A study of the immuno-suppressive activity of Herpes simplex virus type 2 and the tumor enhancing potential of the virus on Yoshida sarcoma.

The relative delays of Yoshida sarcoma (YS) tumor induction were used as indicator for the immunosuppressive potential caused by the subcutaneous infection of Sprague-Dawley rats with approximately 10(7) TCD50 HSV-2. The tumor formation is clearly accelerated and the number of tumors is increased as compared to sham injected rats. The impairment of immunity is at its maximum when the virus and the YS cells are applied simultaneously, whereas virus given after the tumor is of no consequence. The adoptive neutralization test of Winn showed that the neutralization potential of spleen cells originating from HSV-2 infected donors is decreased from day 8 to day 11 post infection but rturns back to normal a week later. The stimulation of spleen cells with PHA is reduced up to 50% of control values on day 6 to 8 post virus infection but PFC and RFC values are not noticeably affected and neither are the hemagglutination titres. The implications of the immuno-suppressive faculty of HSV-2 for human genital malignancies are discuss.ed.