Franca Campanile

IL-9 protects mice from Gram-negative bacterial shock: suppression of TNF-alpha, IL-12, and IFN-gamma, and induction of IL-10.

IL-9 is a T cell-derived cytokine that, similar to the Th2 cytokines IL-4 and IL-10, has been implicated in the response to parasitic infections, allergy, and inflammatory processes. Because both IL-4 and IL-10 can confer protection to mice from septic shock, we investigated whether IL-9 may also be capable of conferring resistance on recipients of an otherwise lethal challenge with Pseudomonas aeruginosa. Prophylactic injections of rIL-9 appeared to be most effective in preventing the onset of a lethal shock, according to a pattern that was both dose dependent and time dependent. The protective effect of IL-9 was correlated with marked decreases in the production of the inflammatory mediators TNF-α, IL-12, and IFN-γ, as well as the induction of the anti-inflammatory cytokine IL-10. Sustained levels of IL-9-specific transcripts could be detected in the spleens of mice recovering from sublethal P. aeruginosa infection. Therefore, IL-9 may be protective in septic shock via a rather unique mechanism involving a complex modulation of inflammatory and anti-inflammatory mediators.

Impaired growth of a radiation-induced lymphoma in intact or lethally irradiated allogeneic athymic (nude) mice.

Radioinduced lymphomas were maintained in mice by serial transplantation of neoplastic cells and mortality of mice was recorded for 60 days. Mice were x- irradiated at a dose rate of 137 R/min. Lethally irradiated mice were resistant to an incompatible lymphoma as determined by 125I-IUdR uptake values of the spleen. The lack of influence of an immunodepressive factor and the observation that lethal irradiation did not abrogate the relative resistance to tumor challenge appeared to exclude the possibility that the reduced growth of the lymphoma in nude mice is the result of a conventional allograft reaction.

Evidence for tumor necrosis factor α as a mediator of the toxicity of a cyclooxygenase inhibitor in Gram-negative sepsis

To investigate the effect of cyclooxygenase inhibition in experimental Gram-negative sepsis, indomethacin was administered to mice at different times (1 or 5 days, or 1 h) before sublethal infection with an intravenous inoculum of Pseudomonas aeruginosa Early indomethacin exposure did not alter the outcome of infection, yet treatment at the time of bacterial challenge resulted in a high mortality rate. Polymerase chain reaction-assisted mRNA amplification in the spleens of infected mice revealed that tumor necrosis factor alpha (TNF-alpha) messenger was selectively expressed by the drug-treated and infected mice during the 24 h preceding death. Higher TNF-alpha levels were found in sera from these mice, whose macrophages produced increased levels of nitric oxide in vitro. Both pentoxifylline, an inhibitor of TNF-alpha synthesis, and an inhibitor of nitric oxide production improved survival in the indomethacin-treated and infected mice, although no such effect followed the administration of TNF-neutralizing antibodies. These data support the notion that cyclooxygenase inhibitors may exert both positive and negative effects in Gram-negative sepsis, the latter presumably involving overproduction of TNF-alpha.

Modulation of colony-stimulating activity by interleukin 1 mice: opposing effects of combined treatment with indomethacin of prostaglandin E2

Following previous observations that interleukin 1 (IL-1) may have both positive and negative effects on the levels of circulating colony-stimulating factors (CSF) in mice, we have investigated the impact of human rIL-1 beta administration on serum concentrations of colony-stimulating activity (CSA, as defined by biossay) and macrophage-specific colony-stimulating factor (CSF-1, measured by RIA). In addition, we have studied the effects of IL-1 administered in conjunction with indomethacin or prostaglandin (PG) E2. Besides confirming the finding that exogenous IL-1 leads to a rapid increase in CSF detection, we obtained evidence that IL-1 may also result in the production of cyclo-oxygenase pathway products that down-regulate the IL-1-induced burst in CSA and CSF-1 levels. While co-treatment of mice with indomethacin led to a further increase in CSF detection, the combined exposure to IL-1 and PGE2 resulted in a significant impairment of the stimulatory activity of IL-1.

Experimental studies of immunotoxicity of a photosensitizing agent (Photofrin II) in mice.

Immunotoxicity studies have been performed on the photosensitizing agent Photofrin II (PHFR), a porphyrin derivative used in photodynamic therapy. Hybrid CD2F1 (H-2d/H-2d) or inbred C57Bl/6 (H-2b) male mice were injected with graded doses of the agent (from 1.2 to 12 mg/Kg ip) on day -5, -3 and -1 before assays. The animals, or spleen cells collected from them on day 0 with respect to PHFR treatment, were tested for: a) competence of producing GVHD upon cell transfer into allogeneic, immunosuppressed recipients; b) graft response against challenge with allogeneic lymphoma cells; c) delayed-type hypersensitivity (DTH) against sheep red blood cells; d) in vitro response to mitogens; e) NK cell activity; f) in vitro generation of alloreactive cytotoxic T lymphocytes (CTL); g) resistance against the challenge of a sublethal dose of Pseudomonas aeruginosa. Moreover the LD50 of the drug given ip has been determined in male CD2F1 mice. The results show that PHFR, even at the highest doses used, does not affect most of the immunological parameters studied, except for a marginal inhibition of CTL generation and increment in proliferative responses to Con A or LPS. These data along with parallel studies performed by our group on human models in vitro, showing increased susceptibility of PHFR-treated tumors to NK or LAK effector cells, point out that PHFR, in the absence of systemic photoactivation, is essentially non-immunotoxic in vivo and could render tumor cells more susceptible to natural immunity.

Modulation of circulating colony-stimulating activity in mice : combined effects of IL-1 and bacterial or indomethacin treatment

We have investigated the effects of interleukin 1 (IL-1) administration on circulating levels of colony-stimulating activity (CSA) in intact or neutropenic mice. Intact or cyclophosphamide-treated mice received human rIL-1 beta according to different regimens, and their sera were assayed for CSA at 4, 24 or 48 h. The results indicated that (1) cyclophosphamide alone significantly increased the level of circulating CSA, (2) administration of IL-1 to intact or neutropenic mice resulted in a biphasic pattern of CSA response, an early burst at 4 h being followed at 24-48 h by a significant decrease. In nongranulocytopenic mice, the combined treatment with IL-1 and bacterial cells also resulted in a biphasic pattern of CSA response. However, when IL-1 was administered in concurrence with the cyclo-oxygenase inhibitor indomethacin, sustained CSA levels could be observed for a prolonged period of time. These data expand upon our previous observations on modulation of CSA by IL-1 in granulocytopenic mice, and further support the concept that IL-1 may have both positive and negative effects on the expression of circulating CSA.

Combination Therapies with Cytokines and Anti-Cytokines in Murine Opportunistic Infections

Systemic administration of purified recombinant cytokines has been performed in various animal models and clinical trials for the treatment of neoplasia, infectious disease, hemapoietic failure and immunosuppression. In particular, in infectious disease, cytokines have radically changed our understanding of the mechanisms of resistance, and have also provided new clues to the elucidation of the mechanisms of both resistance and pathology, such that the use of cytokines or anti-cytokines appears to be extremely promising for treatment of conditions associated with microbial infection.

Natural Resistance Against Tumors “In Vivo”

Host’s immunity against tumor cells can be classified according to two distinct functions, i.e. elicitable responses, evoked by tumor-associated antigens, and natural resistance (NR) not requiring previous exposure to antigenic determinants.