Repeat liver resection for recurrent colorectal liver metastases

BACKGROUND

This study aimed to delineate the role of surgery for recurrent colorectal cancer in the liver and to identify prognosticators for better patient selection and outcome.

METHODS

Data from 90 repeat hepatectomies (second = 75; third = 12; fourth = 3) for recurrent colorectal cancer were collected.

RESULTS

After the second hepatectomy, the 3-and 5-year survival rates were 48% and 31%, respectively. Twenty-seven percent (20 of 75) of patients are alive without recurrence after a median follow-up of 27 months, and 9 survived more than 5 years. Four or more tumors, positive regional lymph node metastases, concomitant extrahepatic disease, and residual tumor were independent poor prognostic factors after the second hepatectomy.

CONCLUSIONS

Repeat hepatectomy should be applied for recurrent colorectal cancer, when curative removal of the tumor is possible, although the benefit from treatment was limited in a patient with regional lymph node metastases, 4 or more metastases, or extrahepatic disease.

Distribution of Vibrio cholerae O1 antigen biosynthesis genes among O139 and other non-O1 serogroups of Vibrio cholerae

The organization and distribution of the genes responsible for O antigen biosynthesis in various serogroups of Vibrio cholerae were investigated using several DNA probes derived from various regions of the genes responsible for O1 antigen biosynthesis. Based on the reactivity pattern of the probes against the various serogroups, the cluster of genes responsible for the O1 antigen biosynthesis could be broadly divided into six groups, designated as class 1-6. The class 3 cluster of genes corresponding to gmd to wbeO, wbeT and a part of wbeU was specific for only the O1 serogroup. The other cluster of genes (class 1, 2, 4-6) reacted with other serogroups of V. cholerae. These data indicate that serotype conversion in V. cholerae does not depend on a simple mutational event but may involve horizontal gene transfer not only between V. cholerae strains but also between V. cholerae and species other than V. cholerae.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

The genes responsible for O-antigen synthesis of vibrio cholerae O139 are closely related to those of vibrio cholerae O22

Several studies have shown that the emergence of the O139 serogroup of Vibrio cholerae is a result of horizontal gene transfer of a fragment of DNA from a serogroup other than O1 into the region responsible for O-antigen biosynthesis of the seventh pandemic V. cholerae O1 biotype El Tor strain. In this study, we show that the gene cluster responsible for O-antigen biosynthesis of the O139 serogroup of V. cholerae is closely related to those of O22. When DNA fragments derived from O139 O-antigen biosynthesis gene region were used as probes, the entire O139 O-antigen biosynthesis gene region could be divided into five classes, designated as I-V based on the reactivity pattern of the probes against reference strains of V. cholerae representing serogroups O1-O193. Class IV was specific to O139 serogroup, while classes I-III and class V were homologous to varying extents to some of the non-O1, non-O139 serogroups. Interestingly, the regions other than class IV were also conserved in the O22 serogroup. Long and accurate PCR was employed to determine if a simple deletion or substitution was involved to account for the difference in class IV between O139 and O22. A product of approx. 15kb was amplified when O139 DNA was used as the template, while a product of approx. 12.5kb was amplified when O22 DNA was used as the template, indicating that substitution but not deletion could account for the difference in the region between O22 and O139 serogroups. In order to precisely compare between the genes responsible for O-antigen biosynthesis of O139 and O22, the region responsible for O-antigen biosynthesis of O22 serogroup was cloned and analyzed. In concurrence with the results of the hybridization test, all regions were well conserved in O22 and O139 serogroups, although wbfA and the five or six genes comprising class IV in O22 and O139 serogroups, respectively, were exceptions. Again the genes in class IV in O22 were confirmed to be specific to O22 among the 155 'O' serogroups of V. cholerae. These data suggest that the gene clusters responsible for O139 O-antigen biosynthesis are most similar to those of O22 and genes within class IV of O139, and O22 defines the unique O antigen of O139 or O22.

