In the present work the kinetics of some indices of immunity (tumor necrosis factor (TNF), interferon (IFN), natural killer cells (NK), lymphocyte proliferation activity, virus-specific antibodies, CD4/CD8 ratio) in response to Marburg virus infection in Macaca mulatta were studied. The different kinetics of immunological parameters for animals which survived Marburg virus infection and for animals which died after infection are shown. A comparison of the indices of IFN, TNF and spontaneous lymphocyte proliferation activity in Macaca mulatta infected with Marburg virus at different stages of life shows the relationship between the increase of these indices and the decrease in the animals' lifespan. Marburg virus immunosuppressive properties were corroborated by studying lymphocyte proliferation activity in response to antigenic stimulation in vitro and the CD4/CD8 index during experimental Marburg virus infection in Macaca mulatta. We conclude that the disease outcome depends on the dynamics of certain immunologic indices such as TNF and IFN.