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The sooty mangabey (SM) (Cercocebus atys) is the natural host of a simian immunodeficiency virus, termed SIVsm, which gave rise to human immunodeficiency virus type 2. Data on the geographic distribution, prevalence, and genetic diversity of SIVsm in the wild remains limited. To address this issue, noninvasive strategies based on screening SM fecal and urine specimens for SIVsm-specific antibodies and virion RNA (vRNA) were developed, and the results were correlated with viral loads in plasma. Twenty-three SIVsminfected and 27 uninfected SMs were evaluated. Time-matched urine, fecal and plasma samples were collected over a 2-month period from 16 captive naturally infected SMs. The remaining 7 infected and 27 uninfected SMs were sampled once. Each specimen was subjected to enhanced chemiluminescence-Western blot analysis and nested reverse transcriptase (RT) PCR. The results showed that urine was highly sensitive (96%) and specific (100%) for detection of SIVsm antibodies, while fecal detection was much less sensitive (16%). Conversely, vRNA detection was more sensitive in feces (50%) than in urine (2%) samples. Fecal-vRNA detection correlated with viral loads in plasma (P < 0.002). SMs with detectable fecal vRNA had a mean viral load in plasma of 458,006 copies/ml, while those with undetectable fecal vRNA had a mean viral load in plasma of 29,428 copies/ml. Moreover, for every log increase in the viral load in plasma, the odds of detecting virus in fecal samples increased 87-fold. Genetic diversity of SIVsm in the SM colony was characterized by sequencing partial gag (846 bp) and gp43 (439 bp) fragments. Surprisingly, four new SIVsm lineages were identified, two of which were initially detected by fecal RT-PCR. This study documents the suitability of noninvasive methods for the detection and molecular characterization of new SIV variants. These assays will be useful for studying the phylogeny and epidemiology of SIVsm infections in the wild, and they hold... [ABSTRACT FROM AUTHOR]

Previous studies have described in vitro serial passage of a Δγ134.5 herpes simplex virus type 1 (HSV-1) strain in SK-N-SH neuroblastoma cells and selection of mutants that have acquired the ability to infect and replicate in this previously nonpermissive cell line. Here we describe the selection of a mutant HSV-1 strain by in vivo serial passage, which prolongs survival in two separate experimental murine brain tumor models. Two conditionally replication-competent Δγ134.5 viruses, M002, which expresses murine interleukin-12, and its parent virus, R3659, were serially passaged within human malignant glioma D54-MG cell lines in vitro or flank tumor xenografts in vivo. The major findings are (i) viruses passaged in vivo demonstrate decreased neurovirulence, whereas those passaged in vitro demonstrate a partial recovery of the neurovirulence associated with HSV-1; and (ii) vvD54-M002, the virus selected after in vivo serial passage of M002 in D54-MG tumors, improves survival in two independent murine brain tumor models compared to the parent (unpassaged) M002. Additionally, in vitro-passaged, but not in vivo-passaged, M002 displayed changes in the protein synthesis profile in previously nonpermissive cell lines, as well as early US11 transcription. Thus, a mutant HSV-1 strain expressing a foreign gene can be selected for enhanced antitumor efficacy via in vivo serial passage within flank D54-MG tumor xenografts. The enhanced antitumor efficacy of vvD54-M002 is not due to restoration of protein synthesis or early US11 expression. This finding emphasizes the contribution of the in vivo tumor environment for selecting novel oncolytic HSV specifically adapted for tumor cell destruction in vivo. [ABSTRACT FROM AUTHOR]

Previous studies have described in vitro serial passage of a Deltagamma(1)34.5 herpes simplex virus type 1 (HSV-1) strain in SK-N-SH neuroblastoma cells and selection of mutants that have acquired the ability to infect and replicate in this previously nonpermissive cell line. Here we describe the selection of a mutant HSV-1 strain by in vivo serial passage, which prolongs survival in two separate experimental murine brain tumor models. Two conditionally replication-competent Deltagamma(1)34.5 viruses, M002, which expresses murine interleukin-12, and its parent virus, R3659, were serially passaged within human malignant glioma D54-MG cell lines in vitro or flank tumor xenografts in vivo. The major findings are (i) viruses passaged in vivo demonstrate decreased neurovirulence, whereas those passaged in vitro demonstrate a partial recovery of the neurovirulence associated with HSV-1; and (ii) vvD54-M002, the virus selected after in vivo serial passage of M002 in D54-MG tumors, improves survival in two independent murine brain tumor models compared to the parent (unpassaged) M002. Additionally, in vitro-passaged, but not in vivo-passaged, M002 displayed changes in the protein synthesis profile in previously nonpermissive cell lines, as well as early U(S)11 transcription. Thus, a mutant HSV-1 strain expressing a foreign gene can be selected for enhanced antitumor efficacy via in vivo serial passage within flank D54-MG tumor xenografts. The enhanced antitumor efficacy of vvD54-M002 is not due to restoration of protein synthesis or early U(S)11 expression. This finding emphasizes the contribution of the in vivo tumor environment for selecting novel oncolytic HSV specifically adapted for tumor cell destruction in vivo.