[1] CATHOLIC UNIV LEUVEN, REGA INST MED RES, MOLEC MED LAB, MINDERBROEDERSST 10, B-3000 LOUVAIN, BELGIUM
[2] YESHIVA UNIV ALBERT EINSTEIN COLL MED, DEPT MICROBIOL & IMMUNOL, BRONX, NY 10461 USA
[3] UNIV ERLANGEN NURNBERG, INST KLIN VIROL, W-8520 ERLANGEN, GERMANY