Bait and switch tactics

• inhibition of humoral immunity

  • virally-encoded Fc receptor blocks effector functions of antibodies bound to infected cells. herpes simplex, cytomegalovirus

  • virally-encoded complement receptor blocks complement-mediated effector pathways (e.g. C3b opsonization). herpes simplex

  • virally-encoded complement control protein inhibits complement activation by the infected cell. vaccinia (the causative agent of smallpox)

• inhibition of inflammatory response

  • virally-encoded chemokine receptor homolog, e.g. β-chemokine receptor; advantage to virus unknown

  • virally-encoded soluble cytokine rerceptor, e.g. IL-1 receptor homolog, TNF receptor homolog, IFN-γ receptor homolog; blocks cytokines by inhibiting interaction with host receptors. vaccinia

  • viral inhibition of adhesion molecule expression

  • protection from NF-κB activation by short sequences that mimic TLRs

• blocking of antigen processing and presentation

  • inhibition of MHC class I expression

  • inhibition of peptide transport by TAP

• immunosuppression of host

  • virally-encoded cytokine homolog of IL-10

Category: Pathology Notes