Mucosal Immunity

Scientists trace the neurons in the throat that sense infections and relay this information to the brain.

ACE2 plays fundamental roles in human physiology and disease. This review summarizes
ACE2’s functions, highlights its relationship with SARS-CoV-2, describes implications
for long COVID, and provides a framework for developing universal therapeutic strategies
against current and future SARS-CoV-2 variants by exploring the ACE2 pathway and interfering
with the spike-ACE2 interaction.

Physicians say they hope the needle-free jab will fuel booster demand, helping squash transmission of the pandemic virus.

An effective nasal vaccine could stop the virus that causes COVID-19 right at its point of entry. But devising one that works has been a challenge for researchers.

The circadian immune system



👉🛑In addition to the many great benefits, early risers also bring the highest level of immune activity.


👉…

Establishing and maintaining tolerance to self-antigens or innocuous foreign antigens is vital for the preservation of organismal health. Within the thymus, medullary thymic epithelial cells (mTECs) expressing autoimmune regulator (AIRE) have a critical role in self-tolerance through deletion of autoreactive T cells and promotion of thymic regulatory T (Treg) cell development1–4. Within weeks of birth, a separate wave of Treg cell differentiation occurs in the periphery upon exposure to antigens derived from the diet and commensal microbiota5–8, yet the cell types responsible for the generation of peripheral Treg (pTreg) cells have not been identified. Here we describe the identification of a class of RORγt+ antigen-presenting cells called Thetis cells, with transcriptional features of both mTECs and dendritic cells, comprising four major sub-groups (TC I–TC IV). We uncover a developmental wave of Thetis cells within intestinal lymph nodes during a critical window in early life, coinciding with the wave of pTreg cell differentiation. Whereas TC I and TC III expressed the signature mTEC nuclear factor AIRE, TC IV lacked AIRE expression and was enriched for molecules required for pTreg generation, including the TGF-β-activating integrin αvβ8. Loss of either major histocompatibility complex class II (MHCII) or ITGB8 by Thetis cells led to a profound impairment in intestinal pTreg differentiation, with ensuing colitis. By contrast, MHCII expression by RORγt+ group 3 innate lymphoid cells (ILC3) and classical dendritic cells was neither sufficient nor required for pTreg generation, further implicating TC IV as the tolerogenic RORγt+ antigen-presenting cell with an essential function in early life. Our studies reveal parallel pathways for the establishment of tolerance to self and foreign antigens in the thymus and periphery, respectively, marked by the involvement of shared cellular and transcriptional programmes. Single-cell transcriptomic and epigenetic analysis has enabled the identification of Thetis cells, a class of RORγt+ antigen-presenting cells with a key role in the differentiation of commensal microbiota-induced peripheral regulatory T cells.

NIH experts offer perspective on next-generation approaches.

Immune dysregulation has long been proposed to be associated with adenomyosis, but
the underlying mediators and mechanisms remain largely unexplored. Here, we used flow
cytometry to investigate the alterations in immune cell subsets in adenomyotic uteri
and analyze the phenotype and function of abnormal immune cells. We found that an
increase in CD8+ T-cell number was the predominant alteration in ectopic lesions in
patients with adenomyosis and was significantly associated with the severity of adenomyosis.

From a murdered concubine, to a literati's muse, to a forgotten deity, "Toilet Goddess," or Zigu (紫姑, “the Purple Lady”), is among China's most underrated…

Most studies of adaptive immunity to SARS-CoV-2 infection focus on peripheral blood, which may not fully reflect immune responses at the site of infection. Using samples from 110 children undergoing tonsillectomy and adenoidectomy during the COVID-19 pandemic, we identified 24 samples with evidence of previous SARS-CoV-2 infection, including neutralizing antibodies in serum and SARS-CoV-2-specific germinal center and memory B cells in the tonsils and adenoids. Single-cell B cell receptor (BCR) sequencing indicated virus-specific BCRs were class-switched and somatically hypermutated, with overlapping clones in the two tissues. Expanded T cell clonotypes were found in tonsils, adenoids and blood post-COVID-19, some with CDR3 sequences identical to previously reported SARS-CoV-2-reactive T cell receptors (TCRs). Pharyngeal tissues from COVID-19-convalescent children showed persistent expansion of germinal center and antiviral lymphocyte populations associated with interferon (IFN)-γ-type responses, particularly in the adenoids, and viral RNA in both tissues. Our results provide evidence for persistent tissue-specific immunity to SARS-CoV-2 in the upper respiratory tract of children after infection. Manthiram and colleagues analyze the peripheral blood, tonsils and adenoids in children undergoing tonsillectomy or adenoidectomy and find evidence of continued tissue-specific immunity to SARS-CoV-2 and viral RNA persistence weeks to months after acute infection.

Inflammatory and infectious upper respiratory diseases (ICD-10: J30-J39), such as diseases of the sinonasal tract, pharynx and larynx, are growing health problems yet their genomic similarity is not known. We analyze genome-wide association to eight upper respiratory diseases (61,195 cases) among 260,405 FinnGen participants, meta-analyzing diseases in four groups based on an underlying genetic correlation structure. Aiming to understand which genetic loci contribute to susceptibility to upper respiratory diseases in general and its subtypes, we detect 41 independent genome-wide significant loci, distinguishing impact on sinonasal or pharyngeal diseases, or both. Fine-mapping implicated non-synonymous variants in nine genes, including three linked to immune-related diseases. Phenome-wide analysis implicated asthma and atopic dermatitis at sinonasal disease loci, and inflammatory bowel diseases and other immune-mediated disorders at pharyngeal disease loci. Upper respiratory diseases also genetically correlated with autoimmune diseases such as rheumatoid arthritis, autoimmune hypothyroidism, and psoriasis. Finally, we associated separate gene pathways in sinonasal and pharyngeal diseases that both contribute to type 2 immunological reaction. We show shared heritability among upper respiratory diseases that extends to several immune-mediated diseases with diverse mechanisms, such as type 2 high inflammation. The shared genetics between upper respiratory diseases have not been well studied. Here, the authors find shared and distinct genetic loci for pharyngeal and sinonasal inflammatory conditions, which show shared heritability with autoimmune conditions and immune deficiency, highlighting the TNFR2 pathway.