Sequence variations in HIV-1 p24 Gag-derived epitopes can alter binding of KIR2DL2 to HLA-C*03:04 and modulate primary natural killer cell function.
OBJECTIVE
The aim of this study was to assess the consequence of sequence variations in HLA-C03:04-presented HIV-1 p24 Gag epitopes on binding of the inhibitory natural killer (NK) cell receptor KIR2DL2 to HLA-C03:04.


METHODS
HIV-1 may possibly evade recognition by KIR+ NK cells through selection of sequence variants that interfere with the interactions of inhibitory killer cell immunoglobulin-like receptors (KIRs) and their target ligands on HIV-1 infected cells. KIR2DL2 is an inhibitory NK cell receptor that binds to a family of HLA-C ligands. Here, we investigated whether HIV-1 encodes for HLA-C03:04-restricted epitopes that alter KIR2DL2 binding.


METHODS
Tapasin-deficient 721.220 cells expressing HLA-C03:04 were pulsed with overlapping peptides (10mers overlapped by nine amino acids, spanning the entire HIV-1 p24 Gag sequence) to identify peptides that stabilized HLA-C expression. The impact that sequence variation in HLA-C03:04-binding HIV-1 epitopes has on KIR2DL2 binding and KIR2DL2+ NK cell function was determined using KIR2DL2-Fc constructs and NK cell degranulation assays.


RESULTS
Several novel HLA-C03:04 binding epitopes were identified within the HIV-1 p24 Gag consensus sequence. Three of these consensus sequence peptides (Gag144-152, Gag163-171 and Gag295-304) enabled binding of KIR2DL2 to HLA-C03:04 and resulted in inhibition of KIR2DL2+ primary NK cells. Furthermore, naturally occurring minor variants of epitope Gag295-304 enhanced KIR2DL2 binding to HLA-C03:04.


CONCLUSIONS
Our data show that naturally occurring sequence variations within HLA-C03:04-restricted HIV-1 p24 Gag epitopes can have a significant impact on the binding of inhibitory KIR receptors and primary NK cell function.
aRagon Institute of MGH, MIT, and Harvard, Cambridge, Massachusetts, USA bExperimental Immunology, Academic Medical Center Amsterdam, Amsterdam, The Netherlands cDepartment of Microbiology and Immunobiology, Harvard Medical School, Boston dDivision of Microbiology, New England Primate Research Center, Southborough, Massachusetts, USA eIrsicaixa AIDS Research Institute - HIVACAT, Autonomous University of Barcelona, Badalona and Institució Catalana de Recerca i Estudis Avancats (ICREA), Barcelona, Spain fCancer and Inflammation Program, Laboratory of Experimental Immunology, SAIC Frederick, Inc., Frederick National Laboratories for Cancer Research, Frederick, Maryland gDepartment of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA hLaboratory for Translational Immunology, University Medical Center Utrecht, Utrecht iCenter for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands jHeinrich-Pette-Institut, Leibniz Institute for Experimental Virology, Hamburg, Germany. *Nienke H. van Teijlingen and Angelique Hölzemer have contributed equally to the writing of the manuscript.
Nienke H
NH
van Teijlingen
Angelique
A
Hölzemer
Christian
C
Körner
Wilfredo F
WF
García-Beltrán
Jamie L
JL
Schafer
Lena
L
Fadda
Todd J
TJ
Suscovich
Christian
C
Brander
Mary
M
Carrington
David T
DT
Evans
Debbie
D
van Baarle
Marcus
M
Altfeld
D015550:Cell Degranulation; D002460:Cell Line; D000939:Epitopes / Q000235:genetics*; D014644:Genetic Variation; D016655:HIV Core Protein p24 / Q000235:genetics*; D015236:HLA-C Antigens / Q000378:metabolism*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D011485:Protein Binding; D054343:Receptors, KIR2DL2 / Q000378:metabolism*
D000939:Epitopes; D016655:HIV Core Protein p24; D015236:HLA-C Antigens; C106548:HLA-C*03:04 antigen; C515077:KIR2DL2 protein, human; D054343:Receptors, KIR2DL2