Differentially induced expression of C-type lectins in activated lymphocytes

Abstract

The human NK gene complex encodes for the leucocyte C-type lectins, CD69, AICL (activation-induced C-type lectin), LLT1 (lectin-like transcript), CD161/NKR-P1A, CD94, and for NKG-2 molecules. These gene products have been implicated in the regulation of the function of natural killer (NK) cells and other lymphocytes. In this study the expression of C-type lectins during the early activation of PMA-stimulated peripheral blood lymphocytes was examined. To investigate the in¯uence of de novo protein synthesis on activation-dependent expression of C-type lectins, cells were cultured in presence of cycloheximide (CHX) and mRNA levels were analyzed by semi-quantitative reverse transcription-polymerase chain reaction. Upregulated levels of CD69, AICL, and LLT1, but less pronounced changes of CD161/NKR-P1A and CD94 mRNA were found at early time points of cellular activation. CD69 was superinduced by CHX at the nuclear precursor transcript and the mRNA level suggesting that regulation of transcriptional activity and mRNA stability contribute to extent of CD69 mRNA accumulation. CHX treatment resulted also in an overexpression of AICL, LLT1, and CD161/NKR-P1A mRNAs. Conversely, CHX blocked CD94 mRNA expression in PMA-stimulated cells, demonstrating that this process is dependent on new protein synthesis. Expression kinetics in context with susceptibility to CHX indicate that the mechanisms responsible for upregulated CD69, AICL, and LLT1 expression are distinct from those which control CD161/NKR-P1A or CD94 expression.

Characterization of the Chicken C-Type Lectin-Like Receptors B-NK and B-lec Suggests That the NK Complex and the MHC Share a Common Ancestral Region

“…B-NK mRNA levels were consistently low in cells stimulated with PMA compared with unstimulated cells, which was only slightly enhanced in the presence of CHX, with ϳ5-fold increase at 2 h posttreatment, rising to ϳ30-fold increase at 6 and 20 h poststimulation compared with unstimulated cells. This is similar to the pattern observed for NKR-P1 (15).…”

“…These results demonstrate that B-lec is an early activation Ag. Moreover, the expression kinetics of B-lec was similar to that observed for CD69 and LLT1, regardless of whether the results were analyzed as described here (fold change away from unstimulated cells at the same time) or as described by Eichler et al (15) (fold changes away from cells stimulated with PMA for 2 h). In contrast to B-lec, smaller (and slower) changes were found in levels of B-NK mRNA, with a decrease in message detected in cells stimulated for 2 h with PMA compared with unstimulated cells.…”

“…mRNAs for these receptors are inducible in PBL with PMA, and superinduction was detected when PBL were stimulated with both PMA and the translational inhibitor CHX (15). To determine whether B-lec is also an activation Ag, chicken PBL were stimulated with PMA in the presence or absence of CHX.…”

Functional Consequences of Interactions between Human NKR-P1A and Its Ligand LLT1 Expressed on Activated Dendritic Cells and B Cells

“…A prior report also demonstrated that PMAstimulated PBMC express LLT1 mRNA (24). After observing that LLT1 was induced on CpG-treated B cells, we examined whether stimulation by other TLR agonists might induce LLT1 expression on peripheral blood leukocytes.…”

Gene expression responses toRiemerella anatipestiferinfection in the liver of ducks

“…AICL is an activation-induced C-type lectin encoded by the human natural killer (NK) gene complex, which has been implicated in the regulation of the function of NK cells and other lymphocytes. An up-regulated level of AICL was found during the early activation of PMA-stimulated peripheral blood lymphocytes (Eichler et al, 2001). AICL has been identified as a myeloid-specific activating receptor that is up-regulated by Toll-like receptor stimulation.…”