Elke Storch

Herpes simplex virus type 1-induced interferon production and activation of natural killer cells in mice.

Cultures of peritoneal exudate cells (PEC) of non-immune C57BL/6 mice reacted to infectious herpes simplex virus type 1 (HSV), but not to non-infectious virions by producing interferon. Similarly, when the virus preparations were injected intraperitoneally (i.p.) and interferon was determined in the wash-out fluid, interferon could only be detected after injection of infectious HSV. All interferons were mixtures of interferon-alpha and -beta. The cell that produced interferon was not sensitive to anti-theta serum or anti-asialo-GM1 serum, it was retained on nylon wool columns and removed by plastic adherence. Silica treatment of PEC abolished HSV-induced interferon production whereas irradiation by 2000 R was without effect. Pure cultures of mouse T cells did not produce interferon when treated with infectious HSV whereas pure cultures of mouse bone marrow macrophages did produce interferon. Thus, we suggest that in PEC the cells which produced interferon were of the macrophage lineage. In further experiments we have analysed in vivo activation of natural killer (NK) cells in the peritoneal cavity of mice. Non-infectious virions were as effective as infectious HSV and doses of HSV too low to induce measurable titres of interferon caused a marked activation of NK cells.

Interferon inducibility in mice treated with corynebacterium parvum

Mice were given single intraperitoneal (i.p.) injections of Corynebacterium parvum, followed, after different time intervals, by i.p. injections of the interferon inducers polyinosinic-polycytidylic acid (poly-I:poly-C), 10-carboxymethyl-9-acridanone (CMA) or herpes simplex virus. With all three inducers production of interferon in the peritoneal cavity was enhanced in C. parvum-pretreated mice. Production of circulating interferon in C. parvum-pretreated mice was enhanced with CMA and depressed with poly-I:poly-C as inducers. This modulation of the interferon response was prominent for at least 10 weeks after C. parvum injection and then gradually reverted. The increased local interferon production seemed to be caused by macrophages still activated several weeks after treatment with C. parvum.

Enhancement by carprofen or indomethacin of interferon induction by 10-carboxymethyl-9-acridanone in murine cell cultures.

Non-steroidal anti-inflammatory drugs such as carprofen or indomethacin enhanced interferon (IFN) production induced by suboptimal concentrations of 10-carboxymethyl-9-acridanone (CMA) in murine cell cultures. This effect was observed in fibroblasts and in different populations of leukocytes as in peritoneal exudate and spleen cells, and was most pronounced in bone marrow-derived macrophages. Carprofen was the most effective compound causing an up to 500-fold increase of CMA-induced IFN production in pure bone marrow-derived macrophages. In these macrophage cultures the potentiating effect on CMA-induced IFN production by carprofen and indomethacin did not depend on inhibition of cyclooxygenase.

Interferons and bacterial infections

SummaryViruses have been established initially as interferon inducers and interferons have been considered to be antiviral proteins only. By our article we wish to draw attention to two observations:a)bacteria and derivatives thereof also are inducing the production of interferonb)interferons activate a number of defense mechanisms that are of potential relevance in antibacterial resistance. These two observations are not new. However, we believe, they deserve renewed attention within the framework of the pleiotropism of interferon effects and of the complexity of antibacterial defense mechanisms.

Prolongation of survival of mice bearing the Eb and Esb lymphoma by treatment with interferon inducers alone or in combination with Corynebacterium parvum

SummaryThe objective of this study was to evaluate if pretreatment with Corynebacterium parvum (C. parvum) augments the effects of interferon (IFN) inducers on survival of DBA/2 mice transplanted with two syngeneic lymphoma variants, the low metastatic Eb and the high metastatic ESb tumor. The involvement of IFN in the treatment effects was investigated. As inducers of IFN-α/β Newcastle disease virus (NDV), polyinosinic-polycytidylic acid (polyI:polyC), and 10-carboxymethyl-9-acridanone (CMA) were injected i. p. at the site of tumor transplantation. The Eb tumor was found to be sensitive to the antiproliferative action of IFN-α/β in vitro. In vivo single injections of each of the inducers retarded growth of the Eb tumor. In C. parvum-pretreated mice the effects of the inducers on survival were markedly increased. There was a correlation between prolonged survival and local IFN levels in response to polyI:polyC or CMA but not upon NDV. Injections of each of the inducers increased cytotoxicity of peritoneal exudate cells against the Eb tumor cells in vitro especially when mice were pretreated with C. parvum. Although other mechanisms cannot be excluded IFN-mediated activation of host defence and also direct antiproliferative effects of endogenously produced IFN seem to be involved in the antitumor effects by these IFN inducers in the Eb model. In the ESb tumor model irrespective of additional pretreatment with C. parvum survival was only slightly prolonged by the treatments and endogenous IFN induction did not result in any real benefit for the animals. When compared with Eb cells the ESb cells were less sensitive to the antiproliferative action of IFN-α/β in vitro and less sensitive to in vitro cytotoxicity by the host cells. Although other mechanisms may additionally be active in vivo the different susceptibility of the Eb and ESb tumor cells to the direct and indirect actions of IFN seems to contribute to the different responsiveness of these tumor cell lines to the treatments with IFN inducers.

Attempts to correlate interferon induction and activation of natural killer cells by corynebacterium parvum

Intraperitoneal (i.p.) injection of Poly I:Poly C resulted in high interferon titers in the peritoneal wash fluid and in the serum of mice, which was maximal at 4 to 6 h after injection. In contrast, no interferon could be measured in the peritoneal fluid at various times after injection of C. parvum. Also, all attempts to induce serum interferon by C. parvum were unsuccessful. However, both Poly I:Poly C and C. parvum were causing the activation of Natural Killer (NK) cells in the cell population recovered from the peritoneal cavity. From adoptive transfer experiments, there was no indication that C. parvum induced a soluble mediator causing the activation of NK cells. There was also no indication that the interferon activity in the peritoneal cavity of C. parvum-treated mice might have been masked by the presence of an inhibitory molecule interfering with the antiviral effect of interferon in the assay. Our data may suggest activation of NK cells by C. parvum to be independent of interferon induction. Accordingly, we have observed that the injection of anti-interferon did not abolish NK cell activation by C. parvum. Thus, there is the interesting possibility of an interferon-independent mechanism of NK cell activation. However, we have additionally shown that doses of murine alpha/beta interferon as low as 1 IU per mouse caused a significant activation of NK cells in the peritoneal cavity upon i.p. injection. Thus, interferon itself is extremely potent in activating NK cells.

Research on Diagnosis and Therapy

In the battle against cancer, diagnosis has a crucial strategic significance. Diagnostic shortcomings will be difficult to counteract by therapy.

Diagnostik- und Therapieforschung

Im Kampf gegen den Krebs hat die Diagnostik eine entscheidende strategische Bedeutung. Was diagnostisch versaumt wird, last sich therapeutisch schwer wieder gut machen.