Introduction. Special issue on analysis of immune function using flow cytometry.
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Biomedical subjects
Publications and source records attributed to Amitabh Gaur.
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The introduction of flow cytometric bead-based technology has added a new approach for investigators to simultaneously measure multiple analytes in biological and environmental samples. This new technology allows for (1) evaluation of multiple analytes in a single sample; (2) utilization of minimal sample volumes to glean data; (3) reproducibility and results comparative with previous experiments; (4) direct comparison with existing assays; and (5) a more rapid evaluation of multiple samples in a single platform. The cytometric bead array (CBA) system enables simultaneous measurement of multiple analytes in sample volumes too small for traditional immunoassays. Results have been presented for the analysis of a variety of human cytokines. In addition, the technology allows for the design and creation of assays to measure a variety of analytes including inflammatory mediators, chemokines, immunoglobulin isotypes, intracellular signaling molecules, apoptotic mediators, adhesion molecules, and antibodies. New initiatives put forward by the Human Genome Project and the FDA require the development and use of assays for the rapid simultaneous quantitation of multiple analytes. The CBA technology provides the ability to quantify multiple proteins within a given sample, with precision and consistency.
The nonobese diabetic (NOD) mouse is a good model for human type 1 diabetes, which is characterized by autoreactive T-cell-mediated destruction of insulin-producing islet beta-cells of the pancreas. The 9-23 amino acid region of the insulin B-chain [B((9-23))] is an immunodominant T-cell target antigen in the NOD mouse that plays a critical role in the disease process. By testing a series of B((9-23)) peptide analogs with single or double alanine substitutions, we identified a set of altered peptide ligands (APLs) capable of inhibiting B((9-23))-induced proliferative responses of NOD pathogenic T-cell clones. These APLs were unable to induce proliferation of these clones. However, vaccinations with the APLs induced strong cellular responses, as measured by in vitro lymphocyte proliferation and Th2 cytokine production (i.e., interleukin [IL]-4 and IL-10, but not gamma-interferon [IFN-gamma]). These responses were cross-reactive with the native antigen, B((9-23)), suggesting that the APL-induced Th2 responses may provide protection by controlling endogenous B((9-23))-specific Th1 (i.e., IFN-gamma-producing) pathogenic responses. One of these APLs that contained alanine substitutions at residues 16 and 19 (16Y-->A, 19C-->A; NBI-6024) was further characterized for its therapeutic activity because it consistently induced T-cell responses (e.g., T-cell lines and clones) that were of the Th2 type and that were cross-reactive with B((9-23)). Subcutaneous injections of NBI-6024 to NOD mice administered either before or after the onset of disease substantially delayed the onset and reduced the incidence of diabetes. This study is the first to report therapeutic activity of an APL derived from an islet beta-cell-specific antigen in type 1 diabetes.