Dados do Trabalho

Título

What to expect for SARS-CoV-2 virus considering IgE response

Introdução

IgE is observed in response to allergens or parasites, but there is evidence that viral antigens trigger it too.

Objetivo (s)

We investigated if COVID-19 and SARS-CoV-2 vaccines would elicit anti- Receptor Binding Domain (RBD) IgE.

Material e Métodos

To do so, we selected samples of 59 volunteers of a healthcare workers cohort of Adolfo Lutz Institute (CAAE 31924420.8.0000.0059) who received two CoronaVac or two ChAdOx1 doses and one BNT162b2 booster vaccines, presented similar timeframe between blood collections and did not have COVID-19 between the vaccine doses. Pre-vaccine (with or without COVID-19 history), post-two doses (CoronaVac or ChAdOx1) and post-booster (BNT162b2) samples were tested by in house ELISA and ELISA-avidity. IgG depletion with protein G was carried out for confirmatory experiments. Pre-pandemic sera served as control throughout all experiments.

Resultados e Conclusão

In our cohort, no symptoms or comorbidities were related to IgE-response. Natural infection let to a mild IgE increase, two vaccine doses showed no significant change, but the volunteers had an IgE enhancement after the booster (p<0.001). No statistical difference was observed comparing CoronaVac+BNT162b2 and ChAdOx1+BNT162b2 schedules, although ChAdOx1 induced slightly elevated antibodies’ levels. IgE-avidity was intermediate after COVID-19 (mean, IQR25—75th, 51.19, 35.95—57.78), and high after vaccination, without significant difference between CoronaVac+BNT162b2 (76.64, 66.9283.26) and ChAdOx1+BNT162b2 (73.53, 59.61—81.64) regimens. To confirm that IgE detection was specific and not a result of unspecific binding of high IgG concentration, 16 random samples (four pre-pandemic controls, four pre-vaccine with COVID, four pre-vaccine without COVID-19, four two doses  and four booster doses) were depleted from IgG, and supernatants were assayed, corroborating ELISA results. We tested if IgE levels and avidity would correlate with neutralizing antibodies (NAbs), available from a previous study which used an inhibition-ELISA (which does not discriminate Ig classes) to test two doses of CoronaVac and ChAdOx1. IgE levels and avidity correlated well with NAbs (r=0.7125 and r=0.7967, respectively). Natural infection and vaccination with different SARS-CoV-2 vaccines induced IgE. It seems that such antibodies bind to RBD with high avidity, especially after vaccination, but further studies are required to fully understand the biological role of IgE in response to SARS-CoV-2.

Palavras Chave

IgE; COVID-19; SARS-CoV-2 vaccines; Avidity