Population coverage by HLA class-I restricted cytotoxic T-lymphocyte epitopes

Vaccination using cytotoxic T-lymphocyte (CTL) epitopes has become a widely used immunization strategy, especially because their structure makes them an attractive alternative to the delivery of whole proteins as immunogens. Nonetheless, their use is limited, in particular because of their specificity, being recognized only by cognate HLA alleles. The potential for immunizing a substantial portion of an ethnically diverse population using a modest number of peptides has been aided by the identification of HLA supertypes. However, the derivation of epitopes is often guided by methods that do not guarantee cross-reactivity, so we consider the feasibility of providing vaccine coverage to a multi-ethnic population under different assumptions. In particular, two large datasets are used to estimate the number of peptides needed to provide > or =90% group-specific coverage of a multiethnic population, when specificity is assumed to be either to a single serologic or molecular type. These assumptions are evaluated utilizing a clinically important epitope repertoire derived from two human cytomegalovirus proteins, and data on the in vitro memory response elicited by these peptides is presented. In summary, our combined theoretical and empiric studies suggest that 90% coverage of some ethnic groups is attainable with 11 uniquely defined HLA-restricted CTL epitopes. The derivation of four or more additional CTL epitopes is needed to attain 90% coverage of Blacks or Asians, the minimally covered groups. Ninety percent coverage of all major ethnic groups in a multi-ethnic population appears feasible without relying on cross-reactivity, but may require two to three times more CTL epitopes than estimated for serologic data, homogenous populations, or HLA alleles grouped as supertypes.

Gender influences herpes simplex virus type 1 infection in normal and gamma interferon-mutant mice

Gender influences the incidence and severity of some bacterial and viral infections and autoimmune diseases in animal models and humans. To determine a gender-based difference, comparisons were made between male and female mice inoculated with herpes simplex virus type 1 (HSV-1) by the corneal route. Mortality was higher in the male mice of the three strains tested: 129/Sv//Ev wild type, gamma interferon (IFN-gamma) knockout (GKO), and IFN-gamma receptor knockout (RGKO). Similarly, in vivo HSV-1 reactivation occurred more commonly in male mice, but the male-female difference in reactivation was restricted to the two knockout strains and was not seen in the 129/Sv//Ev control. Comparison among male mice of the three strains showed a higher mortality of the RGKO mice and a higher reactivation rate of the GKO and RGKO mice than of the 129/Sv//Ev males. In contrast, female RGKO and GKO mice did not differ from female 129/Sv//Ev controls in either mortality or reactivation. HSV-1 periocular and eyelid disease was also more severe in male and dihydrotestosterone (DHT)-treated female mice than in control female mice. These results show a consistent gender difference in HSV-1 infection, with a worse outcome in male mice. In addition, the results comparing GKO and RGKO mice to controls show differences only in male mice, suggesting that some effects of IFN-gamma, a key immunoregulatory molecule, are gender specific.

Induction of CTL response by a minimal epitope vaccine in HLA A*0201/DR1 transgenic mice: dependence on HLA class II restricted T(H) response

CTL play a pivotal role in the immune response during viral infections. In this study, the HLA class II restricted T(H) requirement for optimal in vivo induction of HLA class I restricted CTL responses has been investigated. Towards this goal, transgenic mice expressing both HLA class I (A*0201 or A2.1) and class II (DRB1*0101 or DR1) molecules have been derived. Immunization of these mice with an HLA A*0201-restricted and CMV-specific CTL epitope (pp65(495-503)), and either of three different tetanus toxin-derived MHC class II-binding T(H) epitopes, resulted in a vigorous CTL response. CTL specific for the pp65(495-503) epitope were dramatically enhanced in mice expressing both the HLA-DR1 and HLA-A*0201 transgenes. Notably, preinjection of three TT peptides (TT(639-652), TT(830-843), and TT(947-967)) increased the capability of HLA A*0201/DR1 Tg mice to respond to subsequent immunization with the T(H) + CTL peptide mixture. These results indicate that the use of HLA A*0201/DR1 Tg mice constitute a versatile model system (in lieu of immunizing humans) for the study of both HLA class I and class II restricted T-cell responses. These studies provide a rational model for the design and assessment of new minimal-epitope vaccines based on their in vivo induction of a pathogen-specific CTL response.

