Mucocutaneous inflammation in the Ikaros Family Zinc Finger 1-keratin 5-specific transgenic mice.

BACKGROUND: Our genomewide association study documented an association between cold medicine-related Stevens-Johnson syndrome/toxic epidermal necrolysis (CM-SJS/TEN) and Ikaros Family Zinc Finger 1 (IKZF1). Few studies examined biological and pathological functions of IKZF1 in mucosal immunity. We hypothesized that IKZF1 contributes to the mucocutaneous inflammation. METHODS: Human skin and conjunctival tissues were obtained for immunohistological studies. Primary human conjunctival epithelial cells (PHCjECs) and adult human epidermal keratinocytes (HEKa) also used for gene expression analysis. We also generated K5-Ikzf1-EGFP transgenic mice (Ikzf1 Tg) by introducing the Ik1 isoform into cells expressing keratin 5, which is expressed in epithelial tissues such as the epidermis and conjunctiva, and then examined them histologically and investigated gene expression of the epidermis. Moreover, Ikzf1 Tg were induced allergic contact dermatitis. RESULTS: We found that human epidermis and conjunctival epithelium expressed IKZF1, and in PHCjECs and HEKa, the expression of IKZF1 mRNA was upregulated by stimulation with polyI:C, a TLR3 ligand. In Ikzf1 Tg, we observed dermatitis and mucosal inflammation including the ocular surface. In contact dermatitis model, inflammatory infiltrates in the skin of Ikzf1 Tg were significantly increased compared with wild type. Microarray analysis showed that Lcn2, Adh7, Epgn, Ifi202b, Cdo1, Gpr37, Duoxa1, Tnfrsf4, and Enpp5 genes were significantly upregulated in the epidermis of Ikzf1 Tg compared with wild type. CONCLUSION: Our findings support the hypothesis that Ikaros might participate in mucocutaneous inflammation.

Intracellular glutathione redox status in human dendritic cells regulates IL-27 production and T-cell polarization.

BACKGROUND: Glutathione redox status, changes in intracellular reduced (GSH) or oxidized (GSSG) glutathione, plays a significant role in various aspects of cellular function. In this study, we examined whether intracellular glutathione redox status in human dendritic cells (DCs) regulates the polarization of Th1/Th2 balance. METHODS: Human monocyte-derived DCs (MD-DCs) treated with glutathione reduced form ethyl ester (GSH-OEt) or L-buthionine-(S,R)-sulfoximine (BSO) were stimulated by lipopolysaccharide (LPS), and the levels of polarization cytokines were measured. Next, DCs matured by LPS or thymic stromal lymphopoietin (TSLP) were cocultured with allogeneic CD4(+) naive T cells and Th1/Th2 balance was evaluated by cytokine production from the primed T cells. RESULTS: Monocyte-derived DCs exposed to GSH-OEt and BSO had increased and decreased intracellular GSH contents, respectively. Lipopolysaccharide-induced interleukin (IL)-27 production was enhanced by GSH-OEt and suppressed by BSO, but neither GSH-OEt nor BSO affected the expression of HLA-DR, CD80, CD83, or CD86. Mature GSH-OEt-treated MD-DCs enhanced interferon (IFN)-γ production from CD4(+) T cells compared with nontreated MD-DCs, and small interfering RNA (siRNA) against IL-27 suppressed the effect of GSH-OEt on IFN-γ production. Additionally, although human myeloid DCs activated by TSLP (TSLP-DCs) prime naïve CD4(+) T cells to differentiate into Th2 cells, treatment of TSLP-DCs with GSH-OEt reduced IL-13 production and enhanced IFN-γ production by CD4(+) T cells. Interleukin-27 siRNA attenuated the inhibitory effect of GSH-OEt on Th2 polarization. CONCLUSION: Our results reveal that Th1 and Th2 responses are controlled by intracellular glutathione redox status in DCs through IL-27 production.

