Further studies on the influence of steroids on viral infection in mice.

Certain steroids have been reported to enhance experimental viral infections, whereas others have little or no effect. Interference with the interferon system has been suggested as a possible mechanism for the viral infection-enhancing (VIE) activity of hormones. In the present study, steroids (prednisolone, progesterone, testosterone) which had no effect on MM virus infection demonstrated VIE activity against Mayaro virus infection. It is suggested that the VIE activity of a hormone may be dependent on the viral agent used for challenge. Data are also presented which suggest that, in addition to interference with the interferon system, the VIE activity of steroid hormones may be the result of at least two other actions: (i) alteration of cell membranes; (ii) stimulation of initial viral replication.