Enhanced survival from CLP-induced sepsis following late administration of low doses of anti-IFNγ F(ab')2 antibody fragments.

OBJECTIVE: To assess the impact of different doses of anti-interferon gamma (anti-IFNγ) F(ab')2 fragments, administered prophylactically, on survival and on serum concentration of cytokines in a murine model of sepsis induced by cecal ligation and puncture (CLP). We further explore the impact of therapeutic administration of the most protective dose on survival. SUBJECTS AND TREATMENT: Balb/c mice were prophylactically treated by the intraperitoneal route with anti-IFNγ initiated 2 h before CLP and every 24 h for a total of five times in each of the following doses: 0.01, 0.1, or 1 mg/kg. Sham and control groups received sterile saline solution in a similar scheme. METHODS: Serum tumor necrosis factor (TNF), interleukin (IL)-1ß, IL-6, IL-10 and IFNγ were measured at 3, 24 and 48 h after CLP by ELISA. Survival curves were compared using a Mantel-Haenzel method. RESULTS: Significant prophylactic protection was found only with 0.01 mg/kg, in association with regulation of IL-1ß and IL-10 concentrations. As therapy, anti-IFNγ fragments were protective only when initiated 24 h after CLP. CONCLUSIONS: Delicate modulation of IFNγ at the correct timing, even when the septic process has begun, is an exciting alternative to explore in the treatment of sepsis.

Anti-tumor necrosis factor alpha F(ab')2 antibody fragments protect in murine polymicrobial sepsis: concentration and early intervention are fundamental to the outcome.

BACKGROUND: Negative results are frequent using anti-TNFalpha antibodies in sepsis models and clinical trials. METHODS AND RESULTS: Different prophylactic doses of anti-TNFalpha F(ab')2 antibody fragments were compared for the prevention of death by sepsis induced by cecal ligation and puncture (CLP) in mice. High (10 mg/kg) and very low (0.01 and 0.1 mg/kg) concentrations of anti-TNFalpha antibody fragments were not the most adequate for treating polymicrobial sepsis, since they did not significantly improve survival. To the contrary, intermediate doses (1 mg/kg) significantly protected the challenged animals. Protective activity was also observed when administration of the antibody fragments was initiated early (up to 30 min) after CLP. CONCLUSIONS: These results suggest that in processes where excessive production of cytokines is involved, the aim should be to return them to their physiologically acting range but not to inhibit their production. The timing of initiating therapy should also be considered in order to maximize the possible benefits.