ACE2 and infection: However, intramuscular immunization of K18-hACE2 and C57BL/6 J mice with non-trans-complemented VSV*ΔG-SΔ21 triggered the production of spike-specific antibodies at only very low levels, suggesting that skeletal muscle cells at the vaccine inoculation site were resistant to infection with VSV*ΔG-SΔ21 due to low-level or absent ACE2 expression.