SARS-CoV-2-Specific and Functional Cytotoxic CD8 Cells in Primary Antibody Deficiency: Natural Infection and Response to Vaccine

PURPOSE

CD8 cytotoxic T cells (CTLs) play a critical role in the clearance of virally infected cells. SARS-CoV-2-specific CD8 T cells and functional CTLs in natural infections and following COVID-19 vaccine in primary antibody deficiency (PAD) have not been reported. In this study, we evaluated T cell response following COVID-19 or COVID-19 mRNA vaccination in patients with PADs by assessing SARS-CoV-2 tetramer-positive CD8 T cells and functional CTLs.

METHODS

SARS-CoV-2-specific CD8 and functional CTLs were examined in a patient with X-linked agammaglobulinemia (XLA) and a patient with common variable immunodeficiency (CVID) following COVID-19 infection, and in 5 patients with CVID and 5 healthy controls 1 month following 2nd dose of COVID-19 mRNA vaccine (Pfizer-BioNTech). Cells were stained with SARS-CoV-2 spike protein-specific tetramers, and for functional CTLs (CD8⁺ CD107a⁺ granzyme B⁺ perforin⁺), with monoclonal antibodies and isotype controls and analyzed by flow cytometry.

RESULTS

SARS-CoV-2-specific tetramer + CD8 T cells and functional CTLs in the patient with XLA following COVID-19 infection were higher, as compared to healthy control subject following COVID-19 infection. On the other hand, SARS-CoV2-tetramer + CD8 T cells and functional CTLs were lower in CVID patient following COVID19 infection as compared to healthy control following COVID-19 infection. SARS-CoV2-tetramer + CD8 T cells and functional CTLs were significantly lower in SARS-CoV2-naive CVID patients (n = 10) following vaccination when compared to SARS-CoV-2-naive healthy vaccinated controls (n = 10).

CONCLUSIONS

CVID is associated with reduced SARS-CoV-2-specific CD8 T cells and functional CTLs in both natural SARS-CoV-2 infection and in response to SARS-CoV-2 mRNA vaccine, whereas natural infection in XLA is associated with a robust SARS-CoV-2-specific CD8 and functional CTL responses.

Immune Response to SARS-CoV-2 Vaccine in 2 Men

Introduction

In the trials of corona virus vaccines, detailed analyses of subsets of lymphocytes were not carried out. We present perhaps the most comprehensive immunological analysis of 29 subsets of B and T cells in 2 healthy subjects receiving 2 doses of the Pfizer SARS-CoV-2 (COVID-19) vaccine.

Methods

Analyses were performed prior to vaccination, 3 weeks following the 1st dose, and 4 weeks following the 2nd dose. Total, naïve (T_N), and different memory and effector subsets (T_CM, T_EM, and T_EMRA) of CD4+ and CD8+ T cells; SARS-CoV-2 spike protein-specific tetramer+, and cytotoxic CD8+ T; subsets of T follicular cells (T_FH, T_FH1, T_FH2, T_FH1/T_FH17, and T_FH17); B-cell subsets (mature B cells, naive B cells, transitional B cells, marginal zone B cells, class-switched memory B cells, germinal center B cells, and CD21^low B cells), and plasmablasts; and regulatory lymphocytes (CD4+ Treg, CD8+ Treg, Breg, and T_FR cells) were evaluated with specific monoclonal antibodies by flow cytometry.

Results

A lack of COVID-19 IgG antibodies after the 1st dose in one of 2 subjects was associated with increased regulatory lymphocytes and decreased plasmablasts. Seroconversion after the 2nd dose in this subject was associated with decreased T_FR cells and increased plasmablasts. In both subjects, CD4 T_EM and CD8 T_CM were markedly increased following the 2nd dose. T_FH1 and regulatory lymphocytes were increased (except Breg) following the 1st dose. A striking increase in SARS-CoV-2-specific CD8+ T cells was observed following the 2nd dose.

Conclusion

Our data support the need for 2nd dose of vaccine to induce strong SARS-CoV-2 CD8 T-cell specific response and generation of memory subsets of CD4+ and CD8+ T cells. Regulatory lymphocytes appear to play a role in the magnitude of response.