Biologic effects of interferons: relevance to multiple sclerosis

Recombinant interferon beta has established efficacy for relapsing-remitting MS, but the mechanisms of action in the disease are not well understood. Interferons (IFNs) mediate biologic effects by receptor-mediated gene activation. Binding by IFNs to high-affinity surface receptors results in physophorylation and activation of two cytoplasmic tyrosine kinases. This leads to activation of latent transcription factors in cell cytoplasm that translocate to the nucleus, where activated transcriptional elements interact with the interferon-stimulated response element (ISRE), leading to transcription of the interferon-stimulated genes (ISGs). IFN's biologic effects are mediated by function of the ISGs. The biologic effects of IFNs have been classified as antiviral, antiproliferative and immunomodulatory; effects are complex, however, because there are two separate types of IFN, four separate varieties of type I IFN and approximately 30 known interferon-regulated genes. Known effects of IFN that may plausibly relate to therapy efficacy in MS are discussed.

Antitumor effects of nonconjugated murine Lym-2 and human-mouse chimeric CLL-1 monoclonal antibodies against various human lymphoma cell lines in vitro and in vivo

Lym-2 is a murine monoclonal antibody (MoAb) directed towards a human class II molecule variant reactive with both normal and neoplastic human B lymphocytes. Previous studies have shown that signals transmitted by class II molecules that stimulate normal lymphocytes can be inhibitory for B-cell lymphoma growth by signaling activation-induced cell death. Therefore, we sought to evaluate the effects of nonconjugated murine Lym-2 and a human-mouse chimeric Lym-2 (chCLL-1; with murine variable regions and human constant regions) MoAb on the growth of various human lymphomas by using both in vitro and in vivo assays. Cell lines derived from Burkitt's lymphomas, diffuse large cell B-cell lymphomas, anaplastic large-cell lymphomas, and Epstein-Barr virus-induced B-cell lymphomas were incubated with Lym-2 or chCLL-1 in vitro, and effects on proliferation were determined by [3H]-thymidine incorporation. The effects of Lym-2 in vitro were also compared with those of Lym-1, which is a similar MoAb that has been evaluated clinically. After immobilization, which enhances crosslinking of the MoAbs, both Lym-2 and chCLL-1 were capable of directly inhibiting the growth of various lymphoma lines in vitro. These human lymphomas were then transferred into mice with severe combined immunodeficiency to evaluate the efficacy of these MoAbs in vivo. Treatment with either murine Lym-2 or the chimeric chCLL-1 were significantly effective in improving the survival of tumor-bearing mice. These results indicate that stimulation by nonconjugated chCLL-1 may offer a biological approach to the treatment of various human lymphomas.

Peptides derived from a wild-type murine proto-oncogene c-erbB-2/HER2/neu can induce CTL and tumor suppression in syngeneic hosts

In this analysis, we examined whether peptides derived from a wild-type murine proto-oncogene, c-erbB-2, function as tumor rejection Ags. Expression of murine c-erbB-2 examined by means of reverse transcription-PCR was observed in several normal adult tissues, such as intestine, kidney, and testis. We then transduced human and murine c-erbB-2 cDNA into two mutually noncross-reactive fibrosarcoma lines of BALB/c origin, CMS7 and CMS17. In BALB/c mice immunized with CMS17HE (CMS17 transduced with human c-erbB-2 cDNA), the growth of subsequently challenged CMS7HE (CMS7 transduced with human c-erbB-2 cDNA) was significantly suppressed. CTL against human c-erbB-2-expressing cells were generated from BALB/c spleen cells in vivo and in vitro sensitized by CMS17HE. The CTL activity was also directed against murine c-erbB-2-expressing cells, CMS7ME and CMS17ME, and was blocked by anti-CD8 or anti-Kd mAbs. A series of peptides of human or murine c-erbB-2 compatible with the Kd binding motif was synthesized. The CTL were reactive with P1.HTR (H-2d) pulsed with three of these peptides, p63-71 (human c-erbB-2 derived), p63-71(A) (murine c-erbB-2 derived), and p780-788 (common for human and murine c-erbB-2). Spleen cells immunized in vivo and in vitro with syngeneic spleen cells pulsed with these peptides became cytotoxic for CMS17HE and/or CMS17ME, but not CMS17neo (CMS17 transduced with control vector). The growth of CMS7ME was suppressed in mice immunized with the murine c-erbB-2-derived peptide, p63-71(A) or p780-788. There was no apparent pathologic change in mice that rejected CMS7ME after vaccination with these peptides.

Homodimerization of tumor-reactive monoclonal antibodies markedly increases their ability to induce growth arrest or apoptosis of tumor cells

Monoclonal antibodies (mAbs) that exert antitumor activity can do so by virtue of their effector function and/or their ability to signal growth arrest or cell death. In this study, we demonstrate that mAbs which have little or no signaling activity-i.e., anti-CD19, CD20, CD21, CD22 and Her-2-can become potent antitumor agents when they are converted into IgG-IgG homodimers. The homodimers exert antigrowth activity by signaling G0/G1 arrest or apoptosis, depending upon which cell surface molecule they bind. This activity is specific and, in the case of the anti-CD19 mAb, did not require an Fc portion. These results offer the possibility that homodimers of other tumor-reactive mAbs which have little antitumor activity as monomers might be potent, antitumor agents.

In vivo efficacy and toxicity of a single-chain immunotoxin targeted to CD40

G28-5 sFv-PE40 is a single-chain immunotoxin targeted to CD40, which is highly expressed on human hematologic malignancies, including non-Hodgkin's lymphoma, B-lineage leukemias, multiple myeloma, and Hodgkin's disease, as well as certain carcinomas. In vitro analysis showed that this monovalent immunotoxin had a binding affinity of 3 nmol/L, within 15-fold of the bivalent parental monoclonal antibody. G28-5 sFv-PE40 was stable when incubated in mouse serum at 37 degrees C for 6 hours and cleared from the circulation of mice with a half-life of 16.7 minutes. This immunotoxin was effective in treating human Burkitt's lymphoma xenografted SCID mice with complete responses, defined by an asymptomatic phenotype for greater than 120 days, obtained at doses of 0.13 to 0.26 mg/kg. The efficacy of treatment was dependent on the schedule used, with every three days for five injections being the most effective tested. The toxicity of G28-5 sFv-PE40 was examined in SCID mice, rats, and monkeys, with the maximum tolerated dose being 0.48, 1.0, and 1.67 mg/kg, respectively. Comparative immunohistology showed that the G28-5 specificity was qualitatively similar between human and monkey tissue. In summary, G28-5 sFv-PE40 was effective at inducing complete antitumor responses in lymphoma xenografted mice at doses that were well tolerated in mice, rats, and monkeys.

