THE LYMPHOCYTOSIS-PROMOTING AGENT PERTUSSIS TOXIN AFFECTS VIRUS BURDEN AND LYMPHOCYTE DISTRIBUTION IN THE SIV-INFECTED RHESUS MACAQUE

Pertussis toxin from the gram-negative bacterium Bordetella pertussis is an ADP-ribosylase that modifies G(i) proteins in mammalian lymphocy tes and inhibits their capacity to traffic from blood into lymphoid ti ssues, We used this compound to induce lymphocytosis in rhesus macaque s and to study its effects on SIV infection, Pertussis toxin injected at 25 mu g/kg induced a transient lymphocytosis that peaked 3-8 days a fter administration and caused a rapid, transient decrease in the freq uency of infectious cells in blood as judged by in vitro virus isolati on assays, Lymphocyte subsets were altered during the lymphocytosis in terval and sustained changes in CD8(+) T cell levels were noted as lon g as 53 days after pertussis toxin injection, In situ hybridization st udies showed that pertussis toxin altered the distribution of viral RN A in lymph nodes during the interval of lymphocytosis, and caused long -term changes with decreased virus replication in some tissue specimen s.