Phase II trial of combination intraperitoneal cisplatin and 5-fluorouracil in previously treated patients with advanced ovarian cancer: long-term follow-up

OBJECTIVES

This trial was performed to determine the response rate and progression-free and overall survivals of patients with advanced recurrent ovarian cancer who were treated with intraperitoneal cisplatin and 5-fluorouracil.

METHODS

Twenty-four patients with ovarian cancer were entered on this trial and treated with intraperitoneal (ip) cisplatin (DDP) and ip 5-fluorouracil, every 3 weeks for eight cycles. Following iv hydration, the cisplatin and 5-fluorouracil were administered through an ip catheter in 2 liters of 0.9% normal saline with a 4-h dwell.

RESULTS

All patients were evaluable for progression-free and overall survival and toxicity analysis, and 22 patients for response. The median age was 59 (range, 35-71); initial disease status included 9 patients with residual disease following chemotherapy prior to entry on this study; 5 patients had progressed, and 10 patients had recurrent disease more than 6 months following initial chemotherapy. Of the 9 patients with residual disease, 1 complete response and 3 partial responses were observed; of 10 patients with recurrent disease, 1 complete and 1 partial response were observed for an overall response rate of 27%. No objective responses were seen in the 7 patients who were platinum-refractory on protocol entry. The median progression-free and overall survivals are 7.0 (range, 0.5-137) and 15.5 (range, 3-147) months, respectively. Toxicity included hypomagnesemia, vomiting, abdominal pain, and mild anemia. Only one patient required a dosage adjustment of cisplatin for a serum creatinine elevation >2.0 mg/dl.

CONCLUSIONS

We conclude that the combination of ip cisplatin and 5-FU is an effective regimen for patients with residual or relapsed epithelial ovarian cancer with survival durations, response rates, and toxicity profiles that compare favorably with those of other second-line ovarian cancer regimens. Patients who are primarily platinum-refractory are unlikely to benefit from these agents administered into the peritoneal cavity.

Phase II trial of intraperitoneal cisplatin with intravenous doxorubicin and cyclophosphamide in previously untreated patients with advanced ovarian cancer-long-term follow-up

Forty-three patients with ovarian cancer were entered on this trial and treated with intravenous (iv) cyclophosphamide (C) and doxorubicin (A), and intraperitoneal (ip) cisplatin (DDP), every 21 days for eight cycles. Following iv hydration, the cisplatin was administered through an intraperitoneal catheter in 2 L of 0.9% normal saline with a 4-h dwell. All patients are evaluable for overall and progression-free survival with a median follow-up of 70 months (range: 3-162 months); 39 patients are evaluable for response. All complete responses were surgically confirmed. The median age was 59 (range 28-82 years); 3 patients were stage IC, 5 were IIC, 14 patients were stage III (optimally debulked), 14 patients were stage III (suboptimally debulked), and 7 patients were stage IV. Two patients had received prior alkylator therapy. Six of 8 patients with Stage IC or II remain without evidence of disease at a mean of 12 years following chemotherapy. Of 14 optimally debulked stage III patients, there were 7 complete responses, 3 partial responses, 1 patient with stable disease, and 3 inevaluable patients. Of 14 suboptimally debulked stage III patients there were 4 complete responses, 4 partial responses, 3 with stable disease, 2 progressions on treatment, and 1 inevaluable patient. Five-year progression-free and overall survivals for stage III optimally debulked patients are 21 and 64%, respectively. At 10 years, progression-free and overall survivals for this group are 21 and 29%, respectively. Toxicity included neutropenia (complicated by sepsis in 2 patients), infrequent thrombocytopenia, and mild anemia. Three patients developed transient serum creatinine elevations >2.0 mg/dl; however, decreased creatinine clearance was noted in 93/258 (36%) of evaluable courses which required a cisplatin dose reduction per protocol. Controllable hypomagnesemia, nausea, and emesis were also observed. We conclude that the combination of iv CA and ip DDP is an effective regimen with long-term progression-free and overall survivals that compare favorably with those of other published studies of intravenous or intraperitoneal chemotherapy. This report is unusual in terms of the prolonged follow-up for all patients enrolled. These long-term results lend further support to recently published trials documenting the efficacy of intraperitoneal chemotherapy for patients with this disease.