Stabilization of a recombinant Fv fragment by base-loop interconnection and V(H)-V(L) permutation

We have developed a novel method to stabilize a recombinant antibody Fv fragment. The V(H) and V(L) domains of this Fv fragment, called pFv (permutated Fv), are covalently interconnected to each other at the two "base-loops" that normally connect V(H) beta strand 3 to 3b and V(L) beta strand 3 to 3b. To produce the base-loop stabilized Fv fragment, we connected the N-terminal half of the V(L) domain (V(L) 1-40) of murine antibody anti-Tac to the C-terminal half of V(H) (V(H) 42-115). We also fused the C terminus of V(H) by a (Gly4Ser)3 linker to the N-terminal half of V(H) (V(H) 1-40, thereby generating a permutated V(H) domain). Finally we connected the base loop of V(H) (N-terminal half) to the C-terminal half of V(L) (V(H) 42-115). The anti-Tac pFv fragment was fused to a truncated form of Pseudomonas exotoxin to generate a pFv-immunotoxin. Fvs with the correct structure were produced by refolding of recombinant inclusion body protein using a renaturation protocol that was originally developed for Fab and scFv fragments. Due to the artificially connected and permutated primary sequence, the folding pathway for the pFv structure may possibly be different from the conventional folding of antibody domains. Analysis of antigen binding of anti-Tac pFv, and of the specific cytotoxicity of pFv-immunotoxin towards antigen expressing cancer cells demonstrated that the anti-Tac pFv retained most of its affinity and full specificity when compared to anti-Tac scFv. Also anti-Tac pFv was relatively stable, retaining 25% of its binding activity after a 24 hour incubation in human serum at 37 degrees C. This indicates that connection of base loops can be a useful alternative to linker or disulfide stabilization of Fv fragments.

IgE-mediated allergic reaction to hyaluronidase in paediatric oncological patients

Hyaluronidase has been gaining increasing interest as a spreading factor for better penetration of chemotherapeutics into CNS tumours. Five out of 16 patients with CNS tumours treated with hyaluronidase in addition to chemotherapeutic agents developed symptoms of immediate type allergic reactions, therefore we sought to characterize the harmful allergenic proteins of the bovine testes hyaluronidase enzyme preparation (Neopermease). The role of specific IgE for the allergic reaction was investigated. Using an immunoblotting technique, we investigated sera from 16 children treated with Neopermease (5 of them having developed anaphylactic reactions), 5 patients with atopy (atopic eczema) with high total IgE levels and 4 healthy children. SDS-PAGE of hyaluronidase preparation Neopermease revealed two major bands at 73 and 41-43 kDa. In all 5 sera from patients with adverse reactions, binding of specific IgE antibodies to have 73 and 41-43 kDa bands was found. Two patients reacted with the 73 kDa band exclusively, two patients reacted with both bands, one patient displayed IgE only to the 41-43 kDa band. A specific inhibition of IgE-binding to both bands was achieved after preincubation of the sera in four out of five patients with partially purified bovine hyaluronidase. Furthermore preincubation with gelatin, a stabilising agent in the commercial extract, led to a partial inhibition in the sera of three patients. No specific IgE binding was detected either in the sera of atopic patients, or in the control group.

CONCLUSION

IgE mediated allergic reactions to hyaluronidase may occur in paediatric oncological patients treated with hyaluronidase. Whether these children are sensitized by intravenous hyaluronidase treatment or by cross-reactivity of other preformed IgE antibodies, yet to be specified, remains to be elucidated.

Interleukin-12, an emerging anti-tumour cytokine

Interleukin 12 is a multifunctional cytokine secreted by a wide variety of cells including macrophages and B cells and promotes cell-mediated immunity by its ability to selectively augment Th-1 type immune responses. This pleiotropic cytokine exerts numerous effects on T and NK cells, resulting in an enhancement of cytolytic activity and direct stimulation of IFN-gamma production and studies have demonstrated that this cytokine plays an important role in the promotion of the host resistance to infection by bacterial, fungal and protozoan pathogens. IL-12 has also been shown to cause tumour regression and reduce metastasis in animal models, due to both the promotion of antitumour immunity and also to the significant inhibition of angiogenesis and up-regulation of E-cadherin, a metastasis suppressor. Recent reports using local administration of IL-12 to the tumour site by retroviral vectors and 'gene gun' techniques have resulted in a significant reduction of tumour mass, with complete eradication occurring in several cases. The effects of IL-12 in patients with cancer are currently under investigation. Thus, interleukin-12 represents a cytokine with potent antitumour effects and may therefore be an attractive agent in anticancer therapy.

A physiological role of interferon (IFN)-beta derived from tumor: tumor growth of a mouse bladder carcinoma line MBT-2 is partially suppressed by autocrine IFN-beta

Although some tumor cells endogenously produce a wide variety of cytokines, their physiological roles remain to be fully understood. In this study, we found that mouse subcutaneous tumor induced by inoculation of bladder tumor MBT-2 cells into syngeneic mice secreted a significant amount of interferon (IFN), whereas the cells exhibited no IFN production in in vitro cell culture. Typing experiment using IFN-specific neutralizing antibodies showed that the tumor-derived IFN was exclusively beta type. Since the MBT-2 tumor tissues were homogenous and not infiltrated by immune cells, MBT-2 cells themselves were considered to be IFN-beta producers. By intraperitoneal injection of neutralizing anti-IFN-beta antibodies into MBT-2 cell-inoculated mice, the tumor growth was substantially precipitated and survival days of the tumor-bearing mice were shortened. As the in vitro cell growth of MBT-2 cells was dose-dependently inhibited by IFN-beta, it was suggested that apparent immunogenicity of MBT-2 tumor is partially mediated by tumor suppression by autocrine IFN-beta.

[Nitric oxide and macrophages]

Nitric oxide (NO) is a gaseous radical enzymatically produced from L-arginine by virtually every cell. This versatile molecule is involved in a variety of biological functions including defense against pathogens. Micro-organisms whose development is inhibited by NO include fungi, bacteria, protozoa, helminths and viruses. In murine macrophages, a high output NO synthase (NOS II) is regulated transcriptionally by cytokines and microbial products. In the past few years, investigators have identified many other cell types expressing NOS II. However, in human monocytes/macrophages, the existence of the L-arginine-NO pathway has long been questioned. Recent findings and new developments in this respect are commented in this short review.

Cross-linking CTX, a novel thymocyte-specific molecule, inhibits the growth of lymphoid tumor cells in Xenopus

CTX, a new Xenopus Ig superfamily molecule present on some cortical thymocytes and lymphoid tumor cells, is expressed at the cell surface under six differently glycosylated isoforms as shown by two-dimensional gel analysis and by endo F glycosidase treatment. Following chemical cross-linking before immunoprecipitation, a large fraction of surface CTX forms non-covalently linked dimers at the cell surface. This finding, which is consistent with the presence of a J segment with diglycine beta bulge in the V region of the molecule, suggests that this dimer has the same conformation as a T-cell receptor (TCR) or an Ig molecule. The V8 digest patterns of the monomers and dimers are identical. While this suggests that the dimer is a homodimer of two CTX chains, it does not distinguish whether each CTX chain is encoded by the same or different gene loci. When tumor cells were added to culture wells that had been coated with the anti-CTX monoclonal antibody X71, 30-50% underwent rapid (within 30 min) morphological changes followed by growth inhibition as determined by a decrease in thymidine incorporation and by direct cell counting. No apoptosis, calcium flux or external calcium requirement was noted after cross-linking of CTX. These results suggest that CTX can function as a receptor, and that its interaction with a ligand influences the control of cell proliferation through a signalling pathway that is distinct from the TCR machinery.

