Cytokines in health and disease

Research into cytokines has reached a challenging stage. Their importance to physiological and pathological processes is undoubted and the clinical application of both the molecules and their antagonists is of increasing importance. Every month more novel cytokine molecules are identified, each with a perplexing multiplicity and redundancy of action. In talks that ranged from rheumatoid arthritis, oncology and lymphocyte subsets, to transcription factors and xenopus mesoderm, a recent meeting* in London discussed the latest cytokine news.

The effect of cytokines on cultured mononuclear cells from patients with B cell chronic lymphocytic leukemia

In the past 5 years a number of cytokines have been identified that control B cell development, proliferation, and maturation. The role of such cytokines in the evolution, pathophysiology, and treatment of B cell malignancies is an area of great interest. The in vitro response of freshly isolated peripheral blood mononuclear cells from patients with B cell chronic lymphocytic leukemia (B-CLL) and a high white cell count, to four cytokines, IFN-alpha, IFN-gamma, IL-2 and TNF, was studied. No culture condition or cytokine resulted in a significant increase in cell number over 4 days, cells survived better in autologous serum than in heat inactivated foetal calf serum, and a small but significant increase in blast cells was seen when the cells were cultured in IL-2. There was a discrepancy between uptake of thymidine and increase in cell number which can be explained by the low labelling index of these cultures and the fact that cells can incorporate [3H]-thymidine without going into mitosis. The majority of cultures produced biologically active TNF at levels ranging from 1 to 40 pg/ml. In IFN-alpha treated cultures TNF levels were decreased. Cultures contained biologically active IL-6 at levels ranging from 2 to 2800 U/ml. IL-6 production was not influenced by other cytokines. Thirteen of 28 patients had detectable IL-6 in their serum, but in cells lysed no more than 2 h after removal from the patient, message for IL-6 could not be detected by Northern blotting. Cells also failed to express IL-1 beta mRNA but seven of eight patients had low levels of TNF message. Preliminary data using in situ hybridization techniques revealed that whilst no mRNA for IL-6 was detected, TNF and IL-1 beta mRNA were detected in a minority of mononuclear cells.

Therapy of human ovarian cancer xenografts with intraperitoneal liposome encapsulated muramyl-tripeptide phosphoethanolamine (MTP-PE) and recombinant GM-CSF

Three intraperitoneal human ovarian cancer xenografts (OS, HU, and LA) were used to assess the antitumour activity of intraperitoneal therapy with liposome encapsulated MTP-PE. MTP-PE led to significant prolongation of survival in all three xenograft models, but with varying efficacy. In one tumour model (OS), 80% of mice were cured of tumour by twice weekly therapy for 4 weeks, whereas in another xenograft model (LA), the median survival time was approximately doubled compared to PBS injected and placebo liposome injected controls (median survivals: 30 vs 62.5 days respectively). The antitumor efficacy of MTP-PE did not correlate with the extent of peritoneal neutrophil infiltration after intraperitoneal therapy. Combined therapy with liposome encapsulated MTP-PE and recombinant murine granulocyte-macrophage colony stimulating factor led to increased survival of mice bearing the LA and HU xenografts, compared to tumour bearing mice treated with either agent singly.

Effect of steroid hormones on human colorectal adenocarcinoma xenografts, of known steroid-receptor status, in nude mice

The effect of hormone therapy on the growth of human colonic adenocarcinoma xenografts in nude mice was evaluated. Primary xeno-transplantation for ten different human colorectal adenocarcinomas into nude mice yielded a tumour take of 50%. One of these host tumours was found to contain androgen receptors (8 fmol/mg cytosol protein; Kd 0.73 x 10(-9) M), which were maintained in the xenograft at the third and ninth passages, but not expressed at the tenth and twelfth passages. The host tumour and its xenograft did not express either oestrogen or progesterone receptors. Administration of dihydrotestosterone led to inhibition of xenograft growth at the ninth passage compared with untreated controls (P less than 0.05), but had no effect on xenograft growth at the tenth and twelfth passages when androgen receptors were absent. Stilboestrol and progesterone failed to influence xenograft growth. In conclusion, dihydrotestosterone administration led to inhibition of xenograft growth only in the presence of androgen receptor, suggesting that some colorectal cancers might be considered steroid-hormone-sensitive tumours.

