Complex relationships between shallow muddy benthic assemblages, sediment chemistry and toxicity in estuaries in southern New South Wales, Australia

Synoptic sediment quality triad (contaminants, benthic assemblages, toxicity testing) data were collected for sites in Sydney estuary, adjacent Cooks River and five less-modified southern estuaries. Matching data tested relationships between contaminants and benthic assemblages, correlations with specific contaminants, and the ability of sediment quality guidelines to predict the risk of adverse effects. Significant but weak relationships occurred in complex patterns between assemblages, contaminant concentrations and environmental variables. Maximum benthos abundance occurred where sediment contamination was high and was dominated by polychaetes. Spionidae (polychaete) and Galeommatidae (mollusc) abundances were strongly correlated with site environmental characteristics and with varying mixtures of metals and organic contaminants. The risk of adverse effects on benthic assemblage structure increased with increasing sediment toxicity except for areas of very high contamination and for non-bioavailable anthropogenic chemicals. The overall weight-of-evidence scores differentiated the highly modified sites from less-contaminated southern estuaries, where toxicity scores were higher than predicted.

Anti-interleukin-10R1 monoclonal antibody in combination with bacillus Calmette--Guérin is protective against bladder cancer metastasis in a murine orthotopic tumour model and demonstrates systemic specific anti-tumour immunity

Effective treatment of bladder cancer with bacillus Calmette-Guérin (BCG) depends on the induction of a T helper type (Th) 1 immune response. Interleukin (IL)-10 down-regulates the Th1 response and is associated with BCG failure. In this study, we investigated whether blocking IL-10 signalling could enhance the BCG-induced Th1 response and anti-tumour immunity in a murine orthotopic tumour model. Treatment with BCG and anti-IL-10 receptor 1 monoclonal antibody (anti-IL-10R1 mAb) increased the interferon (IFN)-γ to IL-10 ratio in both splenocyte cultures and urine. Mice bearing luciferase-expressing MB49 (MB49-Luc) tumours were treated and followed for tumour growth by bioluminescent imaging, bladder weight and histology. Mice treated with phosphate-buffered saline (PBS) (group 1), BCG plus control immunoglobulin (Ig)G1 (group 2) or BCG plus anti-IL-10R1 mAb (group 3) showed 0, 6 and 22% tumour regression, respectively. The mean bladder weight of group 3 mice was substantially lower than those of groups 1 and 2 mice. Remarkably, 36% of group 1 and 53% of group 2 mice but no group 3 mice developed lung metastasis (P = 0·02). To investigate the mechanisms underlying the effect of combination therapy, splenocytes were stimulated with S12 peptide (serine mutation at codon 12 of the K-ras oncogene) known to be expressed in MB49-Luc cells. Induction of ras mutation-specific IFN-γ and cytotoxicity was observed in mice treated with combination therapy. These observations indicate that BCG, in combination with anti-IL-10R1 mAb, induces enhanced anti-tumour immunity that is protective against lung metastasis. Anti-IL-10R1 mAb demonstrates systemic effects and may prove useful in clinical practice for treating bladder cancer in high-risk patients.

Utility of quantitative fluorescent in situ hybridization (FISH) to predict non-muscle-invasive bladder cancer (NMIBC) recurrence

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Background: Urovysion's (Abbot Laboratories, Downers Grove, IL) FISH analysis is used to monitor bladder cancer recurrence in patients with a history of NMIBC and is often reported as a binary variable (normal/abnormal). We investigated whether the percentage of abnormal cells as determined by FISH analysis in patients with a history of NMIBC correlated with risk of recurrence.

Methods: At our institution, barbotage FISH analysis is routinely done along with cystoscopy and cytology on both high risk (Ta/T1 high grade or CIS) and low or intermediate risk patients (all others) at every 3-month follow-up for the first year post-resection. We retrospectively reviewed 241 consecutive NMIBC patients and identified 399 FISH analyses for which we had one year follow-up. Normal FISH analyses were defined as 2 or fewer abnormal cells per sample. We calculated the percentage of abnormal cells and correlated that to the number of patients who had a recurrence of NMIBC as defined by positive high grade cytology or tumor on cystoscopy during the first year of follow-up.

Results: The sensitivity, specificity, and positive and negative predictive values of FISH analysis if reported as a binary variable was 55, 43, 16 and 89%, respectively. Considering only those patients with abnormal FISH, the average percentage of abnormal cells for patients who were found to have NMIBC recurrence at 1 year was 38% (range 6–100) compared to 21% (range 6–100) for patients who were recurrence-free at 1 year (p<0.0001). High risk patients who recurred within 1 year had a statistically higher percentage of abnormal cells as compared to those who did not recur within 1 year (50% [range 6–100] vs. 25% [range 6– 100], respectively p=0.001). There was no difference in the percentage of abnormal cells for those patients with low or intermediate risk disease based on recurrence within 1 year (22% [range 6–100] vs. 20% [range 6–100], respectively p=0.25).

Conclusions: The percentage of abnormal cells in FISH analysis correlates with risk of recurrence for patients with high risk disease and can be used to guide surveillance interval decisions in patients with no other evidence of recurrence.

[Table: see text]

Ability of urovysion FISH analysis to select patients with low- or intermediate-risk non-muscle-invasive bladder cancer (LI-NMIBC) for decreased surveillance

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Background: Recurrent LI-NMIBC is difficult to detect cytologically, requiring frequent cystoscopies. Urovysion's (Abbot Laboratories, Downers Grove, IL) fluorescent in situ hybridization assay (FISH) detects genetic changes associated with LI-NMIBC and may be useful in identifying patients for extended screening intervals.

Methods: Charts of 54 consecutive patients with LI-NMIBC who underwent cystoscopy, cytology, and FISH analysis every 3 months for the first year after resection since 2004 were retrospectively identified and reviewed. We analyzed the number of tumors or high-grade cytologies that would have been missed if surveillance cystoscopy, cytology, and FISH analysis had not been done between 3 and 12 months post-resection for patients with a normal cystoscopy, cytology, and FISH analysis at 3 months after initial resection and compared those results to patients with normal cystoscopy, cytology, and abnormal FISH analysis.

Results: Mean age of the 54 patients was 67 (range 25–89) and 41 were males. Thirty-nine patients had normal cystoscopy, cytology, and FISH analysis at 3-months follow-up. If no further surveillance was done until 1 year post-resection, 2 low-grade tumors (3 and 7 mm at 7 months post-resection) and 2 incidents of high-grade cytology would have been missed (4 of 39, 10%). Fifteen patients had normal cystoscopy and cytology but abnormal FISH analysis results at 3 months. If no further surveillance had been done until 1 year after resection, 6 tumors (6 of 15, 40%) (5, 8, 3, 3, 9, 2 mm at 5, 6, 6, 7, 9, 10 months post-resection) and no high-grade cytology would have been missed. Overall, statistically fewer patients with normal compared to abnormal FISH analysis at first follow-up developed tumors before 1 year (4 of 39 vs. 6 of 15, p=0.033).

Conclusions: FISH analysis can be used to significantly increase our ability to select patients suitable for extended screening intervals. It may be prudent to include FISH analysis at the first post-resection follow-up before selecting patients with LI-NMIBC for an extended screening interval.