The isolation and characterization of an immunomodulatory and anti-tumor polysaccharide preparation from Flammulina velutipes

Alkaline-soluble antitumor polysaccharide was prepared from the cell wall of the mushroom Flammulina velutipes. The backbones) of the polysaccharide is mainly composed of beta-(1-->3)-D-linked glucose and its molecular weight was estimated to be about 200 kD. The polysaccharide was found to be non-toxic by brine shrimp assay. When injected into mice intraperitoneally, the polysaccharide triggered proliferation of splenic lymphocytes and also vascular dilation and hemorrhage (VDH) response. The polysaccharide exhibited potent anti-tumor activity against sarcoma SC-180 in vivo but not in vitro.

Carboplatin-induced immune hemolytic anemia

BACKGROUND

A case of acute hemolysis following therapy with carboplatin, an anticancer chemotherapeutic agent, was investigated. Hemolytic anemia has been associated with cisplatin, a related drug, but not with carboplatin.

CASE REPORT

An 8-year-old boy was treated for an astrocytoma by monthly intravenous injections of carboplatin. Lower back pain was noted after 26 monthly injections, and overt intravascular hemolysis occurred after the 27th injection. The direct antiglobulin test was 4+ with anti-IgG and 1+ with anti-C3d.

RESULTS

Blood samples obtained on Days 28 and 56 after the last injection were tested for carboplatin-dependent antibody. The direct antiglobulin test was 1+ with anti-IgG; the eluate was 1+ with and without carboplatin. The serum indirect antiglobulin test was negative in the absence of carboplatin, 3+ to 4+ in the presence of carboplatin, and 1+ with carboplatin-coated cells. Day 56 serum antibody titer was 64 (agglutination at 37 degrees C), 512 (indirect antiglobulin test) in the presence of carboplatin, and 8 (indirect antiglobulin test) with carboplatin-coated cells.

CONCLUSION

The findings indicate a carboplatin-induced antibody reacting in vitro by a complex mechanism combining elements of "immune complex," drug adsorption, and autoantibody mechanisms. Drug-dependent hemolysis is a previously unreported but potentially serious complication of carboplatin therapy.

Targeted delivery of diphtheria toxin via immunoliposomes: efficient antitumor activity in the presence of inactivating anti-diphtheria toxin antibodies

Diphtheria toxin (DT) has attracted considerable attention for anti-cancer therapy. However, its extensive use is prohibited by (i) its non-specific action which can result in substantial toxicity, (ii) most patients have low serum levels of anti-DT antibodies (AT antibodies) which can inactivate DT and (iii) its immunogenicity will boost the circulating AT antibody level, thereby further compromising the antitumor activity. To overcome these limitations, we have developed a new approach for targeted delivery of DT utilizing immunoliposomes. In this approach, protection against the non-specific action of DT is combined with efficient antitumor activity even in the presence of inactivating AT antibodies.

Characterization of monoclonal antibodies against (1R,2R)-cyclohexanediamine platinum(II)-DNA adduct

Two monoclonal antibodies raised against Pt(II)(1R,2R-cyclohexanediamine)-DNA were prepared, and the specificity of the monoclonal antibodies against Pt(II)(cyclohexanediamine)-DNA derivatives was determined by competitive enzyme-linked immunosorbent assay. The binding affinity of the monoclonal antibodies is apparently influenced by the cyclohexanediamine moiety of Pt(II)(cyclohexanediamine)-DNA adducts, but the monoclonal antibodies can not bind to the low molecular analogue, Pt(II)(1R,2R-cyclohexanediamine)-d(GpG), which is the intrastrand binding model compound of Pt(II)(1R,2R-cyclohexanediamine)-DNA. Therefore, the monoclonal antibodies recognize the macromolecular parts, including DNA duplex, in addition to the cyclohexane moieties of the platinum complexes on Pt(II)(cyclohexanediamine)-DNA adducts.

In vitro tumor growth inhibition by bispecific antibodies to human transferrin receptor and tumor-associated antigens is augmented by the iron chelator deferoxamine

Previously, a panel of mouse monoclonal antibodies (mAbs) to several tumor-associated antigens was chemically crosslinked to an IgG1 anti-human transferrin receptor antibody, 454A12. We called this new class of bispecific antibodies (BmAbs) "antigen forks" and showed that these antigen forks inhibited but did not completely prevent tumor cell growth. We speculated that the conjugates acted by heterologously crosslinking two antigens in a manner that interfered with the functions of one or both. The most effective BmAbs all shared one specificity for the human transferrin receptor. A monoclonal antibody to this receptor has been shown by others to reduce tumor cell growth when used with the iron chelator deferoxamine. When we combined our antigen forks with deferoxamine, two of five BmAbs synergized with deferoxamine to arrest tumor cell count at or below input levels. The most effective BmAbs were 317G5/454A12 (3/4) and 520C9/454A12 (5/4). mAb 317G5 recognizes a 42-kDa tumor-associated glycoprotein, and mAb 520C9 recognizes the c-erbB-2 protooncogene product. BmAb 3/4 was most effective against colorectal cancer cell line HT-29, and BmAb 5/4 was most effective against breast cancer cell line SK-BR-3. When deferoxamine and BmAb were replaced by fresh medium after a 6- or 7-day treatment period, no regrowth of tumor cells was observed during the next 4 days, although regrowth was seen if either deferoxamine or BmAb was used alone. Our results show that BmAbs with specificities for transferrin receptor and certain tumor-associated antigens effectively inhibit tumor growth in vitro. When used in combination with deferoxamine, such BmAbs may have therapeutic potential for the treatment of cancer.

Toxicity of chemotherapy

Because anticancer drugs are cytotoxic for normal as well as neoplastic cells, the range of unwanted effects that accompanies their use is broad. Many of the side effects are potentially life-threatening or seriously debilitating. Many are similar to, and readily confused with, direct or indirect (paraneoplastic) consequences of the cancer itself. Recognition of drug side effects is vital for optimal patient care, because early withdrawal of the offending agent and institution of appropriate treatment have the potential to significantly reduce the overall morbidity and mortality associated with the diagnosis of cancer.

Preparation and specificity of antibodies to an anti-tumor beta-glucan, lentinan

Antibodies against beta-glucan, lentinan from "Shiitake" (Lentinus edodes), were raised in the rabbit by subcutaneous immunization. Our antibodies did not recognize the other polysaccharides such as amylose, dextran, laminarin and galactan. It was proved that lentinan contents in mushroom could be measured by ELISA with the anti-lentinan antisera. Its contents were 3.5 mg/g fresh weight in Lentinus edodes. However, lentinan was not contained in Agaricus brazei, Agaricus bisporus and Ramaria bitrytis.

