[Pancreaticoduodenectomy combined with longitudinal pancreaticojejunostomy in the treatment of chronic pancreatitis: initial experience in 11 cases].

Objective: To investigate the surgical strategy for chronic pancreatitis complicated with suspected malignant lesions in the pancreatic head and pancreatolithiasis in the distal pancreas. Methods: This is a retrospective cohort study. Clinical data from 11 patients with chronic pancreatitis who underwent pancreaticoduodenectomy combined with longitudinal pancreaticojejunostomy(PD-L) were retrospectively collected(PD-L group) from the Department of Hepatobiliary Surgery of the First Affiliated Hospital of Xi'an Jiaotong University between December 2021 and September 2023. All patients were male with an age of (49.0±11.2) years(range:32 to 70 years). Their primary preoperative diagnoses included pancreatic lesions, chronic pancreatitis, pancreatolithiasis, and dilatation of the pancreatic duct. Data from 248 patients who underwent pancreaticoduodenectomy(PD) during the same period were retrospectively collected(PD group). There were 157 males and 91 females in the PD group, with an age of (61.5±10.8) years(range:27 to 82 years). Among them, 87 cases were diagnosed as pancreatic cancer or chronic pancreatitis. The propensity score matching method was used to reduce confounding bias between the two groups. The caliper value of 0.1 was used and the 1∶4 nearest neighbor matching method was used for the matching. Comparisons between the two groups were made using the independent sample t test, Mann-Whitney U test or χ2 test,respectively. Results: After complete excision of the specimen during pancreaticoduodenectomy, the key surgical step of PD-L was longitudinal pancreaticojejunostomy in the remaining pancreas. Intraoperative blood loss in the PD-L group was lower than that in the PD group [M(IQR)](300(200)ml vs. 500(500)ml, respectively; P<0.05). Similarly, hospitalization days(21.0(7.0)days vs. 25.0(8.5)days) and postoperative hospitalization days(13.0(8.0)days vs. 17.0(5.0) days) were also lower in the PD-L group compared to the PD group (P<0.05). There were no significant differences in the operation time and postoperative complication rate between the two groups(P>0.05). In the PD-L group, the postoperative follow-up time was 5(5)months(range: 3 to 21 months). One case was lost for follow-up. Abdominal pain was relieved in 10 patients. Additionally, abdominal distension and steatosis were alleviated in 8 cases. Furthermore, 5 cases of diabetes mellitus showed improved control of HbA1c and fasting blood glucose levels after surgery. Conclusions: PD-L treatment can be used to treat chronic pancreatitis complicated by suspected malignant lesions in the pancreatic head and pancreatolithiasis in the distal pancreas. PD-L also has advantages in removing stones from the pancreatic duct and evaporation of pancreatic fluid. However, due to the single-center design and the small sample size of this study, further practice and long-term follow-up are still necessary.

[Effect of pancreatic extracorporeal shock wave lithotripsy on chronic pancreatitis stones].

