SARS-COV-2 VACCINATION INDUCES A PREDOMINENTLY CLASS II (CYTOKINE EFFECTOR) T CELL RESPONSE, BUT THE CLASS I RESPONSE IS AUGMENTED BY ANTI-TNF THERAPY AND VACCINE TYPE

ABSTRACT

BACKGROUND: In response to COVID-19 vaccination, cytotoxic and cytokine effector T cell immune responses are elicited in the T-cell compartment, based on recognition of epitopes presented by Class I or Class II MHC molecules, respectively. The levels of these distinct T-cell responses may have significant implications for immunization strategies and risk assessment. Knowledge of these two responses after vaccination is still largely unknown, especially in the context of immunomodulatory treatment regimens. METHODS: We performed T-cell receptor (TCR) immunosequencing (Adaptive Biotechnologies, Seattle WA) of IBD patients (N=303) and health care worker controls (HCW, N=224) at up to four time points (prior to dose 1, prior to dose 2, 2 weeks after dose 2, 8 weeks after dose 2). Two metrics of TCR response, breadth (# of unique antigen-specific sequences) and depth (expansion of antigen-specific sequences), were calculated for all sequences and Class I- and Class II-specific sequences, and compared to demographics, IBD treatment, and vaccine type. Subjects with exceptional Class I or Class II responses were calculated as significant residuals relative to the Class I vs. Class II regression line. Similar associations were observed for both breadth and depth breadth is presented here for brevity. RESULTS: Both Class I- and Class II-specific T-cell responses peaked 2 weeks after dose 2, and significantly correlated with lower age, female gender, and mRNA vaccine type (mRNA-1273/Moderna and BNT262b/Pfizer, versus vector vaccine AD26CoV2/J&J) (FIGURE). Class II responses comprised ~85% of detected TCR response in both IBD and HCW subjects. Among IBD patients, there was a significant elevation of the class I response with anti-TNF treatment (p=0.04). This effect was most pronounced at later timepoints, suggesting that anti-TNF permitted a more persistent Class I-specific response. Among patients with exceptionally high or low Class I TCR response, there were significant differences in TCR metrics across vaccine types (p=0.0035). 21% of AD26CoV2 patients were highly Class I-biased (Zscore>1, 9.4% and 7.3% for BNT162 and mRNA-1273, respectively), and this was correlated with lower anti-spike serology 2 and 8 weeks after vaccination (p<1E-10). Conversely, mRNA- 1273 patients were Class I-deficient, representing 25.3% of patients but 44.1% of highly Class I-deficient patients (Zscore<1, 0% for AD26CoV2). CONCLUSION: The T-cell clonal response to SARS-CoV-2 vaccine is Class II-predominant, but the Class I-response is augmented by anti-TNF therapy and vector vaccine type. These factors may help guide reimmunization vaccine strategy in immune-impaired populations, and warrant further study of the effects of anti-TNF therapies on vaccine efficacy.(Figure Presented)Figure TCR response time course (left);effect of anti-TNF (middle);effect of vaccine type (right). Breadth was predominantly Class II for most patients, with maximum response at 2 weeks after full vaccination (left). The balance of Class I vs. Class II response was significantly biased towards Class I at 8 weeks after full vaccination for patients receiving anti-TNF treatment for IBD (asterisk, p=0.036). Patients receiving AD26CoV2 vaccines were significantly increased in Class I responses, while patients receiving mRNA-1273 vaccines were significantly reduced for Class I responses (t-tests p=0.0036 at 8 weeks [asterisk], p=0.051 at 2 weeks).