Role of endogenous interferon gamma in murine tumor growth and tumor necrosis factor alpha antitumor efficacy

BACKGROUND

The anticancer role of tumor necrosis factor-alpha (TNF-alpha) has been limited by toxicity. These experiments evaluate blocking endogenous interferon-gamma (IFN-gamma) activity to abrogate TNF-alpha toxicity.

METHODS

C57B1/6 mice bearing MCA 105 tumor were treated with TNF-alpha and anti-IFN-gamma antibody (Ab) to evaluate the effect on the acute lethality of TNF-alpha and their efficacy as evaluated by tumor growth rate, tumor histology, and survival.

RESULTS

Anti-IFN-gamma Ab decreased TNF-alpha lethality. Anti-IFN-gamma Ab alone increased tumor growth significantly more than did nonimmune IgG (p2 < 0.0001). Tumor-bearing mice that received nonimmune IgG and TNF-alpha had slower tumor growth (p2 < 0.02) and a trend toward improved survival (p = 0.07) compared with saline-treated controls. Anti-IFN-gamma Ab abrogated the antitumor effect of TNF-alpha, prevented acute tumor necrosis histologically, and resulted in tumor growth rate and host survival similar to that of controls. The findings in mice that received anti-IFN-gamma Ab and high-dose TNF-alpha were comparable with those in mice that received a lower, equitoxic dose of TNF-alpha alone.

CONCLUSIONS

Blocking endogenous IFN-gamma accelerates tumor growth in this model and partially abrogates the toxic and antitumor activity of exogenous TNF-alpha equally. This suggests that blocking endogenous IFN-gamma activity is not a useful strategy for limiting TNF-alpha treatment toxicity.

Differential in vitro and in vivo antitumor effects mediated by anti-CD40 and anti-CD20 monoclonal antibodies against human B-cell lymphomas

The antitumor effects of CD40 and CD20 monoclonal antibodies (mAbs) were compared on various human B-cell lymphomas by using both in vitro and in vivo assays. Anti-CD40 directly inhibited the proliferation of human B-cell lymphomas in vitro, whereas anti-CD20 exerted no inhibitory effects on the growth of any lymphoma tested. These lymphomas were then injected into immunodeficient mice to examine the antitumor efficacy of these unconjugated mAbs in vivo. This xenogeneic model was used in the evaluation of various potential therapeutic agents against human cancers in an in vivo setting. Surprisingly, in contrast to its negligible effects on lymphoma growth in vitro, anti-CD20 was more efficacious than anti-CD40 in promoting the survival of mice bearing some but not all lymphoma lines. To determine whether the antitumor effects of these mAbs were direct or indirect in vivo, we concurrently treated tumor-bearing mice with mAbs to the murine Fc receptor to block antibody-dependent cell-mediated cytotoxicity (ADCC). When these neutralizing antibodies against Fc receptors were administered at the same time as mAb treatment, the antitumor effects of anti-CD20 in vivo were completely abrogated, whereas anti-CD40 treatment, although also diminished, still provided significant antitumor effects. These results indicate that the in vivo antitumor activity of the murine anti-human CD20 mAb was primarily due to ADCC by murine effector cells, which may not translate into comparable effects in humans. By contrast, anti-CD40 may be of potential clinical use in the treatment of lymphomas in humans because of its additional direct anti-proliferative effects. The results also demonstrate a possible difficulty in accurately evaluating the potential clinical efficacy of murine antibodies against human tumors in a human/mouse model system. Murine monoclonal anti-human antibodies may produce greater effects in human/mouse xenogeneic models, in which they are more likely to elicit host effector systems than when used in vivo in humans.

Transfer factor with anti-EBV activity as an adjuvant therapy for nasopharyngeal carcinoma: a pilot study

Overall survival of nasopharyngeal carcinoma (NPC) at UICC stage IV still remains unsatisfactory even with combination chemotherapy (CT) and radio-therapy (RT). In view of the association of reactivation of Epstein-Barr virus (EBV) with the development and recurrence of NPC, immunotherapy in the form of transfer factor (TF) with specific activity against EBV (TF-B1) was suggested as an adjuvant to a combination of CT and RT in order to improve survival. In the present study, 6 UICC stage IV patients received TF-B1 and another 6 patients matched for disease stage were given TF prepared from peripheral blood leucocytes (TF-PBL). Results were compared with another 18 patients matched by age, sex, and stage of disease who received standard therapy without TF during the same period (C group). After a median follow up of 47.5 months, the survival for the TF-B1 group was found to be significantly better (P = < 0.05) than the PBL and C group. While the 8 patients with distant metastasis (DM), not treated with TF-B1 (6 in the control and 2 in the PBL group), died due to progressive disease (average survival being 14.3 months), both patients with DM in the TF-B1 group had complete remission: one died of tuberculosis after surviving for 3.5 years and another is still alive, disease free, after 4.2 years. Although the series involved a small number of cases, the apparent effect of adjuvant immunotherapy in the form of TF with anti-EBV activity is of considerable interest.

[The role of anti L-asparaginase antibody in childhood acute lymphoblastic leukemia]

The function of IgG antibody with regard to L-asparaginase (L-asp) was investigated in vivo. Blood samples were collected before, during and after IV administration of L-asp (6,000 U/sqm for 10 days) in 18 children with acute lymphoblastic leukemia (ALL) previously treated with L-asp. Using enzyme-linked immunosorbent assay (ELISA), serum levels of L-asp and anti-L-asp IgG antibody were measured simultaneously. In 11 cases, the level of anti-L-asp IgG antibody increased prior to, but decreased to within the normal range after drug administration whereas the level of serum L-asp increased after drug administration. In 5 cases, the level of anti-L-asp IgG antibody increased as the level of serum L-asp decreased after drug administration. In contrast, in the 13 cases with no increase in anti-L-asp IgG antibody during L-asp administration, the serum L-asp level was stable. These data indicate that anti-L-asp IgG antibodies play an important role in the immunoclearance of L-asp. We would like to continue to carefully follow patients showing high titers of anti-L-asp IgG antibody during the administration of L-asp.

Potential mechanisms of interferon neurotoxicity

This article examines potential mechanisms underlying the neurologic toxicities associated with interferon therapy in patients with cancer. The following mechanisms for interferon-related toxicities have been proposed: changes in certain neuroendocrine hormone levels; structural similarities and common pathways between interferon and specific neuroendocrine hormones; and the immunoregulatory effects of interferon. Strategies for the assessment and management of interferon-related neurologic toxicities are discussed. A reduction in dose or discontinuation of interferon may be recommended if interferon neurotoxicity develops. Additional interventions may include reorientation strategies, provision of uninterrupted periods of rest, and safety precautions. Directions for future research are recommended.