Objective: To analyze the therapeutic effect and safety of pancreatic extracorporeal shock wave lithotripsy(P-ESWL) for patients with chronic pancreatitis complicated by stones of the pancreatic duct and to investigate the influencing factors. Methods: A retrospective analysis was performed on clinical data from 81 patients with chronic pancreatitis complicated by pancreatic duct calculus treated with P-ESWL in the Department of Hepatobiliary Surgery, the First Affiliated Hospital of Xi 'an Jiaotong University from July 2019 to May 2022. There were 55 males(67.9%) and 26 females(32.1%). The age was (47±15)years (range: 17 to 77 years). The maximum diameter(M(IQR)) of the stone was 11.64(7.60) mm, and the CT value of the stone was 869 (571) HU. There were 32 patients (39.5%) with a single pancreatic duct stone and 49 patients(60.5%) with multiple pancreatic duct stones. The effectiveness, remission rate of abdominal pain, and complications of P-ESWL were evaluated. Student's t test, Mann Whitney U test, χ2 test, or Fisher's exact test was used to compare the characteristics between the effective and ineffective groups of lithotripsy. The factors influencing the effect of lithotripsy were analyzed by univariate and multivariate logistic regression analysis. Results: Eighty-one patients with chronic pancreatitis were treated with P-ESWL 144 times, with an average of 1.78 (95%CI:1.60 to 1.96) times per person. Among them, 38 patients(46.9%) were treated with endoscopy. There were 64 cases(79.0%) with effective removal of pancreatic duct calculi and 17 cases(21.0%) with ineffective removal. Of the 61 patients with chronic pancreatitis accompanied by abdominal pain, 52 cases(85.2%) had pain relief after lithotripsy. After lithotripsy treatment, 45 patients(55.6%) developed skin ecchymosis, 23 patients(28.4%) had sinus bradycardia, 3 patients(3.7%) had acute pancreatitis, 1 patient(1.2%) had a stone lesion, and 1 patient(1.2%) had a hepatic hematoma. Univariate and multivariate logistic regression analysis showed that the factors affecting the efficacy of lithotripsy included the age of patient(OR=0.92, 95%CI: 0.86 to 0.97), the maximum diameter of the stone(OR=1.12,95%CI:1.02 to 1.24) and the CT value of the stone(OR=1.44, 95%CI: 1.17 to 1.86). Conclusions: P-ESWL is effective in the treatment of patients with chronic pancreatitis complicated by calculi of the main pancreatic duct.Factors affecting the efficacy of lithotripsy include patient's age, maximum stone diameter, and CT value of calculi.

Superiority of thyroid peroxidase DNA over protein immunization in replicating human thyroid autoimmunity in HLA-DRB1*0301 (DR3) transgenic mice.

Murine experimental autoimmune thyroiditis (EAT), characterized by thyroid destruction after immunization with thyroglobulin (Tg), has long been a useful model of organ-specific autoimmune disease. More recently, porcine thyroid peroxidase (pTPO) has also been shown to induce thyroiditis, but these results have not been confirmed. When (C57BL/6 x CBA)F(1) mice, recently shown to be susceptible to mouse TPO-induced EAT, were immunized with plasmid DNA to human TPO (hTPO) and cytokines IL-12 or GM-CSF, significant antibody (Ab) titres were generated, but minimal thyroiditis was detected in one mouse only from the TPO + GM-CSF immunized group. However, after TPO DNA immunization of HLA-DR3 transgenic class II-deficient NOD mice, thyroiditis was present in 23% of mice injected with TPO + IL-12 or GM-CSF. We also used another marker for assessing the closeness of the model to human thyroid autoimmunity by examining the epitope profile of the anti-TPO Abs to immunodominant determinants on TPO. Remarkably, the majority of the anti-TPO Abs was directed to immunodominant regions A and B, demonstrating the close replication of the model to human autoimmunity. TPO protein immunizations of HLA-DR3 transgenic mice with recombinant hTPO did not result in thyroiditis, nor did immunization of other mice expressing HLA class II transgenes HLA-DR4 or HLA-DQ8, with differential susceptibility to Tg-induced EAT. Moreover, our efforts to duplicate exactly the experimental procedures used with pTPO also failed to induce thyroiditis. The success of hTPO plasmid DNA immunization of DR3(+) mice, similar to our reports on Tg-induced thyroiditis and thyrotropin receptor DNA-induced Graves' hyperthyroidism, underscores the importance of DR3 genes for all three major thyroid antigens, and provides another humanized model to study autoimmune thyroid disease.

Cellular immunity to the Her-2/neu protooncogene.

