[Evaluation of micro enzyme immunoassay technique (MEIA) for the demonstration of hepatitis B surface antigen]

The new Micro Particle Enzyme Immunoassay technique (MEIA, IMx HBsAg, Abbott) has been recently introduced for the detection of the presence of hepatitis B surface antigen (HBsAg). The present trial was carried out to determine the feasibility of using the IMx HBsAg with sera and plasma, and for comparison with RIA (Ausria II, Abbott) and RPHA (Reversecell, Megroken). Results obtained were as follows: In the test of 622 sera from inhabitants in Okinawa, 455 (73.1%) using IMx were positive for HBsAg, 454 (73.0%) with RIA, and 330 (53.0%) with RPHA. Five of the 179 tests using plasma from hemodialysis patients were positive for HBsAg with both IMx and RIA. One of these 5 was negative for HBsAg with RPHA. The difference of HBsAg positive rates between IMx and both RIA and RPHA increased with advancing age. Twenty four individuals were followed up from three to ten years and had had it confirmed that HBsAg had become negative in their sera, HBsAg was still positive from one to four years in both IMx and RIA after HBsAg became negative in RPHA. It was noted that HBsAg was assayed within one hour by IMx, and that the procedure was simple because of the autoanalyser equipped for this method. The results indicate that the sensitivity of IMx might be equal to that of RIA more than that of RPHA, and easier to measure than either of the others.

Marked decrease of hepatitis B virus infection among children in Okinawa, Japan

During the period 1980-1989 in Okinawa, Japan, serologic markers of hepatitis B infection (hepatitis B surface antigen; HBsAg, antibody to hepatitis B core antigen; anti-HBc) were investigated in nursery school children (1-4 years of age). Prevalences of HBsAg were 1.1-1.5% in the period from 1980-1984, but decreased to under 1.0% in the period from 1985. In 1989 there were two carriers in nursery schools, both born in 1985 or fathers who were HBsAg carriers. Prevalences of anti-HBc were 3.3-7.1% in the period from 1980-1983 with a decrease to 0.5% by 1988. Since hepatitis B vaccine was available for neonates whose mothers were HBsAg carriers with hepatitis Be antigen (HBeAg) and for nursery school children in 1983, hepatitis B virus infection among nursery school children and HBsAg carriers due to transmission from mother-to-child were markedly reduced. This strategy for immunization is useful in endemic areas. Immunization for children whose fathers are HBsAg carriers may also be necessary.

Frequency of concurrence of hepatitis B surface antigen and antibody in a large number of carriers in Okinawa, Japan

A large number of chronic hepatitis B surface antigen (HBsAg) carriers in Okinawa, Japan were tested for antibody to HBsAg (anti-HBs), by both radioimmunoassay and enzyme immunoassay methods. Concurrence of HBsAg and anti-HBs was found in 166 (26.1%). We found no clear predominance of either liver damage or hepatitis B e antigen (HBeAg) in the concurrent carriers studied. Antibody to pre-S2 antigen (anti-pre-S2) was detected in 16 (9.6%) of 166 subjects with concurrent markers, 15 of these 16 carriers were positive for antibody to HBeAg (anti-HBe). Anti-pre-S2 was correlated with anti-HBe rather than with anti-HBs. The distribution of HBsAg subtypes among carriers determined to have subtypes was 76.7% adw, 22.0% adr, 0.2% ayr, 0.9% adwr, and 0.2% adyr. The distribution of anti-HBs subtypes among concurrent carriers was 51.5% anti-r, 21.4% anti-w, 15.5% anti-d, and 10.7% anti-y. Concurrent carriers had HBsAg of one subtype and heterotypic anti-HBs. Because the HBsAg subtype ay is rare in this area, it is hard to believe that the concurrent carriers with anti-y were infected with hepatitis B virus of which the HBsAg subtype was ay. A dual infection was highly unlikely. It seems that some of the concurrent carriers correlate with compound subtypes adwr and adyr.

