0810 Sleep Disturbances In Returning Veterans That Are Homeless And Combat-exposed

Introduction

Challenges with sleep (i.e., nightmares and insomnia) impact military service members both during and following deployment, but may occur more frequently in combat-exposed individuals. In addition, among the challenges faced following the transition from active duty to Veteran status are periods of homelessness, which may further contribute to sleep disturbances.

Methods

The present analyses utilized data from the Survey of Experiences of Returning Veterans, a national survey of recently returning combat Veterans focused on the examination of sex differences following exposure to traumatic events. The sample (n = 793) consisted of 58% males; females were oversampled and all branches were represented. Ordinal and multiple linear regressions were used to investigate the role of combat exposure and homelessness in predicting nightmare distress and insomnia severity.

Results

An ordinal regression found that combat exposure (b = -.02, p <0.001), homelessness (b = -.31, p = 0.010), and insomnia severity (b = -.10, p <0.001) each significantly predicted nightmare distress. These variables increased risk (SAS parameterizes these models so that negative coefficients are associated with increased risk). Demographic variables were not significantly related to nightmare distress. Similarly, combat exposure (β = .100, p = .002) was associated with insomnia severity, as was nightmare distress (β = .522, p < .001). The moderational role of gender and homeless in the above models are also tested.

Conclusion

For those who have been combat exposed, have a history of homelessness, and report insomnia symptoms there is an increased odds of reporting nightmare distress, sleep disturbance is even more likely to occur. Although combat exposure and nightmare distress were predictive of insomnia severity, history of homelessness was not. These findings suggest that nightmare distress and insomnia symptoms are a significant concern in our returning combat-exposed Veterans, with nightmares being even more problematic for those at risk of homelessness.

Support

This study was funded by VHA CSR&D grant ZDA-01. Dr. Speed is supported, in part, by the VA Advanced Fellowship Program in Mental Health Illness Research and Treatment, the VISN 2 Center of Excellence for Suicide Prevention at the Canandaigua VAMC.

Blending Polymer Labile Elements at Differing Scales to Affect Degradation Profiles in Heart Valve Scaffolds

After more than 22 years of research challenges and innovation, the heart valve tissue engineering paradigm still attracts attention as an approach to overcome limitations which exist with clinically utilized mechanical or bioprosthetic heart valves. Despite encouraging results, delayed translation can be attributed to limited knowledge on the concurrent mechanisms of biomaterial degradation in vivo, host inflammatory response, cell recruitment, and de novo tissue elaboration. This study aimed to reduce this gap by evaluating three alternative levels at which lability could be incorporated into candidate polyurethane materials electroprocessed into a valve scaffold. Specifically, polyester and polycarbonate labile soft segment diols were reacted into thermoplastic elastomeric polyurethane ureas that formed scaffolds where (1) a single polyurethane containing both of the two diols in the polymer backbone was synthesized and processed, (2) two polyurethanes were physically blended, one with exclusively polycarbonate and one with exclusively polyester diols, followed by processing of the blend, and (3) the two polyurethane types were concurrently processed to form individual fiber populations in a valve scaffold. The resulting valve scaffolds were characterized in terms of their mechanics before and after exposure to varying periods of pulsatile flow in an enzymatic (lipase) buffer solution. The results showed that valve scaffolds made from the first type of polymer and processing combination experienced more extensive degradation. This approach, although demonstrated with polyurethane scaffolds, can generally be translated to investigate biomaterial approaches where labile elements are introduced at different structural levels to alter degradation properties while largely preserving the overall chemical composition and initial mechanical behavior.

Abstract P5-10-02: Development and validation of a polygenic score to predict breast cancer risk in unaffected Hispanic women negative for mutations on a multi-gene hereditary cancer panel

Background: Breast cancer (BC) is the most commonly diagnosed cancer and the leading cause of cancer-related death among Hispanic women in the United States. For women of European ancestry, genome-wide association studies (GWAS) have identified common variants, primarily single-nucleotide polymorphisms (SNPs), that individually confer modest risk but together explain a significant proportion of genetic BC predisposition. For Hispanic women, the genetic contribution of SNPs to BC risk is not well understood. In these studies, we aim to develop and validate a polygenic score to improve risk assessment for Hispanic women who test negative for mutations in known BC susceptibility genes.

Methods: Genotypes and clinical histories were collected from consecutive development and validation cohorts of patients referred for hereditary cancer testing. Study subjects include women who report strictly Hispanic or Latin American ancestry, and who test negative for mutations in 11 genes associated with breast cancer (BRCA1, BRCA2, TP53, PTEN, STK11, CDH1, PALB2, CHEK2, ATM, NBN, BARD1).

