The interaction between lymphocyte cell and human immunodeficiency virus (HIV) has been studied at membrane level by atomic force microscopy (AFM) in the repulsive regime of contact mode. Morphological characteristics of noninfected lymphoid cells and HIV infected cells were easily imaged from fixed and dried cell preparations. After HIV exposure we observed a decrease in surface protrusions (lost of microvilli) and the creation of many dips. Some particles, presumably of viral origin (120-130 nm size), were also observed in proximity of the cell surface. Similar changes have been observed by AFM on cells exposed to intense electromagnetic field thus indicating that such cells undergo modifications of their morphology upon suffering from an external agent.