Department of Psychiatry, University of Mainz, Germany.
Using immunohistochemistry and in situ hybridisation, we have studied whether alpha-subunits of nicotinic acetylcholine receptors (nAChRs) are expressed in human lymphocytes. Cells were isolated by differential low speed gradient centrifugation from heparinised venous blood of 10 healthy volunteers. Receptor sites were visualised using the monoclonal antibody WF6 which specifically recognises alpha-isoforms from several species including man. For visualisation of transcripts, digoxigenin-labelled cRNA probes for alpha 4- and alpha 3-subunits were used. Immunostaining revealed specific binding of WF6 to isolated human lymphoid cells. The antibody was bound to most cells and concentrated preferentially in the perinuclear/surface region. The immunoreactivity resembled that observed after application of an antibody recognising CD4 surface proteins which was conducted for comparison. In situ-hybridisation revealed that the alpha 4-subunit genes of nAChRs was expressed in lymphocytes of all probands. The alpha 3-subunit was found, with lower intensity than alpha 4-transcripts, in eight of the 10 individuals. Control incubations with corresponding sense cRNAs were negative. It is concluded that human lymphocytes are able to express alpha-subunit genes of nAChRs.