Most advanced vaccines against severe acute respiratory syndrome coronavirus (SARS-CoV)-2 are designed to induce antibodies against spike (S) protein. Differently, we developed an original strategy to induce CD8 + T cytotoxic lymphocyte (CTL) immunity based on in vivo engineering of extracellular vesicles (EVs). This is a new vaccination approach based on intramuscular injection of DNA expression vectors coding for a biologically inactive HIV-1 Nef protein (Nef mut ) with an unusually high efficiency of incorporation into EVs, even when foreign polypeptides are fused to its C-terminus. Nanovesicles containing Nef mut -fused antigens released by muscle cells can freely circulate into the body and are internalized by antigen-presenting cells. Therefore, EV-associated antigens can be cross-presented to prime antigen-specific CD8 + T-cells. To apply this technology to a strategy of anti-SARS-CoV-2 vaccine, we designed DNA vectors expressing the products of fusion between Nef mut and different viral antigens, namely N- and C-terminal moieties of S (referred to as S1 and S2), M, and N. We provided evidence that all fusion products are efficiently uploaded in EVs. When the respective DNA vectors were injected in mice, a strong antigen-specific CD8 + T cell immunity became detectable in spleens and, most important, in lung airways. Co-injection of DNA vectors expressing the diverse SARS-CoV-2 antigens resulted in additive immune responses in both spleen and lungs. Hence, DNA vectors expressing Nef mut -based fusion proteins can be proposed for new anti-SARS-CoV-2 vaccine strategies.
【저자키워드】 SARS-CoV-2, Extracellular vesicles, CD8+ T cell immunity, Nef, 【초록키워드】 Vaccine, coronavirus, immune response, vaccination, Immunity, antibody, T-cells, lung, CD8, anti-SARS-CoV-2, Antigen, Protein, lymphocyte, DNA, T cell, mice, vector, Lungs, HIV-1, extracellular vesicle, SARS-CoV-2 antigen, fusion protein, in vivo, CTL, spleen, Evidence, Efficiency, airways, Intramuscular injection, antigen-presenting cells, acute respiratory syndrome, viral antigens, coding, C-terminus, polypeptide, MOST, expression vector, EVs, approach, Cell, S1 and S2, detectable, injected, provided, induce, expressing, released, C-terminal, inactive, fused, 【제목키워드】 CD8, response, induced, Simultaneous,