Scientists investigate the immunological memory of the common cold coronavirus before the SARS-CoV-2 pandemic era

In a recent study published in Cell host and microbes Journals, researchers evaluated the immunological memory of common colds coronavirus (CCC) Coronavirus Disease 2019 (COVID-19) Three years before the pandemic.

Background

CCC is a seasonal virus that falls into two genera: alpha coronavirus (CoV), including HCoV-NL63 and HCoV-229E, and beta CoV, including HCoVHKU1 and HCoV-OC43, and is usually a mild disease in humans. Causes.

CCC is an endemic virus that is widely distributed around the world and has been prevalent among humans for some time. Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and Middle East Respiratory Syndrome CoV (MERS-CoV) all cause serious illness in humans. It is a CoV and is related. Phylogenetically with the CCC virus.

Nevertheless, there is inadequate evidence of memory prevalence T cells Response to CCC, especially stability over time. Given the sustained evolution of SARS-CoV-2 during the COVID-19 pandemic, understanding the steady-state dynamics of CCC antibodies and T cell responses in people is of potential importance.

In addition, CCC immunological memory affects the outcome of SARS-CoV-2 infection, and the development of pan-CoV vaccines requires an understanding of this effect.

About research

In the current study, researchers conducted a 6-month to 3-year longitudinal analysis of pre-COVID-19 pandemic samples from 2016 against CCC, other respiratory viruses, and ubiquitous or chronic pathogens. We investigated the reaction between CD4 + T cells and antibodies. They characterized a CD4 + T cell-selective memory reflex against the four prototypically uniquely circulating CCC viruses, namely 229E, NL63, OC43, and HKU1, throughout the longitudinal population.As a method, investigators used ex vivo Treatment of peripheral blood mononuclear cells (PBMCs) with a peptide library that spans the entire proteome of each virus.

The team analyzed PBMC samples from 32 subjects from an observational study of B. pertussis. They examined the magnitude of the CD4 + T cell response to CCC and others. antigen with time. In addition, immunoglobulins (Ig) that bind to the recombinant spike (S) receptor binding domain (RBD) antigen of CCC were examined in matched plasma samples.

result

Researchers found that approximately 72% to 81% of participants had a moderate immune CD4 + T cell memory response to each of the four CCCs under investigation, the size and frequency of which were community and healthcare professionals. We found that it was consistent with the previous values ​​observed in both cohorts of. These values ​​were also comparable to the results of two previous findings. In addition, these immune responses had moderate levels of SARS-CoV-2 cross-reactivity. Interestingly, the magnitude of the CCC-specific response was similar to the immune-dominant and ubiquitous pathogen cytomegalovirus (CMV).

Scientists have discovered a consistent, long-term response of T cells to antibodies to CCC. This is supported by various recent results. Current findings are consistent with the lifespan of immune responses to other viral infections such as SARS-CoV-1 and vaccination, with antigen-selective cells detected 17 and 50 years after infection, respectively. The virus (TTV), which has been very stable for many years after vaccination.

Everyone showed measurable antibody titers against CCC, but the team found that individuals had different levels of T cell reactivity. In addition, the participants most likely to be associated with existing SARS-CoV-2 immunological reactivity were those with significant CCCT cell reactivity and low antibody titers.

Current data also show that some, if not all, have existing T cell memory responsiveness to SARS-CoV-2 due to the level of sequence homology between SARS-CoV-2 and CCC. It means that. In addition, the authors suggested that additional factors may be involved, including recent exposures, human leukocyte antigen (HLA) types, or other personalized environmental factors.

Conclusion

Study data showed how significant long-term immunity to CoV was maintained in the young adult population. Researchers said establishing a pancoronavirus vaccine to combat the SARS-CoV-2 and CCC viruses could provide additional protection.

In particular, the study found that the CCC immune response was frequently seen and long-lasting as comparable to the immune response of other common antigens. Low HLA-DR + CD38 + signals were associated with CCC-specific CD4 + T cell responses, and the size of these responses was not associated with the frequency of CCC infections each year.

Similarly, the CCC-specific S RBD-specific IgG reaction remained constant over time. Finally, existing SARS-CoV-2 immunity was associated with significant CCC-specific CD4 + T cell reactivity rather than antibody titers.

The authors found that overwhelming data indicate that the identified responsiveness is associated with memory and persistent response, even if at least several reinfections may have occurred during the long-term follow-up period. He said he suggested.