Adenoviral vaccines promote protective tissue-resident memory T cell populations against cancer.

BACKGROUND: Adenoviral vectors emerged as important platforms for cancer immunotherapy. Vaccination with adenoviral vectors is promising in this respect, however, their specific mechanisms of action are not fully understood. Here, we assessed the development and maintenance of vaccine-induced tumor-specific CD8+ T cells elicited upon immunization with adenoviral vectors. METHODS: Adenoviral vaccine vectors encoding the full-length E7 protein from human papilloma virus (HPV) or the immunodominant epitope from E7 were generated, and mice were immunized intravenously with different quantities (107, 108 or 109 infectious units). The magnitude, kinetics and tumor protection capacity of the induced vaccine-specific T cell responses were evaluated. RESULTS: The adenoviral vaccines elicited inflationary E7-specific memory CD8+ T cell responses in a dose-dependent manner. The magnitude of these vaccine-specific CD8+ T cells in the circulation related to the development of E7-specific CD8+ tissue-resident memory T (TRM) cells, which were maintained for months in multiple tissues after vaccination. The vaccine-specific CD8+ T cell responses conferred long-term protection against HPV-induced carcinomas in the skin and liver, and this protection required the induction and accumulation of CD8+ TRM cells. Moreover, the formation of CD8+ TRM cells could be enhanced by temporal targeting CD80/CD86 costimulatory interactions via CTLA-4 blockade early after immunization. CONCLUSIONS: Together, these data show that adenoviral vector-induced CD8+ T cell inflation promotes protective TRM cell populations, and this can be enhanced by targeting CTLA-4.

Pneumonitis from immune checkpoint inhibitors and COVID-19: current concern in cancer treatment.

Pneumonitis is a rare but serious adverse event caused by cancer immunotherapy. The diagnosis between COVID-19-induced pneumonia and immunotherapy-induced pneumonitis may be challenging in the era of COVID-19 outbreak. Some clinical symptoms and radiological findings of pneumonitis can be attributed to the coronavirus infection as well as to an immune-related adverse event. Identifying the exact cause of a pneumonitis in patients on treatment with immunotherapy is crucial to promptly start the most appropriate treatment. The proper management of immune checkpoint inhibitors for the risk of pneumonia must take into account a series of parameters. Accurate attention should be payed to symptoms like cough, fever and dyspnea during immunotherapy.