Suppression of delayed type hypersensitivity by desferoxamine

Desferoxamine, a chelating agent, inhibits proliferation of T cells in vitro. We reasoned that it may also suppress T-cell-mediated immune responses in vivo. The effect of desferoxamine on delayed type hypersensitivity reaction to dinitrofluorobenzene was evaluated in Balb/c mice. We report that desferoxamine inhibits sensitization and elicitation of skin test reactivity and that the immunosuppressive effect of desferoxamine is transient. While its mechanism of action remains to be determined, it may be a potentially useful immunosuppressive agent.

Renal cell carcinoma treated by vaccines for active specific immunotherapy: correlation of survival with skin testing by autologous tumor cells

Eighteen patients with metastatic renal cell carcinoma, who were treated by vaccines for active specific immunotherapy, also completed skin testing with autologous tumor cells, both prior to and following vaccine treatment. All patients have now been followed for more than 5 years. Ten patients who remained skin-test-negative following treatment had no clinical responses, and all had expired by 22 months. Eight patients became skin-test-positive; three of these had clinical regressions and three remain alive after more than 69 months. The survival times of the skin-test-positive group were significantly superior to those of the skin-test-negative group. The results suggest that skin testing with autologous tumor cells may accurately identify those patients who have acquired antigen-specific cell-mediated antitumor immunity.

Inhibition of suppressor T lymphocytes by murine interferon beta

We have presented data showing that IFN-beta at 1,000 U/mouse i.v. inhibits the generation of Ts-mediated tolerance to dinitrofluorobenzene (DNFB) and abrogates the transfer of suppression by Ts. We have also presented data showing that IFN-beta up to 10,000 U/mouse i.v. has no adverse effect on sensitization and elicitation. IFN-beta appears to be a suitable agent for evaluation as an adjunct in the immunotherapy of Ts inducing tumors.

Inhibition of suppressor T lymphocytes (Ts) by cimetidine

Cyclophosphamide (CY) is the most extensively studied inhibitor of suppressor T lymphocyte (Ts) function. However, repeated administration of CY can abrogate sensitization. Therefore, we were interested in identifying noncytotoxic inhibitors of Ts function as adjuncts in the immunotherapy of Ts-inducing murine tumors. The effect of cimetidine (a histamine type 2 receptor antagonist) and diphenhydramine (a histamine type 1 receptor antagonist) on the Ts mediating tolerance to 2,4-dinitrofluorobenzene was studied. We report our data regarding the specific inhibition of Ts by cimetidine.

Inhibition of suppressor T lymphocytes (Ts) by cimetidine

Cyclophosphamide (CY) is the most extensively studied inhibitor of suppressor T lymphocyte (Ts) function. However, repeated administration of CY can abrogate sensitization. Therefore, we were interested in identifying noncytotoxic inhibitors of Ts function as adjuncts in the immunotherapy of Ts-inducing murine tumors. The effect of cimetidine (a histamine type 2 receptor antagonist) and diphenhydramine (a histamine type 1 receptor antagonist) on the Ts mediating tolerance to 2,4-dinitrofluorobenzene was studied. We report our data regarding the specific inhibition of Ts by cimetidine.

Specific immunotherapy with suppressor function inhibition for metastatic renal cell carcinoma

In this pilot clinical investigation we have investigated the concept of modulating suppressor T lymphocyte (Ts) function to augment delayed type hypersensitivity (DTH) and antitumor immunity in patients with metastatic renal cell carcinoma. Cyclophosphamide (CY) was used for modulating Ts function. We used three doses of CY per 100 mg/m2, 500 mg/m2, and 1000 mg/m2. Cyclophosphamide was administered i.v. 24 h prior to the first of 6 weekly immunizations with irradiated autologous tumor cells mixed with Corynebacterium parvum. Twenty of 26 patients were evaluable for response. Five of these 20 (25%) evaluable patients had responses, one complete response and four partial responses. Fifteen patients had post-treatment skin testing with autologous tumor cells. Four of these 15 (26%) patients developed DTH to autologous tumor cells. Of the four patients acquiring skin test positivity three also had clinical responses, whereas among the 11 skin-test negative patients, only one clinical response was observed. Six of six (100%) patients who had serial T lymphocyte subset studies done had increases in their mean T helper/inducer:T suppressor/cytotoxic ratios after CY administration and immunization. These observations in an exploratory study suggest that further investigations of Ts modulation, autologous tumor cell skin testing, and T lymphocyte subsets may be of value.