Involvement of HLA class I alleles in natural killer (NK) cell-specific functions: expression of HLA-Cw3 confers selective protection from lysis by alloreactive NK clones displaying a defined specificity (specificity 2).

Abstract

This study was designed to identify the target molecules of the natural killer (NK) cell-mediated recognition of normal allogeneic target cells. As previously shown, the gene(s) governing the first NK-defined allospecificity (specificity 1) were found to be localized in the major histocompatibility complex region between BF gene and HLA-A. In addition, the analysis of a previously described family revealed that a donor (donor 81) was heterozygous for three distinct NK-defined allospecificities (specificities 1, 2, and 5). HLA variants were derived from the B-Epstein-Barr virus cell line of donor 81 by gamma irradiation followed by negative selection using monoclonal antibodies specific for the appropriate HLA allele. Several variants were derived that lacked one or more class I antigen expressions. These variants were analyzed for the susceptibility to lysis by NK clones recognizing different allospecificities. The loss of HLA-A did not modify the phenotype (i.e., "resistance to lysis"). On the other hand, a variant lacking expression of all class I antigens became susceptible to lysis by all alloreactive clones. Variants characterized by the selective loss of class I antigens coded for by the maternal chromosome became susceptible to lysis by anti-2-specific clones. Conversely, variants selectively lacking class I antigens coded for by paternal chromosome became susceptible to lysis by anti-1 and anti-5 clones (but not by anti-2 clones). Since the Cw3 allele was lost in the variant that acquired susceptibility to lysis by anti-2 clones and, in informative families, it was found to cosegregate with the character "resistance to lysis" by anti-2 clones, we analyzed whether Cw3 could represent the element conferring selective resistance to lysis by anti-2 clones. To this end, murine P815 cells transfected with HLA Cw3 (or with other HLA class I genes) were used as target cells in a cytolytic assay in which effector cells were represented by alloreactive NK clones directed against different specificities. Anti-2-specific clones efficiently lysed untransfected or A2-, A3-, and A24-transfected P815 cells, while they failed to lyse Cw3-transfected cells. NK clones recognizing specificities other than specificity 2 lysed untransfected or Cw3- transfected cells. Thus, the loss of Cw3 resulted in the de novo appearance of susceptibility to lysis, and transfection of the HLA- negative P815 cells with Cw3 resulted in resistance to lysis by anti-2 clones. Therefore, we can infer that Cw3 expression on (both human and murine) target cells confers selective protection from lysis mediated by anti-2 NK clones.

Targeting CD20+ Aggressive B-cell Non–Hodgkin Lymphoma by Anti-CD20 CAR mRNA-Modified Expanded Natural Killer Cells In Vitro and in NSG Mice

“…These exPBNK can mediate cytotoxicity of allogeneic and autologous cancer cell lines by specifically activating receptor-ligand interactions. Another mechanism of tumor-cell resistance is by upregulating the expression of KIR-inhibitory ligands (46). In our study, we found that the expanded NK cells express KIRs, such as KIR2DL1, KIR2DL2/3, and KIR3DL1, and Raji, Raji-2R, and Raji-4RH cells express high-level HLA-ABC ( Supplementary Fig.…”

Leukemic Priming of Resting NK Cells Is Killer Ig-like Receptor Independent but Requires CD15-Mediated CD2 Ligation and Natural Cytotoxicity Receptors

“…Lysis occurs when the combination of activation signals overcomes any inhibitory signals provided by ligands on the target cell. The principal ligands for inhibitory molecules appear to be the HLA class I Ags, and susceptibility of tumors to NK-mediated lysis was shown to be related to the degree of expression of these molecules (14). In contrast, the nonsusceptibility of the B lymphoma cell line RAJI to NK-mediated lysis has been attributed to its expression of all of the known classes of ligands for NK-inhibitory molecules.…”

Requirements for control of B‐cell lymphoma by NK cells

“…In primary leukemias, lack of inhibition was not sufficient to confer cytotoxicity [20], but cell lines were rendered NK-resistant by HLA-C transfection, thus indicating a requirement of MHC class I down-regulation for NK-cell activity [21]. On the other hand, cells displaying normal levels of MHC class I were susceptible to NK-cell lysis if effector cells became otherwise activated [22,23].…”