Evidence for tumour necrosis factor/cachectin production in cancer

Labile tumour-necrosis-factor-like (TNF) activity was detected by means of an enzyme-linked immunosorbent assay in 50% of 226 freshly obtained serum samples from cancer patients with active disease. In contrast, only 3% of 32 samples from normal subjects and 18% of 39 samples from cancer patients with no clinically evident disease were positive for this factor, with low levels of activity. Greater proportions of serum samples from patients with ovarian or oat-cell carcinoma were positive (69% and 63%) than those from patients with lymphoma (26%). RNA preparations from peripheral-blood mononuclear cells and solid tumours were probed with TNF complementary DNA; evidence of TNF messenger RNA was found in 8 of 11 samples of peripheral-blood mononuclear cells from cancer patients, but only 1 of 8 normal subjects, and in 2 of 6 colorectal tumours. As yet the inducing stimulus and the clinical significance of TNF production in cancer are not understood.

2',5'-Oligoadenylate synthetase and interferon in peripheral blood after rubella, measles, or mumps live virus vaccine

The temporal activation of the human interferon system by infection with virus was studied by serial measurements of both interferon in serum and activity of 2',5'-oligo adenylate synthetase in peripheral mononuclear leukocytes. A frequency distribution of baseline values of synthetase was established for normal individuals. Following subcutaneous inoculation of rubella vaccine virus, serum interferon rose briefly with a peak on Day 14. The peak concentration of synthetase also occurred on Day 14 but remained elevated for greater than 1 week. After measles virus, serum interferon did not rise above baseline, but synthetase peaked on Day 14 and remained elevated. Subcutaneous inoculation of mumps vaccine virus was associated with a brief period of elevation of the synthetase and no interferon in the serum. Thus, the determination of synthetase levels in tissue may be useful in some situations to reflect a small or transient elevation of endogenous interferon.

Enhancement by gamma-interferon of in vivo tumor radiolocalization by a monoclonal antibody against HLA-DR antigen

Athymic nu/nu (nude) mice bearing s.c. human breast tumors were treated systemically with recombinant human gamma-interferon. These tumors were phenotypically negative for HLA-DR prior to therapy, but after 4 days of treatment, 80% of the cells expressed this antigen in vivo as assessed by immunoperoxidase (F. R. Balkwill et al., Eur. J. Cancer Clin. Oncol., in press, 1986). A radioiodine-labeled murine monoclonal antibody (TAL-1B5) against HLA-DR specifically localized to the tumors in recombinant human gamma-interferon-treated but not in control mice. An isotype-identical murine monoclonal antibody that did not react with control or recombinant human gamma-interferon-treated tumors did not show any specific localization. These results demonstrate that specific localization to tumors of radio-labeled monoclonal antibodies to HLA-DR can be facilitated by systemic therapy with gamma-interferon.

Antiviral and antiproliferative effects of interferons in quiescent fibroblasts are dissociable

Quiescent mouse Swiss 3T3 cells or human fibroblasts treated with interferon for only 2 hr before the addition of serum are effectively protected against virus infection for up to 24 hr after the addition of serum and the removal of interferon. In sharp contrast, exposure of quiescent fibroblasts to interferon only before addition of serum or the peptides epidermal growth factor and insulin, has no inhibitory effect on cell proliferation. Further, even when interferon is added after the addition of growth factors, an exposure of several hours is required to inhibit stimulation of DNA synthesis. These findings strongly suggest that the antiviral action of interferons is dissociable from their ability to inhibit cell proliferation. The implications of these findings for elucidating the molecular events leading to the biological responses elicited by interferon are discussed.

Use of interferon in the management of patients with subacute sclerosing panencephalitis

Six patients (five male, one female) with subacute sclerosing panencephalitis were treated with purified lymphoblastoid interferon, using a combination of intravenous and lumbar intrathecal routes. The first symptoms of the disorder occurred between seven and 16 years of age, and the length of the illness before treatment varied from 1 1/2 to 12 months. All six patients were in the first clinical stage of the disorder. After a limited period of follow-up there has been no clinical improvement. Nil or low levels of interferon were found in CSF two hours after intravenous injection, but CSF levels of interferon were maintained for at least 24 hours after intrathecal injections. Side-effects of interferon included pyrexial reactions, especially after high-dose intravenous therapy (six), lethargy (four), a transient rise in blood pressure (two) and a reduction in platelet count (six). Staphylococcus epidermidis was grown from the CSF of one patient.