Basophils in the giant papillae of chronic allergic keratoconjunctivitis.

AIMS: The essential role of basophils as an initiator of chronic allergic reaction has been elucidated in mouse models. The aim of this present study was to analyse the in situ immunolocalisation of basophils and other relevant inflammatory cells in chronic allergic keratoconjunctivitis. METHODS: Transmission electron microscopic (TEM) analysis was carried out to examine the existence of basophils in the giant papillae obtained from atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC) patients. Cryostat sections of giant papillae were immunostained with basophil-specific antibody BB-1, and with anti-CD4, anti-CD8, anti-CD20, anti-major basic protein (MBP), anti-IgE and anti-FcepsilonRI-beta antibodies. RESULTS: TEM analysis confirmed the existence of basophils in the giant papillae. Small clusters of basophils were observed in the substantia propria of giant papillae, especially at the vicinity of vascular endothelium and subepithelial regions. BB-1-positive basophil clusters were surrounded by T cells, B cells, IgE-positive cells and MBP-positive eosinophils. No BB-1-positive basophils were observed in the control conjunctivae. CONCLUSION: Basophils may infiltrate from either vascular endothelium into the giant papillae. The existence of basophils at the centre of inflammatory cells suggests the role of basophils as an initiator of chronic allergic conjunctivitis.

Association of Fas Ligand gene polymorphism with Stevens-Johnson syndrome.

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are acute severe blistering diseases of the skin and also two of the most devastating ocular surface diseases leading to corneal damage and loss of vision. The extreme rarity of cutaneous and ocular surface reactions to drug therapies led us to suspect individual susceptibility. SJS/TEN patients in the acute stage were reported to manifest increased serum levels of Fas Ligand (FasL). Thus, we performed SNP association analysis of the FasL gene. METHODS: In 76 Japanese SJS/TEN patients with ocular surface complications and 160 Japanese healthy controls, we examined four SNPs of FasL reported in the Japanese Single Nucleotide Polymorphisms (JSNP) database by sequencing. RESULTS: The SNP rs.3830150 A/G showed a significant strong inverse association with SJS/TEN. Analysis of the genotype pattern of SNPs rs.3830150 and rs.2639614 (rs.3830150 A/A-rs.2639614 G/G) also manifested a strong inverse association with SJS/TEN. CONCLUSION: FasL gene polymorphisms might be associated with SJS/TEN.

Human conjunctival epithelial cells express functional Toll-like receptor 5.

PURPOSE: The expression and function of Toll-like receptor 5 (TLR5) was analysed in human conjunctival epithelial cells (HCjEC). METHODS: The expression of TLR5 in HCjEC was studied by reverse transcriptase (RT) PCR and flow cytometry. The amount of interleukin (IL) 6 and IL-8 proteins was determined by ELISA. Messenger RNA expression elicited by stimulation with flagellins derived from Pseudomonas aeruginosa, Serratia marcescens, Salmonella typhimurium, and Bacillus subtilis was assayed by quantitative RT-PCR. The localisation of TLR5 protein in human conjunctival epithelium was detected immunohistochemically. RESULTS: HCjEC expressed TLR5-specific mRNA and TLR5 protein. In HCjEC stimulated with flagellins derived from P. aeruginosa and S. marcescens, IL-6 and IL-8 production was increased and IL-6 and IL-8 mRNA was upregulated. Flagellins from S. typhimurium and B. subtilis did not induce the upregulation of these genes and proteins. TLR5 protein was detected on the basolateral but not the apical side of human conjunctival epithelium. CONCLUSIONS: Human conjunctival epithelium harbours functional TLR5. Considering the spatially selective basolateral localisation of TLR5 protein, it was postulated that flagellins from ocular pathogenic bacteria induce inflammatory responses when disruption of the epithelial barrier permits their transmigration to the basolateral side but not under healthy physiological conditions on the ocular surface.

