The rapidly spreading severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) Omicron variant contains more than 30 mutations that mediate escape from antibody responses elicited by prior infection or current vaccines. Fortunately, T‐cell responses are highly conserved in most individuals, but the impacts of mutations are not clear. Here, we showed that the T‐cell responses of individuals who underwent booster vaccination with CoronaVac were largely protective against the SARS‐CoV‐2 Omicron spike protein. To specifically estimate the impact of Omicron mutations on vaccinated participants, 16 peptides derived from the spike protein of the ancestral virus or Omicron strain with mutations were used to stimulate peripheral blood mononuclear cells (PBMCs) from the volunteers. Compared with the administration of two doses of vaccine, booster vaccination substantially enhanced T‐cell activation in response to both the ancestral and Omicron epitopes, although the enhancement was slightly weakened by the Omicron mutations. Then, the peptides derived from these spike proteins were used separately to stimulate PBMCs. Interestingly, compared with the ancestral peptides, only the peptides with the G339D or N440K mutation were detected to significantly destabilize the T‐cell response. Although more participants need to be evaluated to confirm this conclusion, our study nonetheless estimates the impacts of mutations on T‐cell responses to the SARS‐CoV‐2 Omicron variant.

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T follicular helper (Tfh) cells and their interactions with B cells within the germinal center play extensive roles in human immunodeficiency virus (HIV) pathology. However, their association with immune reconstitution during antiretroviral therapy (ART) is still unclear. The aim of this study was to determine the impact of Tfh and memory B cell function on T helper cell recovery in patients with acute or chronic HIV infection. A total of 100 HIV-infected individuals were enrolled in our study, classified into acute and chronic HIV infection groups (60 and 40, respectively), and subsequently classified into immunological responder (IR) and immunological nonresponder (INR) subgroups according to immune recovery outcomes after 96 weeks of ART. Liquid chromatography-mass spectrometry was used to quantify the temporal regulation patterns of B and CD4 + T-cell profiles among patients, and flow cytometry was used to investigate certain subsets of B and T cells. Here we showed that the prevalence of Tfh cells in the T helper cell population correlated negatively with CD4 + T-cell recovery. The proportion of CXCR3 − Tfh cells in patients with acute or chronic infection was associated with CD4 + T-cell count recovery, and the proportion of CD21 + memory B cells at baseline was significantly higher in those with improved immune recovery outcomes. Universal proteomic dysregulation of B and CD4 + T cells at baseline was detected in patients with acute infected and poor CD4 + T-cell recovery. Proteomics analysis revealed distinct temporal regulation profiles of both T helper cells and B cells between IRs and INRs among patients with