[Table: see text]

A phase I study of intravesical Ad-IFN in superficial bladder cancer patients

e16048

Background: Intravesical BCG (Bacillus Calmette-Guérin) is the gold standard for treatment of superficial bladder cancer. Recurrence is a significant problem. Intravesical interferon α (IFN) demonstrated complete response (CR) in ∼40% patients with most relapsing <1 year. Intravesical Ad-IFN takes advantage of the bladder to allow prolonged exposure to high concentrations of IFN; this is expected to potentiate durable therapeutic responses. Syn3 is an excipient used to increase adenoviral vector (Ad) transfection. Methods: The phase I study is a nonrandomized, open-label, rising-dose, multi-center study of Ad-IFN in patients with papillary bladder cancer, or carcinoma in situ refractory to BCG. Patients with T1 were not enrolled unless they refused cystectomy. A minimum of 3 subjects were enrolled at each dose level. Adverse events and lab abnormalities were graded according to CTC version 3 criteria. The occurrence of treatment-related Grade 3 or Grade 4 toxicity is considered dose-limiting toxicity (DLT). The maximum tolerated dose is defined as the dose which results in DLT in ≤1/6 subjects. Urine from pre-treatment, posttreatment days 0–7, 10, 14, and 28 were tested for IFN, Syn3, Ad-IFN DNA, and research biomarkers. Blood was assayed for IFN, Syn3, Ad-IFN DNA, anti- adenovirus and anti-IFN antibodies. Results: Intravesical administration of 3×109, 1×1010, 3x1010, 1×1011, or 3×1011 particles/ml of Ad-IFN (75ml) in 1mg/ml Syn3 is safe with only minor initial urgency controlled with anticholinergic medication. Of the 13 evaluable patients, 6 are CR, defined as a negative cytology and biopsy at 3 months. CR patients were offered a second dose. Response duration is variable with longest >1 year. Urinary IFN was seen for all patients in a dose-dependent fashion. TRAIL, IP-10, M65, and M30 were also seen. Conclusions: Initial safety and response activity justify further clinical development.

[Table: see text]

Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces human CC- and CXC-chemokines in vitro and in vivo

Both CC- and CXC-chemokines are known to be potent leucocyte activators and chemoattractants and play important roles in inflammatory responses. However, chemokine response to bacillus Calmette-Guérin (BCG) infection remains incompletely defined. In this study, we investigated human CC- [macrophage-derived chemokine (MDC), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha and eosinophil chemoattractant activity (eotaxin)] and CXC-interferon-inducible protein (IP)-10 chemokine production in response to BCG stimulation. BCG efficiently induced all chemokines tested in the urine of four bladder cancer patients undergoing intravesical BCG immunotherapy. The peak urinary chemokine responses occurred generally between the fourth and sixth weekly treatment, except eotaxin, which was less predictable. To evaluate the effect of BCG on induction of chemokines in vitro, urothelial cell lines and peripheral blood mononuclear cells (PBMCs) were used. Although BCG induced no or marginal chemokines from urothelial SV-HUC-1, RT4 and T24 cells, BCG-derived cytokines [interleukin (IL)-1beta, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha] induced all chemokines tested except eotaxin from these cell lines. BCG also efficiently induced all chemokines tested except eotaxin from PBMCs of both BCG-naive and BCG-vaccinated subjects. MCP-1 and MIP-1alpha emerged at 4-5 h post-BCG exposure (early chemokines); IP-10 elevated at day 1 and peaked at day 2 (intermediate chemokine); and MDC elevated at day 1 and peaked at day 7 (late chemokine). This kinetic pattern was paralleled with that of BCG-induced cytokines [early: TNF-alpha; intermediate: IL-6 and IL-10; and late: IFN-gamma and granulocyte-macrophage colony-stimulating factor (GM-CSF)]. Taken together, these results indicate that BCG directly or indirectly induces human CC- and CXC-chemokine production, which may represent one of the mechanisms by which BCG exerts its anti-tumour activity.

Recombinant Mycobacterium bovis bacillus Calmette-Guérin (BCG) expressing mouse IL-18 augments Th1 immunity and macrophage cytotoxicity

Interleukin-18 (IL-18) has been demonstrated to synergize with BCG for induction of a T-helper-type 1 (Th1) immune response. Since successful treatment of superficial bladder cancer with BCG requires proper induction of Th1 immunity, we have developed a recombinant (r) BCG strain that functionally secretes mouse (m) IL-18. This rBCG-mIL-18 strain significantly increased production of the major Th1 cytokine IFN-gamma in splenocyte cultures, at levels comparable to that elicited by control BCG plus exogenous rIL-18. IFN-gamma production by splenocytes was eliminated by addition of neutralizing anti-IL-18 antibody. Endogenous IL-12 played a favourable role whereas IL-10 played an adverse role in rBCG-mIL-18-induced IFN-gamma production. Enhanced host antimycobacterial immunity was observed in mice infected with rBCG-mIL-18 which showed less splenic enlargement and reduced bacterial load compared to control mice infected with BCG. Further, splenocytes from rBCG-mIL-18-infected mice, in response to BCG antigen, displayed increased production of IFN-gamma and GMCSF, decreased production of IL-10, elevated cellular proliferation and higher differentiation of IFN-gamma-secreting cells. rBCG-mIL-18 also enhanced BCG-induced macrophage cytotoxicity against bladder cancer MBT-2 cells in a dose-dependent manner. Neutralizing all endogenous macrophage-derived cytokines tested (IL-12, IL-18 and TNF-alpha) as well as IFN-gamma severely diminished the rBCG-mIL-18-induced macrophage cytolytic activity, indicating a critical role for these cytokines in this process. Cytokine analysis for supernatants of macrophage-BCG mixture cultures manifested higher levels of IFN-gamma and TNF-alpha in rBCG-mIL-18 cultures than in control BCG cultures. Taken together, this rBCG-mIL-18 strain augments BCG's immunostimulatory property and may serve as a better agent for bladder cancer immunotherapy and antimycobacterial immunization.

Interleukin 10 induced augmentation of delayed-type hypersensitivity (DTH) enhances Mycobacterium bovis bacillus Calmette-Guérin (BCG) mediated antitumour activity

Intravesical BCG therapy is effective in the treatment of superficial bladder cancer. Both clinical and experimental results suggest a role for cytokines and delayed-type hypersensitivity (DTH) in BCG-induced antitumour immunity. We characterized the modulatory effects of BCG on bladder cytokine expression and determined the relationship between DTH and BCG antitumour activity. The bladders of mice were instilled with BCG through a catheter. Bladder tissue RNA and urine were collected for evaluation of cytokine expression using reverse transcriptase-polymerase chain reaction (RT-PCR) and/or ELISA. IFN-gamma and TNF-alpha, the two major cytokines associated with DTH, were efficiently induced by BCG. IL10, an important down-regulator of DTH, was also induced by BCG. Constitutive levels of IL4 and IL5 were observed, but neither IL4 nor IL5 were modulated by BCG. Similar results were observed in the kinetic analysis of urinary cytokines in patients after intravesical BCG therapy. Production of Th1 (T helper type 1) cytokines (IFN-gamma, IL2 and IL12) preceded that of the Th2 (T helper type 2) cytokine IL10. A tendency toward higher ratios of IFN-gamma versus IL10 for BCG responders also was observed. In animal studies the absence of IL10 abrogated either by antibody inhibition or the use of genetically modified, IL10 deficient (IL10-/-) mice resulted in enhanced DTH responses. Under conditions of enhanced DTH, a significant enhancement in antitumour activity was observed. These data demonstrate that DTH and its associated mononuclear infiltration and cytokine production are important to the antitumour activity of intravesical BCG therapy, and suggest that effects to diminish IL10 production may have therapeutic value.

