Cell membrane-associated measles virus components inhibit antigen processing

Measles Virus (MV)-induced immune suppression is an important reason for MV -associated mortality and morbidity. Despite numerous studies, the mechanis ms of immune suppression still remain poorly defined. In the present study we analyzed the effect of MV components on the T-cell recognition of specif ic non-MV antigens. We demonstrated that even inactivated MV could inhibit the presentation of unprocessed protein antigen to specific T cells, wherea s MV did not affect the responses of specific T cells to representative syn thetic peptide epitopes derived from complex antigens. The inhibition was i nduced by MV-infected cell membranes. The kinetics of the MV-dependent inhi bition suggested an impaired antigen processing in mononuclear cells as add ition of MV-infected cell debris 4 h after the beginning of cell cultures n o longer inhibited T-cell responsiveness. (C) 2001 Academic Press.