Critical Role of Perforin-dependent CD8+ T Cell Immunity for Rapid Protective Vaccination in a Murine Model for Human Smallpox

Kremer, Melanie; Suezer, Yasemin; Volz, Asisa; Frenz, Theresa; Majzoub, Monir; Hanschmann, Kay-Martin; Lehmann, Michael H.; Kalinke, Ulrich; Sutter, Gerd

Rapidly protective MVA immunization in the absence of NK cells or TLR, RIG-I or Mda5 mediated signaling To elucidate the role of selected components of the innate and adaptive immune system on the rapid protection, we performed MVA immunization experiments in the C57BL/6 mouse/ECTV challenge model [41] . Briefly, we i.n. inoculated mice with 10 8 PFU MVA two days before a lethal respiratory infection with ECTV (200 PFU corresponding to 36LD50) ( Figure 2A ). This immunization fully protected the animals from disease and death after ECTV infection (P = 0.0001). In contrast, unvaccinated control mice started to show signs of morbidity (body weight loss) at about 6 days after challenge infection, and all died within 11 days ( Figure 2A) . Moreover, analysis of the viral loads in liver and lungs of vaccinated animals demonstrated full viral clearance at day 21 post infection (data not shown).