Perturbations in spike-specific peripheral T follicular helper cells in SARS-CoV2 breakthrough convalescent individuals immunized by BBV152 vaccine.

Publication date: Sep 01, 2023

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov2) infection has caused an increase in mortality and morbidity, but with vaccination, the disease severity has significantly reduced. With the emergence of various variants of concern (VOCs), the vaccine breakthrough infection has also increased. Here we studied circulating spike-specific T follicular response (cTfh) in infection-nacEFve vaccinees and convalescent vaccinees (individuals who got the Delta breakthrough infection after two doses of BBV152 vaccine) to understand their response as they are the most crucial cells that are involved in vaccine-mediated protection by helping in B-cell maturation. Our results indicated that cTfh cells in both the groups recognized the wild-type and Delta spike protein but memory response to the wild-type spike was superior in infection-nacEFve than in the convalescent group. The cytokine response, particularly interleukin-21 (IL-21) from cTfh, was also higher in infection-nacEFve than in convalescent vaccinees, indicating a dampened cTfh response in convalescent vaccinees after breakthrough infection. Also, there was a positive correlation between IL-21 from cTfh cells and neutralizing antibodies of infection-nacEFve vaccinees. Multiple cytokine analysis also revealed higher inflammation in convalescent vaccinees. Our data indicated that the necessity of a third booster dose may be individual-specific depending on the steady-state functional phenotype of immune cells.

Concepts Keywords
Antibodies adaptive immune response
Bbv152 BBV152 COVID-19 vaccine
Breakthrough Breakthrough Infections
Coronavirus COVID-19
Therapy Cytokines
inactivated vaccines
neutralizing antibodies
RNA, Viral
RNA, Viral
SARS-CoV2 viral variants
T follicular cells


Type Source Name
disease VO immunized
disease VO vaccine
disease VO Severe acute respiratory syndrome coronavirus 2
disease MESH infection
disease MESH morbidity
disease VO vaccination
disease MESH vaccine breakthrough infection
disease MESH inflammation
disease VO dose
disease IDO adaptive immune response
disease VO COVID-19 vaccine
disease MESH Breakthrough Infections COVID-19

Original Article

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