Lack of gene rearrangement and mRNA expression of the beta chain of the T cell receptor in spontaneous rat large granular lymphocyte leukemia lines.

Abstract

In the rat (1), mouse (2), and human (3), most, if not all, natural killer (NK) activity has been shown to be associated with a distinct subpopulation of cells termed large granular lymphocytes (LGL). It has been suggested that, since LGL express some T cell-associated antigens (4) and can grow in vitro in cultures supplemented with interleukin 2 (IL-2) (5) that LGL represent a population of lymphocytes within the T cell lineage. At present, however, there is very little definitive information regarding either the lineage of these cells or the nature of their cell surface receptors for antigens. To further address the relationship between LGL and T cells, we examined several transplantable LGL leukemia lines for the rearrangement and expression of the genes encoding for the beta chain of the T cell antigen receptor. This receptor has been shown (6) to be expressed in most, if not all, helper and cytotoxic T cells, but not in suppressor T cells. LGL leukemia lines were studied because they provide a convenient source of highly active NK cells with morphological and functional characteristics that closely resemble those of normal LGL (7,8). Previous data (7, 8) also suggest that these tumor cell lines represent the clonal expansion of normal LGL, and, presuming an analogy to cytotoxic T cells, would be expected to demonstrate a unique rearrangement of the various elements of the antigen receptor, possibly corresponding to the genes coding for the T cell antigen receptor.The gene encoding for the beta chain of the T cell antigen receptor has recently been cloned and characterized in both the mouse (9) and human (10). Prerequisites to beta chain gene expression are rearrangements of the variable (V), diversity (D), and joining (J) elements into a transcriptional unit that is completed by the coding exons of the constant (C) region (9). The absence of such rearrangements indicates that a particular cell line does not functionally express the beta chain gene. The rearrangement of this gene is consistent with, but does not prove, transcription and translation of functional messenger RNA (mRNA) or receptor expression. However, the presence of a 1.2-1.3 kilobase

Increased NKG2A found in cytotoxic natural killer subset in HIV-1 patients with advanced clinical status

“…The dysfunctional NK subset expands and the cytotoxic NK subset decreases in patients with chronic HIV-1 infection compared with those without HIV infection [2]. Unlike T and B cells, NK cells do not require gene rearrangements for their receptor maturation [3,4]. The functions of NK cells are regulated by a number of MHC-I-specific inhibitory NK receptors (iNKRs) and natural cytotoxicity receptors (NCR) [5].…”

The Natural Killer Cell‐Like Lytic Activity Expressed by Cytolytic T Lymphocytes is Associated with the Expression of a Novel Function‐Associated Molecule

“…We postulate that this funct ion-associated molecule on these CTL is a novel structure, distinct from either the alpha/beta or delta/ gamma TCR [41,42] for several reasons. One, the moieculc is present on the majority of endogeneous peripheral blood NK cells, cells previously shown not to express TCR molecules [4,43,44], and is not present on freshly isolated peripheral blood T cells (these results and Ref. 25).…”

Exogenously-induced, natural killer cell-mediated neuronal killing: a novel pathogenetic mechanism.

“…taneously with 3.2.3 and anti-CD3 (expressed on all mature T cells [30]) mAbs revealed that the majority of the infiltrating CD8 + cells were 3.2.3 positive, but CD3 negative, thus confirming their NK cell phenotype (31)(32)(33). Normal rat SCGs (Fig.…”

“…tion system and the "antigen" or substance being identified as foreign by NK cells in the ganglia after gnanethidine treatment, remains unknown (3,31,34). Nevertheless, their recognition of targets does not appear to follow the classical rules of induction and memory pertaining to other lymphocyte classes (1)(2)(3).…”