Favorable vaccine-induced SARS-CoV-2 specific T cell response profile in patients undergoing immune-modifying therapies

BACKGROUND

Patients undergoing immune-modifying therapies demonstrate a reduced humoral response after COVID-19 vaccination, but we lack a proper evaluation of the effect of such therapies on vaccine-induced T cell responses.

METHODS

We longitudinally characterized humoral and spike-specific T cell responses in patients with inflammatory bowel disease (IBD), who were on antimetabolite therapy (azathioprine or methotrexate), TNF inhibitors, and/or other biologic treatment (anti-integrin or anti-p40) for up to 6 months after completing 2-dose COVID-19 mRNA vaccination.

RESULTS

We demonstrate that a spike-specific T cell response was not only induced in treated patients with IBD at levels similar to those of healthy individuals, but also sustained at higher magnitude for up to 6 months after vaccination, particularly in those treated with TNF inhibitor therapy. Furthermore, the spike-specific T cell response in these patients was mainly preserved against mutations present in SARS-CoV-2 B.1.1.529 (Omicron) and characterized by a Th1/IL-10 cytokine profile.

CONCLUSION

Despite the humoral response defects, patients under immune-modifying therapies demonstrated a favorable profile of vaccine-induced T cell responses that might still provide a layer of COVID-19 protection.

FUNDING

This study was funded by the National Centre for Infectious Diseases (NCID) Catalyst Grant (FY2021ES) and the National Research Fund Competitive Research Programme (NRF-CRP25-2020-0003).

SARS-CoV-2-specific T cells in infection and vaccination

During viral infections, antibodies and T cells act together to prevent pathogen spread and remove virus-infected cells. Virus-specific adaptive immunity can, however, also trigger pathological processes characterized by localized or systemic inflammatory events. The protective and/or pathological role of virus-specific T cells in SARS-CoV-2 infection has been the focus of many studies in COVID-19 patients and in vaccinated individuals. Here, we review the works that have elucidated the function of SARS-CoV-2-specific T cells in patients and in vaccinated individuals. Understanding whether SARS-CoV-2-specific T cells are more linked to protection or pathogenesis is pivotal to define future therapeutic and prophylactic strategies to manage the current pandemic.

Early T cell and binding antibody responses are associated with COVID-19 RNA vaccine efficacy onset

BACKGROUND

RNA vaccines against coronavirus disease 2019 (COVID-19) have demonstrated ∼95% efficacy in phase III clinical trials. Although complete vaccination consisted of 2 doses, the onset of protection for both licensed RNA vaccines was observed as early as 12 days after a single dose. The adaptive immune response that coincides with this onset of protection could represent the necessary elements of immunity against COVID-19.

METHODS

Serological and T cell analysis was performed in a cohort of 20 healthcare workers after receiving the first dose of the Pfizer/BioNTech BNT162b2 vaccine. The primary endpoint was the adaptive immune responses detectable at days 7 and 10 after dosing.

FINDINGS

Spike-specific T cells and binding antibodies were detectable 10 days after the first dose of the vaccine, in contrast to receptor-blocking and severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) neutralizing antibodies, which were mostly undetectable at this early time point.

CONCLUSIONS

Our findings suggest that early T cell and binding antibody responses, rather than either receptor-blocking or virus neutralizing activity, induced early protection against COVID-19.

FUNDING

The study was funded by a generous donation from The Hour Glass to support COVID-19 research.

A Virus-Specific Immune Rheostat in the Immunome of Patients Recovering From Mild COVID-19

An accurate depiction of the convalescent COVID-19 immunome will help delineate the immunological milieu crucial for disease resolution and protection. Using mass cytometry, we characterized the immune architecture in patients recovering from mild COVID-19. We identified a virus-specific immune rheostat composed of an effector T (T_eff) cell recall response that is balanced by the enrichment of a highly specialized regulatory T (T_reg) cell subset. Both components were reactive against a peptide pool covering the receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein. We also observed expansion of IFNγ⁺ memory CD4⁺ T cells and virus-specific follicular helper T (T_FH) cells. Overall, these findings pinpoint critical immune effector and regulatory mechanisms essential for a potent, yet harmless resolution of COVID-19 infection.

