Control of the immune reaction: T cells in immunized mice which depress the in vivo DNA synthesis response in the lymph nodes to skin painting with the contact sensitizing agent picryl chloride

Abstract

This paper describes the properties of a suppressor population in immune mice which specifically depresses DNA synthesis in vivo in normal mice. Mice were immunized by painting the skin with the contact sensitizing agent picryl chloride—an agent which causes contact sensitivity and antibody production. Five days later the regional lymph nodes or spleens were taken and injected into normal recipients which were then immunized by painting the skin with the same agent. The injection of the immune cells depressed the DNA synthesis response to picryl chloride in the regional lymph nodes when assessed 4 days later by the incorporation of radioactive iododeoxyuridine. The cells in the transferred population responsible for this depression were T cells as shown by the effect of anti-θ serum, their failure to adhere to nylon wool and antiimmunoglobulin columns and their appearance in the fraction of cells lacking receptors for C3(EAC − cells) on resetting with sheep cells coated with antibody and complement. The cells were large and their activity was destroyed by 2500 R in vitro. Their production was prevented by treatment with cyclophosphamide before exposure to antigen but was unaffected by adult thymectomy. In these two aspects they differed from the T cells which suppress contact sensitivity which occur in mice injected with picryl sulphonic acid—an agent which causes unresponsiveness.