Shiga-toxin producing Escherichia coli from healthy cattle in a semi-urban community in Calcutta, India

From October to December 1998, single faecal samples from 67 healthy cattle in a semi-urban community near Calcutta were examined for Shiga toxin producing Esch. coli (STEC) using a multiplex PCR primary screen followed by plating on sorbitol MacConkey agar. STEC was isolated from the faeces of 7 (10.5%) animals. The eight strains isolated belonged to eight serotypes viz, O146:H1, O149:HNT, ONT:H34, ONT:H19, O88:HN, ONT:H2, O82:H8 and O28ac:H21. Bead enzyme linked immunosorbent assay showed that three strains produced Shiga toxin 1, one produced Shiga toxin 2 and four produced both.

A role of protein kinase C in the regulation of cytosolic phospholipase A(2) in bradykinin-induced PGI(2) synthesis by human vascular endothelial cells

The purpose of this study was to elucidate the mechanism by which bradykinin (BK) enhances prostacyclin (PGI(2)) production in human umbilical vein endothelial cells (HUVEC). BK-induced enhancement of PGI(2) synthesis was observed in a dose- and time-dependent manner, and it also increased [Ca(2+)](i) followed by enhancement of cytosolic phospholipase A(2) (cPLA(2)) activity. The PKC inhibitors GF109203X and H7 attenuated the BK-induced increase in [Ca(2+)](i) and inhibited the BK-induced PGI(2) synthesis. Phorbol 12-myristate 13-acetate increased cPLA(2) activity and PGI(2) synthesis but failed to alter [Ca(2+)](i). BK increased cPLA(2) mRNA eightfold by 15 min, and this increase was inhibited by pretreatment with the PKC inhibitors. In response to cycloheximide pretreatment, cPLA(2) mRNA was superinduced. These results suggest that BK stimulates PGI(2) synthesis in HUVEC by activation of cPLA(2) by dual mechanisms: an elevation of [Ca(2+)](i) and a PKC-dependent pathway. Moreover, changes in calcium kinetics and expression of cPLA(2) mRNA may underlie the BK-induced PGI(2) enhancement in these cells.

The mechanism of thrombin-induced prostacyclin synthesis in human endothelial cells with reference to the gene transcription of prostacyclin-related enzymes and Ca2+ kinetics

This study was designed to evaluate the effect of thrombin on prostacyclin (PGI2) production in cultured human vascular endothelial cells in association with intracellular Ca2+ and with the gene expression of prostaglandin H2 synthase (PGHS) and phospholipase A2 (PLA2) using competitive polymerase chain reaction. Thrombin enhanced the PGI2 synthesis dependent with time. Additionally, thrombin increased the intracellular Ca2+, which stimulates PLA2, resulting in arachidonic acid cleavage from membrane phospholipids and its subsequent conversion into PGI2 through the PGHS pathway. The elevation of intracellular Ca2+ was a result of Ca2+ influx and Ca2+ release from its intracellular storage sites. In this study, PGHS-1 mRNA was constitutively expressed, whereas PGHS-2 mRNA was not. With the stimulation of thrombin, cytosolic PLA2 (cPLA2) mRNA increased 9-fold at 15 min, PGHS-1 mRNA increased 3.4-fold at 180 min, and PGHS-2 mRNA increased 38-fold at 60 min. These results suggest that the elevation of intracellular Ca2+ and the expression of cPLA2, PGHS-1, and PGHS-2 mRNA cause PGI2 generation.

Resection of liver metastases after pancreatoduodenectomy: report of seven cases

There has been no English report of a long survivor after hepatectomy for metastasis from periampullary malignancies, who had previously undergone pancreatoduodenectomy (PD) for primary disease. Herein, we report 7 patients of liver metastases who underwent 8 hepatectomies after PD for peri-ampullary malignancies. One patient whose liver metastasis was neuroendocrine tumor, survived 2 years and 6 months without recurrence after hepatectomy. Another patient who had 2 hepatectomies for metastasis from duodenal leiomyosarcoma survived for 3 years and 20 days after the first hepatectomy. Procedure of hepatectomy comprised 4 limited resections (including 1 second hepatectomy) and 4 lobectomies at the first resection. Hepatic inflow clamp was used in 6 out of 8 hepatectomies and 4 out of 8 hepatectomies did not require allogeneic blood transfusion. Bacterial contamination of the drained discharge from the cut surface of the liver, mostly representative of enteric organisms, was identified in all but 2 patients who were not examined. Subphrenic abscesses developed in 2 patients after removal of the drains. Thus, prophylactic use of abdominal drain is indispensable after hepatectomy for the patients with bilioenteric anastomosis.

