New study finds T cells recognize targets against all coronaviruses!

The coronavirus (CoV) family includes a variety of viruses
capable of infecting humans.
Endemic coronaviruses that can cause the common cold belong to the genera α coronaviruses and β coronaviruses, β also contain subgenera associated with zoonotic and pandemic issues, including Sabecocoviruses (SARS-CoV and SARS-CoV-2) and merbecoCoV (MERS-CoV).

Therefore, it is necessary to explore pan-coronavirus vaccine concepts to provide adaptive immune protection against new potential coronavirus outbreaks, especially in the context
of the β coronavirus sublineage.

This article is the original of Translational Medicine Network, please indicate the source for reprinting

Author: kope

In a study recently published in bioRxiv, researchers analyzed the responsiveness of T cells to α and β common cold coronaviruses, informing the development of pan-coronavirus vaccine concepts
.
The study found that early broad-based and multi-antigen T cell responses could address SARS-CoV-2 infection and help reduce viral load
.

Regions of immunodominant T cells

 01 

The study found that while neutralizing antibodies (nAbs) weaken over time, the responsiveness of T cells to SARS-CoV-2 variants remained
.
While they do not protect against reinfection, T cells protect against severe coronavirus disease 2019 (COVID-19).

In addition, they remain effective
in individuals without gammaglobulinaemia and low B-cell counts.

Based on these data, the scientists proposed that conserved regions of immunodominant T cells (across multiple CoVs) could effectively induce pan-coronavirus responses while inducing broadly responsive nAb responses
.
More than 100 studies have extensively explored the SARS-CoV-2-induced T cell epitope catalog
.
However, data
on antigens primarily recognized in T cell responses caused by CCC infection are lacking.

Strikingly, CCC T cell immunity is present in the vast majority of the general population who are unknowingly exposed to CCC and persists over time
.
Data on antigenic immune dominance patterns and data on T cell epitope catalogs determined by the global population after CCC exposure could greatly assist in the development of
future pan-coronavirus vaccines.

Extensive T cell response

 02 

The researchers explored pan-coronavirus vaccines
that can trigger a broad cross-reactive differentiation cluster (CD)4+ T cell response.
They used α (NL63) and β (OC43) viruses as α and βCCC virus prototypes, respectively, which can serve as CCC CD4+ T cell targets
.

Peripheral blood mononuclear cells (PBMCs) were collected from 88 healthy adults (first cohort) with a median age of 46 years and a male-to-female ratio of 52:48
between March 2020 and February 2021.
They were serologically negative for the spike(S) protein of SARS-CoV-2 at the time of sample collection
.
The team used immunoglobulin G enzyme-linked immunosorbent assay (ELISA) to measure antibodies
to OC43 and NL63.

In addition, the researchers performed extensive T cell epitope screening
.
For 18 epitopes, they also experimentally assessed the ability of T cells to cross-recognize sequences from other CoV groups, such as non-β-non-sarbecoCoV
.
In this way, the researchers determined which PBMC samples elicit a broad T cell response
to recognize antigens and epitopes.

Pan-coronavirus vaccine

 03 

The results of the current study show that the structural protein S, membrane (M), nucleocapsid (N) and non-structural protein NSP3 have immune advantages
over both protoviruses.
Regarding CCC-specific immune dominance, they identified NL63-specific T cell responses highlighting NSP2 and OC43-specific T cells recognizing NSP12
.

The main antigens of the new coronavirus are nucleocapsid protein, which also includes membrane protein, envelope protein, spike protein and so on
.
These 4 proteins are the components of the new coronavirus, of which the structural protein is the antigen tissue with the largest content of the new coronavirus, and it will be released in the human body after being infected with the new coronavirus, so the structural protein can be checked to analyze whether there is an infection
.

SARS-CoV-2 has infected the vast majority of the world's population, so generating a dataset containing highly immunodominant epitope and antigen information seems feasible so that they can efficiently induce cross-reactive CD4+ T cells
against several different CoVs.
Overall, the research data may prove very useful
in designing vaccines against the Sabeko coronavirus of zoonotic origin and potential pandemic issues.

Resources:

https://doi.
org/10.
1101/2023.
01.
04.
522794

Note: This article is intended to introduce the progress of medical research and cannot be used as a reference
for treatment options.
If you need health guidance, please go to a regular hospital
.