Bufotenine is able to block rabies virus infection in BHK-21 cells

Background Rabies is a fatal zoonotic neglected disease that occurs in more than 150 countries, and kills more than 55.000 people every year. It is caused by an enveloped single stranded RNA virus that affects the central nervous system, through an infection initiated by the muscular nicotinic acetylcholine receptor, according to many authors. Alkaloids, such as acetylcholine, are widespread molecules in nature. They are present in numerous biological fluids, including the skin secretion of many amphibians, in which they act (together with proteins, peptides and steroids) as protection agents against predators and/or microorganisms. Among those amphibians that are rich in alkaloids, there is the genus Rhinella.Methods Bufotenine was isolated from Rhinela jimi skin secretion after a liquid-liquid partition (H2O:CH2Cl2) and reversed phase high-performance liquid chromatography analyses (RP-HPLC). Bufotenine was also extracted from seeds of Anadenanthera colubrina in acetone solution and purified by RP-HPLC, as well. Structural characterization was performed by mass spectrometry and nuclear magnetic resonance analyses. Cytotoxic tests of bufotenine were performed over baby hamster kidney (BHK-21) cells using MTT test. For the antiviral activity,Rabies virus strain Pasteur vaccine (PV) was used on fluorescence inhibition test and fluorescent foci inhibition test, with both simultaneous and time course treatment of the cells with the virus and bufotenine.Results In the present work we describe the effects of bufotenine, obtained either from toads or plants, that can inhibit the penetration of rabies virus in mammalian cells through an apparent competitive mechanism by the nicotinic acetylcholine receptor. Moreover, this inhibition was dose- and time-dependent, pointing out to a specific mechanism of action...

Bufotenine is able to block rabies virus infection in BHK-21 cells

Background Rabies is a fatal zoonotic neglected disease that occurs in more than 150 countries, and kills more than 55.000 people every year. It is caused by an enveloped single stranded RNA virus that affects the central nervous system, through an infection initiated by the muscular nicotinic acetylcholine receptor, according to many authors. Alkaloids, such as acetylcholine, are widespread molecules in nature. They are present in numerous biological fluids, including the skin secretion of many amphibians, in which they act (together with proteins, peptides and steroids) as protection agents against predators and/or microorganisms. Among those amphibians that are rich in alkaloids, there is the genus Rhinella.Methods Bufotenine was isolated from Rhinela jimi skin secretion after a liquid-liquid partition (H2O:CH2Cl2) and reversed phase high-performance liquid chromatography analyses (RP-HPLC). Bufotenine was also extracted from seeds of Anadenanthera colubrina in acetone solution and purified by RP-HPLC, as well. Structural characterization was performed by mass spectrometry and nuclear magnetic resonance analyses. Cytotoxic tests of bufotenine were performed over baby hamster kidney (BHK-21) cells using MTT test. For the antiviral activity,Rabies virus strain Pasteur vaccine (PV) was used on fluorescence inhibition test and fluorescent foci inhibition test, with both simultaneous and time course treatment of the cells with the virus and bufotenine.Results In the present work we describe the effects of bufotenine, obtained either from toads or plants, that can inhibit the penetration of rabies virus in mammalian cells through an apparent competitive mechanism by the nicotinic acetylcholine receptor. Moreover, this inhibition was dose- and time-dependent, pointing out to a specific mechanism of action.Conclusions This work do not present or propose bufotenine as a drug for the treatment of rabies due to the hallucinogen and psychotropic effects of the molecule. However, continued studies in the elucidation of the antiviral mechanism of this molecule, may lead to the choice or development of a tryptamine analogue presenting potential clinical use.(AU)

Antibody response in cattle after vaccination with inactivated and attenuated rabies vaccines

Despite the absence of current official reports showing the number of cattle infected by rabies, it is estimated that nearly 30,000 bovines are lost each year in Brazil. In order to minimize the important economic losses, control of the disease is achieved by eliminating bat colonies and by herd vaccination. In this study, we compare the antibody response in cattle elicited by vaccination with an attenuated ERA vaccine (AEvac) and an inactivated-adjuvanted PV (IPVvac) vaccine. The antibody titers were appraised by cell-culture neutralization test and ELISA, and the percentage of seropositivity was ascertained for a period of 180 days. IPVvac elicited complete seropositivity rates from day 30 to day 150, and even on day 180, 87 per cent of the sera showed virus-neutralizing antibody titers (VNA) higher than 0.5IU/ml. There were no significant differences between the VNA titers and seropositivity rates obtained with IPVvac in the two methods tested. AEvac, however, elicited significantly lower titers than those observed in the group receiving inactivated vaccine. In addition, the profiles of antirabies IgG antibodies, evaluated by ELISA, and VNA, appraised by cell-culture neutralization test, were slightly different, when both vaccines were compared.