Immune Responses
The EBV system is a valuable model to study the host-virus interactions in both acute and primary infection and lifelong persistent infection phases. Although EBV-specific T cells have been studies intensively, there is still research gap in the generation of polyfunctional T cells (PFCs) upon stimulation with EBV lytic and latent antigen stimulation Since PFCs have been shown to play important roles in effective control of different virus infections, this project is to investigate the PFCs in three cohorts of EBV-infected individuals: healthy long term EBV carriers, patients with infectious mononucleosis (IM), and patients with hemophagocytic lymphohistiocytosis (HLH).
To investigate whether PFCs are essential in control of EBV:
The PFCs in healthy long term carriers who have established effective long term control of EBV were analyzed and compared with those in patients with PTLD who have defective anti-EBV immunity. A 9-color flow cytometric assay was developed to stimultaneously analyze five functions of CD4+ and CD8+ T cells. EBV-specific PFCs was studied in details upton stimulation with overlapping peptide pools of EBV lytic (BZLF1) and latent proteins (EBNA1, 3A-3C, LMP2), respectively.
To study the development of EBV-specific PFCs from acute primary infection stage to long term persistency:
The response magnitude and functional characteristics of EBV-specific CD4+ and CD8+ T cells would be assessed longtitudinally in ten IM patients from onset of disease to one year post-infection. PFCs specific to four EBV lytic (BZLF1,BRLF1, BMLF1, gp350) and five latent (EBNA1, EBNA 3A, EBNA 3B, EBNA 3C, LMP2) proteins would be studiew at each time point by multi-color flow cytometry. Viral load in PBMCs at different time points would be determined as an indicator of effectiveness of viral control.
To study EBV specific T cell responses in HLH patients during remission stage:
Whether HLH patients can generate normal EBV-specfic T cell responses and PFCs upon stimulation with EBV lytic and latent antigens during remission stage would be investigated.