Salvage intravesical therapy with interferon-alpha 2b plus low dose bacillus Calmette-Guerin is effective in patients with superficial bladder cancer in whom bacillus Calmette-Guerin alone previously failed

PURPOSE

We determined whether combining low dose bacillus Calmette-Guerin (BCG) interferon-alpha 2B would be effective for patients in whom previous BCG failed.

MATERIALS AND METHODS

A total of 40 patients in whom 1 (19) or more (21) previous induction courses of BCG failed received 6 to 8 weekly treatments of 1/3 dose (27 mg.) BCG plus 50 million units interferon-alpha 2B. Additional 3 week miniseries of further decreased BCG (1/10, 1/30 or 1/100) titrated to symptoms without changing the interferon-alpha 2B dose were given at 5, 11 and 17 months. In 12 patients a second induction course was given with 1/10 BCG plus 100 million units interferon-alpha 2B. There was multifocal disease in 39 patients, previous BCG had failed within 6 months in 34, disease was aggressive (stage T1, grade 3 or carcinoma in situ in 31, there had been 2 or more previous recurrences in 25 and disease history was greater than 4 years in 13.

RESULTS

At a median followup of 30 months 63% and 53% of patients were disease-free at 12 and 24 months, respectively. Patients in whom 2 or more previous BCG courses had failed fared as well as those with 1 failure. Of the 18 failures 14 occurred at the initial cystoscopy evaluation. Of 22 patients initially counseled to undergo cystectomy 12 (55%) are disease-free with a functioning bladder. Combination therapy was well tolerated.

CONCLUSIONS

While longer followup and larger multicenter studies are required to validate these encouraging findings, intravesical low dose BCG plus interferon-alpha 2B appears to be effective in many cases of high risk disease previously deemed BCG refractory. However, early failure while on this regimen should be aggressively pursued with more radical treatment options.

Recombinant bacille Calmette-Guérin (BCG) expressing human interferon-alpha 2B demonstrates enhanced immunogenicity

To increase its immunostimulatory properties, BCG was genetically engineered to secrete recombinant human interferon-alpha 2B (rhIFN-alpha) under control of the mycobacterial heat shock protein (hsp)60 promoter and the alpha antigen signal sequence. Expression of rhIFN-alpha was readily detectable by ELISA and on Western blotting. When compared with control BCG, rhIFN-alpha BCG was substantially more active in inducing the production of IFN-gamma and IFN-inducible protein 10 (IP-10) from human peripheral blood mononuclear cells, while IL-10 production was correspondingly decreased. These effects were reversible upon antibody neutralization of rhIFN-alpha. Among 10 patients tested, rhIFN-alpha BCG enhanced IFN-gamma production in all patients ranging from 1.4- to 23.7-fold with a general trend toward greatest enhancement among those with weakest baseline responses to control BCG. Correspondingly, rhIFN-alpha BCG decreased IL-10 production in all patients by 1.2-4.8-fold. The onset of IFN-gamma production induced by rhIFN-alpha BCG was also more rapid, occurring within 4 h after stimulation versus > 24 h with wild-type BCG. The observation that the maximum IFN-gamma induction depends on the simultaneous presence of both IFN-alpha and BCG highlights the advantages of rhIFN-alpha BCG. Taken together, these immunostimulatory properties of rhIFN-alpha BCG suggest that it may be a superior agent for immunotherapeutic protocols involving live BCG in humans.

BCG-induced urinary cytokines inhibit microvascular endothelial cell proliferation

PURPOSE

Angiogenesis is thought to depend on a net balance of molecules that inhibit or stimulate microvascular endothelial cells. A variety of molecules that affect angiogenesis are induced locally by the administration of intravesical bacille Calmette-Guerin (BCG) for superficial bladder cancer. We sought to determine whether BCG-induced urinary cytokines alter the effects of patient urine on assays of angiogenic activity.

MATERIALS AND METHODS

Patients undergoing BCG treatment provided urine samples before and at peak cytokine production times after BCG instillation. Fifty-four urine samples from 8 patients were analyzed by ELISA for a panel of molecules known to affect angiogenesis, and tested for angiogenic activity in human dermal microvascular endothelial cell (HDMEC) proliferation and migration assays. To assess the role of specific BCG-induced cytokines, urinary HDMEC proliferation assays were repeated in the presence of neutralizing antibodies to tumor necrosis factor-alpha (TNF-alpha), interferon-inducible protein-10 (IP-10), and/or interferon-gamma (IFN-gamma).

RESULTS

Urinary IFN-gamma, IP-10, TNF-alpha, and vascular endothelial growth factor (VEGF) were induced to nanogram/ml amounts by BCG treatment. While pre-BCG treatment urine samples minimally stimulated microvascular endothelial cell proliferation (+ 9%), post-BCG treatment urine became progressively inhibitory to endothelial cells (to -85%, p = 0.005) during weekly treatment courses. Neutralizing antibodies to TNF-alpha or to IP-10, either alone or in combination, greatly reduced this inhibitory effect.

CONCLUSIONS

Intravesical BCG induces a cytokine-rich urinary microenvironment that is inhibitory to human endothelial cells. Urinary cytokine profiles and assays of angiogenic inhibition may provide prognostically important information regarding BCG treatment outcomes.

Co-expression of interleukin-2 and green fluorescent protein reporter in mycobacteria: in vivo application for monitoring antimycobacterial immunity

Recombinant Mycobacterium bovis bacillus Calmette-Guérin expressing green fluorescent protein (rBCG-GFP), driven by the mycobacterial heat shock protein 70 (HSP 70) promoter from an autonomously replicating plasmid, was genetically engineered to co-express mouse interleukin-2 (IL-2) by introduction of an independent HSP 60 promoter. To monitor host antimycobacterial immunity, C57BL/6 mice were intravenously infected with IL-2 expressing and non-expressing GFP rBCGs. Both rBCGs were clearly imaged and easily quantified with ultraviolet microscopy of tissue sections and whole organ suspensions. Enhanced mycobacterial clearance from the spleens of mice infected with the rBCG-IL-2/GFP strain was apparent by both diminished bacterial counts and spleen weights during the first 6 weeks post-infection relative to rBCG-GFP. T helper type 1 (TH1) cytokine production and proliferative response to BCG restimulation was also elevated from in vitro splenocyte cultures taken from the rBCG-IL-2/GFP-infected group. Taken together, these results suggest that IL-2 expression from rBCG augmented host protective immunity to mycobacterial infection via an enhanced TH1 immune response. Mycobacterial expression vectors that allow simultaneous but independent production of reporter proteins and bioactive substances provide an ideal means for monitoring the in vivo fate of recombinant mycobacteria.

Clinical and pathological characteristics of micropapillary transitional cell carcinoma: a highly aggressive variant

PURPOSE

We present preliminary clinical, histochemical and molecular findings for 5 patients with micropapillary transitional cell carcinoma of the bladder, a rare histological variant not widely recognized in the urological literature.

