Capillary electrophoresis: a useful tool for studying superantigens

M. CRISTINA VESCINA; MARISA M. FERNÁNDEZ; MAURICIO C. DE MARZI; ELINA I. BALDINI; EMILIO L. MALCHIODI

Francia

Simposio; 15 International Symposium on Capilary electroseparation tecniques; 2006

Superantigens (SAgs) are bacterial toxins or viral proteins with immunoestimulatory properties. They bind to major histocompatibility class II molecules on antigen presenting cells as no processed proteins and activate vigorously T-lymphocytes proliferation by interaction with a subset of T-cell bearing specific receptors (TCR) variable (V) b chain. This activation leads to production of cytokines such as TNF-a, IFN-g and IL-2. This large activation of T-cells results in disease, such as food poisoning and toxic shock, which may be lethal.  Since the power of SAgs resides in their ability to be active at picomolar concentrations and their presence in diverse biological matrix (food, blood, etc) was reported as undetectable levels by the conventional techniques, it is the highest significance to develop methods such as capillary electrophoresis (CE) described bellow. CE is a powerful separation technique. However, the limited sample volume that can be loaded into a capillary without significant deterioration of the separation results in compromised concentration detection limits. Working with biological samples where the compound of interest is at trace level, like SAg, some strategies have been developed to overcome this problem. In this work, two approaches to on-column capillary preconcentration of SAgs in capillary electrophoresis are presented. Also, some advantages and disadvantages of both approaches will be discussed.