Should the bile duct be preserved or removed in radical surgery for gallbladder cancer?

BACKGROUND/AIMS

It is unclear whether resection of the extrahepatic bile duct in radical surgery for gallbladder cancer should be performed when direct infiltration into the hepatoduodenal ligament is absent.

METHODOLOGY

The results of radical surgery with or without bile duct resection were compared in 55 patients with gallbladder cancer without direct extension to the hepatoduodenal ligament. Lymph node dissection and combined resection of involved organs were carried out according to the extent of the tumor.

RESULTS

Nodal involvement was present in 43% of patients with tumors more advanced than pT1. Survival rates were similar between patients with or without bile duct resection in stages I-III, while significantly better survival was observed with bile duct resection in stage IV.

CONCLUSIONS

Considering the adverse effect of bilioenteric anastomosis, preservation of the extrahepatic bile duct is recommended in radical surgery for gallbladder cancer when the tumor is less advanced than stage IV and does not extend to the hepatoduodenal ligament.

Clonal diversity among recently emerged strains of Vibrio parahaemolyticus O3:K6 associated with pandemic spread

The genomes of the O3:K6 strains of Vibrio parahaemolyticus which abruptly emerged in Calcutta, India, in February 1996 and which demonstrated an unusual potential to spread and an enhanced propensity to cause infections were examined by different molecular techniques to determine clonality. No restriction fragment length polymorphism (RFLP) in the gene encoding the thermostable direct hemolysin was observed among the O3:K6 isolates of V. parahaemolyticus. Clonal diversity among the O3:K6 strains became evident by examining the RFLPs of the rrn operons and by the use of pulsed-field gel electrophoresis. Five ribotypes were distinguished among the O3:K6 strains examined, with ribotype R4 constituting the major type. Strains of O3:K6 isolated between June and August 1996 showed different pulsotypes compared to the pulsotypes of strains isolated before and after this period, indicating genetic reassortment among these strains, but those isolated between August 1996 and March 1998 showed identical or nearly similar pulsotypes. It is clear that there is a certain degree of genomic reassortment among the O3:K6 clones but that these strains are predominantly one clone.

Primary hepatic carcinoid tumors confirmed with long-term follow-up after resection

Primary carcinoid tumor of the liver is very rare. Only 30 cases have been reported in the English literature. However, most of those cases were diagnosed only on the basis of diagnostic imaging and surgical exploration, their follow-up periods being up to 5 years. Considering the slow progression of the tumor, long-term follow-up is required to exclude occult extrahepatic primaries which may manifest afterwards, and to determine the clinical course of this disease. We experienced 3 patients with primary hepatic carcinoid tumors who underwent total resections. They all survived more than 7 years and were clinically confirmed as hepatic primary by failing to detect other primaries during their courses. One patient is disease-free for more than 7 years after resection. The other 2 were found to have recurrence in the remnant liver; 1 underwent transcatheter arterial embolization several times and is alive more than 4 years after recurrence, and the other underwent 2 more operations and survived 8 years after the 1st recurrence. Surgery might offer a possible chance of cure for primary hepatic carcinoid tumor, and transcatheter arterial embolization might be a good treatment option when an unresectable disease is confined to the liver.

Interleukin-1alpha stimulated prostacyclin release by increasing gene transcription of prostaglandin H synthase and phospholipase A2 in human vascular endothelial cells

This study was conducted to evaluate the effects of interleukin-1alpha (IL-1alpha) on prostacyclin (PGI2) production in cultured human vascular endothelial cells in association with intracellular Ca2+, inositol 1,4,5-trisphosphate (IP3), and with prostaglandin H synthase (PGHS) and phospholipase A2 (PLA2) gene expression by using the competitive polymerase chain reaction (PCR) method. IL-1alpha did not increase PGI2 production for 15 min, but induced an increase of about three-fold relative to that in controls at 60 and 180 min. IL- 1alpha had no effect on intracellular Ca2+ levels throughout the experimental period. In this study, consistent with previous reports, PGHS-1 messenger RNA (mRNA) was constitutively expressed, whereas PLA2 mRNA was not. After stimulation with IL-1alpha, PLA2 mRNA level showed an eightfold increase within 15 min, and PGHS-2 mRNA level increased by 76-fold within 180 min. PGHS-1 mRNA level was increased 1.6-fold at 180 min. These results suggest the existence of regulatory mechanisms of IL-1alpha-induced PGI2 production, which involve PGHS and PLA2 gene transcription.