Suppression of tumor growth by intra-muscular transfer of naked DNA encoding adrenomedullin antagonist.

We have recently reported that the intra-tumoral injection of adrenomedullin (AM) antagonist (AMA; AM (22-52)) peptides significantly reduced the in vivo growth of a pancreatic cancer cell line in severely combined immunodeficient (SCID) mice. In the present study, we examined the effects of intra-tumoral and intra-muscular transfers of naked DNA encoding AMA on the in vivo growth of cancer cell lines. We demonstrate that these treatments induce the regression of a pancreatic cancer cell line and a breast cancer cell line inoculated in SCID mice. Furthermore, CD31-positive cells disappear completely from tumor tissues, following treatment, indicating that neo-vascularization is entirely inhibited. These results suggest that the intra-tumoral or intra-muscular transfer of naked DNA encoding AMA might be a promising alternative modality for treating human cancers.

Regulation of LPS induced IL-12 production by IFN-gamma and IL-4 through intracellular glutathione status in human alveolar macrophages.

Interleukin-12 (IL-12) is secreted from monocytes and macrophages; it exerts pleiotropic effects on T cells and natural killer (NK) cells, and stimulates interferon-gamma (IFN-gamma) secretion. Glutathione tripeptide regulates the intracellular redox status and other aspects of cell physiology. We examined whether IFN-gamma and IL-4 affect the balance between intracellular reduced glutathione (GSH) and oxidized (GSSG) glutathione, as this may affect IL-12 production in human alveolar macrophages (AM). We used both AM from healthy non-smokers obtained by bronchoalveolar lavage and the monocytic THP-1 cell line in this study. Incubation of AM for 2 h with the GSH precursor N-acetylcysteine (NAC) increased the intracellular GSH/GSSG ratio, and enhanced lipopolysaccharide (LPS)-induced IL-12 secretion by AM. In THP-1 cells, NAC increased the GSH/GSSG ratio and the expression of LPS-induced IL-12 mRNA, whereas L-buthionine-[S,R]-sulphoximine (BSO) decreased these. NAC and BSO offset their own effects on the intracellular GSH/GSSG ratio and the expression of LPS-induced IL-12 mRNA. Furthermore, exposure of AM to the helper T cell type 1 (Th1) cytokine IFN-gamma or the helper T cell type 2 (Th2) cytokine IL-4 for 72 h increased and decreased the GSH/GSSG ratio, respectively. Lipopolysaccharide (LPS)-induced secretion of IL-12 in AM was enhanced by IFN-gamma but inhibited by IL-4. These results suggest that IFN-gamma and IL-4 oppositely affect the GSH/GSSG balance, which may regulate IL-12 secretion from AM in response to LPS.

Abundant expression of common cytokine receptor gamma chain (CD132) in rheumatoid joints.

OBJECTIVE: Activated macrophages upregulate surface expression of common cytokine receptor gamma chains (gammac, CD132), triggering of which induces secretion of proinflammatory cytokines. Rheumatoid synovial tissues contain a number of macrophages that play a pathogenic role by secreting proinflammatory cytokines. We studied the expression of gammac in the rheumatoid synovial tissues. METHODS: Cryosections of synovial tissues from patients with active rheumatoid arthritis (RA) or with osteoarthritis (OA) were stained with an anti-gammac Mab. Single-cell suspensions from the rheumatoid synovial tissues were stained with the same antibody and an anti-CD14 monoclonal antibody (Mab) for 2-color flow cytometric analysis. A soluble form of gammac in synovial fluids collected from rheumatoid or OA joints was quantitated by ELISA. RESULTS: Rheumatoid synovial tissues, but not the OA tissues, expressed gammac at a high level. Flow cytometric analysis showed that gammac were expressed by virtually all CD 14 positive synovial cells in RA. Synovial fluid derived from the rheumatoid joints contained a high concentration of soluble gammac. CONCLUSION: Membrane bound and soluble forms of gammac are abundant in rheumatoid joints. They might play a complex role in the pathology of RA.