Developmental changes of tropoelastin synthesis by rat pulmonary fibroblasts and effects of dexamethasone

Lung elastin is an important extracellular structural protein and it has been postulated that it plays a regulatory role in alveolar formation. To study the developmental regulation of elastin gene expression, we examined the tropoelastin (TE) production in primary culture of rat pulmonary fibroblasts (RPF). We found that developmental changes in elastin production as assessed by TE synthesis and 3.6-kb TE mRNA levels were similar for RPF and whole tissue except those results from late gestation animals, with peak elastin expression occurring 7 d postnatally with a decline out to 21 d. At late gestation (20 d), TE mRNA was barely detectable in RPF but clearly detectable TE mRNA in the whole tissue, indicating that there are elastogenic cells other than RPF in the tissue at this age. When TE-producing cells were treated with dexamethasone, there was a dose-dependent stimulation of TE synthesis with the maximum response at 10(-9) to 10(-7) M. Interestingly, dexamethasone had no stimulatory effect on cells from late gestation animals. The developmental window of elastin synthesis in this RPF model between late gestation and 21 d postnatal seems to correlate with the reported period of secondary alveolar formation, and thus we speculate that RPF elastogenic activity reflects that of the alveolar wall.

Polyethylene glycol modification of the monoclonal antibody A7 enhances its tumor localization

The F(ab')2 fragment of murine monoclonal antibody A7 was covalently bonded to polyethylene glycol (PEG, molecular weight: 5000) and the conjugate was compared to the parent F(ab')2 fragment by in vitro and in vivo studies. PEG-conjugated antibody fragment retained its antigen-binding activity in a competitive radioimmunoassay. The conjugate had a longer half-life and showed increased accumulation in tumors. Although the tumor: blood ratio for parent F(ab')2 fragment was higher than that for the conjugate, it showed higher value than whole MAb A7. The tissue: blood ratios were kept low with the conjugate, indicating that the conjugate was uptaken to normal organ with lesser extent, as compared with parent F(ab')2 fragment. Our findings indicate that this PEG-conjugated F(ab')2 fragment could be a promising carrier for use in targeting cancer chemotherapy.

[Immunoresponses and efficacy after arterial infusion of immunoconjugate A7-NCS in patients with colon cancer]

We prepared an immunoconjugate, A7-NCS, of a mouse-derived anti-human colon cancer monoclonal antibody A7 and the macromolecular protein anticancer agent neocarzinostatin (NCS), and evaluated changes in human anti-mouse antibody (HAMA) by ELISA in the serum of patients intraarterially administered this agent. IgG and IgM class HAMA were detected in all patients, but no IgE class HAMA. In patients with stage V disease, the survival rate was higher in a group treated with A7-NCS at an NCS dose of 4,000 units or more than in that treated at an NCS dose of less than 4,000 units. In these patients, the survival rate was higher in a group treated with A7-NCS at an NCS dose of 4,000 units or more than in one not treated with it. These results suggest the usefulness of A7-NCS administration at high dose for prolonging survival of patients with advanced colon cancer.

[An epidemiologic study of anti-ATLA (antibody to adult T-cell leukemia-associated antigen) by category of disease in the Karatsu and Higashimatsuura districts of northern Kyusyu by enzymeimmunoassay]

The Kyusyu district is known as an endemic area of HTLV-I. But the prevalence of anti-ATLA in Saga prefecture was reportedly relatively low. In this study, in order to determine the distribution of antibody to ATL-associated antigen (anti-ATLA) in the Karatsu and Higashimatsuura districts of the northern Kyusyu, the determination of anti-ATLA status of patients in Karatsu Red Cross Hospital was carried out from September to October, 1985. Sera from 757 patients were tested for presence of anti-ATLA by Enzyme immunoassay (EIA) prepared by Eisai Co., Ltd. Tokyo, Japan. Results obtained are as follows: 1) Overall prevalence of anti-ATLA was 13.7 per cent (104 of 757 individuals). Prevalence of anti-ATLA increased with age, reaching a maximum of 21.1 per cent for people from 60 to 69 years old. 2) Prevalence of anti-ATLA was 9.5 per cent (36 of 376) in males and 17.8 per cent (68 of 381) in females. A significant difference by sex was recognized. (p less than 0.001) 3) The positive rates of patients with non-malignant diseases were high in the Chinzei, Hizen, and Hamatama areas facing the Sea of Genkai. The positive rate of the seaside area was significantly higher than that of the mountain area. (p less than 0.001). 4) Anti-ATLA was most prevalent in the patients with neoplasms (26.1%). The positive rate of ATL patients was 100 per cent, and that of patients with malignancies other than ATL was 25.9 per cent. These results suggest that HTLV-I infection is likely to increase the incidence of other types of malignancy.