Expression of mitogen activated protein kinases in labial salivary glands of patients with Sjögren's syndrome

OBJECTIVE

The expression of CD40 and CD40 ligand (CD40L) in mononuclear cells (MNCs) infiltrating the salivary glands of patients with Sjögren's syndrome (SS) has recently been reported. This study determined the expression of mitogen activated protein kinase (MAP kinase) superfamilies, which act as downstream effector molecules of CD40, in MNCs infiltrating labial salivary tissues in SS patients.

METHODS

Six HTLV-I seronegative SS patients and 10 HTLV-I seropositive patients including five HTLV-I associated myelopathy (HAM) patients were examined. The expression of MAP kinase superfamilies in labial salivary glands was examined by immunohistochemistry containing the mirror section technique.

RESULTS

Both active forms of c-Jun N-terminal kinase (JNK) and p38 were found in salivary infiltrating MNCs of SS patients. Only minimal expression of the active form of extracellular signal regulated kinase (ERK) was observed in these tissues, however, co-expression of active JNK and active p38 was confirmed by the mirror section technique. Furthermore, these protein kinases were co-expressed in CD40(+) MNCs. No difference in expression levels of active JNK and p38 was found in patients who were positive or negative for anti-HTLV-I antibody.

CONCLUSION

These results indicate that JNK and p38, but not ERK, function as downstream effector molecules of CD40 in salivary infiltrating MNCs in SS patients, and suggest that these molecules may be involved in the pathological process of chronic sialadenitis in SS.

Clonal analysis of non-toxigenic Vibrio cholerae O1 associated with an outbreak of cholera

We examined the clonal relationships among eight clinical isolates of non-toxigenic (NT) V. cholerae O1 associated with a cluster of cases of cholera in Warangal, Andhra Pradesh in south India and compared their relatedness to toxigenic O1 strains of classical and E1Tor biotypes and with O139 Bengal strains of V. cholerae by pulsed-field gel electrophoresis (PFGE). Phylogentic analysis of the NotI restriction fragment length polymorphism showed that all the NT. V. cholerae O1 strains formed a tight cluster with more than 80 per cent similarity. Interestingly, the NT V. cholerae O1 cluster was more closely related to V. cholerae O139 than to classical and E1Tor biotypes of V. cholerae O1 indicating closer genetic relationships between NT V. cholerae 01 and O139 Bengal strains that were isolated during the same time-frame.

Inhibitory effect of a new anti-rheumatic drug T-614 on costimulatory molecule expression, cytokine production, and antigen presentation by synovial cells

The present study was undertaken to investigate the immunoregulatory effects of T-614 (3-formylamino-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-o ne) on synovial cells in vitro. Synovial cells were cultured with T-614 in the presence or absence of various cytokines. After incubation, the costimulatory molecule expression on synovial cells and cytokine production in culture supernatants were analyzed by an indirect immunofluorescence method and enzyme-linked immunosorbent assay, respectively. We also examined the effect of T-614 on the function of synovial cells as antigen-presenting cells (APCs). The costimulatory molecules including CD54, CD58, and CD106 were constitutionally expressed on the surface of synovial cells. However, neither CD80 nor CD86 nor CD102 was found on the surface, and these costimulatory molecules could not be induced by any cytokines. T-614 itself did not affect the costimulatory molecule expression and cytokine production of unstimulated synovial cells. The stimulation of synovial cells with interferon-gamma (IFN-gamma), interleukin-1beta, or 12-O-tetradecanoyl phorbol 13-acetate enhanced the expression of costimulatory molecules and the proinflammatory cytokine production of these cells. Both the up-regulated expression of these costimulatory molecules and the enhanced production of proinflammatory cytokines were significantly inhibited by T-614. Autologous T cell proliferation in response to purified protein derivative by IFN-gamma-treated synovial cells was significantly suppressed by T-614. T-614 has considerable immunosuppressive effects on synovial cells by inhibiting the costimulatory molecule expression and cytokine production of these cells and the antigen-specific T cell proliferation mediated by the synovial cells. These results suggest that T-614 plays an important immunoregulatory role in rheumatoid synovial tissues.

