HIV COLONIZING PERIPHERAL-BLOOD MONOCYTES FOLLOWS LYMPHOCYTIC ISOLATES IN SHIFTING FROM NSI TO SI GENOTYPE

Non-syncytium inducing (NSI) and syncytium inducing (SI) variants of h uman immunodeficiency virus (HIV) isolated from peripheral blood monon uclear cells (PBMC) could be definitely typed by sequence analysis of the env-gene V3 region. It was thus possible to compare the genotypes of viral variants isolated from PBMC and accompanying monocyte culture s and those derived directly from the patients' blood cells prior to c ultivation. Within the investigated group of patients it was shown tha t HIV variants colonizing monocytes displayed a similar shift from NSI to SI as observed previously for PBMC, i.e. lymphocyte derived isolat es. Lymphocytic SI variants could be isolated from the blood of patien ts, while simultaneously the predominant provirus in both blood and mo nocytic isolate was NSI. Consequently, we observed a delayed switch in the predominant provirus genotype found in blood which was associated with a synchronous change in the genotype of the corresponding monocy tic isolate. The results show that monocytes/macrophages can be coloni zed by heterogeneous HIV variants in vivo and can therefore also funct ion as carriers for the spread of highly virulent SI variants into the tissues.