Helminth antigens differentially modulate the activation of CD4+ and CD8+ T lymphocytes of convalescent COVID-19 patients in vitro.
BMC Med
; 20(1): 241, 2022 06 28.
Article
in En
| MEDLINE
| ID: mdl-35764965
ABSTRACT
BACKGROUND:
The coronavirus disease 2019 (COVID-19) is a respiratory disease caused by SARS-CoV-2, a recently discovered strain of coronavirus. The virus has spread rapidly, causing millions of death worldwide. Contrary to the predictions, prevalence and mortality due to COVID-19 have remained moderate on the African continent. Several factors, including age, genetics, vaccines, and co-infections, might impact the course of the pandemic in Africa. Helminths are highly endemic in Sub-Saharan Africa and are renowned for their ability to evade, skew, and suppress human immune responses through various immune-modulatory mechanisms. Such effects will likely impact SARS-CoV-2 transmission and disease progression.METHODS:
Here, we analyzed in vitro the impact of antigen extracts from three major helminth parasites, including Onchocerca volvulus, Brugia malayi, and Ascaris lumbricoides, on the immune reactivity to SARS-CoV-2 peptides in COVID-19 patients. Activation of CD4+ and CD8+ T cells was investigated using flow cytometry to monitor the expression of CD137 (4-1BB) and CD69. Cytokine expression, including IL-6, IL-10, IFN-γ, and TNFα, was measured by Luminex in cell culture supernatants.RESULTS:
We observed that helminth antigens significantly reduced the frequency of SARS-CoV-2-reactive CD4+ T helper cells. In contrast, the expression of SARS-CoV-2-reactive CD8+ T cells was not affected and even significantly increased when PBMCs from COVID-19 patients living in Benin, an endemic helminth country, were used. In addition, stimulation with helminth antigens was associated with increased IL-10 and a reduction of IFNγ and TNFα.CONCLUSIONS:
Our data offer a plausible explanation for the moderate incidence of COVID-19 in Africa and support the hypothesis that helper T cell-mediated immune responses to SARS-CoV-2 are mitigated in the presence of helminth antigens, while virus-specific cytotoxic T cell responses are maintained.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
COVID-19
Type of study:
Prognostic_studies
/
Risk_factors_studies
Limits:
Humans
Country/Region as subject:
Africa
Language:
En
Journal:
BMC Med
Journal subject:
MEDICINA
Year:
2022
Document type:
Article
Affiliation country:
Germany