Dietary beta-carotene and ultraviolet-induced immunosuppression

Ultraviolet (UV)-induced immunosuppression is a critical step in UV carcinogenesis, permitting tumour outgrowth. We investigated the effect of dietary beta-carotene on UV suppression of contact hypersensitivity (CHS) to trinitrochlorobenzene (TNCB) in BALB/c mice. Mice were fed for 10-16 weeks chow alone or supplemented with 1% beta-carotene or placebo as beadlets. Serum beta-carotene was detectable by high performance liquid chromatography (HPLC) analysis only in beta-carotene-fed mice (2.06 +/- 0.15 micrograms/ml). Serum retinol was 0.22-0.27 micrograms/ml in all three groups. Mice (n = 41/dietary group) were irradiated with 0, 4.5, 9 or 18 kJ/m2 of UVB and the CHS response was measured. Decreased CHS responses were observed in all UV-irradiated groups compared with unirradiated controls. UV dose-responses for suppression of CHS derived by first-order regression analyses of plots of percentage suppression of CHS as a function of log10UV dose showed significant slopes (P < 0.02) for all three dietary groups and similar residual variances between groups, P > 0.05. The UV dose for 50% suppression of CHS was 6.3 kJ/m2 for control, 6.4 kJ/m2 for placebo, and 5.5 kJ/m2 for beta-carotene-fed mice. No significant differences in slopes or elevations between UV dose-responses were observed, P > 0.05. Skin levels of the initiator of UV-induced immunosuppression, cis urocanic acid, were determined by HPLC in mice given 0 or 9 kJ/m2 of UV (n = 28/dietary group). No significant differences were observed between dietary groups (range 35.2-41.1 ng/mg skin, P > 0.15) We conclude feeding beta-carotene to BALB/c mice does not alter susceptibility to UV immune suppression, in contrast to human studies.

Binding characteristics and antitumor properties of 1A10 bispecific antibody recognizing gp40 and human transferrin receptor

The bispecific murine monoclonal antibody (MAb) 1A10 has specificity for the human transferrin receptor (TfR) and the human tumor-associated antigen gp40. This antibody, therefore, functions as an "antigen fork" by binding to two distinct antigens on the same malignant cell. Highly purified 1A10 inhibits the growth of cells coexpressing high levels of human TfR and the tumor-associated antigen gp40 by binding to both target antigens. In SW948 cells, the majority of 1A10 binding is via its gp40 specificity, and half-maximal inhibition of cell growth by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay requires 20-30-micrograms/ml concentrations of 1A10. The binding of 1A10 correlates with growth inhibition in the cell lines HT-29, SK-OV-3, OVCAR-2, and OVCAR-3. The growth of OVCAR-10 cells, which express little gp40 and TfR, is not inhibited by 1A10. However, SK-BR-3 cells, which express abundant gp40 and extremely high levels of TfR, are insensitive to the effects of 1A10. In some cell lines, combined exposure to 1A10 and the iron chelator deferoxamine mesylate has synergistic antiproliferative effects. A single i.p. dose of 600 micrograms 1A10 is sufficient to achieve an estimated tumor concentration of at least 30 micrograms/ml for 7 days in C.B17/Icr-scid mice bearing SW948 human tumor xenografts. Treatment of scid mice bearing day 2 or day 4 SW948 xenografts with single or multiple 1A10 doses inhibits tumor growth in a dose-related fashion. Antitumor effects are not seen with therapy using either parental antibody of 1A10. The antiproliferative properties of 1A10 in tumor cells overexpressing gp40 and TfR suggest avenues for the development of new bispecific antibody-promoted treatment strategies.

A recombinant Listeria monocytogenes vaccine expressing a model tumour antigen protects mice against lethal tumour cell challenge and causes regression of established tumours

Listeria monocytogenes is an intracellular organism that has the unusual ability to live in the cytoplasm of the cell. It is thus a good vector for targeting protein antigens to the cellular arm of the immune response. Here we use a model system, consisting of colon and renal carcinomas that express the influenza virus nucleoprotein and a recombinant L. monocytogenes that secrets this antigen, to test the potential of this organism as a cancer immunotherapeutic agent. We show that this recombinant organism can not only protect mice against lethal challenge with tumour cells that express the antigen, but can also cause regression of established macroscopic tumours in an antigen-specific T-cell-dependent manner.

[Development of interferon antibodies during the treatment of skin diseases with low-dose recombinant interferon alpha-2a]

In this study, we determined the frequency of interferon antibodies in patients with skin diseases treated with low doses of recombinant interferon alpha 2a (1.5 - 18 x 10(6) IU). We assayed serum specimens from 181 patients with malignant melanoma or cutaneous T cell lymphomas (78 patients treated with recombinant interferon alpha 2a and 103 patients in control group) for interferon antibodies before treatment and every 6 months for at least 18 months. Neutralizing interferon alpha 2a antibodies were detected in 27 of 77 treated patients (35%), but none in control group (p < 10(-6)): 38.2% in melanoma and 12.5% in T cell lymphomas. However antibody formation was not correlated with nonresponse or with frequency of interferon antibodies in patients receiving the combined therapy: interleukin-2 and interferon alpha 2a.

Reduction of toxicity of a vinca alkaloid by an anti-vinca alkaloid antibody

Inadvertent oncolytic overdoses occur rarely, but can have serious consequences. We have investigated the possibility of using an antibody, 27.8.1A, reactive with vinca alkaloids, as a means of reducing the toxicity associated with overdose situations. In vitro cytotoxicity of a vinca derivative, 4-desacetyl- vinblastine-3-carbox-hydrazide (DAVLBHYD), with and without the addition of 27.8.1A, was determined. Using CCRF-CEM, a human acute lymphoblastic leukemia cell line, as a target in this assay, we observed a greater than 90% increase in cell viability using 100 micrograms/ml 27.8.1A with a 0.1 microgram/ml concentration of DAVLBHYD. 27.8.1A had no effect on cell viability when doxorubicin was used as a control drug in this assay. Similarly, the addition of an irrelevant antibody. EGFrL11, had no effect on the toxicity of DAVLBHYD. In an in vivo survival experiment, nude mice were injected with a toxic dose of DAVLBHYD and subsequently given four doses of 27.8.1A. All anti vinca antibody-treated mice survived, in contrast to the untreated group or irrelevant antibody-treated group in which only 25% and 10% of the mice survived, respectively.

