Killer-cell immunoglobulin-like receptor genotyping and HLA killer-cell immunoglobulin-like receptor-ligand identification by real-time polymerase chain reaction

Abstract

The effector function of natural killer (NK) cells is modulated by surface expression of a range of killer-cell immunoglobulin-like receptors (KIRs) that interact with human leukocyte antigen (HLA) class I ligands. We describe the use of real-time polymerase chain reaction (PCR) assays that allow easy and quick detection of 16 KIR genes and the presence/absence of KIR-ligands based on allelic discrimination at codon 80 in the HLA-A/B Bw4 and HLA-C C1/C2 genes. These methods overcome the tedious and expensive nature of conventional KIR genotyping and HLA class I typing using sequence-specific primer (SSP) PCR, sequence-specific oligonucleotide (SSO) hybridization or sequence-based typing (SBT). Using these two cost-effective assays, we measured the frequencies of KIRs, KIR-ligands and KIR/KIR-ligand pairs in a cohort of Black women recruited in South Africa.

Figure 1

(A) Melt curve analysis of killer immunoglobulin–like receptor (KIR)-polymerase chain reaction (PCR) products melting to the right of the internal control galactosylceramidase (GALC) (74.89°C) and (B) KIR-ligand PCR amplicons melting to the right of the internal control albumin (ALB) (75.62°C).

Figure 2

Frequency of killer immunoglobulin–like receptor (KIR)-ligand allele combinations in a South African Cohort (n=81). On the basis of allelic discrimination at codon 80 the KIR-ligand assay can identify the presence/absence of KIR-ligands human leukocyte antigen (HLA)-A (Bw4:I⁸⁰ and non-Bw4:T⁸⁰) and HLA-B (Bw4:I⁸⁰, Bw4:T⁸⁰A⁸¹, Bw4:T⁸⁰L⁸¹ and Bw6:N⁸⁰) and HLA-C (C1 and C2).