Transmission of simian acquired immunodeficiency syndrome with a type D retrovirus: immunological aspects

Abstract Simianacquired immunodeficiency syndrome (SAIDS) was transmitted to four of four rhesus macaqueswith blood from rhesus macaquesnaturally infected with a type D retrovirus, simian retrovirus-2 (SRV-2). Three of the four blood recipients died with SAIDS at 13, 15, and 26 weeks postinoculation. The fourth animal is alive with SAIDS. All four test monkeys became viremic and produced antiviral antibody. None of the inoculated monkeys produced measurable neutralizing antibody to SRV-2. The survivor produced higher levels of antiviral antibody than the monkeys that died. Phytohemagglutininand concanavalin A reactivity of peripheral blood lymphocytes was depressed from weeks 6 to 12 after innoculation. Clinical findings included development of splenomegaly in all four monkeys, and diarrhea in two monkeys. Blood counts remained within the normal range except for a depression in the number of polymorphonuclear lymphocytes in two monkeys. Hematocrits were decreased in two monkeys just prior to their death. All four test monkeys developed lymph node atrophy and bone marrow hypoplasia. Total proteins and immunoglobulin production were normal. This report provides evidence that SRV-2, as well as other type D retroviruses, causes SAIDS in macaquespecies.