MATERIALS AND METHODS

The 5 patients were prospectively identified. In 3 cases immunohistochemical staining for expression of CD31, p53, E-cadherin, and alpha, beta and gamma-catenin was performed on paraffin embedded tissue. Sequencing was used to identify point mutations in exons 5 to 9 of p53, and exons 1 and 2 of H-ras.

RESULTS

Of the patients 2 died within 1 year of presentation to our institution with rapid local extension along the bladder serosal surface and ureteral sheaths. Another patient had progression to invasive disease within 22 months. In the 3 cases with immunohistochemical staining p53 was negative, despite positive staining of nonmicropapillary transitional cell carcinoma within the same specimen. Stains for the angiotrophic marker CD31 were negative. In all 3 cases normal membrane associated alpha, beta and gamma-catenin expression was present. Examination of p53 sequences revealed a single point mutation in exon 8 of 1 case. In 2 cases different mutations in exon 1 of H-ras were noted.

CONCLUSIONS

Micropapillary transitional cell carcinoma is a rare and highly aggressive variant. Paradoxically, our study demonstrated no significant p53 abnormalities. The lacunar histological pattern did not appear to represent invasion of vascular spaces. Rather, these tumors seemed to have the ability to disrupt and replace the normal stromal matrix to achieve rapid nonendothelial extension. Thus, micropapillary histology may predict a lesser likelihood of surgical cure.

Interleukin-12. Opportunities for the treatment of bladder cancer

Despite incomplete understanding of the human immune system, the rapid progress in tumor immunology provides a framework for more effective and safe interventions in the near future. Early approaches in patients with cancer that have focused on the nonspecific and broad stimulation of the immune system by interferons and IL-12 will be replaced by the highly specific stimulation of immune reactions targeting precisely defined tumor antigens. IL-12 has several biologic properties that seem useful in immune therapy for bladder cancer. The striking antitumor responses with IL-12 in preclinical animal models of bladder cancer provide optimism that future clinical trials involving this agent may impact on the risk and mortality associated with this disease.

Role of IL-12 in the induction and potentiation of IFN-gamma in response to bacillus Calmette-Guérin

Although Mycobacterium bovis bacillus Calmette-Guérin (BCG) has been accepted as the most effective agent in clinical use against superficial bladder cancer, its mechanism of action remains incompletely understood. A kinetic analysis in assessing the potential role of cytokines from BCG-stimulated murine splenocytes showed that IL-12 expression preceded that of other cytokines. Experiments subtracting endogenous BCG-driven IL-12 using neutralizing Ab or augmenting its activity with supplemental rIL-12 revealed not only that IL-12 plays a dominant role in IFN-gamma induction but also that it is normally dose limiting. A striking increase in IFN-gamma production could be generated in both mouse and human immunocompetent cell culture by the addition of even a small amount of rIL-12. Moreover, this same synergistic effect could be replicated during in vivo administration of BCG plus rIL-12 into the mouse bladder and was observed in a patient receiving intravesical combination therapy. In costimulation cultures, this synergy appeared to partially rely on IL-18 and IL-2 and could be down-regulated by IL-10. This suggests that a dynamic interplay between Th1 and Th2 cytokines is responsible for net IFN-gamma production. The ability of supplemental exogenous IL-12 to strongly shift this balance toward Th1 provides an immunological basis for using it in conjunction with intravesical BCG for bladder cancer immunotherapy.

Mutated ras p21 as a target for cancer therapy in mouse transitional cell carcinoma

PURPOSE

To establish an experimental mouse model for bladder cancer immunotherapy using mutated ras as a target.

MATERIALS AND METHODS

A tumorigenic mouse bladder transitional cell carcinoma (TCC) line MB49 (C57BL/6 origin) was analyzed for its c-ras gene status by DNA cloning and sequencing. Aberrant expression of the ras gene was measured with Western blotting. 13-mer peptides corresponding to residues 5 to 17 of the ras protein were synthesized and tested for immunogenicity in syngeneic C57BL/6 mice. Induction of specific immune responses was evaluated by analyzing splenocyte activity in vitro and tumor suppression in vivo.

RESULTS

MB49 cells were found to contain a single amino acid substitution of serine for glycine at codon 12 in K-ras loci and an abundant amount of cellular mutated ras p21 protein. C57BL/6 mice immunized with the 13-mer serine-containing ras peptide exhibited mutation-specific immune responses in splenocyte proliferation, cytokine production and cytotoxicity. Specific antitumor immunity in the form of tumor growth delay in vivo was observed in mice immunized with the same mutant peptide followed by subcutaneous MB49 tumor challenge and was enhanced by the addition of low dose interleukin-12.

CONCLUSIONS

The mouse bladder TCC line MB49 contains a serine mutation at codon 12 of its K-ras gene that is sufficient to induce mutation-specific immune responses in vitro and specific protective immunity to MB49 tumor in vivo. Mutated oncoproteins may be ideal targets for the development of specific immunotherapy regimens for bladder cancer immunotherapy.

An in vivo comparison of bacillus Calmette-Guérin (BCG) and cytokine-secreting BCG vaccines

A recombinant bacillus Calmette-Guérin (BCG) vaccine has been developed, which constitutively secretes interleukin (IL)-2. Groups of deer were immunized with either normal BCG (Pasteur 1173 P2 strain) or recombinant BCG (rBCG/IL-2) and their immune responses were monitored over 3 months. Animals gained weight over this period and showed no signs of adverse reactions to either vaccine. Lymphocyte transformation responses did not differ significantly between the two groups. No antibody that was specific for BCG was detected in any animal. Intradermal skin-test responses to BCG antigens showed that the rBCG/IL-2 induced a smaller delayed-type hypersensitivity response than the normal BCG. Cytokine transcription was determined by reverse transcription-polymerase chain reaction (RT-PCR). While IL-2 and interferon-gamma (IFN-gamma) levels did not differ significantly between the two groups, the level of IL-4 was found to be lower in the group given rBCG/IL-2. This resulted in a strong interferon-gamma:IL-4 ratio, suggesting a skewing of the immune response towards a Type 1 response. The rate at which the vaccine was eliminated from the host was the same regardless of whether BCG or rBCG was used. At autopsy (3 months after vaccination) 99.99% of the organisms had been eliminated. The small number of organisms isolated from the draining lymph node of animals given rBCG/IL-2 were grown in antibiotic-containing media. They were shown to still contain the shuttle plasmid and to secrete biologically active IL-2, indicating that the plasmid was stably maintained despite the host's immune response and in the absence of antibiotic selection.

IFN-alpha 2B enhances Th1 cytokine responses in bladder cancer patients receiving Mycobacterium bovis bacillus Calmette-Guérin immunotherapy

Combination therapy with intravesical bacillus Calmette-Guérin (BCG) plus IFN-alpha for superficial bladder cancer has been demonstrated to be more effective than either single agent alone in animal studies and of suggested greater efficacy in clinical studies. However, the mechanism by which IFN-alpha enhances BCG-mediated antitumor activity is poorly understood. Using PBMCs from bladder cancer patients, IFN-alpha was found to substantially enhance the efficacy of BCG to induce IFN-gamma production. Among 34 patients tested, 80% showed >4-fold increase. This effect of IFN-alpha was observed in both initial and memory responses to BCG. In addition, IFN-alpha up-regulated BCG-induced IL-12 and TNF-alpha and down-regulated BCG-induced IL-10. Neutralizing endogenous IL-10 or adding exogenous IL-12 provided further synergy for IFN-gamma production. In clinical practice, intravesical IFN-alpha 2B (50 million units (MU)/dose) was observed to accelerate urinary IFN-gamma production to low-dose BCG (one-tenth or one-third of a full dose) in patients treated with combination therapy compared with BCG alone. These results suggest that IFN-alpha is a potent BCG enhancer that polarizes the BCG-induced immune response toward the cellular immune pathway by promoting Th1 cytokine expression and reducing Th2 cytokine expression. This study provides an immunological basis for future rational use of IFN-alpha in conjunction with intravesical BCG for bladder cancer immunotherapy.