Binding, internalization and the cytotoxicity of monoclonal antibody A7-neocarzinostatin conjugates (A7-NCS) in target cells

To study the mechanism of action of the monoclonal antibody A7-neocarzinostatin conjugates (A7-NCS), the internalization of the antibody and its conjugate into target cells was examined. The incubation of radiolabeled A7 and A7-NCS with target cells revealed that both were taken up by target cells in a time dependent fashion. The immunocytochemical study using anti-NCS also revealed the intracellular localization of the conjugates. The cytotoxicity of the conjugate was markedly reduced when the binding sites were occupied by an excess of antibody on the cell surface. These results showed that A7-NCS was internalized into target cells and that its cytotoxicity was mediated through specific binding and internalization.

[Missile therapy of colorectal and pancreatic cancers--clinical trial of monoclonal antibody, A7-NCS, in 73 patients with colorectal and pancreatic cancers]

Monoclonal antibody-drug conjugate, A7-NCS, was applied for 73 patients with colorectal and pancreatic cancer, including metastasis of liver, lung and peritoneum. Monoclonal antibody A7, from a mouse splenocyte immunized against human colon cancer was bound covalently to Neocarzinostatin (NCS), Mitomycin C (MMC) and Adriamycin (ADM) to form A7-NCS, A7-MMC and A7-ADM, respectively. Fifty-four patients with colon cancer, fifteen patients with postoperative liver metastasis of colorectal cancer and one patient with advanced pancreatic cancer were given A7-NCS intra-arterially. Two patients with postoperative lung metastasis of colon cancer were injected intra-venously and one patient with postoperative peritoneal metastasis of colon cancer was given it intraperitoneally. Three patients with liver metastasis showed evidence of tumor reduction on CT scan and three claimed pain relief. Postoperative survival of the patients with distant metastasis exhibited slightly higher survival rate in the patients with A7-NCS, as compared with the patients without A7-NCS. There was no serious adverse effect in the patients given A7-NCS. Human anti-mouse antibody (HAMA) was detected in all patients given the conjugate. Repeated injections of A7-NCS for several consecutive days following the first injection brought about the same A7 pattern as the first injection.

[An epidemiological study of HBV and HTLV-I among high risk groups in Fukuoka City]

Sera from 69 adult prostitutes, 139 juveniles in the reformatory for boys, and 63 juveniles in the reformatory for girls, were collected between 1986 and 1987 in Fukuoka City. These samples were tested for the presence of antibody to human T-cell leukemia virus type-I (anti-HTLV-I), for hepatitis B surface antigen (HBsAg), and for antibody to hepatitis B core antigen (anti-HBc). The juveniles in the reformatory for girls were surveyed for the incidence of venereal diseases (VD) and for a history of intravenous drug use. Anti-HTLV-I was detected in 5.8% of the prostitutes, 0.7% of the boys, and 1.6% of the girls. Prevalence of anti-HTLV-I among the prostitutes was higher than that among the controls, but no significant difference was recognized. HBsAg was detected in 7.2% of the prostitutes, but was absent in the boys and girls. Prevalence of HBsAg among the prostitutes was higher than that among the controls, but no significant difference was recognized. Anti-HBs was detected in 39.1% of the prostitutes, 10.1% of the juvenile boys, and 17.5% of the juvenile girls. In each group prevalence of anti-HBc was higher than that in the controls. Especially between the prostitutes and the controls a significant difference was recognized (p less than 0.005). In the reformatory for girls anti-HBc was detected in 40.0% of 11 girls who were exposed to VD and in 7.0% of 43 girls who were not exposed to VD. Prevalence of anti-HBc among the exposed group was significantly higher than that among the non-exposed group (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical study of urinary excretion of Ga-67

Ga-67 urinary excretion was examined in 59 patients. The 72-hour urinary excretion rate ranged from 4.3 to 67.8% of the injected dose. Within the first 24 hours, 60.9% of the 72-hour urinary excretion was excreted. There was no significant difference in the Ga-67 urinary excretion rate between males and females, nor between the Ga-67 positive and negative cases. A significant negative correlation was found between the 72-hour Ga-67 urinary excretion rate and the unsaturated iron binding capacity. Notably, four patients with hyperferremia, which was considered secondary to leukemia and/or chemotherapy or liver cirrhosis, excreted more than 46.8% of Ga-67 within 72 hours. A significant negative correlation was also found between the 72-hour Ga-67 urinary excretion rate and age. Urinary excretion of Ga-67 may be related to the glomerular filtration rate, which decreases with age.