Her-2/neu (HER-2) is a 185-kDa receptor-like glycoprotein that is overexpressed by a variety of tumors such as breast, ovarian, gastric, and colorectal carcinomas. Overexpression of this oncogene is directly associated with malignant transformation of epithelial cells. The frequency of HER-2 overexpression varies among the different types of cancers, but universally represents a marker of poor prognosis. The critical role of HER-2 in epithelial oncogenesis as well as its selective overexpression on malignant tissues makes it an ideal target for immunotherapy. Antibodies and T cells reactive to HER-2 are known to naturally occur in patients with HER-2 positive tumors, confirming the immunogenicity of the molecule. Both antibodies as well as T cells reactive to HER-2 have been utilized for immunotherapy of HER-2 positive tumors. The "humanized" monoclonal antibody Herceptin has been tested in several clinical trials and found to be an effective adjuvant therapy for HER-2 positive breast and ovarian cancer patients. However, the frequency of patients responding to Herceptin is limited and a majority of patients initially responding to Herceptin develop resistance within a year of treatment. The use of vaccination strategies that generate T cell responses with or without accompanying antibody responses may serve to mitigate the problem. Various strategies for generating T cell-mediated responses against HER-2 are currently being examined in animal models or in clinical trials. The potential advantages of the various approaches to immunotherapy, their pitfalls, and the mechanisms by which HER-2 positive tumors can evade immune responses are discussed in this review.

Degradation signals in ErbB-2 dictate proteasomal processing and immunogenicity and resist protection by cis glycine-alanine repeat.

ErbB-2 is ubiquitinated and degraded when dissociated from its membrane chaperone or bound by specific antibody. Reagents which induce such degradation have demonstrated antitumor activity and may impact ErbB-2 immunogenicity. To further understand ErbB-2 degradation and immunogenicity, a glycine-alanine repeat (GAr) or the reverse proline-alanine repeat (PAr) which protects certain proteins from proteasome degradation, was inserted after amino acid 5 (GAr5/PAr5) or 55 (GAr55/PAr55) of ErbB-2. When dissociated from the membrane with geldanamycin, E2-GAr5 and E2-PAr5 were not protected and still ubiquitinated and degraded by the proteasome, despite the presence of GAr. Insertional mutagenesis with GAr sequences at a.a. 55 of E2 enhanced proteasome degradation rendering E2-GAr55 and E2-PAr55 unstable on the membrane, but rescued in the cytosol by proteasome inhibitors. Immunization with E2-GAr induced antitumor immunity and CTL which lysed tumor cells expressing chimeric E2-GAr or wild-type E2 proteins, demonstrating efficient presentation through MHC I pathway. Improved understanding of the strong degradation signals in ErbB-2 may facilitate the development of anticancer agents or vaccines.

Foreign antigenic peptides delivered to the tumor as targets of cytotoxic T cells.

Cytotoxic T cells (CTL) are readily activated by immunogenic peptides and they exert potent anti-tumor activity if the same peptides are displayed on class I major histocompatibility complex (MHC) of the tumor cells. A handful of tumor-associated antigens have been identified and many of them are weak antigens. As an alternative strategy, strongly antigenic foreign peptides are delivered to the tumor, marking them for CTL recognition. To establish the principle of this new strategy, in vitro and in vivo tumor destruction was tested with BALB/c CTL to L(d)-associated beta-galactosidase (beta-gal) peptide p876. In vitro, anti-p876 CTL destroyed tumor cells in a single-cell suspension or in 3-D tumor boluses when exogenous p876 was added. Exogenous IL-2 was required to sustain CTL activity for complete destruction of tumor boluses. In vivo, BALB/c mice were immunized with p876 and a CD4 activating Pan DR reactive epitope (PADRE). PADRE, which binds to several different MHC class II antigen and activates CD4 T cells, induced delayed-type hypersensitivity and stimulated T cell proliferation. Immunized mice were injected with tumor cells loaded with p876 and mixed with PADRE. Starting from the day after tumor injection, mice received five rounds of peptide injection at the tumor sites and all tumors were rejected. Injection with saline had no effect. Injection with PADRE had minor anti-tumor activity. Immunization and treatment with p876 alone was not protective. Therefore, by delivering CD4 and CD8 reactive foreign peptides to the tumor, peptide-specific T cells rejected the tumors as demonstrated by the in vitro and in vivo tests.

Vaccination with cytoplasmic ErbB-2 DNA protects mice from mammary tumor growth without anti-ErbB-2 antibody.

