Antiretroviral and cytotoxic activities of Tityus obscurus synthetic peptide.

New drugs are constantly in demand, and nature's biodiversity is a rich source of new compounds for therapeutic applications. Synthetic peptides based on the transcriptome analysis of scorpion venoms of Tityus obscurus, Opisthacanthus cayaporum, and Hadrurus gertschi were assayed for their cytotoxic and antiretroviral activity. The Tityus obscurus scorpion-derived synthetic peptide (FFGTLFKLGSKLIPGVMKLFSKKKER), in concentrations ranging from 6.24 to 0.39 µM, proved to be the most active one against simian immunodeficiency virus (SIV) replication in the HUT-78 cell line and in primary human leukocytes, with the lowest toxicity for these cells. The immune cellular response evaluated in primary human leukocytes treated with the most promising peptide and challenged with SIV infection exhibited production of cytokines such as interleukin (IL)-4, IL-6, IL-8, IL-10, and interferon-γ, which could be involved in cell defense mechanisms to overcome viral infection through proinflammatory and anti-inflammatory pathways, similar to those evoked for triggering the mechanisms exerted by antiviral restriction factors.

HTLV-1/2 prevalence in two Amazonian communities.

INTRODUCTION: The human T-cell lymphotropic virus type 1 (HTLV-1) is aetiologically linked to myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T cell leukaemia (ATL) besides other less incident pathologies, while the type 2 has not been definitively linked to any diseases. OBJECTIVES: To determine the HTLV-1/2 seroprevalence in two Brazilian communities in northern Brazil. METHODS: In 2010 and 2015, HTLV-1/2 serological surveys were carried out in the Oiapoque county at the Brazilian border with French Guiana and in Santa Cruz do Arari, Marajó Island. Serum and breast-milk samples from 317 women (pregnant, lactating and non-pregnant non-lactating) resident in the Oiapoque county, together with serum samples from 217 females and 70 males living in Santa Cruz do Arari county, were twice screened by two distinct commercial immunoassay methods for antibodies to HTLV-1/2. Seroreactivity was confirmed by a commercial Western blot technique. Participants were interviewed for data concerning their health, socioeconomic and educational status. RESULTS: None of the Oiapoque women, mostly young and descendants of migrants, had antibodies to HTLV-1/2, despite the high HTLV-1 prevalence in neighbouring French Guiana and Caribbean Islands, while five females and three males living in Santa Cruz do Arari county were HTLV-1 infected as confirmed by Western blot testing. In contrast, the Santa Cruz do Arari community lives in relative isolation and is descended mostly from black African people with high consanguinity. CONCLUSION: Despite the proximity between Oiapoque and Santa Cruz do Arari counties, ethnic, age differences, community isolation and consanguinity may explain the distinct HTLV-1/2 epidemiology in these areas of northern Brazil.

Antiviral activity of animal venom peptides and related compounds

Abstract Viruses exhibit rapid mutational capacity to trick and infect host cells, sometimes assisted through virus-coded peptides that counteract host cellular immune defense. Although a large number of compounds have been identified as inhibiting various viral infections and disease progression, it is urgent to achieve the discovery of more effective agents. Furthermore, proportionally to the great variety of diseases caused by viruses, very few viral vaccines are available, and not all are efficient. Thus, new antiviral substances obtained from natural products have been prospected, including those derived from venomous animals. Venoms are complex mixtures of hundreds of molecules, mostly peptides, that present a large array of biological activities and evolved to putatively target the biochemical machinery of different pathogens or host cellular structures. In addition, non-venomous compounds, such as some body fluids of invertebrate organisms, exhibit antiviral activity. This review provides a panorama of peptides described from animal venoms that present antiviral activity, thereby reinforcing them as important tools for the development of new therapeutic drugs.

Antiviral activity of animal venom peptides and related compounds

Viruses exhibit rapid mutational capacity to trick and infect host cells, sometimes assisted through virus-coded peptides that counteract host cellular immune defense. Although a large number of compounds have been identified as inhibiting various viral infections and disease progression, it is urgent to achieve the discovery of more effective agents. Furthermore, proportionally to the great variety of diseases caused by viruses, very few viral vaccines are available, and not all are efficient. Thus, new antiviral substances obtained from natural products have been prospected, including those derived from venomous animals. Venoms are complex mixtures of hundreds of molecules, mostly peptides, that present a large array of biological activities and evolved to putatively target the biochemical machinery of different pathogens or host cellular structures. In addition, non-venomous compounds, such as some body fluids of invertebrate organisms, exhibit antiviral activity. This review provides a panorama of peptides described from animal venoms that present antiviral activity, thereby reinforcing them as important tools for the development of new therapeutic drugs.(AU)