Identification of natural antigenic peptides of a human gastric signet ring cell carcinoma recognized by HLA-A31-restricted cytotoxic T lymphocytes.

Peptides of human melanomas recognized by CD8+ CTLs have been identified, but the nature of those of nonmelanoma tumors remains to be elucidated. Previously, we established a gastric signet ring cell carcinoma HST-2 and HLA-A31 (A*31012)-restricted autologous CTL clone, TcHST-2. In the present study, we determined the natural antigenic peptides of HST-2 cells. The purified preparation of acid-extracted Ags was submitted to the peptide sequencer, and one peptide, designated F4.2 (Tyr-Ser-Trp-Met-Asp-Ile-Ser-Cys-Trp-Ile), appeared to be immunogenic. To confirm the antigenicity of F4.2 further, we constructed an expression minigene vector (pF4.2ss) coding adenovirus E3, a 19-kDa protein signal sequence plus F4.2. An introduction of pF4.2ss minigene to HST-2 and HLA-A31(+) allogeneic tumor cells clearly enhanced and induced the TcHST-2 reactivity, respectively. Furthermore, when synthetic peptides of F4.2 C-terminal-deleted peptides were pulsed to HST-2 cells, F4.2-9 (nonamers), but not F4.2-8 or F4.2-7 (octamer or heptamer, respectively), enhanced the reactivity of TcHST-2, suggesting that the N-terminal ninth Trp might be a T cell epitope. This was confirmed by lack of antigenicity when using synthetic substituted peptides as well as minigenes coding F4.2 variant peptides with Ala or Arg at the ninth position of F4.2. Meanwhile, it was indicated that the sixth position Ile was critically important for the binding to HLA-A31 molecules. Thus, our data indicate that F4.2 may work as an HLA-A31-restricted natural antigenic peptide recognized by CTLs.

Improvement of erythroid toxicity by lentinan and erythropoietin in mice treated with chemotherapeutic agents.

Lentinan, an antitumor polysaccharide, has been assessed for its potential in vivo to augment erythroid progenitor cells and protect them from the cytotoxic effects of antitumor chemotherapeutics. Lentinan augmented the level of burst-forming units-erythroid (BFU-E) and accelerated the recovery of the reduced number of BFU-E in mice treated with 5-fluorouracil (5-FU); lentinan did not influence red blood cell counts or colony-forming unit-erythroid (CFU-E) numbers in the femoral marrow. A significant decrease in stem cell inhibitory factor (SCIF) activities in bone marrow and an increase in colony-forming unit-spleen (CFU-S) formation were observed in the lentinan-treated mice. The mechanism of augmented BFU-E formation may be partly due to augmented production of stem cells, giving rise to both CFU-GM and BFU-E. Furthermore, when lentinan administration was followed by administration of erythropoietin (Epo) in 5-FU-treated mice, increases in femoral marrow and splenic CFU-E formation and augmentation of reticulocyte counts were observed beyond the level observed in mice treated with Epo alone. These results suggest that lentinan may augment the effects of Epo on erythropoiesis in the course of anemia and the decreased erythropoiesis in cancer patients receiving chemotherapy.

Cancer cell progression and chemoimmunotherapy--dual effects in the induction of resistance to therapy.

