Clonal structure of rapid-onset MDV-driven CD4+ lymphomas and responding CD8+ T cells

Area of Science:

• Oncology
• Virology
• Immunology

Background:

• Lymphoid oncogenesis is a severe complication of persistent viral infections.
• Marek's Disease Virus (MDV), an avian alpha-herpesvirus, causes CD4+ T cell tumors in poultry.
• Understanding tumor clonal dynamics and immune responses is crucial for studying virus-induced cancers.

Purpose of the Study:

• To investigate the clonal structure of Marek's Disease Virus-induced CD4+ T cell lymphomas.
• To determine the clonality of CD8+ T cells infiltrating MDV-associated tumors.
• To elucidate the dynamics of tumor cell dissemination and immune suppression in MDV infection.

Main Methods:

• TCRβ repertoire analysis was employed to assess T cell clonality.
• Analysis of tumor sites and blood samples from infected birds.
• Identification and characterization of T cell receptor (TCR) CDR3 sequences.

Main Results:

• MDV-driven CD4+ T cell tumors were dominated by a few large clones within an oligoclonal framework.
• Metastatic tumor clones were detectable in the blood early in infection, correlating with immune suppression.
• Tumor-infiltrating CD8+ T cells exhibited large oligoclonal expansions, suggesting recognition of a limited set of MDV antigens.

Conclusions:

• MDV-induced lymphomas are characterized by a highly restricted clonal expansion of CD4+ T cells.
• The CD8+ T cell response is oligoclonal, indicating recognition of specific MDV antigens.
• MDV serves as a valuable model for studying virus-induced oncogenesis and T cell dynamics.