Table 2. Potential effects of SHS/direct CS/direct or secondary nicotine on macrophage function against TB.

Macrophage phenotype and function	Effects of SHS/direct CS/direct or secondary nicotine
M1 phenotype	Skewed macrophages to the M2 phenotype (52)(H). Induced PD-L1/2, resulting in a deactivated phenotype (56,57,58)(M/H,H,H).
Cell surface markers	Smoker AM had less expression of CD11a, CD71, and CD54; smoker AM have greater density of CD11c (but not percentage of AM positive for CD11c) (59)(H).
Phagocytosis	Effect of SHS/direct CS on phagocytosis is conflicting, from no effect to inhibition of phagocytosis (40,45,60,61)(M,H,H,H).
Efferocytosis	Inhibited efferocytosis (55,62,63)(M/H,H,H)
Phagosome-lysosome fusion	Inhibited phagosome-lysosome fusion (64,65,66)(R,H,M/H)
Autophagy	Inhibited autophagy by CS (51,67)(M/H,H) and nicotine (68)(M/H).
Apoptosis	Inhibited apoptosis (69,70)(H,M/H).

M, murine; H, human; M/H, murine and human; AM, alveolar macrophage.