Fig. 2

Complement activation pathways and antibody neutralization effects of HAdV infection. Left part: IgM triggers the activation of the complement system via the classical pathway. When IgM attaches to HAdV, it causes conformational changes that lead to the binding of complement protein C1q to antibodies. Once bound, C1 cleaves complement proteins C2 and C4. As a result, C4b and C2b combine to form C3 invertase, known as C4b2b. The C4b2b complex then cleaves C3 into C3a and C3b. Right part: The virus-antibody complex recruits TRIM21 to bind to IgG. This binding allows for the targeted transportation of the virus-antibody complex to the proteasome through E3 activity. Created by http://www.Biorender.com