Wild-type ErbB-2 (E2) positive D2F2/E2 tumors are rejected by active vaccination with ErbB-2 DNA. However, anti-ErbB-2 Ab response can cause cardiac toxicity or interfere with cellular immunity. It will be advantageous to induce only cellular immunity by active vaccination. A panel of E2 DNA vaccines were constructed, and their vaccination efficacy was ranked as E2 > tyrosine kinase-deficient ErbB-2 (E2A) > full-length ErbB-2 targeted to the cytoplasm (cytE2) > tyrosine kinase-deficient cytE2 (cytE2A). E2A is a tyrosine kinase-deficient mutant containing a single residue substitution. CytE2 or cytE2A encodes a full-length protein that is targeted to and rapidly degraded in the cytosol by the proteasomes. Covaccination with cytE2A and GM-CSF or IL-2 DNA resulted in equivalent anti-tumor activity as E2. However, anti-ErbB-2 Ab was induced by E2 or E2A, but not cytE2 or cytE2A. Therefore, cytE2A appears to induce anti-tumor immunity without an Ab response. ErbB-2-specific CTL were detected in mice immunized with cytE2A and GM-CSF and have rejected tumor challenge. Depletion of CD8, but not CD4 T cells reduced anti-tumor immunity, indicating CTL as the effector cells. Covaccination with E2A and cytE2A induced synergistic anti-tumor activity, supporting enhanced peptide presentation from cytE2A, which was further evidenced by superior CTL activation using APCs expressing cytE2 vs E2. Taken together, cytoplasmic ErbB-2 DNA induced anti-tumor CTL, but not humoral response, demonstrating the feasibility of eliciting individual effector mechanism by targeted DNA vaccine.

Complementary antitumor immunity induced by plasmid DNA encoding secreted and cytoplasmic human ErbB-2.

A plasmid DNA was constructed to encode the N-terminal 505 aa of human ErbB-2 (E2, HER-2/neu) and designated as secreted ErbB-2 (secE2). Recombinant secE2 protein was detected in the transfected cells and was secreted as an 80-kDa glycoprotein. Vaccination of BALB/c mice with secE2 DNA induced both IgG1 and IgG2a ErbB-2-specific Abs and protected approximately 90% of mice against mouse mammary tumor D2F2, which expressed human ErbB-2 (D2F2/E2). The efficacy of secE2 vaccine was comparable with that of wild-type ErbB-2 DNA, which encodes the entire 1258 aa of ErbB-2 protein, induced only IgG2a E2-specific Abs, and stimulated greater CTL activity. Immune lymphocytes were stimulated in vitro with irradiated 3T3 cells, which expressed ErbB-2, K(d), and B7.1. CTL activity was measured by the lysis of E2-positive target cells and by intracellular IFN-gamma production. To enhance CTL activation, mice were immunized with a combination of secE2 and cytoplasmic E2 (cytE2); the latter encodes the 1258-aa ErbB-2 protein that was released into the cytoplasm upon synthesis. Significant increase in CTL activity was demonstrated after mice were immunized with the combined vaccines and all mice were protected from D2F2/E2 tumor growth. Therefore, secE2, which induced Th2 Ab and weak CTL, conferred similar protection as E2, which induced Th1 Ab and strong CTL. Combined vaccination with secE2 and cytE2 resulted in Th2 Ab, strong CTL, and the most effective protection against tumor growth. The strategy of coimmunization with DNA that direct Ags to different subcellular compartments may be adapted as appropriate to optimize immune outcome.

Progression of head and neck cancer in an in vitro model.

