Anti-tumor efficacy of plasmid encoding emm55 in a murine melanoma model

Area of Science:

• Immunology
• Oncology
• Vaccinology

Background:

• Streptococcus pyogenes (S. pyogenes) Emm55 gene cloned into plasmid DNA vaccine (pAc/emm55).
• Investigated anti-tumor efficacy of pAc/emm55 in a B16 murine melanoma model.

Purpose of the Study:

• To evaluate the anti-tumor efficacy of pAc/emm55 in a preclinical melanoma model.
• To assess the impact of pAc/emm55 on tumor-infiltrating immune cells, particularly T cells.
• To explore combination therapy with anti-PD-1 antibodies.

Main Methods:

• Intralesional (IL) injections of pAc/emm55 in B16 murine melanoma model.
• Analysis of CD4+ and CD8+ T cell infiltration into tumors.
• CD4+ or CD8+ T cell depletion experiments.
• Combination treatment with pAc/emm55 and anti-PD-1 antibody.

Main Results:

• IL pAc/emm55 significantly delayed tumor growth compared to control.
• Increased infiltration of CD8+ T cells and antigen-specific T cells into tumors post-treatment.
• Depletion of CD4+ or CD8+ T cells abolished the anti-tumor effect.
• Combination therapy significantly enhanced anti-tumor immunity and delayed tumor growth more than monotherapy.

Conclusions:

• pAc/emm55 demonstrates significant anti-tumor efficacy in melanoma by enhancing T cell responses.
• Combination of pAc/emm55 with PD-1 blockade represents a promising strategy for improving melanoma treatment.
• Further investigation is warranted for clinical translation in melanoma patients.