Intraoperative cleansing of the impacted colon using an endotracheal tube

A simple technique for intraoperative cleansing of the impacted colon is described. Saline-irrigation through the torn balloon of the endotracheal tube (38 French) and massaging the impacted feces facilitated drainage of the obstructed colon. This technique was done in two emergent colon operations and immediate anastomosis could be performed safely. An endotracheal tube is always available in an operating room, so this technique is useful and effective in an emergent colon operation without special preparation.

Antibody to p40tax protein of human T cell leukemia virus 1 and infectivity

To investigate the physiologic significance of antibody to human T cell leukemia virus type 1 (HTLV-1) tax gene product (p40tax), 147 male and 243 female HTLV-1 carriers were examined for anti-p40tax, and 104 carriers were checked for anti-p40tax an average of 5.4 times during an 8-year period. Prevalence of anti-p40tax was significantly higher in female (62.6%) than in male subjects (51.0%; P less than .05). Anti-p40tax status did not change in most during the observation period. There were significantly more HTLV-1 carriers among children of anti-p40tax-positive mothers (45.3%) than among those from anti-p40tax-negative mothers (20.0%; P less than .01). However, no significant difference was observed between wives of p40tax-positive and -negative men. The p40tax antibody may be a marker of relative infectivity of HTLV-1, albeit an imperfect one.

[Host factors that changes the distribution of immunotoxin]

Mouse monoclonal antibody A 7, which was raised against human colon cancer, was used for preparing the conjugates with neocarzinostatin, mitomycin C and adriamycin. The tissue distribution of these three conjugates were examined in athymic nude mice transplanted with human colon cancer. The distribution in tumor was different in these three conjugates. The route of administration of the conjugate affected its distribution in tumor tissues. In the case of tumor transplanted in the back of mice, intravenous administration seemed to superior to intraperitoneal one. In clinical trials of immunoconjugate composed of A 7 and polypeptide anticancer drug neocarzinostatin (A 7-NCS), human anti-mouse antibody (HAMA) was observed in most cases without serious immune response such as anaphylactic shock. Human antibody against neocarzinostatin could not be detected in any case receiving A 7-NCS.

Study of seroconversion of antibody to human T-cell lymphotropic virus type-I in children of Okinawa, Japan

From 1983 to 1986, 1,813 children in nursery schools in Ishigaki Island and 1,228 children under 15 years old in the rural area in the Yaeyama District of Okinawa, Japan, were tested for anti-HTLV-I; 18 children (1.0%) in Ishigaki Island and 39 children (3.2%) in the rural area were positive. In order to survey when anti-HTLV-I developed in these children, their older serum samples were investigated retrospectively for 1 to 5 years. Two cases of seroconversion from anti-HTLV-I negative to positive were found between the age of 2 and 4, and there were no cases of seroconversion over 4 years old. Among the children who suffered maternal transmission of HTLV-I and developed anti-HTLV-I before the age of 15, about 80% of the children were considered to have anti-HTLV-I before the age of 2, and the remainder developed anti-HTLV-I before the age of 4.

Prevalence of IgM anti-HBc among HBsAg carriers in Okinawa, Japan

To evaluate the presence of IgM antibody to hepatitis B core antigen (IgM anti-HBc) in hepatitis B surface antigen (HBsAg) carriers, serial serum specimens of 698 carriers in Okinawa, Japan, from infants to adults, were studied by radioimmunoassay. IgM anti-HBc was detected in 7.6% of these carriers, with no difference between the sexes. The prevalence of IgM anti-HBc was higher in the age groups 0-9, 50-59 and over 60 than in the age group 20-29 and 30-39 years. In hepatitis B e antigen (HBeAg) positive carriers, the prevalence of IgM anti-HBc was 15.4%, a value significantly higher than in the HBeAg-negative carriers at 6.6%. In carriers with liver damage, the prevalence of IgM anti-HBc was 33.3%, a level significantly higher than the 6.3% in carriers without liver damage. However, IgM anti-HBc was detected in 34 carriers with neither HBeAg nor liver damage. These carriers are being closely followed. We discussed the presence of IgM anti-HBc in association with HBeAg or liver damage. The presence of IgM anti-HBc among HBsAg carriers was closely associated with liver damage.

