INTESTINAL MANIFESTATIONS OF EXPERIMENTAL SIV-INFECTION IN RHESUS-MONKEYS (MACACA-MULATTA) - A HISTOLOGICAL AND ULTRASTRUCTURAL-STUDY

Intestinal lesions were studied in 32 rhesus monkeys experimentally in fected with different strains of simian immunodeficiency virus SIVmac (251/32H, 251/32H-SPL and 251/MPBL) by light microscopy, transmission and scanning electron microscopy. A spectrum of primary and secondary manifestations of SIV-infection mere detected. Primary changes include d 'SIV-enteropathy' in 12 monkeys and virus-induced syncytial giant ce ll formation (GCF) of the intestine in two animals. A primary virus-in duced enteropathy occurred both as only histologically visible 'SIV-en teropathy' and as 'AIDS-enteropathy' accompanied by clinical signs of enteritis. Secondary opportunistic infections (Balantidium coli, Crypt osporidium, Trichuris, Trichomonas, Spironucleus, Mycobacteria and Cyt omegalovirus) were identified in 27 animals and three monkeys develope d malignant lymphomas involving the intestinal tract. Compared to inte stinal lesions in HIV-infected patients, differences were found concer ning the incidence of GCF and the range of opportunistic infections, w ith cryptosporidium, cytomegalovirus and mycobacteria occurring in bot h SIV-infected macaques and AIDS patients. The present observations re vealed that SIV-infected rhesus monkeys provide an excellent model bot h for studies on the pathogenesis of HIV-enteropathy and opportunistic infections and for the development of therapies against cryptosporidi al, cytomegalovirus and mycobacteria infection. Comparison of three SI V-strains revealed differences in primary and secondary lesions observ ed: SIVmac251/MPBL was correlated with severe primary SIV-induced path ologic changes and SIVmac251-SPL-infected animals showed a higher inci dence of malignant lymphomas.