2. Materials and methods
2.1. Virus
EBO subtype Zaire adapted to guinea pigs through
eight passages in outbred animals (further designated as
adEBO) was used [6]. The virus had three passages in
Vero cell culture. Five plaques were isolated and characterized.
The viral replication of each plaque was
determined in Vero cells and their infectivity was tested
in guinea pigs. For infecting monkeys, plaque 4 was
chosen; its initial infectivity was 5.5 lg LD50:ml for
guinea pigs or 4.9 lg PFU:ml in Vero cell culture.
2.2. Animals
Three Papio hamadryas (two females, one male)
weighing 5–7 kg were used. Animals were obtained
from the Sukhumi Monkey Farm, held in quarantine in
animal facility of the SRC VB ‘Vector’, and kept on a
standard diet ration of monkey chow and fresh fruit.
Water was available ad libitum. All animals were previously
tested for the absence of antibodies to EBO and
Marburg virus. All manipulations with monkeys were
conducted in accordance with the relevant federal and
local regulations.
2.3. Experimental design
The monkeys were infected subcutaneously into the
rear middle third of their left thigh at a dose of 100
PFU:animal with the culture medium of the Vero cells
infected with adEBO plaque 4. Clinical observations
and measurements of rectal temperature were performed
daily. All experiments with infected animals
were performed in a BSL-4 facility by personnel wearing
positive pressure protective suits.
Blood was taken from the surface veins of either
upper or lower limbs once prior to infection, and on
daily basis after infection. Prior to infection and blood
collection, all the animals were sedated intramuscularly
with kalipsol (Gedeon-Richter, Hungary) at a dose of 5
mg:kg of animal weight. One animal was killed at the
agonal stage, and liver was removed aseptically. Livers
from other two animals were taken postmortem. Serial
10-fold dilutions of 10% suspension of homogenized
liver tissue were assessed for viral titers by plaque assay
in Vero cell culture [9].
Blood samples for immunological assays were collected
into tubes containing 10 AU:ml heparin or
sodium citrate (9.25 mg:ml); for biochemical tests they
were put into dry tubes to obtain serum; and for
coagulation tests, into silicone tubes containing 3.8%
solution of sodium citrate (with the presence of E-animocapron
acid) at a ratio of 1:9. The blood was
centrifuged for 10 min at 1500 rpm to obtain plasma
and serum.
2. Materials and methods2.1. VirusEBO subtype Zaire adapted to guinea pigs througheight passages in outbred animals (further designated asadEBO) was used [6]. The virus had three passages inVero cell culture. Five plaques were isolated and characterized.The viral replication of each plaque wasdetermined in Vero cells and their infectivity was testedin guinea pigs. For infecting monkeys, plaque 4 waschosen; its initial infectivity was 5.5 lg LD50:ml forguinea pigs or 4.9 lg PFU:ml in Vero cell culture.2.2. AnimalsThree Papio hamadryas (two females, one male)weighing 5–7 kg were used. Animals were obtainedfrom the Sukhumi Monkey Farm, held in quarantine inanimal facility of the SRC VB ‘Vector’, and kept on astandard diet ration of monkey chow and fresh fruit.Water was available ad libitum. All animals were previouslytested for the absence of antibodies to EBO andMarburg virus. All manipulations with monkeys wereconducted in accordance with the relevant federal andlocal regulations.2.3. Experimental designThe monkeys were infected subcutaneously into therear middle third of their left thigh at a dose of 100PFU:animal with the culture medium of the Vero cellsinfected with adEBO plaque 4. Clinical observationsand measurements of rectal temperature were performeddaily. All experiments with infected animalswere performed in a BSL-4 facility by personnel wearingpositive pressure protective suits.Blood was taken from the surface veins of eitherupper or lower limbs once prior to infection, and ondaily basis after infection. Prior to infection and bloodcollection, all the animals were sedated intramuscularlywith kalipsol (Gedeon-Richter, Hungary) at a dose of 5mg:kg of animal weight. One animal was killed at theagonal stage, and liver was removed aseptically. Liversfrom other two animals were taken postmortem. Serial10-fold dilutions of 10% suspension of homogenizedliver tissue were assessed for viral titers by plaque assayin Vero cell culture [9].Blood samples for immunological assays were collectedinto tubes containing 10 AU:ml heparin orsodium citrate (9.25 mg:ml); for biochemical tests theywere put into dry tubes to obtain serum; and forcoagulation tests, into silicone tubes containing 3.8%solution of sodium citrate (with the presence of E-animocapronacid) at a ratio of 1:9. The blood wascentrifuged for 10 min at 1500 rpm to obtain plasmaand serum.
การแปล กรุณารอสักครู่..