An allelic variant at the ATM locus is implicated in breast cancer susceptibility

We have tested a simple procedure, disease association by locus stratification, for identifying breast cancer patients with pathogenetic allelic variants at several candidate loci. The strategy was based on the assumption of epistatic interactions of the candidates. We analyzed 66 independent cases from sib pairs affected with breast cancer that had previously been collected during an investigation of pathogenetic-allele-sharing at the HRAS1 mini-satellite locus. An exon 24 polymorphism of ATM, substituting arginine for proline was associated with breast cancer in these cases with an overall odds ratio of 4.5 (95% confidence interval, 1.2-20.5, nominal p = 0.02, 2-tail Fisher exact test). In the presence of a rare HRAS1 allele, the odds ratio increased to 6.9 (95% CI, 1.2-38.3, p = 0.03). Thus, our procedure identified at least one allelic variant of ATM associated with breast cancer, and indicated that the ATM locus may interact with HRAS1.

Comparison of two doses of intravenous immunoglobulin after allogeneic bone marrow transplants

Intravenous immunoglobulin has been used after bone marrow transplants to prevent infections and acute graft-versus-host disease. However, the minimum dose required for protection is unknown. This may have significant economic implications. A multicenter randomized clinical trial compared the impact of two intravenous immunoglobulin doses on systemic infections and acute graft-versus-host disease in transplant recipients. Either 250 mg/kg or 500 mg/kg was given weekly from day -8 to day +111. Multivariate analysis was used to assess the effect of dose and other risk factors on event-free survival, systemic infection, and acute graft-versus-host disease. The two-dose cohorts had similar event-free survival and infection frequencies. The higher dose was associated with less acute graft-versus-host disease (P = 0.03).

Recombinant human thrombopoietin in combination with granulocyte colony-stimulating factor enhances mobilization of peripheral blood progenitor cells, increases peripheral blood platelet concentration, and accelerates hematopoietic recovery following high-dose chemotherapy

Lineage-specific growth factors mobilize peripheral blood progenitor cells (PBPC) and accelerate hematopoietic recovery after high-dose chemotherapy. Recombinant human thrombopoietin (rhTPO) may further increase the progenitor-cell content and regenerating potential of PBPC products. We evaluated the safety and activity of rhTPO as a PBPC mobilizer in combination with granulocyte colony-stimulating factor (G-CSF) in 29 breast cancer patients treated with high-dose chemotherapy followed by PBPC reinfusion. Initially, patients received escalating single doses of rhTPO intravenously (IV) at 0.6, 1.2, or 2.4 micrograms/kg, on day 1. Subsequent patients received rhTPO 0.6 or 0.3 micrograms/kg on days -3, -1, and 1, or 0.6 micrograms/kg on days -1 and 1. G-CSF, 5 micrograms/kg IV or subcutaneously (SC) twice daily, was started on day 3 and continued through aphereses. Twenty comparable, concurrently and identically treated patients (who were eligible and would have been treated on protocol but for the lack of study opening) mobilized with G-CSF alone served as comparisons. CD34(+) cell yields were substantially higher with the first apheresis following rhTPO and G-CSF versus G-CSF alone: 4.1 x 10(6)/kg (range, 1.3 to 17.6) versus 0.8 x 10(6)/ kg (range, 0.3 to 4.2), P =.0003. The targeted minimum yield of 3 x 10(6) CD34(+) cells/kg was procured following a single apheresis procedure in 61% of the rhTPO and G-CSF-mobilized group versus 10% of G-CSF-mobilized patients (P =.001). In rhTPO and G-CSF mobilized patients, granulocyte (day 8 v 9, P =.0001) and platelet recovery (day 9 v 10, P =.07) were accelerated, and fewer erythrocyte (3 v 4, P =.02) and platelet (4 v 5, P =.02) transfusions were needed compared with G-CSF-mobilized patients. Peripheral blood platelet counts, following rhTPO and G-CSF, were increased by greater than 100% and the platelet content of PBPC products by 60% to 110% on the first and second days of aphereses (P <.0001) with the greatest effect seen with repeated dosing of rhTPO at 0.6 microgram/kg. rhTPO is safe and well tolerated as a mobilizing agent before PBPC collection. Mobilization with rhTPO and G-CSF, in comparison to a comparable, nonrandomized G-CSF-mobilized group of patients, decreases the number of apheresis procedures required, may accelerate hematopoietic recovery, and may reduce the number of transfusions required following high-dose chemotherapy for breast cancer.

