An infectious disease specialist is preparing a grand rounds presentation on the diverse strategies that human pathogens use to evade the host immune system and establish productive infections. The presentation highlights several distinct mechanisms, including the subversion of cellular peptide transport, the secretion of immunomodulatory analogs, escaping intracellular degradation, and the constant alteration of surface antigens. Match the following pathogens to their corresponding primary molecular mechanism of immune evasion or intracellular survival.
- Epstein-Barr virusSynthesis of an interleukin-10 homolog that inhibits Th1 immune responses and prevents macrophage activation.
- Herpes simplex virus type 1Production of a protein that binds to and inhibits the transporter associated with antigen processing (TAP), preventing MHC class I loading.
- *Neisseria gonorrhoeae*Extensive antigenic variation achieved through homologous recombination of silent gene cassettes into an active expression locus.
- *Listeria monocytogenes*Secretion of a sulfhydryl-activated cytolysin that mediates escape from the phagolysosome into the host cell cytoplasm.
Answer
Epstein-Barr virus produces an IL-10 homolog; Herpes simplex virus type 1 inhibits the TAP complex; Neisseria gonorrhoeae undergoes pilin antigenic variation; and Listeria monocytogenes secretes a cytolysin to escape the phagolysosome.
Each pathogen has evolved unique molecular mechanisms to establish infection and evade host defenses. Epstein-Barr virus mimics host immunosuppressive cytokines, Herpes simplex virus blocks intracellular antigen presentation, Neisseria gonorrhoeae constantly alters its surface antigens via genetic recombination, and Listeria monocytogenes escapes destruction by physically breaking out of the phagolysosome.
Step-by-Step Solution
Key Concept
Specific molecular mechanisms of immune evasion and intracellular pathogenesis used by viral and bacterial pathogens.
Estimated Time:1m 30s