Intravesical bacille Calmette-Guérin induces the antiangiogenic chemokine interferon-inducible protein 10

OBJECTIVES

Intravesical bacille Calmette-Guérin (BCG) induces a variety of cytokines into the urine of patients with superficial transitional cell carcinoma (TCC) of the bladder. Recent data have shown that some cytokines have antiangiogenic activity. We sought to determine whether the potently antiangiogenic chemokine interferon-inducible protein 10 (IP-10) and its inducing antiangiogenic cytokines, interferon-gamma (IFN-gamma) and interleukin-12 (IL-12), are increased during intravesical BCG immunotherapy of bladder TCC.

METHODS

Voided urine samples were collected sequentially from 8 patients before and after each weekly intravesical BCG treatment and from 4 patients receiving maintenance BCG treatments. The urinary output of IP-10, IFN-gamma, and IL-12 over 12 post-treatment hours was assessed by enzyme-linked immunosorbent assay. In vitro BCG and cytokine stimulations of human TCC and primary endothelial cell lines were also performed, and their supernatants were studied for IP-10.

RESULTS

In all cases after intravesical BCG, patient urine was found to contain significant elevations of IP-10. Urinary IFN-gamma and IL-12 levels also increased in similar patterns after intravesical BCG. The peak weekly cytokine response per patient usually occurred between the fourth and sixth treatment for IFN-gamma and IP-10, but was less predictable for IL-12. Human TCC and endothelial cell lines were able to secrete IP-10 in response to BCG or interferon stimulation in vitro.

CONCLUSIONS

Our small series demonstrates that IP-10 and its inducing cytokines are elevated in response to intravesical BCG. These data suggest that, in addition to a cellular immune response, BCG may induce a cytokine-mediated antiangiogenic environment that aids in inhibiting future tumor growth and progression.

Superficial bladder cancer: the role of interferon-alpha

PURPOSE

We evaluate the clinical experience with recombinant interferon-alpha in superficial transitional cell carcinoma and discuss the most rational use of recombinant interferon-alpha in the context of current treatment options.

MATERIALS AND METHODS

The available data were reviewed and discussed at a consensus conference in August 1996. The conclusions and recommendations are those of the authors based on the consensus reached at that meeting.

RESULTS

While bacillus Calmette-Guerin (BCG) is recognized as the most efficacious intravesical agent in the prophylaxis and treatment of superficial transitional cell carcinoma, it is associated with significant toxicities and a 20 to 40% relapse rate. Interferons, particularly recombinant interferon-alpha, have demonstrated efficacy against primary and recurrent papillary transitional cell carcinoma and carcinoma in situ with minimal toxicity, although the response and relapse rates are inferior to BCG. Intravesical recombinant interferon-alpha therapy has also produced responses in patients who failed to respond or were refractory to BCG or chemotherapy.

CONCLUSIONS

The clinical experience suggests that recombinant interferon-alpha has an important role in the treatment of superficial transitional cell carcinoma, particularly as second line therapy following failure of BCG or chemotherapy, and it may have synergistic effects when combined with chemotherapy or BCG. We propose a prospective randomized study comparing the efficacy of recombinant interferon-alpha, BCG and BCG plus recombinant interferon-alpha as maintenance following complete response to primary BCG therapy. The proposed study would also investigate the efficacy of BCG plus recombinant interferon-alpha as second line therapy following BCG failure. This study will be important to determine the most effective strategy to integrate recombinant interferon-alpha into current treatment options for superficial bladder cancer.

Prognosis of intravesical bacillus Calmette-Guerin therapy for superficial bladder cancer by immunological urinary measurements: statistically weighted syndrome analysis

PURPOSE

The goal of this research was to discover new biological indicators in urine which could be used for short-term prognosis of local Bacillus Calmette-Guerin (BCG) therapy outcome in patients with superficial bladder cancer.

PATIENTS AND METHODS

We measured and statistically evaluated soluble immunological molecules in urine from bladder cancer patients (n = 34) receiving BCG intravesically. Urine was collected following each of 6 weekly treatments, processed and assayed. The data base included measurements of interleukin-1 (IL-2, IL-4, IL-6, IL-10, IL-12, soluble intercellular adhesion molecule-1 (sICAM-1), tumour necrosis factor-alpha (TNF alpha), soluble CD14 (sCD14), interferon-gamma (IFN gamma), GM-CSF, volume of urine and its pH. The clinical response was evaluated by urine histology and random quadrant biopsy 3 months after the start of therapy. Patients were divided into 2 groups, with good and poor therapeutic effect. The initial complete response rate was 62% (21/34). The data base was analyzed using traditional multivariate statistical methods and a pattern recognition method which deals with combinatorial-statistical analysis (statistically weighted syndromes (SWS) method) of the gradated features. The SWS method is capable of identifying robust patterns in small "fuzzy" sets with high dimensional objects and some missing values.

RESULTS

Only one parameter gave significant differences at p < 0.05, GM-CSF at instillation 6. Repeated measurement analysis of variance, backward stepwise multiple logistic regression and linear discriminant analysis failed to show any significance. However, significant differences in the structure of correlation between features in the groups with and without therapeutic effect were observed and four highly informative variables (the masses of sICAM-1, TNF alpha, sCD14 and pH) relating to 5th-6th installations were selected by SWS. These features provided accurate individual prediction of therapeutic outcome for all our patients. Cross-validation analysis and computer simulation showed the statistically significant stability of the prediction.

CONCLUSION

We have selected a set of urinary variables that could be considered as a perspective combination of indicators (syndromes) of outcome of pre-operation BCG therapy of patients with superficial bladder cancer. A larger patient database will provide testing and evaluation of the biological and clinical significance of selected features. The computational syndrome-disease approach should be applicable for the solution of decision-making problems for management of cancer.

The genetic reconstruction of BCG as a new immunotherapeutic tool

The bacillus of Calmette and Guérin (BCG), long appreciated for its role as a live vaccine for the prevention of tuberculosis, is undergoing a rebirth as a recombinant delivery vehicle for foreign antigens and bioactive proteins. Recombinant BCG causes long-lived specific humoral and cellular immunity and may ultimately prove to be a powerful and cost-effective new weapon against both infectious pathogens and certain cancers.

Pharmacological biocompatibility between intravesical preparations of BCG and interferon-alpha 2B

PURPOSE

To determine if BCG and interferon alpha-2B are mutually compatible as mixed intravesical agents for clinical bladder cancer therapy.

MATERIALS AND METHODS

Mutual compatibility was assessed by measuring IFN-alpha's effect on BCG metabolic activity, growth rate, and clumping tendency and conversely by observing BCG's effect on IFN-alpha's anti-viral activity. Optical density at 600 nm. (OD600) was used to estimate the number of colony forming units of BCG in suspension during 3 hours measurements of clumping and 8 days measurements of BCG proliferation. BCG viability was evaluated using a substrate marker, MTT, which correlates with BCG density and metabolic activity. The anti-viral activity of IFN-alpha was determined in a cytopathic protection bioassay using the encephalomyocarditis virus/FS-4 cell system.