Phase I trial of intraperitoneal iododeoxyuridine with and without intravenous high-dose folinic acid in the treatment of advanced malignancies primarily confined to the peritoneal cavity: flow cytometric and pharmacokinetic analysis

In this Phase I study, the maximally tolerated doses (MTDs) of i.p. iododeoxyuridine (IdUrd) alone and in combination with i.v. calcium leucovorin (LV) were determined. The pharmacokinetics and pharmacological advantage of IdUrd were evaluated, and flow cytometric analysis allowed examination of the extent of incorporation of IdUrd into tumor cells with and without the addition of i.v. LV. Thirty-nine patients with advanced neoplasms primarily confined to the peritoneal space were enrolled in a dose-escalation trial using 4-h dwells of IdUrd administered i.p. daily for 4 days with and without an i.v. infusion of LV 500 mg/m2/day for 4.5 days. Twenty-three patients received single-agent therapy, and 13 patients received i.p. IdUrd in combination with i.v. LV. The MTD of single-agent IdUrd administered on this schedule was 4125 mg/m2/day for 4 days; and that of the IdUrd in combination was 3438 mg/m2/day. Dose-limiting toxicities were myelosuppression and stomatitis. During the period of the dwell, the peritoneal AUC (area under the curve) of IdUrd exceeded the plasma AUC of IdUrd by one or two orders of magnitude in all patients at all doses tested; there was a possible effect of LV on peritoneal AUC. The geometric mean pharmacological advantage (AUCperitoneal/ AUCplasma) was 181 at 625 mg/m2/day and 90 at 4538 mg/m2/day. Flow cytometric analysis suggests saturation of IdUrd measured in DNA at the 2500-3125 mg/m2 dose level, without an increase after the addition of LV. Twelve patients received 4-12 courses of therapy. One patient with recurrent ovarian cancer who received 16 courses of therapy experienced complete resolution of her ascites, near normalization of CA-125 levels, and improved quality of life; two patients with high-risk tumors receiving "adjuvant" therapy are disease-free at 3 and 6 years after treatment; other patients experienced transient clearing of ascites. The recommended Phase II dose of i.p. IdUrd using a 4-h dwell daily for 4 days is 3750 mg/m2/day alone or 3125 mg/m2/day in combination with continuous i.v. LV at 500 mg/m2/day for 4.5 days. Although flow cytometric data suggest that DNA incorporation of IdUrd is not affected by the addition of LV, the cytotoxicity of the combination regimen may be increased due to LV-enhanced, IdUrd-related inhibition of thymidylate synthase. For this reason, we recommend that efficacy studies of the combination continue in parallel with studies of IdUrd alone.

Speed congenics: a classic technique in the fast lane (relatively speaking)

Marker-assisted selection protocol (MASP)-based strategies produce congenic strains with the target gene contained on clearly defined donor-derived genomic intervals in less than half the member of generations required by the classic protocol. Thus, the quality and speed of congenic strain construction are enhanced by this methodology. Here, Edward Wakeland and colleagues compare various MASP-based strategies and discuss their advantages with reference to immunological traits.