Molecular and structural requirements of a lipoteichoic acid from Enterococcus hirae ATCC 9790 for cytokine-inducing, antitumor, and antigenic activities

Comparison was made between the immunobiological and antigenic properties of two lipoteichoic acid (LTA) fractions (LTA-1 and -2) from Enterococcus hirae ATCC 9790, their glycolipid portions, and synthetic compounds partially mimicking the above bacterial products. The more lipophilic LTA-2 fraction was capable of inducing serum tumor necrosis factor alpha and interleukin-6 in muramyldipeptide-primed mice and serum gamma interferon in those primed with Propionibacterium acnes. The LTA-2 fraction also induced tumor necrosis factor alpha, interleukin-6, and thymocyte-activating factor (essentially interleukin-1) in murine peritoneal macrophage cultures. Consecutive intravenous injections of muramyldipeptide and the LTA-2 fraction in Meth A fibrosarcoma-bearing BALB/c mice caused hemorrhagic necrosis and marked regression leading to complete regression of the tumor with no accompanying weakening or lethal effects. The LTA-2 fraction was at least 10,000-fold less pyrogenic in rabbits than a reference endotoxic lipopolysaccharide. The more hydrophilic LTA-1 fraction, on the other hand, showed at most marginal activity in the in vivo and in vitro assays. Natural glycolipids (NGL-1 and -2) which were prepared from a chloroform-methanol extract of Streptococcus pyogenes and E. hirae cells, and comparable in structure to the lipid moieties of the LTA-1 and -2 fractions, respectively, were practically inactive in all of the assays. None of the test synthetic compounds was immunobiologically active, although synthetic partial counterparts of the structure of LTA proposed by W. Fischer (Handb. Lipid Res. 6:123-234, 1990) reacted with murine monoclonal antibody TS-2, which was raised against OK-432, a penicillin-killed S. pyogenes preparation, and capable of neutralizing the cytokine-inducing activities of the LTA-2 fraction.

Characterization of immunological activity of a low toxicity antitumor lipopolysaccharide from Bordetella pertussis

Immunological properties of a low toxicity lipopolysaccharide (BP-LPS) extracted from Bordetella pertussis (Tohama strain) which was reported to have high antitumor activity against murine tumors were examined and compared with those of LPS extracted from other enterobacteria. The activation or stimulation of murine macrophages and lymphocytes by these LPS, including TNF induction, was found to be similar. However, BP-LPS was clearly less active in its stimulation of murine and human neutrophils as estimated by neutrophil-adherence assay and by their TNF production than E. coli LPS. Furthermore, BP-LPS also suppressed the activation of human neutrophils by Escherichia coli LPS. A comparative study with 7 LPS preparations indicated that their toxicity in terms of animal body weight loss correlated with their ability to induce human neutrophil adherence. The inability of BP-LPS to activate neutrophils may thus have some bearing on its low toxicity.

New glycolipids (chitooligosaccharide derivatives) possessing immunostimulating and antitumor activities

New glycolipids, derived from chitooligosaccharides of dp 2-4 and containing both free and acylated amino groups, were synthesized. The structure of the key compounds (di-, tri-, and tetra-saccharides acylated with different fatty acids) were elucidated by 13C NMR spectroscopy. Only the amino group of the reducing end of the chitooligosaccharides was found to be acylated when equimolecular amounts of reagents were used. The compounds obtained were shown to possess a low toxicity and certain immunostimulatory and antitumor activities. An induction of interleukin-1 and tumor necrosis factor by the immunocompetent cells and an augmentation by 140-180% of the mean life of mice with the Erlich carcinoma were observed.

Hydroperoxides in oxidized d-limonene identified as potent contact allergens

Hydroperoxides of d-limonene were shown to be potent contact allergens when studied in guinea-pigs. Limonene-2-hydroperoxide (2-hydroperoxy-p-mentha-6,8-diene, a mixture of trans and cis isomers) was synthesized for the first time. The ratio between the trans and cis forms was 3:1. These two hydroperoxides were identified as the major hydroperoxides in autoxidized d-limonene. In photo-oxidized d-limonene, they constituted a minor part of the hydroperoxide fraction. Hydroperoxides may bind to proteins of the skin to make antigens either via a radical mechanism or after reactions to give epoxides. The cross-reactivity between the epoxide limonene-1,2-oxide, a potent contact allergen, and the hydroperoxides was therefore studied. No significant pattern of cross-reactivity was found. Further studies to identify and test the allergenicity of single hydroperoxides are needed to elucidate the mechanism of the allergenicity.

Multidrug-resistant colonic cancer cell line LoVoDx is efficiently killed by lymphokine-activated killer cells from patients with carcinoma of the colon

Multidrug-resistant (MDR+) cancer cells have the ability to grow in the presence of cytotoxic concentrations of antineoplastic drugs as a result of possessing the transmembrane drug efflux pump p-glycoprotein. The MDR+ colonic cancer cell line LoVoDx (derived from the drug-sensitive line LoVo) was tested for sensitivity to lymphokine-activated killer (LAK) cell-mediated toxicity. LAK cells were cultured from patients with colonic cancer and from matched controls with benign disorders. LAK cells from patients with cancer were as effective as those from controls in mediating cytotoxicity. The MDR+ cell line was significantly more sensitive to LAK cell-mediated cell killing than its parental drug-sensitive line LoVo (P < 0.05). These results indicate a possible role for adoptive immunotherapy in MDR+ tumours expressing p-glycoprotein.

Locoregional immunotherapy of head and neck cancers utilizing allogeneic spleen cells--a report of 2 cases

Frozen-stored human spleen cells (SC) cultured with streptococcus preparation OK-432 acquired direct cytotoxicity to autologous as well as allogeneic tumor cells. The activated cells started to produce cytocidal cytokine TGIF, which is distinct from previously known cytokines. We examined the possibility of allogeneic adoptive immunotherapy (AIT) using these OK-432-stimulated spleen cells (OK-SC) in two cancer patients. Rapid necrosis of cancer tissue and remarkable decreases of tumor markers in tumor effusion were observed. There were no severe side effects.

Enhancement of anti-tumor activity of recombinant interleukin-2 (rIL-2) by immunocomplexing with a monoclonal antibody against rIL-2

We have investigated biological properties of an immune complex of recombinant interleukin-2 (rIL-2) and a monoclonal antibody against rIL-2 in mice for induction of killer cells and for anti-tumor activity. We have also examined the clearance of subcutaneously-injected immune complex in mice and compared it with that of rIL-2 alone. Plasma rIL-2 levels were sustained longer in mice given the immune complex than in mice given rIL-2 alone at a dose of 10 micrograms/mouse, and they were detectable even at 24 hours after the administration of the immune complex, while they fell to undetectable levels by 6 hours after the administration of rIL-2 alone. A more significant portion of rIL-2 was detected in lymph nodes after subcutaneous injection of the immune complex than that of rIL-2 alone. Splenic lymphocytes from mice given the immune complex demonstrated a higher killer cell activity against YAC-1 cells than those from mice given rIL-2 alone. The immune complex also exerted more significant anti-tumor effect in a dose-dependent manner in Meth-A fibrosarcoma-bearing mice than rIL-2 alone. Our results indicate that immunocomplexing of rIL-2 with an antibody against rIL-2 provides a useful tool as the drug delivery system for cancer therapy using rIL-2.