Analysis of the genes responsible for the O-antigen synthesis in enterohaemorrhagic Escherichia coli O157

The genes responsible for O157 O-antigen synthesis were cloned from Shiga toxin 1 (Stx1)-producing enterohaemorrhagic Escherichia coli O157:H-. Based on the published sequence of the rfbE(EcoO157:H7) gene, the rfbE gene was amplified by PCR and used as the probe. One clone (1-4-1) out of ten agglutinated using the slide agglutination test with O157 antiserum. The DNA sequence of a 31.5 kb fragment in p1-4-1 was determined and found to contain 26 open reading frames (ORFs). These ORFs were organized as two clusters of genes, comprising orf2 to orf16 and orf17 to orf24 regions, which were aligned in opposite directions. The GC contents of orf1, orf12 and orf14 to orf26 were similar to the overall GC content of the E. coli chromosome (51%). However, orf2 to orf11 and orf13 showed a much lower GC content of 30.0 to 39.4%. The minimum region essential for O157 O-antigen expression in E. coli K-12 lay between orf2 and orf13, which corresponded to the region of low GC content in E. coli O157. A colony hybridization test was carried out against reference strains of E. coli representing serogroups O1 to O173 using O157 O-antigen synthesis genes (orf2-orf13) of E. coli O157 as probes. With the exception of orf12, all probes from E. coli O157 O-antigen synthesis gene cluster did not hybridize with DNA from E. coli O1 to O173, except O157 reference strains, under high stringency conditions. These data suggest that the region from orf2 to orf13 has originated from a non-E. coli species with a low GC content.

Induction of human leukocyte antigen (HLA)-A2-restricted and MAGE-3-gene-derived peptide-specific cytolytic T lymphocytes using cultured dendritic cells from an HLA-A2 esophageal cancer patient

BACKGROUND AND OBJECTIVES

Using peripheral blood mononuclear cells (PBMCs) from a 10-year survivor with established human leukocyte antigen (HLA)-A2(+) and MAGE-3(+) esophageal cancer cell line (KYSE-170), we examined the induction of HLA-A2-restricted and MAGE-3-gene-derived peptide (FLWGPRALV, amino acids 271-279)-specific cytolytic T lymphocytes (CTLs).

METHODS

Autologous dendritic cells (DCs) cultured with granulocyte-macrophage colony stimulating factor and interleukin-4 were used as antigen presenting cells. PBMCs were stimulated by peptide-pulsed DCs in vitro.

RESULTS

PBMC cocultured with FLWGPRALV-pulsed DCs could induce the relevant peptide-specific CTLs, which had tumor necrosis factor production and specific cytotoxicity against relevant peptide-pulsed autologous DCs (34%, effector:target ratio = 40:1). Moreover, they showed specific cytotoxicity against the autologous esophageal cancer cell line KYSE-170 (17%, effector:target ratio = 40:1).

CONCLUSIONS

These results suggest that FLWGPRALV-pulsed cultured DCs would be a potent candidate for peptide vaccine against HLA-A2(+) and MAGE-3(+) esophageal cancer.

