Research Fellow Boston Children's Hospital, United States
Disclosure(s):
Colleen Sedney, PhD: No financial relationships to disclose
Introduction/Rationale: Immunocompromised hosts, including those with lymphoid or hematological malignancies and solid organ transplant recipients, are more susceptible to contracting infections and thus require protection from various pathogens but often have reduced responses to vaccination. Repeat immunizations against various pathogens including SARS-CoV-2, influenza, and Respiratory Syncytial Virus (RSV) have been offered, and we have previously demonstrated that the cellular immune response to such immunizations was sub-optimal, but more preserved than the humoral immune response, in terms of frequencies of post-immunization antigen-specific T cells.
Objective: To evaluate functional and phenotypic fingerprints of vaccine-induced T-cell responses of several cohorts of immunocompromised patients.
Methods: Peripheral blood draws from immunocompromised hosts were collected pre-vaccination and post-vaccination (SARS-CoV-2 mRNA vaccine, SARS-CoV-2 adjuvanted protein vaccine, and RSV adjuvanted or non-adjuvanted protein vaccine). Antigen-specific cellular immune responses were captured using the Activation-Induced Marker (AIM) assay, enabling flow cytometry-based quantification of antigen-specific T cells and additional immunophenotyping. Antigen-specific T cells assessed include SARS-Cov-2, influenza, and RSV.
Results: Human in vitro modeling was successfully utilized to complete deep immunophenotyping of T cells responses both pre- and post-vaccination. An increase in antigen-specific T cells could be observed in a subset of each cohort. Ongoing analyses will reveal whether specific T-cell functionalities or phenotypes are associated with successful increase in T-cell frequencies post-immunization.
Conclusion: T cell responses from immunocompromised hosts demonstrated heterologous responses to vaccination. These results could be contributed to varying medication types utilized by patients and additional investigation is required to understand the continuation of immunosuppressive drugs on vaccine responses.
