Effect of an elevated temperature on the replication of HIV1 in a monocytic cell line

Physical parameters may affect viral replication by preventing or limiting the expression of viral genes. The effect of a supraoptimal temperature (39 degrees C) on the production of HIV1 was investigated in promonocytic latently infected U1 cells. The amount of viral particles released from the cells 2 days after TNF alpha and/or IL6 stimulation was lower at 39 degrees C than at 37 degrees C, and this was not a consequence of an intracellular accumulation of virions at 39 degrees C. Cell viability and metabolism at 39 degrees C were not modified when compared to those at 37 degrees C, and the TNF alpha activation system was unaltered at high temperature. We hypothesized that a stage of the viral replication was affected at 39 degrees C; accordingly total RNA were prepared and hybridized, after Northern Blot, with a virus-specific probe. The RNA coding for structural proteins (9.2 and 4.3 kb) were present in lower amounts at 39 degrees C, whereas the abundance of those coding for regulatory proteins was almost unaltered. Our results show that the accumulation of single-spliced and unspliced transcripts is lower at 39 degrees C than at 37 degrees C, suggesting an implication of the Rev protein in this inhibition.