Monoclonal antibodies that distinguish between subspecies of human interferon-alpha and that detect interferon oligomers

Monoclonal antibodies to human interferons (HuIFN) of the alpha-class have been prepared by screening against 125I-labeled IFN in a rapid liquid-phase radioimmunoassay. All of the six antibodies produced react with HuIFN-alpha 2 and with some components of HuIFN-alpha N (Namalwa); three of the antibodies also bind HuIFN-alpha 1, and these either do not bind or bind very weakly the 25K component of Namalwa. Reaction of the antibodies with IFN components blotted onto nitrocellulose after separation on reducing gels suggests that two of the antibodies are against conformational determinants, whereas the epitopes recognized by the other antibodies are not destroyed by reduction or SDS treatment; these antibodies can be used to detect the presence of oligomers in IFN preparations. From the reaction of the antibodies with different alpha-IFN in immunoblots, in an antiviral assay, and in an ELISA, it was concluded that at least five different epitopes are recognized by the six antibodies, only one of which is non-neutralizing.

Monoclonal antibodies that distinguish between subspecies of human interferon-alpha and that detect interferon oligomers

Monoclonal antibodies to human interferons (HuIFN) of the alpha-class have been prepared by screening against 125I-labeled IFN in a rapid liquid-phase radioimmunoassay. All of the six antibodies produced react with HuIFN-alpha 2 and with some components of HuIFN-alpha N (Namalwa); three of the antibodies also bind HuIFN-alpha 1, and these either do not bind or bind very weakly the 25K component of Namalwa. Reaction of the antibodies with IFN components blotted onto nitrocellulose after separation on reducing gels suggests that two of the antibodies are against conformational determinants, whereas the epitopes recognized by the other antibodies are not destroyed by reduction or SDS treatment; these antibodies can be used to detect the presence of oligomers in IFN preparations. From the reaction of the antibodies with different alpha-IFN in immunoblots, in an antiviral assay, and in an ELISA, it was concluded that at least five different epitopes are recognized by the six antibodies, only one of which is non-neutralizing.

A paralytic disease in nude mice associated with polyoma virus infection

Nude mice (nu/nu), heterotransplanted with human tumours and kept in isolators, were found to suffer from wasting and posterior paralysis. Electron microscopy of spinal cord tissue revealed virus particles in the oligodendrocytes consistent in size (35 to 40 nm), morphology and distribution with those of the polyoma--SV40 sub-group of papovaviruses. Serology and restriction enzyme analysis of the virus genome showed that the virus was the murine polyoma A2 strain. Inoculation of uninfected nude mice with 10(7) TCID50 of polyoma A2 strain virus produced a similar disease in these mice with wasting and, after 10 to 23 weeks, paralysis of the hind legs of all surviving mice. Extensive myelin disruption was seen throughout the brain stem and sacral region of the spinal cord and high titres of polyoma virus were found in the whole brain (10(8.8) TCID50/brain) and in the spinal cord (10(6.8) TCID50/spinal cord).

Demyelination and wasting associated with polyomavirus infection in nude (nu/nu) mice

Nude (nu/nu) mice bearing human tumour heterografts were affected with posterior paralysis and wasting. There was demyelination and infection of the oligodendrocytes of the spinal cord with a papovavirus. Similar virus particles and inclusion bodies were found in the bronchial epithelium, which showed histopathological changes. Similar changes were shown by the epithelia of the renal pelvis, ureter and choroid plexus. The virus was found in a transplantable human tumour, and evidence of spread by contact was also obtained. Intracerebral injection of spinal cord suspension from infected mice resulted in virus infected cutaneous carcinomata, demyelination with virus particles in the oligodendrocytes and posterior paralysis with wasting in adult nude mice. The suspension injected intraperitoneally into newborn Syrian hamsters produced tumours similar to those produced by murine polyoma. No evidence of infection was found in mice from the colony of origin. The virus was identified as murine polyoma Wild Type A2.

Inhibition by lymphoblastoid interferon of growth of cells derived from the human breast

Human lymphoblastoid interferon inhibited the growth in vitro of fibroblasts and epithelial cells from normal, hyperplastic and neoplastic human breast tissue. At an interferon concentration of 10(3) inter-national units (IU) per ml, the inhibitory effects on monolayer growth were completely reversible but the growth potential of cells at lower density in colony-forming cultures was not completely recovered. Studies on the cell cycle distribution of interferon-treated cells demonstrated that the growth-inhibitory effect was not due to an effect on one specific phase of the cell cycle, but to a lengthening of all phases.