Filler leachability of composites stored in distilled water or artificial saliva

Though dental composite materials leach filler elements when stored in distilled water, it is not known whether similar leaching occurs in saliva. The hypothesis to be tested was that due to ion exchange occurring at the filler surfaces, more filler elements leach from composites stored in a salt solution simulating saliva than from composites stored in distilled water. Another aim was to determine how matrix selection, filler composition, and filler silanization affect filler leachability of composites after storage in the simulated saliva and water media. We made 128 batches of experimental composites. Half of these used a bis-GMA/TEGDMA matrix and the other a UEDMA/TEGDMA matrix. Either silica or barium glass filler particles were incorporated into these matrices. Filler silanization was followed by a filler drying at 60 degrees C for 24 h. Half of the silanized particles received an additional heat treatment for 1 h at 110 degrees C in vacuum. One specimen per batch was stored in distilled water and the other in artificial saliva at 37 degrees C. After each 30-day interval for one year, the specimens were transferred to either freshly distilled water or newly mixed artificial saliva. The "old" solutions were analyzed by ICP for determination of the Si, Ba, and Al concentrations. Analysis of variance revealed that storage solution, filler composition, and total time in the storage solution had strong effects on the leachability (p < 0.0001 in all cases). The average monthly leakage of Si for quartz-filled composites was 0.22 +/- 0.20 microgram/mL (distilled water) and 2.80 +/- 1.20 microgram/mL (artificial saliva). For barium-glass-filled composites, the corresponding Si leaching values were 0.73 +/- 0.48 microgram/mL and 5.00 +/- 2.20 microgram/mL. The monthly means of the barium leaching values were 2.00 +/- 1.00 microgram/mL (distilled water) and 3.10 +/- 1.80 microgram/mL (artificial saliva). The large difference between leaching in artificial saliva and in distilled water, as well as the interaction between storage medium and filler, cast doubt on the clinical relevance of in vitro studies using distilled water.

Effects of treatment and storage conditions on ceramic/composite bond strength

During the past few years, the interest in using ceramic inlays and veneers has increased. New materials and methods have been introduced to bond these restorations to resinous materials. Since our knowledge of how to optimize such bonding is limited, the objective of this study was to test the hypothesis that various surface treatment variables and combinations of these variables affect the strength of the ceramic/composite interphase of ceramic inlays differently. The influences of material composition, surface-roughening method, silane treatment, silane heat treatment, and storage condition on bond strength were investigated. Three ceramics (Dicor, Mirage, Vitabloc), three surface-roughening methods (etching, sandblasting, grinding), three silane treatments (gamma-methacryloxypropyltrimethoxysilane [MPS], MPS+paratoluidine, vinyltrichlorosilane), two heat treatments (20 degrees C for 60 s, 100 degrees C for 60 s), and two storage conditions (24-hour dry, one yr in water at 37 degrees C) were studied. For each of the 108 combinations, five specimens were tested. Ceramic cylinders were treated according to group assignment and bonded to blocks of the same ceramic material with a dual-cured resin. The shear bond strength was determined, and the experimental factors were evaluated by analysis of variance. The results showed that surface-roughening method had the strongest effect on bond strength, while ceramic selection had the least significant effect. Of the surface-roughening methods, etching was associated with higher bond strength values than either sandblasting or grinding.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental care use by U.S. veterans eligible for VA care

Military veterans eligible for dental care in U.S. Department of Veterans Affairs (VA) facilities cooperated for a mailed survey about their dental care utilization. Subjects were selected because of their eligibility for continuing dental care in VA facilities at no monetary cost. However, only 48% reported the VA as their only or primary source of dental care; this allowed us the opportunity to compare dental care frequency by those who received dental care at no monetary cost with those who did not, as well as measure delivery system effects on dental care use. Consequently, we tested respondent-level and delivery system-level hypotheses regarding determinants of veterans' dental care use. Predisposing characteristics (dentate status, usual reason for dental visits, and the importance placed on dental care and oral health) were the strongest determinants of interval since last dental visit. Enabling determinants (current source of dental care, and having a regular source of care) were also significant, but measures of need for dental care (perceived oral health and perceived need for treatment) were not. More recent dental care use by veterans who used the VA delivery system as their source of dental care, even with dental care payment source and other determinants accounted for, suggests that the VA delivery system may have promoted more regular use compared to other systems.