A mouse/human chimeric anti-(ganglioside GD3) antibody with enhanced antitumor activities

Ganglioside GD3, which is one of the major gangliosides expressed on the cell surface of human tumors of neuroectodermal origin has been focused on as a target molecule for passive immunotherapy. We have cloned the cDNA encoding the immunoglobulin light and heavy chains of an anti-GD3 monoclonal antibody KM641 (murine IgG3, kappa), and constructed the chimeric genes by linking the cDNA fragments of the murine light and heavy variable regions to cDNA fragments of the human kappa and gamma 1 constant regions, respectively. The transfer of these cDNA constructs into SP2/0 mouse myeloma cells resulted in the production of the chimeric antibody, designated KM871, that retained specific binding activity to GD3. Indirect immunofluorescence revealed the same staining pattern for chimeric KM871 and the mouse counterpart KM641 on GD3-expressing melanoma cells. When human serum and human peripheral blood mononuclear cells were used as effectors in complement-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity respectively, the chimeric KM871 was more effective in killing GD3-expressing tumor cells than was the mouse counterpart KM641. Intravenous injection of chimeric KM871 markedly suppressed tumor growth in nude mice. The chimeric KM871, having enhanced antitumor activities and less immunogenicity than the mouse counterpart, would be a useful agent for passive immunotherapy of human cancer.

Radioimmunodetection of prostatic cancer: in vivo use of antibody against r-seminoprotein for diagnosis of prostatic cancer

Forty patients (25 cases of prostatic cancer and 15 cases of benign prostatic hyperplasia) were examined with radioimmunodetection (RAID) using antibody against r-Seminoprotein (r-Sm). The images of malignant tumor sites were revealed from the scan of single photon emission computerized tomography with the tracing of dual radionuclide and computer digital subtraction technique. Of the 25 patients with prostatic cancer tested, twenty-four were demonstrated in RAID with a positive rate of 96%. The ratio of taking in nuclide radioactivity between the tumor tissue and normal tissue (T/N) was 6.9 and the best showing time was the 96th hr from injection of radioactive antibody against r-Sm. The minimum diameter of the tumor detected in RAID was 0.5 cm. All of the 8 cases of metastatic prostatic cancer in pelvic or bone location were detected, with a rate of 100%. Of the 15 cases of benign prostatic hyperplasia, only one showed mild positive result. B-ultrasonography and CT showed a positive detective rate of 72.7% and 65%, respectively. Our results have indicated that RAID using 131I-labeled antibody against r-Sm possesses more advantages in specificity, because RAID not only defines the involved sites, but also shows the sites of the original tumors, and the metastatic location as well as the relationship between them.

Immunopharmacological characterization of a highly branched fungal (1-->3)-beta-D-glucan, OL-2, isolated from Omphalia lapidescens

The immunopharmacological activities of a fungal (1-->3)-beta-D-glucan, OL-2, isolated from "Leiwan" Omphalia lapidescens were examined. Intraperitoneal (i.p.) administration of OL-2 to ICR mice induced a significant number of peritoneal exudate cells (PEC) and white blood cells over the period of a few days. Spleen cell numbers were also increased by i.p. administration of OL-2 at about a week. These changes reverted to the normal level within a month. Responses of spleen cells and bone marrow cells (BM) to colony stimulating factors (CSF) were augmented by OL-2 administration assessed by cell proliferation assay. Sera from OL-2 administered mice contained an increased concentration of colony stimulating activity. Gene expressions of interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha in the spleen were also increased. These results suggested the activation of hematopoietic responses, and would well relate to the incremental increase in PEC, white blood cell and spleen cell numbers. OL-2 also increased the serum concentration of fibronectin and complement component C-3. However, OL-2 did not show adjuvant activity to SRBC and antitumor activity against the solid form of Sarcoma 180 by i.p. administration. Yet, OL-2 did not interfere with the antitumor activity of SSG against the same tumor system. These facts suggested that OL-2 could enhance nonspecific host defense mechanisms by enhancing hematopoietic responses, but would not enhance or inhibit the specific immunity mediated by lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adverse haematological complications of anticancer drugs. Clinical presentation, management and avoidance

Haematological complications frequently occur in patients treated with chemotherapeutic agents. The degree and duration of bone marrow suppression depends upon the type of agent used. In general, agents that are cell cycle phase-specific tend to cause early myelosuppression with rapid marrow recovery, as compared to the non-phase-specific agents. Host factors including patient age, nutritional status, marrow infiltration or damage, and hepatic and renal function also affect haemotoxicity. Chemotherapeutic agents suppress proliferating or potentially proliferating precursors of neutrophils, platelets and red blood cells to the same extent. With most drugs, neutropenia tends to be dose limiting and more severe than thrombocytopenia. Because of the longer life span of red blood cells, severe anaemia is rarely a problem. The management of myelosuppression is multifaceted, and consists of aggressive antibiotic therapy to treat or prevent the infections that occur with neutropenia, as well as red blood cell and platelet transfusion support to correct anaemia and prevent bleeding. The role of the haemopoietic growth factors including erythropoietin, colony-stimulating factors and the interleukins is currently being evaluated in clinical trials. Haemolytic uraemic syndrome, haemolytic anaemia and therapy-induced myelodysplasia and/or acute leukaemia are uncommon and potentially severe complications of chemotherapeutic agents.

Stimulating effect of DEODAN (an oral preparation from Lactobacillus bulgaricus "LB51") on monocytes/macrophages and host resistance to experimental infections

DEODAN is a lysozyme lysate from Lactobacillus bulgaricus for oral administration which has shown antitumor activity in mice and humans. The effects of this preparation on some functions of monocytes/macrophages and on host resistance to experimental infections were examined. The oral administration to mice of DEODAN-150 mg/kg daily (the recommended dose in humans) caused an increase of the spreading ability and phagocytic activity of peritoneal macrophages, which showed morphological signs of cell activation. The level of Interleukin-1 (IL-1) secreted in the culture supernatant of peritoneal macrophages of DEODAN-treated mice was found to be slightly increased only when the mice were treated with 150 mg/kg DEODAN for 10 days. However, the in vitro incubation of human blood monocytes with DEODAN resulted in induction of membrane-bound and cytoplasmic IL-1 and Tumor Necrosis Factor (TNF)-alpha. The oral treatment of mice with DEODAN also caused a decrease in mortality after experimental infections with Klebsiella pneumoniae and Listeria monocytogenes. These results indicate that DEODAN activates the phagocytic and secretory functions of mononuclear cells and increases host resistance to bacterial infections.

