The parameters of nonspecific immunity (interferon, interleukin-1, tum
or necrosis factor, and natural killers) changed in immune BALB/c mice
after challenge with Machupo virus in doses of 1000 and 5000 PFU. Aft
er challenge with 1000 PFU the activity of the above parameters increa
sed during the first three days and no cases of animal death occurred.
After challenge with 5000 PFU the maximal values of interferon, inter
leukin-1, tumor necrosis factor, and natural killers were observed on
days 5-7, the animals dying at the height of these values. Hence, the
formation of specific humoral and cell-mediated immune response in BAL
B/c mice immunized with inactivated Machupo virus does not protect the
animals from infection with the homologous virus in a dose of 5000 PF
U. High mediator activity of nonspecific immunity factors on days 5-7
after infection augments the disease course and leads to earlier death
of vaccinated animals in comparison with the same nose of the virus i
n nonimmune mice.