Table 3.

Role of protective alleles in control of/and resistance to human immunodeficiency virus (HIV)-1 infection

	Putative mechanisms	Outcome and references
NK alleles
KIR3DL1high	Increased NK licensing, heightened NK cell responses	Delayed progression to AIDS [87]
		Reduced risk of HIV-1 infection [28]
KIR3DS1	Augmented NK activation, heightened NK cell responses	Delayed progression to AIDS [125]
		Reduced risk of HIV-1 infection [17]
KIR2DL2/DL3	Augmented NK activation, heightened NK cell responses	Reduced risk of HIV-1 infection [2]
MHC alleles
HLA-Bw4 80*I (including HLA-B*57)	Increased NK licensing, heightened T cell responses	Delayed progression to AIDS [87,125]
		Reduced risk of HIV-1 infection [28]
MHC class II DRB	Increased protective MHC class II restricted T cell responses	Reduced risk of HIV-1 infection [29]
HLA-B*4901 + HLA-B*5301	Increased NK surveillance in the placenta during mother-to-infant transmission	Reduced risk of HIV-1 infection [13]
HLA-E*0103	Increased HLA-E expression, increased NK surveillance	Reduced risk of HIV-1 infection [90]
HLA-G*0105N	Loss of HLA-G expression, reduced inhibition of NK cells	Reduced risk of HIV-1 infection [90]

AIDS, acquired immune deficiency syndrome; HLA, human leucocyte antigen; NK, natural killer; MHC, major histocompatibility complex.