Autoreactive and heat shock protein 60-recognizing CD4+ T-cells show antitumor activity against syngeneic fibrosarcoma

A CD4+ heat shock protein (hsp) 60-recognizing autoreactive T-cell line (BASL1) and clone (BASL1.1) were examined for their antitumor activity against major histocompatibility complex class II- syngeneic Meth A fibrosarcoma (Meth A), which was immunofluorescently stained with monoclonal antibody specific for hsp 60. In in vitro proliferative assay, BASL1.1 was suggested to recognize Meth A-derived hsp 60 presented by syngeneic antigen-presenting cells in a major histocompatibility complex class II-restricted manner. This cell line and clone showed antitumor activity in tumor-neutralizing (Winn) assay. BASL1 and BASL1.1 cells produced gamma-interferon, tumor necrosis factor, and interleukin 2 but not interleukin 4 by the stimulation with syngeneic spleen cells. In cytolytic assay, these cell lines and clones showed neither direct nor indirect (bystander) cytolysis against Meth A. In cytostatic assay, these cells inhibited the proliferation of Meth A in the presence of syngeneic macrophages, and this activity was abrogated by the addition of anti-gamma-interferon monoclonal antibody. Recombinant gamma-interferon could induce cytostatic activity only in the presence of macrophages, and tumor necrosis factor synergized this activity. Antitumor activity induced by BASL1 was abrogated by the administration of anti-CD8 monoclonal antibody in vivo, suggesting that CD8+ cytotoxic T-lymphocytes are essential and final effector cells for BASL1-mediated Meth A rejection. These findings indicate that CD4+ autoreactive and hsp 60-recognizing T-cells show two types of antitumor activity: cytostasis and induction of tumor-specific cytotoxic T-lymphocytes. Furthermore, these results imply that tumor-specific immunity could be elicited by CD4+ helper T-cells which recognize hsp.

Targeting of anti-tumor responses with bispecific antibodies

T cells can be induced to specifically lyse tumor cells with bispecific antibodies containing anti-T cell receptor mAbs crosslinked to anti-tumor mAbs. Such "targeted cytolysis" requires that the target cell be bound directly to the cytotoxic cell. In addition, targeted T cells mediate a second activity, the secretion of factors that can block the growth of both tumor target cells and bystander tumor cells. When given to nude mice bearing intraperitoneal human ovarian carcinoma, targeted human T cells cause the rapid removal of most tumor cells from the peritoneum, and markedly prolong the times of survival of treated mice. The efficacy of targeted T cells for treating human cancer is currently being tested in clinical trials.

Highly sensitive enzyme-linked immunosorbent assay for marograstim (KW-2228), a mutant of human granulocyte colony-stimulating factor

An enzyme-linked immunosorbent assay (ELISA) for marograstim (KW-2228) was established. This ELISA proved to be highly sensitive with the detection limit of 0.01 ng/ml (about 0.5 fmol/ml) of KW-2228 and the assay range between 0.01 and 2 ng/ml. When 0.02 to 2 ng/ml of KW-2228 added to human plasma was determined, the variation coefficiencies of intra-day and inter-day assays were 0.4 to 7.6% and 5.2 to 15.8%, respectively, with good recoveries. These results indicate that this ELISA will be applicable to pharmacokinetic studies on KW-2228. With respect to the specificity, recombinant human granulocyte colony-stimulating factor (rhG-CSF) produced in Escherichia coli as well as KW-2228 which does not have sugar chains in its structure showed slightly less immunoreactivity toward the antibody raised against KW-2228. The rhG-CSF produced in Chinese hamster ovary cells (CHO) having sugar chains showed the lower immunoreactivity. The antigenic domains of KW-2228 were evaluated using a number of variants of hG-CSF. The variants having different amino acids from KW-2228 in the 1st to 5th residue of the N-terminus showed almost equal immunoreactivities to KW-2228. The immunoreactivities of the variants lacking 7 to 18 amino acids of N-terminus were less than 50% of that of KW-2228. No immunoreactivity was observed for the variants deleted in the area of 70th to 130th amino acids from the N-terminus. In addition, the immunoreactivity of a variant lacking the 10 amino acids from the C-terminus was 20% of that of KW-2228.(ABSTRACT TRUNCATED AT 250 WORDS)

An anti-doxorubicin monoclonal antibody modulates kinetic and dynamic characteristics of the drug

A monoclonal antibody (MAb) directed against doxorubicin (DXR), denominated MAD II, was found to exert an antidotal action by modulating the kinetic and dynamic characteristics of the drug. In vitro, MAD II has been found to reduce the cytotoxicity of DXR and the drug uptake on spleen lymphocytes more efficiently than on tumor cells (P388 leukemia cells). In vivo, the anti-DXR MAb modified the drug distribution; the drug uptake was found to be reduced in the intestine and myocardial tissues and increased in the tumor, liver and spleen. In mice treated with DXR, the administration of anti-DXR MAb exerted an antidotal activity which was proved by the reduction in body-weight loss and mortality. In contrast, the therapeutic efficacy of the drug in P388-tumor-bearing mice was not influenced by the anti-DXR MAb.

An enzyme immunoassay for determining plasma concentrations of didemnin B

Didemnin A was conjugated at the amino terminus of the N-methylleucine residue, via the linkers N-succinimidyl-3-(2-pyridyldithio)-propionate and trans-1,4-maleimidomethyl-cyclohexane carboxylic acid, to keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA). The didemnin-KLH conjugates were used to hyperimmunize rabbits. The resulting high titer antisera were employed with didemnin-BSA conjugate-coated microtiter plate wells to develop an indirect competitive inhibition enzyme immunoassay (CIEIA) that was fully cross reactive with didemnin B. A CIEIA is described that is capable of detecting the drug in plasma from didemnin B-treated patients at concentrations down to 1-3 ng/ml. This simple, sensitive CIEIA has been employed to demonstrate plasma drug clearance profiles with samples from didemnin B-treated patients.

B30-MDP, a synthetic muramyl dipeptide derivative for tumour vaccination to enhance antitumour immunity and antimetastatic effect in mice

The effect of a muramyl dipeptide derivative (B30-MDP) on the augmentation of antitumour immunity against highly metastatic L5178Y-ML25 mouse lymphoma cells was examined in CDF1 (Balb/c x DBA/2) mice. Mice immunized with a mixture of X-irradiated tumour cells (10(3)) and B30-MDP (100 micrograms) on 7 days prior to challenge by viable tumour cells displayed a significant decrease in metastasis towards the target organs, liver and spleen, compared with that of untreated mice. Immunization of mice with the mixture on day 5 or 7 after tumour challenge, when the level of glutamic-pyruvic transaminase (GPT) and glutamic-oxaloacetic transaminase (GOT) in sera of mice inoculated with viable tumour cells was observed to be normal, caused less metastasis than immunization with X-irradiated tumour cells alone. Sensitization with X-irradiated tumour cells admixed with B30-MDP induced almost two times higher cytotoxicity of spleen cells against L5178Y-ML25 lymphoma cells than sensitization with X-irradiated tumour cells without B30-MDP. In contrast, cytotoxic activity of spleen cells against another target, L1210 lymphoma cells derived from BDF1 mice, was not observed by immunization with X-irradiated L5178Y-ML25 cells with or without B30-MDP. Specific lysis by splenic cells of the immunized mice against L5178Y-ML25 cells decreased to the normal level when T cells were deleted from the immunized spleen cells by the treatment of rabbit anti-mouse Thy1.2 antibody and rabbit complement. These results indicate that B30-MDP is able to augment a specific tumour immunity due to the enhancement of cytotoxicity mediated by T lymphocytes, and is useful as an immunopotentiating agent for active immunization of inactivated tumour cells.