OBJECTIVE: To identify alterations in angiogenesis and cell cycle regulation as preneoplastic cells progress to cancer in an in vitro model of head and neck tumor progression. METHODS: Immortal human gingival keratinocyte (IHGK) cells (preneoplastic) were derived from normal oral keratinocytes and were immortalized with human papillomavirus 16. Transformation of IHGK cells with a carcinogen (NNK, 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone) gave rise to IHGKN cells. We determined the growth rates, cell cycle phase, expression of cell cycle regulators, and expression of vascular endothelial growth factor along with the organotypic features of these cells and compared them with characteristics of head and neck cancer cells. RESULTS: IHGK and IHGKN cells grown in raft culture were morphologically similar to severe dysplasia and carcinoma, respectively. The proportion of cells in G(0)/G(1) was similar between IHGK and IHGKN. However, the proportion of IHGK cells was 35% greater in S phase as compared with the IHGKN cells, while a greater percentage (40%) of IHGKN cells were in G(2)/M. The expression of the other cell cycle regulators tested was unchanged. IHGK cells secreted less vascular endothelial growth factor on day 1 when compared with IHGKN (50.6 vs 245.6 pg/mL), along with a lower overall production rate (79% vs 133%). CONCLUSIONS: Transformation of IHGK cells resulted in the activation of vascular endothelial growth factor associated with angiogenesis. Inactivation of the G(1) cell cycle regulation occurred during immortalization and before transformation, and was sustained after carcinogen exposure. These alterations correspond to changes observed in patients with head and neck squamous cell carcinoma. This model can be useful in testing novel therapeutic and preventive strategies.

Anti-CD3/anti-CD28 bead stimulation overcomes CD3 unresponsiveness in patients with head and neck squamous cell carcinoma.

OBJECTIVES: To test whether T-cell CD3 responses are altered in patients with advanced-stage head and neck squamous cell carcinoma (HNSCC) and whether anti-CD3/anti-CD28 (alphaCD3/alphaCD28) bead stimulation could reverse CD3 unresponsiveness. DESIGN: Anti-CD3 (alphaCD3) monoclonal antibody immobilized on tissue culture plastic was used to stimulate lymph node mononuclear cells (LNMCs) and peripheral blood mononuclear cells (PBMCs) from patients with advanced-stage HNSCC. Proliferation, T-cell phenotype, and cytokines were measured during 8-day in vitro stimulation. Immune-enhancing properties of alphaCD3/ alphaCD28 beads were also tested on LNMCs and PBMCs. Cytotoxicity of bead-activated T cells (ATCs) was measured against autologous and allogeneic HNSCC. RESULTS: Six patients were nonresponders to alphaCD3 stimulation defined by tritium (3H) incorporation of less than 3500 cpm, whereas 11 patients were responders with 3H incorporation of 3500 cpm or more. Responders produced higher levels of interleukin (IL)-12 and interferon gamma (IFN-gamma) after alphaCD3 stimulation than nonresponders. No phenotypic or clinical differences were identified between groups. Stimulation with alphaCD3/alphaCD28 beads enhanced IFN-gamma and IL-2 produced by both groups. Bead ATCs were generated from PBMCs of patient 11 in the responder group and lysed (+/- SD) 100% +/-1% of autologous tumor and 49% +/-1% of allogeneic tumor. Bead ATCs from LNMCs of this patient lysed 58%+/-1% of autologous tumor and 63%+/-1% of allogeneic tumor. CONCLUSIONS: A subpopulation of patients with HNSCC who are nonresponders to alphaCD3 stimulation has been identified, showing reduced proliferation and IL-12 and IFN-gamma secretion. Nonresponders stimulated with alphaCD3/alphaCD28 beads reversed immune unresponsiveness and induced a type 1 cytokine response. Bead-generated ATCs from patient 11 in the responder group lysed autologous and allogeneic HNSCC in vitro, suggesting a possible effective immunotherapeutic modality in the treatment of HNSCC.

Dendritic cells generated from CD34+ progenitor cells with flt3 ligand, c-kit ligand, GM-CSF, IL-4, and TNF-alpha are functional antigen-presenting cells resembling mature monocyte-derived dendritic cells.