RESULTS

Continuous shaking of reconstituted BCG for 3 hours at 37C resulted in a marginal (11.3%) drop in OD600 which was minimally altered by inclusion of IFN-alpha at 2 million units (MU)/ml. (12.7% drop). Metabolic activity and growth rate of BCG alone or BCG with IFN-alpha were essentially identical. IFN-alpha's antiviral activity was not affected by incubation with BCG.

CONCLUSIONS

The inclusion of IFN-alpha into the usual BCG formulation for intravesical administration has no apparent effect on BCG's viability or tendency to form clumps in suspension. Similarly, the physical mixing of IFN-alpha with BCG does not impair its biological activity. Thus, both agents are pharmacologically compatible for future clinical studies involving combination intravesical therapy.

Streptococcal preparation OK-432 is a potent inducer of IL-12 and a T helper cell 1 dominant state

Streptococcal preparation OK-432 is a bacterial immunopotentiator extensively used in Japan for adjuvant cancer therapy. Using a C57BL/6 mouse model, OK-432 was found to induce multiple cytokines including the Th1 polarizing cytokine IL-12. Expression of IL-12 protein by murine splenocytes was restricted to macrophages and B cells and led to high levels of IFN-gamma production from both CD4+ and CD8+ T cells. Of the Th2 cytokines IL-4 and IL-10, only IL-10 protein was detected and originated primarily from the adherent cell population. Its expression was delayed relative to IL-12. A similar pattern of cytokine induction was observed from human PBMCs. OK-432-driven IFN-gamma production was inhibited by anti-IL-12 Ab, anti-IL-2 Ab, anti-TNF-alpha Ab, and anti-IL-2R alpha Ab, suggesting that IFN-gamma production from Th1 cells is induced by the cooperation action of these cytokines through the IL-2R alpha pathway. When compared with another widely used immunopotentiator bacillus Calmette-Guérin (BCG), OK-432 was a stronger IL-12 and IFN-gamma inducer. Furthermore, the mechanism of IFN-gamma induction by OK-432 differed from BCG in that coincident granulocyte-macrophage CSF and IL-1 expression played little to no role. These results suggest that OK-432 is a potent multicytokine inducer, specifically a strong inducer of IL-12, and that OK-432 may exert its antitumor effect by promoting a Th1-dominant state.

Streptococcal preparation OK-432 is a potent inducer of IL-12 and a T helper cell 1 dominant state

Streptococcal preparation OK-432 is a bacterial immunopotentiator extensively used in Japan for adjuvant cancer therapy. Using a C57BL/6 mouse model, OK-432 was found to induce multiple cytokines including the Th1 polarizing cytokine IL-12. Expression of IL-12 protein by murine splenocytes was restricted to macrophages and B cells and led to high levels of IFN-gamma production from both CD4+ and CD8+ T cells. Of the Th2 cytokines IL-4 and IL-10, only IL-10 protein was detected and originated primarily from the adherent cell population. Its expression was delayed relative to IL-12. A similar pattern of cytokine induction was observed from human PBMCs. OK-432-driven IFN-gamma production was inhibited by anti-IL-12 Ab, anti-IL-2 Ab, anti-TNF-alpha Ab, and anti-IL-2R alpha Ab, suggesting that IFN-gamma production from Th1 cells is induced by the cooperation action of these cytokines through the IL-2R alpha pathway. When compared with another widely used immunopotentiator bacillus Calmette-Guérin (BCG), OK-432 was a stronger IL-12 and IFN-gamma inducer. Furthermore, the mechanism of IFN-gamma induction by OK-432 differed from BCG in that coincident granulocyte-macrophage CSF and IL-1 expression played little to no role. These results suggest that OK-432 is a potent multicytokine inducer, specifically a strong inducer of IL-12, and that OK-432 may exert its antitumor effect by promoting a Th1-dominant state.

A painful knee in an immunocompromised patient

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Susceptibility to cell death induced by mutant SV40 T-antigen correlates with Purkinje neuron functional development

Purkinje cells are uniquely susceptible to a number of physical, chemical, and genetic insults both during development and in the mature state. We have previously shown that when the postmitotic state of murine Purkinje cells is altered by inactivation of the retinoblastoma tumor susceptibility protein (pRb), immature as well as mature Purkinje cells undergo apoptosis. DNA synthesis and neuronal loss are induced in postmitotic Purkinje cells dependent upon the pRb-binding portion of SV40 large T antigen (T-ag). In the present study, Purkinje cell targeting of a mutant T-ag, PVU, which does not bind pRb, reveals disparate cerebellar phenotypes dependent upon temporal differences in transgene expression. Strong embryonic and postnatal transgene expression in three lines alters Purkinje cell development and function during the second postnatal week, causing ataxia without Purkinje cell loss. In contrast, two other transgenic lines reveal that PVU T-ag expression following normal Purkinje cell maturation causes rapid Purkinje cell degeneration. The second and third postnatal weeks of cerebellar development, which include the major period of synaptogenesis, appear to be the defining stage for the two PVU-induced phenotypes. These data indicate that Purkinje cell death susceptibility varies with developmental stage.

A novel method for monitoring Mycobacterium bovis BCG trafficking with recombinant BCG expressing green fluorescent protein

To better understand intracellular and extracellular trafficking of Mycobacterium bovis bacillus Calmette-Guérin (BCG) when used as an intravesical agent in the treatment of transitional cell carcinoma (TCC) of the bladder, recombinant BCG (rBCG) expressing the jellyfish green fluorescent protein (GFP) was created. When the MB49.1 murine TCC cell line was incubated with GFP-expressing rBCG, internalization of the pathogen could be directly visualized by UV microscopy and quantitated by flow cytometry. The in vitro internalization of the GFP rBCG by the bladder tumor cells was temperature dependent, occurring most readily at 37 degrees C and being severely inhibited at 4 degrees C. Optimum internalization was achieved in vitro at a 10:1 BCG-to-tumor cell ratio over 24 h during which approximately 16% of the tumor cells became infected. Cytochalasin B, a phagocytosis inhibitor, abrogated the ingestion by almost 100% at a concentration of 200 micrograms/ml, indicating that contractile microfilaments likely played an important role in this process. By using mitomycin, a DNA cross-linking reagent, to inhibit proliferation of MB49.1 cells, clearance of about 40% of the green rBCG was achieved by 3 days postinfection. No significant difference between the GFP rBCG and wild-type BCG was observed in the ability to induce the expression of cell membrane proteins of major histocompatibility classes I and II, ICAM-I and -II, B7-1 and -2, of Fas from MB49.1 cells or cytokine production from mouse spleen cells. These results indicate that GFP rBCG may serve as a useful substitute for wild-type BCG in future studies of in vivo trafficking experimental and clinical immunotherapy.

