Review Article

Intracellular Pathogens: Host Immunity and Microbial Persistence Strategies

Table 3

Selected mechanisms for modulation/suppression of host immune response by persistent intracellular pathogens.

MechanismPathogen(s)Pathogen typeRemarksReference(s)

Subversion of host defenseBrucella spp.BInhibit fusion with host lysosomal compartment and alter lysosomal pH[211]
Chlamydiae spp.BDegradation of host proteins and deactivation of neutrophils by chlamydial protease-like activating factor[212, 213]
Francisella tularensisBEscape into cytosol[214]
Anaplasma phagocytophilumBInhibits autophagosomal-lysosomal fusion[215]
Legionella pneumophilaBMembrane-bound vacuole and effector protein (Ank protein) release[216]
Listeria monocytogenesBEscape into cytosol[217]
Mycobacterium tuberculosisBInhibition of phagolysosome formation[183]
Rickettsia spp.BEscape into cytosol and replicate in cytoplasm of host cell[218]
Salmonella enterica TyphiBInhibit fusion with host lysosomal compartment and alter lysosomal pH[36, 219, 220]
Toxoplasma gondiiBGenerate own vesicle[221]

Resistance to host effector mechanismsCytomegalovirusVInhibition of humoral immunity and inflammatory response. Blockage of Ag processing and presentation[63]
Epstein-Barr virusVInhibition of inflammatory response[204, 222]
Herpes simplex virusVInhibition of humoral immunity and blockage of Ag processing and presentation[27, 205]
Leishmania spp.PSilent phagocytosis[206]
Mycobacterium tuberculosisBAbility to persist in macrophages[183]
Vaccinia virusVInhibition of humoral immunity and inflammatory response[223ā€“225]

Induction of inappropriate immune responses/immunosuppression/TregsHepatitis C virus (HCV)BImmunosuppression by complement regulatory pathway[160, 226ā€“228]
Mycobacterium lepraeBImmunosuppression of Th2 cytokines, indoleamine 2, 3-dioxygenase[159, 229]
HCVVInduction of Tregs[160, 227]
Human immunodeficiency virusVInduction of Tregs[161]
Leishmania majorPInduction of Tregs[103, 230]
M. TuberculosisBInduction of Tregs[231]
Plasmodium spp.PInduction of Tregs[232]

Ag: antigen; B: bacteria; P: protozoa; Th2: type 2 helper T cells; Tregs: regulatory T cells; V: virus.