Reduction of tumorigenicity by an interferon-gamma-gene-transduced tumor on another syngeneic tumor in a murine model

To evaluate the effect of interferon-gamma-gene-transduced cells, DS mice were inoculated into their footpads with syngeneic mammary adenocarcinoma SC42 admixed with interferon-gamma producing mammary adenocarcinoma SC115Kgamma, which had been established by an interferon-gamma-gene transduction in another syngeneic mammary adenocarcinoma SC115 using retroviral vectors. These mice rejected both tumor cells and developed resistance to subsequent challenges with either SC115 or SC42 cells inoculated into their opposite posterior footpads. These results thus indicate that systemic immunological memory to each of the independent tumor cell lines developed in these mice. Although the SC42 cells admixed with irradiated SC115Kgamma cells were rejected by these mice, the SC42 cells admixed with irradiated SC115neoR, in which the neo-gene had been transduced, were observed to proliferate. Tumor rejection was reversed by an in vivo administration of anti-interferon-gamma antibody, thus suggesting that locally produced interferon-gamma plays an important role in tumor elimination and immunological memory induction. In conclusion, interferon-gamma-gene-transduced tumor cells are therefore considered to have a therapeutic potential for other types of malignant tumor cell lines.

Factors influencing survival of patients undergoing hepatectomy for colorectal metastases

BACKGROUND

The extent of surgical margin is still a matter of controversy with regard to outcome after liver resection for metastatic disease. The aim of this study was to clarify the significant prognostic factors after hepatectomy for colorectal metastases, with special reference to the surgical margin.

METHODS

Ninety-six patients who underwent initial hepatic resection for liver metastases from colorectal cancer between 1992 and 1994 were studied.

RESULTS

Overall 1-, 3- and 5-year survival rates were 94, 61 and 51 per cent respectively. All of the independent factors associated with poor prognosis after hepatic resection were tumour-related factors, such as the number of tumours (four or more), presence of portal vein invasion, hepatic vein invasion and absence of a fibrous pseudocapsule. A positive resection margin was not an independent prognostic factor, because of its strong relationship with the number of tumours resected.

CONCLUSION

A generous surgical margin is not essential for curative hepatic resection, although positive surgical margins should be avoided. New potential risk factors which affect survival, such as the presence of portal vein or hepatic vein invasion and the absence of a pseudocapsule, may be helpful for defining the indications for postoperative adjuvant treatment.

Resection of peritoneal metastases from hepatocellular carcinoma

BACKGROUND/AIMS

To evaluate whether resection of peritoneal metastases arising from hepatocellular carcinoma (HCC) has a role to play in the management of the disease.

METHODOLOGY

Resections of peritoneal metastases from HCC were performed in 6 patients. The survival of the patients was evaluated in relation to feature of primary liver tumor, number of peritoneal metastases and period between hepatectomy and resection of peritoneal metastases.

RESULTS

Two patients had peritoneal metastases at the time of hepatectomy for HCC, their resection being carried out synchronously. In the other 4 patients, peritoneal metastases became evident between 6 and 34 months (mean: 18) after hepatectomy; resection was performed at the time of presentation of the metastases. Patient survival after resection of the peritoneal metastases ranged from 3-31 months. The 4 patients who survived for more than 1 year had the following features: 1) a small number of metastatic nodules (= or < 4); 2) low alpha-fetoprotein (AFP) values (mean: 205 ng/ml); and, (3) metachronous occurrence of the peritoneal metastases.

CONCLUSIONS

Resection of peritoneal metastases arising from HCC may be of value in improving patient survival.

Analysis of effector cells in tumor-bearing mice pre-treated with active specific immunization followed by cyclophosphamide

In order to analyse the effector population in an immunization model, we treated BALB/c mice with intraperitoneal (i.p.) active specific immunization (ASI), which consists of interleukin (IL)-1-beta and sonicated tumor supernatant (SS) of a plasmacytoma MOPC-104E followed by i.p. injection of cyclophosphamide (CY). This ASI-CY treatment provoked a protective immunity against i.p. tumor inoculation more strongly than that of ASI alone. The main effector cells in tumor neutralizing assay were CD4+ T cells at this pont. The number of spleen cells of the ASI-CY treated mice were significantly lower than that of ASI alone treated mice but it increased significantly 6 days thereafter while this increase was not observed on the mice treated with ASI alone. The spleen cells of the ASI-CY treated mice responded to SS in vitro in the presence of IL-2, more profoundly in CD4 enriched population which produced high amount of TNF-alpha. In vivo tumor-neutralizing activity at a later stage was dependent on CD8+ T cells in addition to CD4+ T cells. These results suggest that antitumor activity by ASI and CY is transduced by sequential population shift from CD4 alone to both of CD4 and CD8.