Ofer Levi | Search PubMed

PubMed2005

Inhibition of the NKp30 activating receptor by pp65 of human cytomegalovirus.

Human cytomegalovirus, a chief pathogen in immunocompromised people, can persist in a healthy immunocompetent host throughout life without being eliminated by the immune system. Here we show that pp65, the main tegument protein of human cytomegalovirus, inhibited natural killer cell cytotoxicity by an interaction with the activating receptor NKp30. This interaction was direct and specific, leading to dissociation of the linked CD3zeta from NKp30 and, consequently, to reduced killing. Thus, pp65 is a ligand for the NKp30 receptor and demonstrates a unique mechanism by which an intracellular viral protein causes general suppression of natural killer cell cytotoxicity by specific interaction with an activating receptor.

Animals↗

PubMed2003

Integrated bio-fluorescence sensor.

Due to the recent explosion in optoelectronics for telecommunication applications, novel optoelectronic sensing structures can now be realized. In this work, we explore the integration of optoelectronic components towards miniature and portable fluorescence sensors. The integration of these micro-fabricated sensors with microfluidics and capillary networks may reduce the cost and complexity of current research instruments and open up a world of new applications in portable biological analysis systems. A novel optoelectronic design that capitalizes on current vertical-cavity surface-emitting laser (VCSEL) technology is explored. Specifically, VCSELs, optical emission filters and PIN photodetectors are fabricated as part of a monolithically integrated near-infrared fluorescence detection system. High-performance lasers and photodetectors have been characterized and integrated to form a complete sensor. Experimental results show that sensor sensitivity is limited by laser background. The laser background is caused by spontaneous emission emitted from the side of the VCSEL excitation source. Laser background will limit sensitivity in most integrated sensing designs due to locating excitation sources and photodetectors in such close proximity, and methods are proposed to reduce the laser background in such designs so that practical fluorescent detection limits can be achieved.

Biosensing Techniques↗