Suppressor deletion therapy: selective elimination of T suppressor cells in vivo using a hematoporphyrin conjugated monoclonal antibody permits animals to reject syngeneic tumor cells
✍ Scribed by J. Kevin Steele; Daniel Liu; Anthea Tench Stammers; Stephen Whitney; Julia G. Levy
- Book ID
- 104663625
- Publisher
- Springer-Verlag
- Year
- 1988
- Tongue
- English
- Weight
- 709 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0340-7004
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✦ Synopsis
A MAb (B16G) which recognizes a constant epitope on TsC and their soluble factors in DBA/2 mice has been described previously. In this study, we show that when this MAb is covalently linked to the photoactivable molecule Hp, and injected i.v. into P815 tumor-bearing mice which were subsequently exposed to light, tumors undergo permanent regression in 10%-40% of these mice (depending on the individual experiment). All control animals died within an average of 22-24 days after tumor cell injection. It is suggested that tumor regression is attributable to immune mechanisms facilitated by the elimination of a population of TsC. When splenocytes of B16G-Hp-treated mice were assayed in vitro for the generation of CTL active against P815 tumor cells, it was found that 24 h after treatment, a significant increase in killer cell activity was noted but that this effect was gone by 48h. We also show that B16G-Hp conjugates are capable in vitro of specifically killing cells of a TsC hybridoma, A10 (which has been shown previously to secrete a T suppressor factor reactive with P815 cell surface antigens). This conjugate had no cytotoxic effect on P815 cells under conditions in which A10 cells were killed.