Dendritic cells (DCs) are powerful antigen-presenting cells. Because DCs are rare cells, methods to produce them in vitro are valuable ways to study their biologic properties and to generate cells for immunotherapy. This study defines the antigen-presenting properties of DCs generated in vitro from CD34+ cells of patients with breast cancer. The combination of cytokines flt3 ligand + c-kit ligand + granulocyte-macrophage colony-stimulating factor (GM-CSF) + interleukin-4 (IL-4) + tumor necrosis factor-alpha (TNF-alpha) was used to maximize the output of mature DCs in the culture of CD34+ cells while minimizing the production of monocytes. Cells grew and differentiated into DCs as measured by a time-dependent upregulation of cell surface antigens major histocompatibility complex class II, CD1a, CD80, CD86, CD40, and CD4, so that 40% +/- 9% (n = 6) of cells in culture at day 15 were CD1a+CD14-. Markers were acquired in the same sequence as on monocytes induced to differentiate with GM-CSF + IL-4. Differentiation was marked by a time-dependent increase in allostimulatory function, which, at its peak, was more potent than in cultures of DCs generated from monocytes with GM-CSF + IL-4, but was comparable on a cell-to-cell basis to that of mature monocytes cultured in flt3-ligand + c-kit-ligand + GM-CSF + IL-4 + TNF-alpha. Both CD34+ cell-derived and monocyte-derived DCs were able to process and to present tetanus toxoid and keyhole limpet hemocyanin to autologous T cells and to present major histocompatibility class I-binding peptides to CD8+ cytotoxic T lymphocytes inducing interferon-gamma production. Altogether, these results suggest that DCs generated from CD34+ cells of patients with breast cancer with flt3 ligand, c-kit ligand, GM-CSF, IL-4, and TNF-alpha are competent antigen-presenting cells, particularly for CD8+ cytotoxic T lymphocytes, and resemble mature monocyte-derived DCs in the assays described here.

Anti-CD3/anti-CD28 monoclonal antibody-coated suture enhances the immune response of patients with head and neck squamous cell carcinoma.

OBJECTIVE: To test whether anti-CD3/anti-CD28 (alphaCD3/alphaCD28) monoclonal antibodies could be coated on surgical suture and used to enhance T-cell immune function in patients with advanced-stage head and neck squamous cell carcinoma (HNSCC). DESIGN: AlphaCD3/alphaCD28 monoclonal antibodies at varying concentrations and ratios were coated on surgical sutures and tested on peripheral blood mononuclear cells from normal donors to identify the optimal stimulating condition. Immune-enhancing properties of alphaCD3/alphaCD28 monoclonal antibody suture were tested on peripheral blood mononuclear cells and regional lymph node mononuclear cells isolated from patients with advanced HNSCC and on normal donor peripheral blood mononuclear cells. Proliferation, T-cell phenotype, and cytokines were measured during 8-day in vitro stimulation with alphaCD3/alphaCD28 suture and compared with alphaCD3/alphaCD28-coated tissue culture plastic, a previously recognized carrier. RESULTS: Optimal stimulation was observed with monofilament nylon incubated with alphaCD3/alphaCD28, 2 microg/mL, at a 1:1 ratio for 18 hours at 37 degrees C. Strong proliferation of peripheral blood mononuclear cells and lymph node mononuclear cells in patients with HNSCC was induced by alphaCD3/alphaCD28 suture. There was no difference in maximal proliferation between alphaCD3/alphaCD28 plastic and suture. On day 6 after alphaCD3/alphaCD28 suture stimulation, T-cell subpopulations expressing CD3, CD4, CD8, CD28, and CD45RO were enhanced. Suture stimulation significantly enhanced interleukin 2 secretion when compared with plastic stimulation (P = .01). Both alphaCD3/alphaCD28 suture and plastic stimulated interferon gamma secretion. CONCLUSIONS: To our knowledge, this study is the first to report the modification of surgical suture to create an immunomodulant. AlphaCD3/alphaCD28-coated suture expanded T cells from patients with HNSCC and induced a T(H)1 immune response, which may be a useful therapeutic tool in the treatment of HNSCC and other diseases.

Dendritic cells generated either from CD34+ progenitor cells or from monocytes differ in their ability to activate antigen-specific CD8+ T cells.

