Multidrug transporter activity in lymphocytes

I Multidrug transporters play a dual role in haematopoietic cells, mediating the efflux of xenobiotics and regulating cell migration. 2 For several reasons including the lack of specific antibodies, reports of multidrug transporter distribution on lymphocytes conflict. Murine B cells have been reported to completely lack transporter activity. 3 Through analysis of parental and 'knockout' mice we show that, contrary to previous studies, murine B and T lymphocytes possess at least three active multidrug transporters and also a hitherto unrecognised drug-specific import activity. 4 Surprisingly, the drug specificity of P-glycoprotein appears cell type dependent. The data indicate that a range of developmentally regulated, multidrug transporters can impose a barrier to treatment of immune disorders.