Table 2 Alteration of phenotype and function of NK cells in virus infections

Hepatitis C virus (HCV)

NKG2D downregulation

Weakened NK cell-mediated cytotoxic capability and IFN-γ production

[82]

NKp30 downregulation but expression levels of NKG2D, NKG2A, NKp46, or CD16 remained unchanged

Inhibition of ADCC + Inhibition of IFN-γ, and TNF-α production

[83]

NKp46 and NKp30 downregulation + NKG2A upregulation

Reduction in NCR mediated target cell killing

[84]

NKp30 and NKp46 upregulation + increases in IL-10 production

Conserved cytotoxic activity in NK cells + influence the communication between NK cells and dendritic cells (DCs) in the liver leading to distortion of adaptive immune responses and the inability to control the virus effectively

[85]

NKG2D and NKP30 downregulation

Reduction in NK cells’ ability to degranulate and lyse target cells and decline of IFN-γ production through direct cell-to-cell interaction between NK cells and HCV-infected hepatocytes

[86]

Hepatitis B virus (HBV)

NKG2D/DAP10 and 2B4/SAP downregulation

Weakened NK cell-mediated cytotoxic capability and IFN-γ generation

[87]

HBV antigens leading to reduction in NKp30, NKp44, and 2B4 while,the expression of inhibitory receptor NKG2A is considerably augmented

The function of NK cells was directly hindered by HBV antigens (HBsAg and HBeAg), as they prevented NK cell activation, cytokine generation, and the release of cytotoxic granules

[88]

CD16 and NKp30 downregulation + NKG2D upregulation + LAG3, CD274 (PD-L1), EGR2 and 3, NR4A2, and TOX upregulation + impaired mTOR

NK cell exhaustion

[78]

Upregulation in T cell immunoglobulin- and mucin-domain containing molecule-3 (Tim-3)

Suppress NK cell functions

[89]

Human T-lymphotropic virus 1 (HTLV-1)

Declining in frequency of NKp30⁺ NK cells + CD107a upregulation (degranulation marker)

Elevated degranulation activity and production of perforin and granzyme B + Reductions in the level of NKp30 expression may impact the operational effectiveness of NK cells among individuals with HAM/TSP

[90]

Declining in rate of CD56⁺ and CD56^dim cells expressing CD16 + CD107a upregulation

Decrease in NK cell mediated ADCC + elevated degranulation activity

[91]

Human immunodeficiency virus (HIV)

CD56 downregulation

Increase in dysfunctional CD56^neg NK cells with modified array of activating and inhibitory receptors

[92]

Reduction in NKp30, NKp44, NKp46 and NKG2A but no change in NKG2D

Impairment of NK cell function

[93, 94]

Human papillomavirus (HPV)

Reduction in NKp30, NKp46 and NKG2D

Low NK cell cytolytic activity

[12]