학술논문
Humoral and T cell responses to SARS-CoV-2 reveal insights into immunity during the early pandemic period in Pakistan
Document Type
Report
Author
Masood, Kiran Iqbal; Qaiser, Shama; Abidi, Syed Hani; Khan, Erum; Mahmood, Syed Faisal; Hussain, Areeba; Ghous, Zara; Imtiaz, Khekahsan; Ali, Natasha; Hasan, Muhammad; Memon, Haris Ali; Yameen, Maliha; Ali, Shiza; Baloch, Sadaf; Lakhani, Gulzar; Alves, Paula M.; Iqbal, Najeeha Talat; Ahmed, Kumail; Iqbal, Junaid; Bhutta, Zulfiqar A.; Hussain, Rabia; Rottenberg, Martin; Simas, J. Pedro; Veldhoen, Marc; Ghias, Kulsoom; Hasan, Zahra
Source
BMC Infectious Diseases. December 1, 2023, Vol. 23 Issue 1
Subject
Language
English
ISSN
1471-2334
Abstract
Author(s): Kiran Iqbal Masood[sup.1] , Shama Qaiser[sup.1] , Syed Hani Abidi[sup.2] , Erum Khan[sup.1] , Syed Faisal Mahmood[sup.3] , Areeba Hussain[sup.1] , Zara Ghous[sup.1] , Khekahsan Imtiaz[sup.1] , Natasha Ali[sup.1] [...]
Background Protection against SARS-CoV-2 is mediated by humoral and T cell responses. Pakistan faced relatively low morbidity and mortality from COVID-19 through the pandemic. To examine the role of prior immunity in the population, we studied IgG antibody response levels, virus neutralizing activity and T cell reactivity to Spike protein in a healthy control group (HG) as compared with COVID-19 cases and individuals from the pre-pandemic period (PP). Methods HG and COVID-19 participants were recruited between October 2020 and May 2021. Pre-pandemic sera was collected before 2018. IgG antibodies against Spike and its Receptor Binding Domain (RBD) were determined by ELISA. Virus neutralization activity was determined using a PCR-based micro-neutralization assay. T cell - IFN-[gamma] activation was assessed by ELISpot. Results Overall, the magnitude of anti-Spike IgG antibody levels as well as seropositivity was greatest in COVID-19 cases (90%) as compared with HG (39.8%) and PP (12.2%). During the study period, Pakistan experienced three COVID-19 waves. We observed that IgG seropositivity to Spike in HG increased from 10.3 to 83.5% during the study, whilst seropositivity to RBD increased from 7.5 to 33.3%. IgG antibodies to Spike and RBD were correlated positively in all three study groups. Virus neutralizing activity was identified in sera of COVID-19, HG and PP. Spike reactive T cells were present in COVID-19, HG and PP groups. Individuals with reactive T cells included those with and without IgG antibodies to Spike. Conclusions Antibody and T cell responses to Spike protein in individuals from the pre-pandemic period suggest prior immunity against SARS-CoV-2, most likely from cross-reactive responses. The rising seroprevalence observed in healthy individuals through the pandemic without known COVID-19 may be due to the activation of adaptive immunity from cross-reactive memory B and T cells. This may explain the more favourable COVID-19 outcomes observed in this population. Keywords: Spike, Receptor binding domain, SARS-CoV-2, IgG, T cells, Interferon-gamma
Background Protection against SARS-CoV-2 is mediated by humoral and T cell responses. Pakistan faced relatively low morbidity and mortality from COVID-19 through the pandemic. To examine the role of prior immunity in the population, we studied IgG antibody response levels, virus neutralizing activity and T cell reactivity to Spike protein in a healthy control group (HG) as compared with COVID-19 cases and individuals from the pre-pandemic period (PP). Methods HG and COVID-19 participants were recruited between October 2020 and May 2021. Pre-pandemic sera was collected before 2018. IgG antibodies against Spike and its Receptor Binding Domain (RBD) were determined by ELISA. Virus neutralization activity was determined using a PCR-based micro-neutralization assay. T cell - IFN-[gamma] activation was assessed by ELISpot. Results Overall, the magnitude of anti-Spike IgG antibody levels as well as seropositivity was greatest in COVID-19 cases (90%) as compared with HG (39.8%) and PP (12.2%). During the study period, Pakistan experienced three COVID-19 waves. We observed that IgG seropositivity to Spike in HG increased from 10.3 to 83.5% during the study, whilst seropositivity to RBD increased from 7.5 to 33.3%. IgG antibodies to Spike and RBD were correlated positively in all three study groups. Virus neutralizing activity was identified in sera of COVID-19, HG and PP. Spike reactive T cells were present in COVID-19, HG and PP groups. Individuals with reactive T cells included those with and without IgG antibodies to Spike. Conclusions Antibody and T cell responses to Spike protein in individuals from the pre-pandemic period suggest prior immunity against SARS-CoV-2, most likely from cross-reactive responses. The rising seroprevalence observed in healthy individuals through the pandemic without known COVID-19 may be due to the activation of adaptive immunity from cross-reactive memory B and T cells. This may explain the more favourable COVID-19 outcomes observed in this population. Keywords: Spike, Receptor binding domain, SARS-CoV-2, IgG, T cells, Interferon-gamma