Dendritic cells (DC) can be generated in vitro from monocytes (M-DC) or from CD34+ hemopoietic progenitor cells (CD34-DC) but their precursors are not equivalent cells, prompting a comparison of the functional capacities of these APC. Both types of DCs established from the same individuals using the same cytokines displayed a comparable phenotype of mature DC (CD1a+, CD83+, CD86+, CD4+, HLA-DR++, CD14-, CD15- ) and were equally potent stimulators of allogeneic T cell proliferation, being both more powerful than immature M-DCs. An autologous panel of APCs produced in HLA-A2+ individuals, including CD34-DC, M-DC, monocytes, and EBV-lymphoid cell line was comparatively evaluated for presentation of the Erb-B2 peptide E75 to a CTL line. After short exposures (5 h) to E75-loaded APCs, similar levels of intracellular IFN-gamma were induced in Ag-specific CD8+ T cells regardless of APC type. In sustained cultures (4-14 days), more Ag-specific T cells were obtained when peptide was presented on CD34-DC (p < 0.05) rather than on M-DC, EBV-lymphoid cell lines, or monocytes, and these effects were dose-dependent. Activated T cells expressed 4-1BB, and the presence of 4-1BB-Ig fusion protein partially blocked Ag-specific CD8+ cell activation after CD34-DC or M-DC presentation. Our results show that 34-DC have a preferential capacity to activate CD8+ T cells and that this property is not strictly correlated to their ability to induce allogeneic T cell proliferation but due to mechanisms that remain to be defined.

Protection against mammary tumor growth by vaccination with full-length, modified human ErbB-2 DNA.

ErbB-2 is overexpressed in several human cancers and conveys a transforming activity that is dependent on tyrosine kinase activity. Antibodies and T cells to ErbB-2 have been isolated from cancer patients, indicating ErbB-2 as a potential target of active vaccination. In this study, 3 mutant ErbB-2 DNA constructs encoding full-length, ErbB-2 proteins were tested as tumor vaccines. To eliminate tyrosine kinase activity, the ATP binding lysine residue 753 was substituted with alanine by replacing codon AAA with GCA in mutant ErbB-2A. To direct recombinant ErbB-2 to the cytoplasm where major histocompatibility complex (MHC) I peptide processing takes place, the endoplasmic reticulum (ER) signal sequence was deleted in cyt ErbB-2. The third construct cyt ErbB-2A contained cytoplasmic ErbB-2 with the K to A mutation. Expression of recombinant proteins was measured by flow cytometry in transfected murine mammary tumor cell line D2F2. Transmembrane ErbB-2 and ErbB-2A were readily detected. Cytoplasmic ErbB-2 and ErbB-2A were detected only after the transfected cells were incubated overnight with a proteasome inhibitor, indicating prompt degradation upon synthesis. ErbB-2 autophosphorylation was eliminated by the K to A mutation as demonstrated by Western blot analysis. Growth of ErbB-2-positive tumor in BALB/c mice was inhibited after vaccination with ErbB-2 or ErbB-2A, but not with cyt ErbB-2 or cyt ErbB-2A. ErbB-2A that is free of tyrosine kinase activity is a potential candidate for anticancer vaccination. The 3 mutant constructs should be useful tools to delineate the role of individual immune effector cell in ErbB-2-specific antitumor immunity and to develop strategies for enhancing such immunity.

Neoplastic progression of breast epithelial cells--a molecular analysis.