Bacillus Calmette-Guérin plus interleukin-2 and/or granulocyte/macrophage-colony-stimulating factor enhances immunocompetent cell production of interferon-gamma, which inhibits B16F10 melanoma cell growth in vitro

Although immunotherapy with bacillus Calmette Guérin (BCG) is an established adjuvant treatment for malignant melanoma, the mechanism of its role in this process is unclear. To investigate the possible contribution of tumor-inhibitory cytokines induced by BCG, B16F10 melanoma cell growth in culture was assessed in response to purified cytokines and conditioned media of BCG-stimulated splenocytes. Interferon-gamma (IFN gamma) was the most potent single agent (IC50 approximately 50 pg/ml). Tumor necrosis factor alpha was substantially weaker (IC50 > 10 ng/ml) but provided synergy with IFN gamma. None of the other cytokines such as interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-12, or granulocyte/macrophage-colony-stimulating factor had direct antitumor activity against B16F10 melanoma cells. However, when IL-2 and/or GM-CSF were combined with BCG either by exogenous addition or through endogenous production by novel cytokine-secreting recombinant BCG (rBCG), a substantial increase in INF gamma production by splenocytes was observed. Antitumor activity of this conditioned medium directly correlated with IFN gamma concentration and was completely blocked by neutralizing antibody to IFN gamma. These results suggest that BCG may exert part of its antitumor action on melanoma through the induction of IFN gamma, which can be greatly enhanced through the concomitant addition of IL-2 and/or GM-CSF. Furthermore, by utilizing rBCG that secrete these cytokines, it may be possible to potentiate the antitumor effect of BCG directly at the site of BCG inoculation.

Coexpression of a nonsyncytium inducer HIV-1 glycoprotein inhibits syncytium formation by another HIV-1 Env protein

The biosynthesis and biological properties of the envelope glycoprotein from a primary isolate of the human immunodeficiency virus type 1, HIV-1 YU2, and the Env product from the laboratory-adapted strain, HIV-1 LAI were compared in the absence of viral replication. We found that the level of expression and proteolytic processing into gp120/gp41 complexes of both glycoproteins was equivalent and independent of the cell type used. Although the two glycoproteins were detected on the surface of HeLa cells expressing high levels of CD4, only the HIV LAI Env product induced significant syncytium formation. Interestingly, when both glycoproteins were coexpressed in HeLa-CD4 cells, syncytium formation was greatly reduced. However, cell fusion could be restored by increasing amounts of the LAI envelope gene product. HeLa-CD4 cells expressing either glycoprotein fused with high efficiency to CEM-A cells, a hybrid of CEM and peripheral blood mononuclear cells, indicating that both glycoproteins were expressed in a biologically active form on the surface of these cells. These studies suggest that primary isolates and laboratory adapted stains may require, in addition to the CD4 receptor, independent accessory membrane components for the fusion activation step. Our results agree with the concept that virus entry requires the concerted activation of each glycoprotein subunit of the Env oligomeric complex.

Bacillus Calmette-Guérin immunotherapy for superficial bladder cancer. New prospects for an old warhorse

The use of live M. bovis BCG to treat superficial bladder cancer has endured its seemingly anachronistic origin in the early days of tumor immunology to emerge as the therapy of choice for superficial bladder cancer. Its superiority over conventional intravesical therapy has been established for tumor prophylaxis and treatment of residual disease and CIS, providing long-term results that have translated into improvements in disease progression and survival. Although its exact mechanism of action remains elusive, extensive studies suggest that this intracellular pathogen stimulates the immune system to produce powerful cytokine mediators and effector cells that act locally to destroy bladder tumors. Although unique toxicities occur by virtue of BCG's use as a live vaccine, this same liability has opened the door for new opportunities through the use of recombinant DNA technology. Exciting prospects include the use of BCG as a cytokine carrier and as a tumor antigen depot. Genetic engineering may also yield varients that are both intrinsically safer and more specific in bladder tumor targeting.

Recombinant Mycobacterium bovis BCG secreting functional interleukin-2 enhances gamma interferon production by splenocytes

Mycobacterium bovis BCG was genetically engineered to express and secrete mouse interleukin-2 (IL-2) and rat IL-2. Genes encoding IL-2 were inserted into an Escherichia coli-BCG shuttle plasmid under the control of the BCG HSP60 promoter. To facilitate study of proteins produced in this system, the IL-2 gene product was expressed (i) alone, (ii) with the mycobacterial alpha-antigen secretion signal sequence at the amino terminus, (iii) with an influenza virus hemagglutinin epitope tag at the amino terminus, and (iv) with both the secretion signal sequence and the epitope tag. When expressed with the alpha-antigen signal sequence, biologically active IL-2 was secreted into the extracellular medium. Western blot (immunoblot) analysis of the intracellular IL-2 and extracellular IL-2 revealed that the secretion signal was appropriately cleaved from the recombinant lymphokine upon secretion. To assess the ability of recombinant BCG to stimulate cytokine production in a splenocyte population, mouse splenocytes were cultured together with wild-type or IL-2-producing BCG. IL-2-secreting BCG clones stimulated substantial increases in gamma interferon production, which could be reproduced by the addition of exogenous IL-2 to BCG. Levels of IL-6, IL-10, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor were not significantly changed, while IL-4 and IL-5 remained undetectable (less than 50 pg/ml). The enhanced production of gamma interferon in response to IL-2-secreting BCG was strain independent. Recombinant BCG expressing mammalian cytokines provides a novel means to deliver cytokines and may augment the immunostimulatory properties of BCG in immunization and cancer therapy.

Prostate cancer screening: role of the digital rectal examination and prostate-specific antigen

BACKGROUND

This study was designed to determine the efficacy of digital rectal examination (DRE) and serum prostate-specific antigen (PSA) for early detection of prostate cancer in men > or = 50 years of age.

METHODS

A prospective single-center clinical trial was conducted to screen 644 asymptomatic men, who were elicited by newspaper and radio advertisements, with DRE and PSA. Quadrant biopsy examinations of the prostate were performed if PSA > 4 ng/ml or if DRE was suspicious.

RESULTS

Thirty-seven percent of the men (n = 241) had an abnormality of DRE or elevated PSA. Of the 163 patients who underwent transrectal ultrasound and quadrant biopsies of the prostate, 77% had normal biopsies, 14 (8%) had prostatic intraepithelial neoplasia, and 24 (15%) had carcinoma of the prostate. PSAs ranged from 0.3 to 65.5 ng/ml, with a mean of 2.35 and a median of 1.6. Ninety-five patients had a PSA > 4 ng/ml, of whom 17 had a PSA > 10 ng/ml. Sensitivity of PSA was 75% and specificity 87%; for DRE the sensitivity was 75% and the specificity 69%. Clinical stage of patients who underwent radical prostatectomy was B1 in 15 and B2 in five. Fifteen of 20 patients (75%) had organ-confined disease; the other five had specimen-confined disease. No patient was found to have nodal involvement.

CONCLUSION

The combination of PSA and DRE seems to improve the stage of diagnosis of patients with prostate cancer. Larger, randomized studies will be necessary to evaluate the effect of screening on overall survival.