To determine whether resistance to chemoimmunotherapy is acquired during therapy, we investigated the effects of chemotherapeutic agents and anti-tumour polysaccharide, lentinan, on the progression of Rous sarcoma virus-induced S908.D2 fibrosarcomas. The chemoimmunotherapy was effective against the parental S908.D2-bearing mice. Nearly all the mice that were treated with cyclophosphamide (CY) and lentinan achieved complete tumour regression. Only a few of the mice that achieved complete regression of the primary tumours showed a recurrence of the tumour in regional lymph nodes. S908.D2-vp.1 was established from metastatic tumours that developed in the regional lymph nodes of parental S908.D2-bearing mice during therapy. S908.D2-vp.2-or vp.3 cells were sequentially derived in a similar way from S908.D2-vp.1-or-vp.2-bearing mice respectively, in which complete tumour regression at each primary site was achieved during therapy. These lines acquired resistance to CY and lentinan and also to 5-fluorouracil (5-FU)/5'-deoxy-5-fluorouracil and lentinan. No significant difference in either the sensitivity to 5-FU or 4-deoxycyclophosphamide in vitro or in the susceptibility to immune effector cells was observed between the parental and progressed lines (S908.D2-vp1 -vp3). There was an increase in the level of prostaglandin E2 (PGE2) in the progressed lines during repeated therapy (parental, 1171 pg ml(-1); vp.1, 2199 pg ml(-1); vp.2, 5500pg ml(-1); vp3, 16187 pg ml(-1)). There was no significant increase in the production of transforming growth factor beta (TGF-beta). The amount of interleukin-2 (IL-2) produced by spleen cells isolated from the S908.D2-vp.2-bearing mice was decreased compared with the amount produced by the parental S908.D2- bearing mice. Furthermore, combination therapy with lentinan and IL-2 achieved complete tumour regression in all the mice transplanted with S908.D2 progressed tumour lines, although IL-2 alone did not show any anti-tumour effects in either the S908.D2 parental or progressed lines. The findings suggest that the reduced production of IL-2 induced an increase in the production of the PGE2 by progressed tumour lines is involved in the acquisition of resistance.

Sensitive enzyme-linked immunosorbent assay for adult T-cell leukemia-derived factor and normal value measurement.

Four different monoclonal antibodies against recombinant adult T-cell leukemia-derived factor (ADF), identical to thioredoxin, were established and used for the determination of ADF concentration in serum. Using two of the monoclonal antibodies, we developed a two-step enzyme-linked immunosorbent assay (ELISA) for ADF. This ELISA showed a highly specific reactivity on ADF with no cross-reactivity to several proteins with homologue sequence on the active center. The detection limit of the assay was 2.0 ng/ml (mean +/- 2 SD). The intra- and interassay coefficients of variation (CV) were 0.81-3.74% (n = 8) and 4.78-6.97% (n = 7), respectively. The normal value of ADF mean concentration from 145 healthy donors was 40.8 ng/ml.

Lentinan augments skin reaction induced by bradykinin: its correlation with vascular dilatation and hemorrhage responses and antitumor activities.

The effects of lentinan, an antitumor polysaccharide, on vascular reactions against vasoactive mediators were investigated in murine systems. Lentinan augmented intradermal reactions against bradykinin. Induction of acute phase proteins (APP) and the vascular dilatation hemorrhage (VDH) reaction on the ears have been reported to reflect the host responses to lentinan. The strain difference in the intensity of skin reactions coincided with those observed in VDH responses and with lentinan-induced antitumor effects against Sarcoma 180. Augmentation of skin reactions was not observed in T-cell-deficient mice. Inhibitors of lipoxygenase, thrombin and plasmin which reduced skin reactions also decreased the incidence of tumor necrosis positive mice among FBL-3-bearing mice treated with lentinan. Furthermore, B10D2 mice treated with fluorouracl (5-FU) and lentinan 10 days after S908.D2 transplantation showed complete tumor regression and augmented skin reactions, whereas augmentation of skin reactions and tumor regression were not observed in mice treated with 5-FU and lentinan 32 days after tumor inoculation. Taken together, these results suggest that these vascular reactions might play crucial roles in antitumor effects of lentinan and that the skin reaction, the convenient method for investigating vascular reactions, is a promising tool to monitor host sensitivity to lentinan in antitumor responses.

Synergistic antimetastatic effects of lentinan and interleukin 2 with pre- and post-operative treatments.