Molecular changes associated with breast cancer progression were characterized using the MCF-10F cell series. MCF-10F was established from fibrous mastectomy tissue of a patient without detectable cancer. In vitro treatment of MCF-10F cells with benzo(a)pyrene resulted in a transformed subclone MCF-10F-BP1 (BP1). Transfection of clone BP1 with T24-Hras resulted in the tumorigenic line MCF-10F-BP1-Tras (BP1-Tras). Using flow cytometry, the expression of HLA I, ERBB-2 and MUC-1 was found to be comparable in 'normal' MCF-10F, transformed BP1 and tumorigenic BP1-Tras cells. Glycosylated mucin is elevated in BP1 but reduced in BP1-Tras cells. Using mRNA differential display analysis, cDNA profiles of the 'normal', transformed and tumorigenic cell lines were strikingly similar, yet distinct and elevated expression of several common cDNA fragments was detected in BP1 and BP1-Tras when compared with MCF-10F cells. These fragments were cloned and sequenced. The sequences of clones T1-360 and C4-310 are homologous to two reported EST cDNA clones from human fetal tissue and were further characterized. Elevated expression of the genes corresponding to clones T1-360 and C4-310 was verified using Northern blotting. High-level expression of these genes was also detected in the breast cancer cell line MCF-7 that was derived from the pleural effusion of a patient with advanced breast cancer. Therefore, specific molecular changes associated with breast cancer development were identified and may be indicators of neoplastic progression.

Inhibition of tumor growth by peptide specific cytotoxic T lymphocytes in a three-dimensional collagen matrix.

Tumor associated, MHC I restricted antigenic peptides have been identified in both human and mouse tumors. Cytotoxic T lymphocytes (CTL) which recognize these tumor associated antigenic peptides are potential anti-cancer effectors. The anti-tumor activity of CTL is usually measured in vitro by the 51Cr release assay and in mice by tumor growth inhibition which is the most direct assessment of anti-tumor effect. In clinical studies, an in vivo tumor growth inhibition assay is not an option and an in vitro assay which corroborates with in vivo tumor growth is needed to assess the long-term outcome of CTL activity. Here, a three-dimensional (3-D) collagen gel assay was developed to measure in vitro the inhibition of mouse mammary tumor growth by anti-tumor CTL. BALB/c mouse CTL were induced with peptide E474 SFAVATTAL which was expressed by mouse mammary tumor cells D2F2. To measure D2F2 tumor growth inhibition in vitro, a mixture of tumor cells and anti-E474 CTL in a 1 microl cell bolus was embedded in the collagen gel. Complete eradication of tumor growth was observed at E:T ratio of or greater than 1:1. rIL-2 supplementation was necessary to achieve long-term tumor growth inhibition. Even spontaneous D2 tumor explant could be grown in the collagen gel and addition of anti-E474 to this culture reduced tumor growth. This assay system provides a realistic and sensitive alternative to the in vivo tumor growth inhibition assay and allows easy adaptation to test additional therapeutic reagents.

Induction of cytotoxic T lymphocytes to murine mammary tumor cells with a Kd-restricted immunogenic peptide.

A synthetic peptide E474 SFAVATTAL, derived from the sequence of mouse mammary tumor virus envelope protein, was previously shown to bind class I MHC Kd. Immunization of BALB/c mice with E474 in 50% incomplete Freund's adjuvant (IFA) followed by in vitro stimulation of immune cells with E474-coated antigen-presenting cells resulted in peptide-specific cytotoxic T lymphocytes (CTL). Furthermore, anti-E474 CTL lysed mammary tumor cell lines D2F2 and D2A1, derived from a spontaneous tumor that arose in BALB/c pre-neoplastic hyperplastic alveolar nodule (HAN) D2 line. Expression of Kd by D2A1 and D2F2 cells was verified by flow cytometry, and lysis of D2 tumor cells was blocked by monoclonal antibody 31-34-S, which interacted with the peptide-binding region of Kd, supporting the recognition of E474 in Kd by anti-E474 CTL. Immunization of BALB/c mice with E474 before D2F2 tumor challenge resulted in reduced tumor growth. Therefore, E474 is naturally processed and presented by these tumor cells and can induce anti-tumor immunity.

PEPMOTIF: a program for locating class I major histocompatibility complex restricted peptides in protein sequences.

PEPMOTIF is a computer program which analyzes protein sequences for the occurrence of peptides up to ten residues in length which contain motifs presented by particular class I major histocompatibility complexes. Any peptide motifs defined by the user can be identified in a protein sequence of interest. PEPMOTIF generates a listing of all motif-containing peptides found in the protein, and two modes of data output are provided: (1) direct printout, or (2) storage in a text file on disk.