The transmembrane glycoprotein of human immunodeficiency virus type 1 induces syncytium formation in the absence of the receptor binding glycoprotein

To study the intracellular transport and biological properties of the human immunodeficiency virus type 1 (HIV-1) transmembrane glycoprotein (TM; gp41), we constructed a truncated envelope gene in which the majority of the coding sequences for the surface glycoprotein (SU; gp120) were deleted. Transient expression of this truncated env gene in primate cells resulted in the biosynthesis of two proteins with M(r)s of 52,000 and 41,000, respectively. Immunofluorescence studies with antibodies to the HIV-1 TM protein indicated that the intracellular and surface localization of these proteins were indistinguishable from those of the native HIV-1 gp120-gp41 complex. These results indicate that the oligosaccharide processing and cell surface transport of the HIV-1 TM protein were not dependent on the presence of the receptor binding subunit, gp120. Syncytium formation was readily detected upon expression of the deleted HIV-1 env gene into COS and CD4+ HeLa cell lines, suggesting that in the absence of gp120, the TM protein retained biological activity. This observation was confirmed by infection of primate and mouse cell lines with a recombinant vaccinia virus (vvgp41) expressing the truncated HIV-1 env gene. These results strongly suggest that (i) the two biological activities of the HIV-1 envelope glycoprotein can occur independently and (ii) the association of the two glycoprotein subunits may restrict the fusion activity of the transmembrane component to CD4+ cells.

An analysis of lactose permease "sugar specificity" mutations which also affect the coupling between proton and lactose transport. II. Second site revertants of the thiodigalactoside-dependent proton leak by the Val177/Asn319 permease

The double mutant of the lactose permease containing Val177/Asn319 exhibits proton leakiness by two pathways (see Brooker, R. J. (1991) J. Biol Chem. 266, 4131-4138). One type of H+ leakiness involves the uncoupled influx of H+ (leak A pathway) while a second type involves the coupled influx of H+ and galactosides in conjunction with uncoupled galactoside efflux (leak B pathway). In the current study, 14 independent lactose permease mutants were isolated from the Val177/Asn319 parent which were resistant to thiodigalactoside growth inhibition but retained the ability to transport maltose. All of these mutants contained a third mutation (besides Val177/Asn319) at one of two sites. Eight of the mutants had Ile303 changed to Phe, while six of the mutants had Tyr236 changed to Asn or His. Each type of triple mutant was characterized with regard to sugar transport, H+ leakiness, and sugar specificity. Like the parental strain, all three types of triple mutant showed moderate rates of downhill lactose transport and were defective in the uphill accumulation of sugars. However, with regard to proton leakiness, the triple mutants fell into two distinct categories. The mutant containing Phe303 was generally less H+ leaky than the parent either via the leak A or leak B pathway. In contrast, the triple mutants containing position 236 substitutions (Asn or His) were actually more H+ leaky via the leak A pathway and exhibited similar H+ leakiness via the leak B pathway at high thiodigalactoside concentrations. The ability of the position 236 mutants to grow better than the parent in the presence of low concentrations of thiodigalactoside appears to be due to a decrease in affinity for this particular sugar rather than a generalized defect in H+ leakiness. Finally, the triple mutants showed a sugar specificity profile which was different from either the Val177/Asn319 parent, the single Val177 mutant, or the wild-type strain. These results are discussed with regard to the effects of mutations on both the sugar and H+ transport pathways.

Regulation of the anti-Sm autoantibody response in systemic lupus erythematosus mice by monoclonal anti-Sm antibodies

The administration of certain monoclonal anti-Sm antibodies (2G7, 7.13) induced most MRL/lpr mice to become anti-Sm positive by 5 mo of age, although other anti-Sm monoclonals (Y2, Y12) suppressed the spontaneous response. Positive anti-Sm antibody enhancement occurred efficiently only in MRL/lpr mice and not in other systemic lupus erythematosus mice that have little spontaneous anti-Sm production. The enhancement by anti-Sm antibodies was specific for the anti-Sm response. The mechanism of the passive antibody enhancement was apparently not isotype- or idiotype-related. The fine specificity of the anti-Sm monoclonal antibody may be essential to its enhancing or suppressing effects, since both enhancing monoclonals recognized only the D Sm polypeptide, whereas both suppressing monoclonals saw the D and the B polypeptides. Furthermore, analysis of serial bleeds from unmanipulated MRL mice that developed anti-Sm positivity showed that the D specificity almost always appeared first. We hypothesize, therefore, that those animals in which an anti-Sm response is initiated by D-specific B-cell clones can become serologically positive with the aid of a positive feedback loop. In contrast, animals in which the initial specificity is for both B and D peptides would be prevented from developing a full anti-Sm response.

Specificity and idiotypic analysis of a monoclonal anti-Sm antibody with anti-DNA activity

To investigate the mechanisms of anti-Sm expression in murine systemic lupus erythematosus (SLE), the idiotypic determinants of a monoclonal anti-Sm antibody were studied. This antibody, 2G7, was derived from the fusion of spleen cells of an autoimmune MRL-lpr/lpr mouse with the 653 myeloma. Specificity for Sm was demonstrated by an ELISA with the use of affinity-purified Sm as well as immunoprecipitation of radiolabeled RNA. An anti-2G7 antiserum was prepared in a rabbit and rendered specific for idiotype by extensive absorption against BALB/c and MRL-lpr/lpr monoclonal proteins. The resulting antiserum detected determinants found on 2G7 as well as on two MRL anti-DNA antibodies, 6/P and 6/N, an independently derived MRL-lpr/lpr anti-Sm called 7.13, and the BALB/c myeloma FLOPC 21. Two distinct determinants could be demonstrated by the creation of cross-reactive idiotype systems by using the various monoclonal antibodies as ligands for the anti-idiotype. Both idiotypes were demonstrated in sera of normal and autoimmune mice, although MRL +/-/+/- mice had the highest levels of strains tested. To explain the pattern of idiotypic relatedness, 2G7 was tested for anti-DNA activity by ELISA. 2G7 displayed activity for single-stranded DNA as well as synthetic DNA and RNA homopolymers. Absorption analysis indicated that the anti-DNA and anti-Sm binding activities were the product of the same antibody. These results suggest that anti-Sm and anti-DNA may be related by both idiotype and antigenic specificity, providing a mechanism for their common expression in SLE.

Specificity and idiotypic analysis of a monoclonal anti-Sm antibody with anti-DNA activity

To investigate the mechanisms of anti-Sm expression in murine systemic lupus erythematosus (SLE), the idiotypic determinants of a monoclonal anti-Sm antibody were studied. This antibody, 2G7, was derived from the fusion of spleen cells of an autoimmune MRL-lpr/lpr mouse with the 653 myeloma. Specificity for Sm was demonstrated by an ELISA with the use of affinity-purified Sm as well as immunoprecipitation of radiolabeled RNA. An anti-2G7 antiserum was prepared in a rabbit and rendered specific for idiotype by extensive absorption against BALB/c and MRL-lpr/lpr monoclonal proteins. The resulting antiserum detected determinants found on 2G7 as well as on two MRL anti-DNA antibodies, 6/P and 6/N, an independently derived MRL-lpr/lpr anti-Sm called 7.13, and the BALB/c myeloma FLOPC 21. Two distinct determinants could be demonstrated by the creation of cross-reactive idiotype systems by using the various monoclonal antibodies as ligands for the anti-idiotype. Both idiotypes were demonstrated in sera of normal and autoimmune mice, although MRL +/-/+/- mice had the highest levels of strains tested. To explain the pattern of idiotypic relatedness, 2G7 was tested for anti-DNA activity by ELISA. 2G7 displayed activity for single-stranded DNA as well as synthetic DNA and RNA homopolymers. Absorption analysis indicated that the anti-DNA and anti-Sm binding activities were the product of the same antibody. These results suggest that anti-Sm and anti-DNA may be related by both idiotype and antigenic specificity, providing a mechanism for their common expression in SLE.