Recruitment of lymphocytes is an important feature of the host immune response against pathogens. However, the mechanisms by which lymphocytes are attracted are not yet fully understood. Recently, ...the cDNA of a lymphocyte-specific chemokine, lymphotactin (Lptn), was isolated from murine and human T cells and was also found to be expressed in murine NK cells and human NK cell clones. This study investigated the influence of interleukin (IL)-2 and IL-12 on the expression of Lptn, also known as SCM (single cysteine motif)-1alpha, and SCM-1beta, a 97% homolog of Lptn, in freshly isolated human NK cells and the human NK cell line NK-92. Northern blot analysis and RT-PCR confirmed that nonactivated human NK cells expressed both genes at low level. After activation with IL-2 or IL-12, the expression of both Lptn and SCM-1beta was upregulated within hours. NK-92 cells maintained in medium supplemented with IL-2 constitutively expressed SCM-1 mRNA. However, after 24 h of IL-2 starvation and subsequent culturing at various IL-2 concentrations, the expression of Lptn/SCM-1alpha was upregulated in a dose-dependent manner, whereas the expression of SCM-1beta remained consistently high. These observations indicate that NK cells, in addition to T lymphocytes, express Lptn/SCM-1alpha and SCM-1beta after cytokine activation. The upregulation of these chemokines in NK cells on activation likely acts to increase the number of effector cells reaching the site of an immune response such as inflammation.
Photonic nano-structure of R. Gigantea Suet Ying Ching; Gui Xin Li; Hoi Lam Tam ...
2010 3rd International Nanoelectronics Conference (INEC),
2010-Jan.
Conference Proceeding
Rhomborhina Gigantea (R. Gigantea) was examined for its iridescent properties in its exocuticle. The iridescence was explained by the theories of the optical reflectors causing the structural colors ...and the concepts of cholesteric liquid crystals (CLCs). The exocuticle was examined for its optical properties through experiments of reflection and diffraction. Reflection spectra showed contrast results in transverse electric (TE) and transverse magnetic (TM) modes. The cross-section of the beetle cuticle structure was investigated using scanning electron microscope (SEM). The experimental values of average refraction index (n av ) and the half-pitch (P h ) were derived from the optimal Bragg condition. The observed P h from SEM images was similar to the experimental values in linear polarization. The average refractive indices determined from the optical data in both TE and TM modes were in god agreement to the predicted value. The consistency of the results implied that the structure responsible for the iridescent beetle was a biological analogue to CLCs.
The pathogenesis of nasopharyngeal carcinoma (NPC) is multifactorial. Associations have been reported between HLA and NPC. We studied the HLA-DR and -DQ regions on the molecular level in 136 persons ...(51 NPC patients and 85 healthy controls) from southern China, a particularly high-prevalence area for NPC. Restriction fragment-length polymorphism (RFLP) was used to genotype the MHC class II DRβ, DQα, and DQβ regions of the subjects. Polymerase chain reaction (PCR) using sequence-specific primer (SSP) for DQβ genes was also performed. By RFLP, no significant difference was observed with respect to DRB, DQA, and DQB genes. By PCR SSP typing, we confirmed that there was no significant difference between NPC patients and controls with respect to DQβ alleles. Our study suggests that HLA-DQ and -DR genes are not associated with NPC in southern Chinese and there may be other gene loci that predispose them to have such a high prevalence of the disease.
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