Oncolytic viruses sensitize human tumor cells for NY-ESO-1 tumor antigen recognition by CD4+ effector T cells

Area of Science:

• Immunology
• Virology
• Oncology

Background:

• Oncolytic viruses (OV) stimulate antitumor immunity by releasing tumor-associated antigens (TAA) and danger signals from infected tumor cells.
• The precise mechanisms by which OV enhance TAA presentation and subsequent immune recognition are still under investigation.

Purpose of the Study:

• To investigate if lysis of tumor cells by various OV impacts their capacity to present TAA, specifically NY-ESO-1.
• To determine if OV-induced tumor cell lysis facilitates TAA intercellular transfer and subsequent immune cell recognition.

Main Methods:

• Co-culture of melanoma cells with differing NY-ESO-1 and HLA-DP4 expression levels, infected with various OV (measles, vaccinia, VSV, HSV-I, adenovirus, enterovirus).
• Assessment of intercellular transfer of NY-ESO-1 and subsequent recognition by an HLA-DP4/NY-ESO-1-specific CD4+ cytotoxic T cell clone (NY67).
• Validation in a second model using an HLA-DP4+ melanoma cell line with low NY-ESO-1 expression, evaluating recognition by the NY67 clone in the presence of OV infection.

Main Results:

• OV-induced lysis of NY-ESO-1-positive melanoma cells led to intercellular transfer of NY-ESO-1 to NY-ESO-1-negative cells.
• This transfer enabled NY-ESO-1-negative tumor cells to be recognized by NY67 CD4+ T cells.
• OV infection significantly increased the recognition of low NY-ESO-1-expressing melanoma cells by the NY67 clone.

Conclusions:

• Oncolytic viruses stimulate antitumor immune responses through a novel mechanism involving TAA loading onto tumor cells.
• OV-mediated TAA presentation sensitizes tumor cells for direct recognition by effector CD4+ T cells.
• These findings support the therapeutic application of OV in cancer immunotherapy.