. 2015 Apr 14;145(1):1–10. doi: 10.1111/imm.12454

Table 2.

Comparison of the immature, mature and tolerant responses to endotoxin stimulation

Immature immune response relative to mature response	Relative effect of difference	Tolerance recapitulates immature immune response?
Cellular adhesion functions
↓Leucocyte adhesion and extravasation⁵	Impaired ability to fight infections⁵	Yes²⁰
PRR/Signal transduction
↓TLR4 receptor expression¹³^,¹⁸^,²⁰^,²²	Minimal effects¹³^,¹⁸^,²⁰^,²²	Yes⁸^,²¹^,³⁷
↓Soluble TLR4 co-receptor expression¹⁸	Minimal effects¹⁸	Yes⁸^,²¹^,³⁷
↓TLR/MyD88 pathway signalling¹⁴^,²³^,²⁴	↓ROS production²⁴	Yes²^,⁸^,²¹^,³⁷
Regulation of the adaptive response
↑Th2-skewing cytokine production⁴^,¹²^,¹⁴^,¹⁸	↑Humoral immune response³³	Yes²^,²¹
↓Th1-skewing cytokine production⁴^,¹²^,¹⁴^,¹⁸	↓Pro-inflammatory immune response⁴^,¹²^,¹⁴^,¹⁸	Yes²^,²¹
↓Stimulated T-cell proliferation⁴	↓Cytotoxic T-cell response and ↓Adaptive response⁴^,²⁴	Yes⁴⁴
↑Th17/Treg differentiation^a ¹³^,¹⁶^,²⁰^,²²^,²³^,²⁷	↑Anti-inflammatory response¹³^,¹⁶^,²⁰^,²²^,²³^,²⁷	Unknown
Soluble factors
↑Maternally produced factors (TGF-β, progesterone, PGE₂)¹²	↑Th2-skewed response¹²	Similar PGE2 (macrophage-produced)²¹
↑Adenosine¹²^,¹⁸^–²⁰^,³¹	↑Th2-skewed response¹²^,¹⁸^–²⁰^,³¹	Unknown
↓Antimicrobial protein peptides³¹	Impaired ability to fight infections³¹	Unknown
Cell–cell interactions
↓CD8⁺ T-cell activation²⁴	↓Cytotoxic response²⁴	Yes⁸
↓CD4⁺ stimulation by APCs³³	↑Th2-skewed response³³	Yes²
↑Apoptosis of CD4⁺ Th1 cells²⁴	↑Th2-skewed response²⁴	Yes²
↓Memory T cells⁹	↓Eradication of viral and intracellular pathogens⁵^,¹³	Unknown

PGE₂, prostaglandin E₂; PRR, pattern recognition receptor; ROS, reactive oxygen species; TGF-β, transforming growth factor-β; Th2, T helper type 2; TLR, Toll-like receptor; Treg, regulatory T.

Conflicting evidence exists regarding the impact of Th17 and Treg differentiation in the immature immune response.