.

Conclusion

Our study revealed the complex nature of immune disorders in sepsis and identified circulating ASCs population as a useful biomarker for predicting mortality in elderly septic patients, which provided a novel clue to combat this severe disease.

Fab and Fc contribute to maximal protection against SARS-CoV-2 following NVX-CoV2373 subunit vaccine with Matrix-M vaccination

Recently approved vaccines have shown remarkable efficacy in limiting SARS-CoV-2-associated disease. However, with the variety of vaccines, immunization strategies, and waning antibody titers, defining the correlates of immunity across a spectrum of antibody titers is urgently required. Thus, we profiled the humoral immune response in a cohort of non-human primates immunized with a recombinant SARS-CoV-2 spike glycoprotein (NVX-CoV2373) at two doses, administered as a single- or two-dose regimen. Both antigen dose and boosting significantly altered neutralization titers and Fc-effector profiles, driving unique vaccine-induced antibody fingerprints. Combined differences in antibody effector functions and neutralization were associated with distinct levels of protection in the upper and lower respiratory tract. Moreover, NVX-CoV2373 elicited antibodies that functionally targeted emerging SARS-CoV-2 variants. Collectively, the data presented here suggest that a single dose may prevent disease via combined Fc/Fab functions but that two doses may be essential to block further transmission of SARS-CoV-2 and emerging variants.

Ameliorative effects of eosinophil deficiency on immune response, endoplasmic reticulum stress, apoptosis, and autophagy in fungus-induced allergic lung inflammation

Background

Respiratory fungal exposure is known to be associated with various allergic pulmonary disorders. Eosinophils have been implicated in tissue homeostasis of allergic inflammation as both destructive effector cells and immune regulators. What contributions eosinophils have in Aspergillus fumigatus (Af)-induced allergic lung inflammation is worthy of investigating.

Methods

We established the Af-exposed animal asthmatic model using eosinophil-deficient mice, ∆dblGATA1 mice. Airway inflammation was assessed by histopathological examination and total cell count of bronchoalveolar lavage fluid (BALF). The protein level in BALF and lung mRNA level of type 2 cytokines IL-4, IL-5, and IL-13 were detected by ELISA and qRT-PCR. We further studied the involvement of endoplasmic reticulum (ER) stress, apoptosis, and autophagy by western blots, qRT-PCR, immunofluorescence, TUNEL, or immunohistochemistry. RNA-Seq analysis was utilized to analyze the whole transcriptome of Af-exposed ∆dblGATA1 mice.

Results

Hematoxylin and eosin (HE) staining and periodic acid–Schiff staining (PAS) showed that airway inflammation and mucus production were alleviated in Af-challenged ∆dblGATA1 mice compared with wild-type controls. The protein and mRNA expressions of IL-4, IL-5, and IL-13 were reduced in the BALF and lung tissues in Af-exposed ∆dblGATA1 mice. The results demonstrated that the significantly increased ER stress markers (GRP78 and CHOP) and apoptosis executioner caspase proteases (cleaved caspase-3 and cleaved caspase-7) in Af-exposed wild-type mice were all downregulated remarkably in the lungs of ∆dblGATA1 mice with Af challenge. In addition, the lung autophagy in Af-exposed ∆dblGATA1 mice was found elevated partially, manifesting as higher expression of LC3-II/LC3-I and beclin1, lower p62, and downregulated Akt/mTOR pathway compared with Af-exposed wild-type mice. Additionally, lung RNA-seq analysis of Af-exposed ∆dblGATA1 mice showed that biological processes about chemotaxis of lymphocytes, neutrophils, or eosinophils were enriched but without statistical significance.

Conclusions

In summary, eosinophils play an essential role in the pathogenesis of Af-exposed allergic lung inflammation, whose deficiency may have relation to the attenuation of type 2 immune response, alleviation of ER stress and apoptosis, and increase of autophagy. These findings suggest that anti-eosinophils therapy may provide a promising direction for fungal-induced allergic pulmonary diseases.

Sendai Virus-Vectored Vaccines That Express Envelope Glycoproteins of Respiratory Viruses

Human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), and human parainfluenza viruses (HPIVs) are leading causes of respiratory disease in young children, the elderly, and individuals of all ages with immunosuppression. Vaccination strategies against these pneumoviruses and paramyxoviruses are vast in number, yet no licensed vaccines are available. Here, we review development of Sendai virus (SeV), a versatile pediatric vaccine that can (a) serve as a Jennerian vaccine against HPIV1, (b) serve as a recombinant vaccine against HRSV, HPIV2, HPIV3, and HMPV, (c) accommodate foreign genes for viral glycoproteins in multiple intergenic positions, (d) induce durable, mucosal, B-cell, and T-cell immune responses without enhanced immunopathology, (e) protect cotton rats, African green monkeys, and chimpanzees from infection, and (f) be formulated into a vaccine cocktail. Clinical phase I safety trials of SeV have been completed in adults and 3–6-year-old children. Clinical testing of SeVRSV, an HRSV fusion (F) glycoprotein gene recombinant, has also been completed in adults. Positive results from these studies, and collaborative efforts with the National Institutes of Health and the Serum Institute of India assist advanced development of SeV-based vaccines. Prospects are now good for vaccine successes in infants and consequent protection against serious viral disease.