Human lymphoblastoid and fibroblast interferon in the treatment of chronic hepatitis B

Twenty-six patients, positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus (HBV)-deoxyribonucleic acid (DNA), and DNA polymerase activity, were treated with human lymphoblastoid interferon (IFN-alpha) or human fibroblast interferon (IFN-beta) after enoxolone glycoside (glycyrrhizinic acid), given for four weeks and then withdrawn. The interferons were given continuously for four weeks. Four months after the treatment, six of 12 patients treated with IFN-alpha were both HBeAg-negative and HBV-DNA-negative while three of 14 patients treated with IFN-beta were HBV-DNA-negative and one was HBeAg-negative. None of the ten untreated control patients became negative for either HBeAg or HBV-DNA. All patients studied remained HBsAg-positive. Both interferons were generally well tolerated. A persistent low-grade fever was reported by more patients in the IFN-beta group and hair and weight loss were more common in the IFN-alpha group. The results indicate that the combination of enoxolone glycoside withdrawal and IFN-alpha treatment reduces HBV replication more effectively than does interferon alone.

Procaine inhibits cyclic AMP-induced steroidogenesis in isolated bovine adrenocortical cells

Effects of procaine on dibutyryl adenosine 3',5'-cyclic monophosphate ((Bu)2cAMP)-, Ca2(+)- or forskolin-induced steroidogenesis were examined in isolated bovine adrenocortical cells. Procaine (less than 1.0 mM) caused a marked suppression of (Bu)2cAMP- or forskolin-induced steroidogenesis in the absence of extracellular Ca2+, but did not affect on Ca2(+)-induced steroidogenesis in the cells. (Bu)2cAMP decreased the cell associated 45Ca2+. However, procaine (300 microM) inhibited this effect of (Bu)2cAMP. These results suggest that procaine may abolish (Bu)2cAMP-induced Ca2+ release from intracellular calcium store(s) and inhibits steroidogenesis.

Antigenic modulation and internalization of monoclonal antibody to human colonic carcinoma cells detected by enzyme-linked immunosorbent assay

We studied antigenic modulation and internalization of monoclonal antibody (MAb) A7 using the enzyme-linked immunosorbent assay (ELISA) and biotin-labelled antibody-staining techniques. Incubation of the colonic SW1116 cell line with an excess of MAb A7 induced modulation of the cell-surface antigen. When the line was assayed by ELISA, a change in cellular reactivity with MAb A7 was seen after 1 hr. After 24 hr, the cellular reactivity showed a 52% decrease in absorbance. Modulation was inhibited by 0.1% sodium azide and acetone fixation, suggesting that this is an energy-dependent phenomenon. The internalization of biotinylated MAb A7 was examined. Internalized biotinylated MAb A7 was detected in cells fixed before labelling with avidin-biotin peroxidase complex. It was observed that the amount of MAb A7 which remained associated with the cell surface had decreased since A7 was internalized.

Intradermal hepatitis B vaccination for mentally retarded patients

We investigated immune responses in 63 mentally retarded patients each given a low-dose (4 micrograms) intradermally of plasma-derived hepatitis B vaccine made in Japan and which was repeated after 1 and 6 months. Two doses of the vaccine induced antibodies in 85.5% these patients. A further dose 6 months later induced antibodies in 93.5% of the recipients and markedly increased the proportion of recipients with acceptable or high concentrations of antibody. The numbers of acceptable and high responders decreased slightly during a period of 12 months. The rate of acquiring antibody was significantly higher in the males. No significant differences in antibody response with regard to age and type of disease were observed. One patient with Down's syndrome, who acquired a low concentration of antibody after vaccination, was infected with hepatitis B virus. Supplementary vaccination may be necessary for poor responders in order to obtain protection. Side-effects resulting from the vaccination were not severe in any patients. These results suggest that low-dose, intradermal hepatitis B vaccination is safe and effective.

Hepatitis B virus infection among mentally retarded patients in institutions, Okinawa, Japan

To determine whether transmission of hepatitis B virus occurs among mentally retarded patients in six institutions, from 1986 to 1988, 373 patients (males 203, females 170, 18-53 years of age, mean age 29.9) were tested for hepatitis B markers. Seventy five of them had Down's syndrome. Overall prevalences were 9.1% for hepatitis B surface antigen (HBsAg), 39.7% for antibody to HBsAg (anti-HBs) and 48.0% for antibody to hepatitis B core antigen (anti-HBc). Prevalence of HBsAg was significantly higher in patients with Down's syndrome than in other mentally retarded patients. Five patients (three males and two females) in four institutions were infected with hepatitis B virus during the two years of observation. Four of these five patients were the other mentally retarded and became both anti-HBs and anti-HBc positive. The remaining one, who was 29 years old and Down's syndrome, became an HBsAg carrier. These observations indicate that hepatitis B virus transmission frequently occurs among mentally retarded patients in institutions and therefore vaccination of susceptible institutionalized patients is necessary. Vaccination to patients with Down's syndrome is particularly warranted, because they are uniquely predisposed to develop chronic hepatitis B infection following exposure.

