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. 2018 Nov 18;43(2):123–144. doi: 10.1093/femsre/fuy043

Table 2.

Immune evasion strategies of K. pneumoniae.

Immune evasion strategies Mechanism Bacterial factor References
(i) Stealth pathogen
Preventing the antimicrobial action of soluble innate immune effectors
 Preventing complement bactericidal effect, and opsonisation Limiting C3b deposition CPS, LPS O-polysaccharide Merino et al.1992; Alvarez et al.2000; de Astorza et al.2004
 Limiting antimicrobial activity of collectins Blunting interaction with SP-A and SP-D CPS Kabha et al.1997; Ofek et al.2001; Kostina et al.2005
 Counteracting bactericidal action CAMPs and polymyxins Limiting the interaction with the bacterial surface. Efllux of CAMPs. CPS, LPS lipid A decorations, AcrAB Campos et al.2004; Llobet et al.2011; Kidd et al.2017; Mills et al.2017; Padilla et al.2010
Attenuating the interaction with immune cells
 Attenuating engulfment by epithelial cells CPS Cortes et al.2002; Regueiro et al.2006
 Avoiding phagocytosis by neutrophils CPS, OmpK36 Regueiro et al.2006; Pan et al.2011
 Avoiding phagocytosis by macrophages CPS, LPS lipid A decorations, OmpA, OmpK36 March et al.2013
Limiting the activation of PPRs Limiting the recognition of LPS by TLR4 LPS lipid A 2-hydroxylation Llobet et al.2015
(ii) Subversion host defences
Attenuating cell-intrinsic immunity
 Controlling maturation dendritic cells CPS, LPS O-polysaccharide Evrard et al.2010
 Manipulation phagosome maturation Activation PI3K-AKT-Rab14 axis Unknown Cano et al.2015
 Controlling cell death Cytotoxicity in epithelial cells. Triggering apoptosis in macrophages. CPS Unknown Cano et al.2009; Leone et al.2016
Abrogating TLR-controlled inflammatory responses:
 Abolishing TLR signalling CPS, LPS O-polysaccharide, OmpA, T2SS March et al.2011; Frank et al.2013; Tomas et al.2015
 Blunting NF-κB signalling Upregulation deubiquitinase CYLD by targeting NOD1 and EGFR. CPS, and other unknown factor(s) Regueiro et al.2011; Frank et al.2013
 Blunting MAPKs Upregulation MAPKs phosphatase MKP-1 via NOD1 activation. Unknown Regueiro et al.2011
Manipulating mucosal immunity Induction of IL10. Unknown Greenberger et al.1995; Yoshida et al.2001
Counteracting nutritional immunity Secretion of several siderophores Yersiniabactin, salmochelin, aerobactin Lawlor, O’connor and Miller 2007; Bachman et al.2011; Russo et al.2011