Natural killer cell heterogeneity: cellular dysfunction and significance in HIV-1 immuno-pathogenesis

Natural killer (NK) cells are innate immune effectors that provide first line of defence against viruses. Human NK cells are heterogeneous in nature, and their functions rely on a dynamic balance between germ-line-encoded activating and inhibitory receptors. HIV-1 infection results in altered NK cell receptor repertoire and impaired effector functions including the ability to lyse virus-infected cells and secretion of antiviral cytokine IFN-gamma. Over the last decade, additional NK cell subset-specific molecules have been identified, leading to emergence of a more complex cellular diversity than previously thought. Herein, we discuss NK cell subset redistribution, altered receptor repertoire and influence of interaction of polymorphic leucocyte antigen (HLA) and killer cell immunoglobulin-like receptors (KIR) on HIV-1 disease progression.