Evaluation and comparison of automated biopsy devices. Work in progress

The performance of four automated biopsy devices (Bard Biopty, Bard Monopty, Microvasive ASAP 18, Medical Device Technologies Ultra-Cut) was compared when they were used to obtain 96 liver and 96 kidney samples from eight dogs under ultrasound guidance. There was no significant difference in the lengths of the samples obtained with the four devices. The Monopty device yielded a significantly greater mean weight of both kidney (30.8%) and liver (31.6%) samples compared with the other devices. There were no significant differences between the four devices relative to cellular and histologic preservation, crush artifact, and number of renal glomeruli or liver lobules and portal triads. Renal subcapsular hematomas were identified in most instances, and there was no difference between the devices in the amount of renal trauma resulting from their use. There was only one instance of severe injury to the liver. The choice of instrument should remain one of personal preference, since all four devices were satisfactory and none produced significantly greater renal or hepatic injury.

Eligible veterans' choice between VA-covered and non-VA-covered dental care

Veterans who were eligible for dental care in Department of Veterans Affairs (VA) facilities at no monetary cost responded to a mailed questionnaire. Seventy-one percent were aware that they were actually eligible for VA dental care. However, only 48 percent reported the VA as their only or primary source of dental care. Eligibility status, perceived quality of VA dental care, use of VA medical care, perception that one's income meets expenses, and perceived need for dental care were significant correlates of using the VA as one's current source of dental care. Level of formal education, perception that one's income meets expenses, transportation pattern, geographic distance from a VA facility, and eligibility status were significant correlates of using the VA as one's current medical care source. Research on VA utilization offers the opportunity to study issues of access to, and use of, a large public health care system whose patients largely receive care at no monetary cost. Veterans' use of VA dental and medical care is apparently influenced by a wide variety of factors, ranging from barriers to access to non-VA systems, to characteristics of the VA delivery system itself, to need for treatment.

Factors influencing the effectiveness of mailed health surveys

The authors investigated sources of bias in health surveys by examining responses to their 1989 questionnaire mailed to 1,255 Massachusetts men who were eligible for dental care provided by the Department of Veterans Affairs. After a maximum of three mailings and one telephone call to nonrespondents, a total of 1,049 veterans had responded out of 1,228 finally determined to be eligible, a response rate of 85 percent. The investigators found that small differences in univariate estimates would have occurred had the field phase been terminated after the first mailing, which had a response rate of 61 percent. To evaluate multivariate distributions, they duplicated their previously published logistic regression model for sources of dental care, using only those who responded to the first and second mailings. Although model fits would have been substantively the same had the field phase been terminated after the first or the second mailings, analysis of parameter estimates and their statistical significances suggested bias that would have led to different substantive conclusions, in some instances. Another potential source of bias in surveys was found to be item omission. Fifty-eight percent of respondents answered all 46 survey questions, and 90 percent answered at least 91 percent of the questions. Fewer questions were answered by those whose responses were received last, but trends regarding missing data by age or education were not statistically significant. Although the survey using this methodology met all objectives, subject nonresponses, the ineligibility of potential respondents, item nonresponses, and skewed distributions of outcome variables combined to reduce the statistical power to detect differences among groups or to alter the analysis of the differences. These factors need to be planned for by investigators undertaking similar surveys.

The utility of postmortem lung for RNA studies; variability and correlation of the expression of surfactant proteins in human lung

Postmortem human lung tissue was evaluated for its utility in studies of the mRNAs for the surfactant proteins. Data obtained from different analytical procedures indicated that surfactant protein mRNAs are quite stable in these tissues with a half-life of 10 to 12 h. These analyses revealed no major regional differences in the mRNA levels for the surfactant protein A (SP-A) and surfactant protein B (SP-B) although small differences were present in the levels for the surfactant protein C (SP-C). Analysis of adult surgical lung specimens indicated that there is greater individual variation in the mRNA levels for SP-A and SP-B compared to SP-C among individuals. Furthermore, in a given individual the level of SP-A mRNA correlated well with that of SP-B, whereas the level of SP-C mRNA did not correlate with either that of SP-A or SP-B.