Luzheng Liu | Search PubMed

PubMed2002

Visualization and quantification of T cell-mediated cytotoxicity using cell-permeable fluorogenic caspase substrates.

We have developed a non-radioactive flow-cytometry assay to monitor and quantify the target-cell killing activities mediated by cytotoxic T lymphocytes (CTLs). This flow-cytometry CTL (FCC) assay is predicated on measurement of CTL-induced caspase activation in target cells through detection of the specific cleavage of fluorogenic caspase substrates. Here we show that this assay reliably detects antigen-specific CTL killing of target cells, and demonstrate that it provides a more sensitive, more informative and safer alternative to the standard 51Cr-release assay most often used to quantify CTL responses. The FCC assay can be used to study CTL-mediated killing of primary host target cells of different cell lineages, and enables the study of antigen-specific cellular immune responses in real time at the single-cell level. As such, the FCC assay can provide a valuable tool for studies of infectious disease pathogenesis and development of new vaccines and immunotherapies.

Animals↗

PubMed1999

A global learning algorithm for a RBF network.

This article presents a new learning algorithm for the construction and training of a RBF neural network. The algorithm is based on a global mechanism of parameter learning using a maximum likelihood classification approach. The resulting neurons in the RBF network partitions a multidimensional pattern space into a set of maximum-size hyper-ellipsoid subspaces in terms of the statistical distributions of the training samples. An important feature of the algorithm is that the learning process includes both the tasks of discovering a suitable network structure and of determining the connection weights. The entire network and its parameters are thought of evolved gradually in the learning process.

Journal Article↗