Mason-Pfizer monkey virus and simian AIDS

Milk Transmission of Mammalian Retroviruses

The transmission of viruses from one host to another typically occurs through horizontal or vertical pathways. The horizontal pathways include transmission amongst individuals, usually through bodily fluids or excretions, while vertical transmission transpires from mother to their offspring, either during pregnancy, childbirth, or breastfeeding. While there are more than 200 human pathogenic viruses to date, only a small number of them are known to be transmitted via breast milk, including cytomegalovirus (CMV), human immunodeficiency virus type 1 (HIV-1), and human T cell lymphotropic virus type 1 (HTLV-1), the latter two belonging to the family Retroviridae. Breast milk transmission is a common characteristic among mammalian retroviruses, but there is a lack of reports summarizing our knowledge regarding this route of transmission of mammalian retroviruses. Here, we provide an overview of the transmission of mammalian exogenous retroviruses with a focus on Orthoretrovirinae, and we highlight whether they have been described or suspected to be transmitted through breast milk, covering various species. We also elaborate on the production and composition of breast milk and discuss potential entry sites of exogenous mammalian retroviruses during oral transmission.

Type D retrovirus specific sequences in lymphocytes of the children with Burkitt-type lymphoma and their parents

Type D retroviruses cause immunodeficiency in monkey. Earlier we have revealed genetical and serological markers of type D retroviruses in children with Burkitt-type lymphoma. Using PCR/Southern blotting assay we have found sequences related to MPMV in PBMC's DNA from children with Burkitt-type lymphoma and from their parents. Moreover, the data on sequencing of virus specific sequences from one ill child and from his mother have been presented.

Antiviral effects of 3'-azido-3'-deoxythymidine, 2',3'-dideoxycytidine, and 2',3'-dideoxyadenosine against simian acquired immunodeficiency syndrome-associated type D retrovirus in vitro

The simian acquired immunodeficiency syndrome (SAIDS) in macaques at the Washington Regional Primate Research Center is associated with a type D retrovirus known as SAIDS-D/WA. We tested the ability of 3'-azido-3'-deoxythymidine (AZT), 2',3'-dideoxycytidine (ddC), and 2',3'-dideoxyadenosine (ddA) to inhibit the in vitro cytopathic effect (syncytium formation) and infectivity of the SAIDS-D/WA virus. Raji cell cultures were infected with virus and treated with various concentrations of AZT, ddC, and ddA. The ability of these drugs to inhibit replication of the SAIDS-D/WA virus in Raji cells was monitored by syncytium formation, expression of viral antigen, and reverse transcriptase assay. At concentrations of 4, 40, and 400 microM, AZT completely blocked the viral infectivity and inhibited the cytopathic effect of SAIDS-D/WA. Likewise, ddC was inhibitory at concentrations of 5 and 50 microM and ddA was inhibitory at 100 and 200 microM. AZT, ddC, and ddA became cytostatic to Raji cells with increasing drug concentrations. AZT also partially inhibited SAIDS-D/WA replication in previously infected Raji cell cultures, and viral inhibition increased in response to the concentration of AZT. These data indicate that AZT, ddC, and ddA are effective antiretroviral agents that merit further evaluation, including clinical trials, in animal models with AIDS-like diseases.

Suppression of human lymphocyte mitogen response by retroviruses of type D. II. Non-activity of Mason-Pfizer monkey virus versus activity of human cell line derived virus PMFV

In contrast to the human cell line derived type D retrovirus PMFV, the Mason-Pfizer monkey virus (MPMV) does not suppress the mitogen response of normal human lymphocytes. Both viruses have been propagated on the same cell lines and purified by the same methods. MPMV did not contain a factor able to abolish PMFV-induced suppression of the mitogen response. Neither could MPMV suppress the mitogen response of lymphocytes from rhesus monkeys or baboons. PMFV however inhibited their reactivity.