Researchers recently evaluated three different cohorts’ serological and mucosal immunity in a study that was published on the medRxiv* preprint server.
They were those with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta or Omicron BA.2 variant of concern (VOC) breakthrough infections, COVID-19-recovered vaccinees (vaccinated and convalescent), and COVID-19-vaccinated only vaccinees (uninfected and vaccinated) (BTI, infected and vaccinated).
Vaccinations against SARS-CoV-2, particularly booster doses of messenger ribonucleic acid (mRNA), produce systemic anti-SARS-CoV-2 antibodies that guard against COVID-19 severity results. However, the limited SARS-CoV-2 neutralizing antibodies produced by the existing COVID-19 vaccinations at mucosal locations.
The lack of mucosal antibody (Ab)-based protection could result in SARS-CoV-2 infections that are resistant to current vaccines. In order to create methods for long-lasting immune protection, it may be helpful to assess the capacity of humoral functional immunological responses at mucosal surfaces.
Researchers in the current study assessed systemic and mucosal immune responses in COVID-19 vaccine recipients who had previously contracted SARS-CoV-2 and those who had not.
The team selected participants from a previously published study cohort with either a positive or negative prior COVID-19 history, who had received booster doses of the mRNA vaccine and the nCoV-19 vaccines ChAdOx1 from AstraZeneca and BNT162b2 from Pfizer-BioNTech.
Moreover, COVID-19 vaccine recipients with BA.2 VOC or Delta VOC BTIs that have been confirmed by PCR were sought out. Samples of blood and saliva were taken both before and after the COVID-19 vaccine.
Using multiplexed beaded arrays, the immune responses involving anti-SARS-CoV-2 IgM, IgA, and IgG and their subclasses in sera, saliva, and tear fluid from the pre-COVID-19 pandemic cohort and COVID-19 vaccinees were assessed.
The arrays included the spike (S) protein, receptor-binding domain (RBD), spike subunit 1 (S1), and subunit 2 from the SARs-CoV-2 Wuhan-Hu-1 strain (S2)
