Transmission of HTLV-I to rats via peripheral blood mononuclear cells and serum from a patient with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) with amyotrophic lateral sclerosis (ALS)-like features

Human T-lymphotropic virus type-1 (HTLV-1) in Israeli patients and their family relatives and its transmission to rats

We tested the possibility that lymphocytes, sera and saliva, obtained directly from healthy human T-lymphotropic virus type 1 (HTLV-1) carriers and patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) of Iranian Mashhadi origin, as well as lymphocytes from patients with mycosis fungoides (MF) and their family relatives (MFR), may be infective. Peripheral blood mononuclear cells (PBMC), sera, PBMC cultured with phytohaemagglutinin A and phorbol myristate acetate, cell-free supernatant from these cultures, saliva cells and cell-free saliva were injected into adult WKA (n=107) and F344 (n=47) female rats. The appearance of anti-HTLV-1 antibodies in the rat sera was tested by particle agglutination assay and ELISA, and positive results were confirmed by western blot assay. Higher titers (1:1024) of anti-HTLV-1 antibodies were found in the F344 rats as compared to the WKA rats (1:256). The PA agglutination test was the most sensitive for the detection of HTLV-1 antibody. The HTLV-1 provirus was detected in both strains of rats infected with body fluids and cells from the Iranian Mashhadi Jews, in various organs (PBMC, spleen, thymus, salivary glands, spinal cord, kidney and brain) by nested PCR. However, the HTLV-1 provirus was not detected in 100% of the rats. The negative rats were only immunized and not infected. The spleen, thymus, spinal cord and salivary glands of the seropositive rats were found to be infectious and to transmit the HTLV-1 to healthy rats. F344 rats infected with PBMC cultures obtained from HTLV-1 antibody positive MF patients and their MFR who were only 20% positive showed anti-HTLV-1 antibodies, but only in 20% of rats without showing the HTLV-1 provirus; these rats were probably not infected but only immunized. This is one of the few studies on the transmission of HTLV-1 to rats by inoculation with human infectious fluids or cells from HTLV-1 infected healthy carriers (42%), HAM/TSP patients of Iranian Mashhadi origin (58%) as well as lymphocyte cultures obtained from HTLV-1 antibody positive MF and MFR of nonIranian origin.

Association of primate T-cell lymphotropic virus infection of pig-tailed macaques with high mortality

Natural infection of humans with human T-cell lymphotropic virus type I (HTLV-I) and of old world nonhuman primates with the simian counterpart, STLV-I, is associated with development of neoplastic disease in a small percentage of individuals after long latent periods. HTLV-I is also the etiologic agent of a more rapidly progressive neurologic disease, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Macaques have been used experimentally in studies to evaluate HTLV-I candidate vaccines for efficacy, but no evidence of disease was observed. Here we report experimental infection of pig-tailed macaques with STLV-I(sm) and HTLV-I(ACH), both of which were associated with a disease syndrome characterized by rapid onset, hypothermia, lethargy, and death within hours to days. Other pathologic sequelae included diarrhea, rash, bladder dysfunction, weight loss, and, in one animal, arthropathy. Both retroviruses were detected in the central nervous systems of some animals, either by culture or by direct antigen capture for p19 Gag in cerebrospinal fluid. Although virus was recovered throughout infection from peripheral blood mononuclear cells (PBMC), all infected macaques maintained low antiviral antibody titers and stable proviral burdens, which generally ranged between 10 and 100 copies per 10(6) PBMC. However, of 13 macaques infected with HTLV-I(ACH) or STLV-I(sm), seven animals (54%) died between 35 weeks and 412 years after infection. This unexpected high mortality within a relatively short time suggests that infection of pig-tailed macaques might be a useful model for studying immune responses to and pathologic events resulting from HTLV-I infection.