The antimetastatic activity of a combination of lentinan and interleukin 2 (IL-2) was evaluated against spontaneously metastatic 3-methylcholanthrene-induced DBA/2.MC.CS.T fibrosarcoma. Although pre-operative treatment with either IL-2 or lentinan alone exerted little effect on the reduction of lung metastasis colony numbers (7.1% or 28.4% reduction, respectively), the combination exhibited a synergistic effect (85% reduction). Furthermore, 3 of 13 mice given the pre-operative combination treatment achieved complete cure, while no mice given saline did. Although the post-operative combination treatment also reduced the colony number (71% reduction), it caused little prolongation of survival and no mouse achieved complete cure. Synergistic effects were observed between pre- and post-operative treatments with lentinan and IL-2: 8 of 12 mice were completely cured. The anti-metastatic activity was abolished in mice treated simultaneously with antibodies to CD4 and CD8 antigens, whereas either CD4, CD8, or NK1.1 antibody alone was ineffective. Analysis of the cellular mechanism involved in the antimetastatic activity revealed the involvement of a tumor-associated antigen-specific delayed-type hypersensitivity response. These data suggest that the life-prolonging effect of the combination of lentinan and IL-2 is mediated by antigen-specific T cells and that the combination of pre- and post-operative therapy with lentinan and IL-2 may be effective to prevent cancer recurrence and metastasis after surgical resection.

[Study on intratumor administration of lentinan--primary changes in cancerous tissues].

Lentinan was administered for gastric cancer in order to determine what type of changes would occur as a consequence. In an experimental study, the intraperitoneal administration of lentinan on cancerous tissues caused a marked development of reticular fibers, along with an enhanced interstitial response. Findings which support the relationship between a marked development of reticular fibers and an anti-tumor effect, were also obtained. Furthermore, lentinan was administered for human gastric cancer to evaluate whether or not an increase in interstitial response would be observed. As a result, reticular fibers developed in tumor sites with a resultant fragmentation of cancer cell nests. Many T lymphocytes infiltrated cancer sites where the lentinan was administered. These findings suggest that the intratumor administration of lentinan enhanced an interstitial response and also activated an anti-tumor immune response in the human gastric cancer tissues.

Antitumor and immunological activity of lentinan in comparison with LPS.

Lentinan manifests marked antitumor and antimetastatic activity in numerous tumor/host systems, and prevents chemical and viral carcinogenesis. Modulation of immune or vascular functions by lentinan is involved in its antitumor effects. The impact of lentinan on the functions of macrophages is distinct from that of LPS. One of the effects of lentinan on the vascular system is the vascular dilatation and hemorrhage (VDH) reaction, and the effect can be monitored as augmented skin reactions to vasoactive mediators. Lentinan induces the VDH-like reaction at the tumor site, resulting in the induction of hemorrhagic necrosis and complete regression of the tumor. In contrast to LPS-induced tumor necrosis (Shwartzman's-like reaction), lentinan-induced tumor necrosis is T-cell dependent.

Reconstitution of anti-tumor effects of lentinan in nude mice: roles of delayed-type hypersensitivity reaction triggered by CD4-positive T cell clone in the infiltration of effector cells into tumor.

