Expansion of tissue-resident CD8+ T cells and CD4+ Th17 cells in the nasal mucosa following mRNA COVID-19 vaccination

Ssemaganda, Aloysious; Nguyen, Huong Mai; Nuhu, Faisal; Jahan, Naima; Card, Catherine M.; Kiazyk, Sandra; Severini, Giulia; Keynan, Yoav; Su, Ruey-Chyi; Ji, Hezhao; Abrenica, Bernard; McLaren, Paul J.; Ball, T. Blake; Bullard, Jared; Van Caeseele, Paul; Stein, Derek; McKinnon, Lyle R.

Vaccines against SARS-CoV-2 have shown high efficacy in clinical trials, yet a full immunologic characterization of these vaccines, particularly within the upper respiratory tract, remains lacking. We enumerated and phenotyped T cells in nasal mucosa and blood before and after vaccination with the Pfizer-BioNTech COVID-19 vaccine (n =21). Tissue-resident memory (Trm) CD8+ T cells expressing CD69+CD103+ expanded ∼12 days following the first and second doses, by 0.31 and 0.43 log10 cells per swab respectively (p=0.058 and p=0.009 in adjusted linear mixed models). CD69+CD103+CD8+ T cells in the blood decreased post-vaccination. Similar increases in nasal CD8+CD69+CD103-T cells were observed, particularly following the second dose. CD4+ Th17 cells were also increased in abundance following both doses. Following stimulation with SARS-CoV-2 spike peptides, CD8+ T cells increased expression of CD107a and CD154. These data suggest that nasal T cells may be induced and contribute to the protective immunity afforded by this vaccine.