Smooth muscle isoactin and elastin in fetal bovine lung

The formation of elastic fiber network in the lung is developmentally regulated. In this study we first demonstrated that tropoelastin mRNA per unit total RNA in the fetal bovine lung increased from 110 to 250 days of gestation (270 day term) as measured by Northern blot analysis. To examine the extent that smooth muscle (SM) type cells contribute to this gestational increase in elastin phenotype, we utilized a dual immunofluorescent staining technique on lung sections with anti-elastin polyclonal and anti-SM isoactin monoclonal antibodies. Elastin staining was always found to localize in proximity to SM isoactin-positive cells at various stages of prenatal lung parenchymal development. Minimal, if any, elastin was seen at interstitial fibroblasts, which were negative for the SM isoactin staining. Distribution of SM (type) cells and elastic fiber together along the airways became sparse and discontinuous distally, and it seemed that formation of air sacs was between the discontinuous elastic fibers. We speculate that smooth muscle (type) cells may be the major elastogenic cells of distal airways and may play an important role in alveolar formation.

Comparison of delayed imaging with Tc-99m PMT and Tc-99m DEIDA for visualization of hepatoma

Delayed imaging was performed after the intravenous administration of Tc-99m DEIDA and Tc-99m PMT in 18 patients with hepatocellular carcinoma. Using Tc-99m DEIDA imaging, sharp uptake by liver tumors was observed in four patients (22%), but the uptake was similar to that of the surrounding normal liver in eight patients (44%). Using Tc-99m PMT imaging, the uptake by the tumor was notable in ten patients (56%) and normal in two (11%). Tc-99m PMT and Tc-99m DEIDA were both concentrated in hepatocellular carcinomas, but the former showed intense uptakes more frequently, and thus is suggested to be useful in the diagnosis of hepatocellular carcinoma.

Functional hearing loss in children

This report reviewed 39 school-age children diagnosed as having a functional hearing loss utilizing auditory brainstem response (ABR) audiometry during the past 5 years at the Department of Otolaryngology, Kyushu University Hospital in Japan. Twenty-seven cases were females and 12 were males. Seven cases had a hearing loss unilaterally and 32 bilaterally. Although pure-tone audiometry revealed a variety of audiogram shapes, two-thirds of the cases had a flat or saucer-shaped audiogram with a mild to moderately severe hearing loss. ABR audiometry for the frequencies of 1, 2 and 4 kHz indicated a normal hearing threshold in 65 ears of 35 patients, and mild threshold elevations of at least one frequency in the remaining 6 ears of 4 patients. Three illustrative cases were demonstrated, and a discussion was held regarding the features in audiometric tests, and environmental factors surrounding the children with this condition. We emphasized that the physiological hearing measurement such as ABR audiometry should be performed when any discrepancy was noted between the patient's history and results of pure-tone audiometry, because of not infrequent occurrence of functional hearing loss.

[Application of immunotoxin in cancer therapy; its usefulness and problems in the future]

Highly specific anti-human colorectal carcinoma monoclonal antibody(A7) was developed by fusion of mouse myeloma cells with mouse spleen cells immunized by colon cancer cells. Neocarzinostatin (NCS) was bound to A7 preserving both antibody and drug activities. This conjugate (A7-NCS) was applied for clinical trial. No serious side effects were reported, and half of the eight patients with metastatic liver tumor responded to A7-NCS well. To overcome the variety in the expression of tumor-specific antigen on tumor cells, new types of conjugates were developed. Mitomycin C(MMC) was bound to Dextran sulphate. And this conjugate (M MC-Dex) was bound to A7 with the expectation that MMC would release from Dextran that was delivered to the surface of the cancer cells. This type of conjugate would be effective not only against cancer cells that express antigens detected by A7 but also against any cells around cancer cells detected by A7. The possibility and problems in cancer therapy using immunotoxin are discussed.