Lentinan, an antitumor polysaccharide used clinically in Japan, requires the intact T cell compartment to manifest its antitumor effects. The aim of the current study was to clarify the mechanisms playing crucial roles in the T cell requirement in the expression of antitumor effects of lentinan. Lentinan treatment of BDF1 mice transplanted intradermally with FBL-3 induced complete tumor regression and a marked increase in survival time. The antitumor action of lentinan was abolished in mice treated simultaneously with antibodies to CD4 and CD8 antigens, whereas antibody to CD4, CD8 or NK1.1 alone was ineffective. The natural killer, cytotoxic T lymphocyte, and helper T cell activities were already augmented in this FBL-3/BDF1 system and thus further augmentation of these activities by lentinan was not observed. These activities did not correlate with the antitumor activity of lentinan, as was confirmed in lymphocyte subset depletion experiments. On the contrary, the delayed-type hypersensitivity (DTH) response against tumor-associated antigens was triggered by lentinan and was abrogated only in mice treated simultaneously with antibodies to CD4 and CD8 antigens. Furthermore, a non-cytolytic tumor-associated antigen-specific CD4+ T cell clone able to induce the DTH response in concert with lentinan reconstituted the antitumor effects in B6 nude mice when administered with lentinan. These results suggest that, in addition to the augmentation of immune effector cell activity against tumors, infiltration of these cells into the tumor burden initiated by the DTH responses at tumor sites may be involved in eradication of tumors by lentinan.

Curative effects of combination therapy with lentinan and interleukin-2 against established murine tumors, and the role of CD8-positive T cells.

The antitumor activity of a combination of an antitumor polysaccharide, lentinan (a beta 1-3 glucan with beta 1-6 branches), and interleukin-2 (IL-2) was evaluated against established MBL-2 lymphoma and S908.D2 sarcoma at i.d. sites. Treatment of the MBL-2-tumor-bearing BDF1 mice with lentinan and IL-2 induced complete regression of tumor in 87.5% of mice treated. In contrast, treatments using either lentinan or IL-2 alone failed to induce complete regression of tumor, although temporal growth inhibition of tumor was observed about in half of the mice treated. Improvements of antitumor effects by the combination of lentinan and IL-2 were also observed in the MBL-2/B6 and S908.D2/B10.D2 systems. Expression of the antitumor effects of lentinan/IL-2 treatments required the intact T cell compartment, because the effects were not observed when nude mice were used. In the MBL-2/B6 system, the antitumor action of lentinan/IL-2 treatment was abolished in mice treated with antibody to CD8 antigen, whereas antibodies to CD4 or NK1.1 were ineffective. Furthermore, augmented tumor-specific cytotoxic T lymphocyte (CTL) activity was observed in regional lymph node cells of the mice after lentinan and IL-2 administration. These data indicate that the antitumor effects of lentinan/IL-2 are mediated by CD8+ CTL but not by CD4+ T cells or NK1.1+ NK/LAK cells, and suggest that this combined therapy may be effective against even established tumors that are resistant to IL-2 therapy.

The analysis of internal image-bearing anti-idiotypic monoclonal antibody in relation to carcinoembryonic antigen.

Five anti-Id mAb (Ab2) were prepared from a BALB/c mouse immunized with anti-carcinoembryonic Ag (CEA) mAb MA208 (Ab1) in a syngeneic system. These anti-Id mAb appear to recognize unique idiotopes at the combining site of mAb MA208, because they were specifically reactive with mAb MA208 and showed the inhibitory activity against the binding of mAb MA208 to CEA. These anti-Id mAb were divided into three groups: group 1 (M7-625), group 2 (M7-413, M7-914), and group 3 (M7-049, M7-418), according to the analysis of anti-anti-Id antibodies (Ab3) induced with each anti-Id mAb (Ab2). Anti-anti-Id mAb M7-625 antisera (Ab3) reacted with purified CEA in binding assay and in Western blot analysis, and competed with Ab1 binding to CEA. Furthermore, the binding of anti-Id mAb M7-625 (Ab2) to mAb MA208 (Ab1) was inhibited with CEA, indicating that Ab2 mimicks the structure of the epitope in CEA which was recognized with Ab1. These serologic findings suggest that anti-Id mAb M7-625 carries the internal image of the Ag. According to the amino acid sequences of CDR 1, 2, and 3 of the mAb M7-625 variable region, there exists a homology of amino acid sequences between CDR2 in the H chain (5 amino acids of 10) and CDR3 in the L chain (3 amino acids of 9) of mAb M7-625 and domain III of CEA (545-554).