Loss of RNF40 Decreases NF-κB Activity in Colorectal Cancer Cells and Reduces Colitis Burden in Mice

BACKGROUND AND AIMS

Inflammatory bowel diseases are linked to an increased risk of developing colorectal cancer [CRC]. Previous studies suggested that the H2B ubiquitin ligase RING finger protein-20 [RNF20] inhibited inflammatory signaling mediated by the nuclear factor kappa-light-chain-enhancer of activated B cells [NF-κB]. However, the role of RNF40, the obligate heterodimeric partner of RNF20, in the context of inflammation and CRC has not been addressed. Here, we examined the effect of RNF40 loss on CRC cells in vitro and on inflammation and inflammatory signaling in vitro and in vivo.

METHODS

We evaluated H2Bub1 levels in human and murine colorectal tumors by immunohistochemistry. Moreover, we correlated H2Bub1 and RNF40 levels in vivo and assessed the consequences of RNF40 depletion on cellular phenotype and gene expression in CRC cells in vitro. Finally, we examined the effect of a colon-specific loss of Rnf40 in a murine model of colitis, and assessed both local and systemic inflammation-associated consequences.

RESULTS

In vitro studies revealed that the tumorigenic phenotype of CRC cells decreased after RNF40 depletion and displayed gene expression changes related to chromosome segregation and DNA replication, as well as decreased induction of several NF-κB-associated cytokines. This effect was associated with decreased nuclear localization of NF-κB following tumor necrosis factor alpha treatment. Consistently, the colon-specific loss of Rnf40 exerted a protective local, as well as systemic, effect following acute colitis.

CONCLUSIONS

Our findings suggest that RNF40 plays a central role in the maintenance of tumorigenic features and inflammatory signaling by promoting nuclear NF-κB activity.

Role of Dlx-1 and Dlx-2 genes in patterning of the murine dentition

The molecular events of odontogenic induction are beginning to be elucidated, but until now nothing was known about the molecular basis of the patterning of the dentition. A role for Dlx-1 and Dlx-2 genes in patterning of the dentition has been proposed with the genes envisaged as participating in an ‘odontogenic homeobox gene code’ by specifying molar development. This proposal was based on the restricted expression of the genes in molar ectomesenchyme derived from cranial neural crest cells prior to tooth initiation. Mice with targeted null mutations of both Dlx-1 and Dlx-2 homeobox genes do not develop maxillary molar teeth but incisors and mandibular molars are normal. We have carried out heterologous recombinations between mutant and wild-type maxillary epithelium and mesenchyme and show that the ectomesenchyme underlying the maxillary molar epithelium has lost its odontogenic potential. Using molecular markers of branchial arch neural crest (Barx1) and commitment to chondrogenic differentiation (Sox9), we show that this population alters its fate from odontogenic to become chondrogenic. These results provide evidence that a subpopulation of cranial neural crest is specified as odontogenic by Dlx-1 and Dlx-2 genes. Loss of function of these genes results in reprogramming of this population of ectomesenchyme cells into chondrocytes. This is the first indication that the development of different shaped teeth at different positions in the jaws is determined by independent genetic pathways.

[Bone histomorphometric study of iliac crest in normal Chinese subjects]

The aim of the present study was to make available the reference data of bone histomorphometric parameters for iliac crest of normal Chinese subjects. 178 subjects were studied, including group A:97 patients with minor orthopaedic disorders (53 males and 44 females) and group B:81 healthy subjects of sudden death (52 males and 29 females). Bone samples were taken from the iliac 2 cm below the crest. With Polycut microtome, 5 microns undecalcified sections were made and stained with 1% toluidine blue. Under light microscope, bone sections were evaluated with Zeizz MOP-Video plan, elaborating 16 parameters for statistics. The data showed that some of them, such as CV/TTV, BV/TTV, TBV/SBV, S/V and MWT, had significant correlations with age, but some had not. Comparisons were made between group A and B, showing significant differences in several parameters. In discussion, an attempt was made to explain the significance of each parameter. It is suggested that bone histomorphometric parameters fluctuates with age and can be used for monitoring bone changes. In conclusion, bone histomorphometry is recommended as a useful research tool for clinical investigation of metabolic bone diseases of different kinds.