Based on a development cohort ascertained through June 2017, we evaluated an 86-SNP Residual Risk Score (RRS) that was previously developed and validated for women of European ancestry. In the same cohort we are developing a Hispanic Residual Risk Score (HRRS) optimized for women of Hispanic ancestry. BC associations of individual SNPs are being established through meta-analysis of the development cohort and published Hispanic studies.

Multivariate logistic regression models were used to evaluate the 86-SNP RRS, and were the primary statistical tool for evaluation of individual SNPs and candidate polygenic scores. All models included personal/family cancer history and age as independent variables. P-values are based on likelihood ratio test statistics, and reported as two-sided. The development and validation studies are being conducted according to a protocol approved by the Quorum Institutional Review Board.

Results: The development cohort included 5,454 Hispanic women, 24% of whom reported a personal history of BC. The 86-SNP RRS was significantly associated with a personal history of BC after accounting for personal and family cancer history (p<10-19) with odds ratio per unit standard deviation 1.39 (95% CI = 1.30-1.50). To date, more than 5,000 Hispanic women have been ascertained for inclusion in the validation cohort. Results comparing discriminatory accuracy of the RRS and the HRRS will be presented.

Conclusions: The implementation of a clinically validated polygenic score may improve risk assessment and medical management of Hispanic women who test negative for monogenic BC mutations. The HRRS will be validated in an independent study population according to a pre-specified statistical analysis plan.

Citation Format: Hughes ER, Wagner S, Pruss D, Gallagher SK, Swedlund B, Bulka K, Hoff R, Jammulapati S, Morris B, Perry T, Lanchbury JS, Gutin A. Development and validation of a polygenic score to predict breast cancer risk in unaffected Hispanic women negative for mutations on a multi-gene hereditary cancer panel [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-10-02.

Meso-scale topological cues influence extracellular matrix production in a large deformation, elastomeric scaffold model

Physical cues are decisive factors in extracellular matrix (ECM) formation and elaboration. Their transduction across scale lengths is an inherently symbiotic phenomenon that while influencing ECM fate is also mediated by the ECM structure itself. This study investigates the possibility of enhancing ECM elaboration by topological cues that, while not modifying the substrate macro scale mechanics, can affect the meso-scale strain range acting on cells incorporated within the scaffold. Vascular smooth muscle cell micro-integrated, electrospun scaffolds were fabricated with comparable macroscopic biaxial mechanical response, but different meso-scale topology. Seeded scaffolds were conditioned on a stretch bioreactor and exposed to large strain deformations. Samples were processed to evaluate ECM quantity and quality via: biochemical assay, qualitative and quantitative histological assessment and multi-photon analysis. Experimental evaluation was coupled to a numerical model that elucidated the relationship between the scaffold micro-architecture and the strain acting on the cells. Results showed an higher amount of ECM formation for the scaffold type characterized by lowest fiber intersection density. The numerical model simulations associated this result with the differences found for the change in cell nuclear aspect ratio and showed that given comparable macro scale mechanics, a difference in material topology created significant differences in cell-scaffold meso-scale deformations. These findings reaffirmed the role of cell shape in ECM formation and introduced a novel notion for the engineering of cardiac tissue where biomaterial structure can be designed to both mimick the organ level mechanics of a specific tissue of interest and elicit a desirable cellular response.

Nitro-Oleic Acid (NO2-OA) Release Enhances Regional Angiogenesis in a Rat Abdominal Wall Defect Model

Ventral hernia is often addressed surgically by the placement of prosthetic materials, either synthetic or from allogeneic and xenogeneic biologic sources. Despite advances in surgical approaches and device design, a number of postsurgical limitations remain, including hernia recurrence, mesh encapsulation, and reduced vascularity of the implanted volume. The in situ controlled release of angiogenic factors from a scaffold facilitating abdominal wall repair might address some of these issues associated with suboptimal tissue reconstruction. Furthermore, a biocomposite material that combines the favorable mechanical properties achievable with synthetic materials and the bioactivity associated with xenogeneic tissue sources would be desirable. In this report, an abdominal wall repair scaffold has been designed based on a microfibrous, elastomeric poly(ester carbonate)urethane urea matrix integrated with a hydrogel derived from decellularized porcine dermis (extracellular matrix [ECM] gel) and poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with nitro-oleic acid (NO₂-OA). NO₂-OA is an electrophilic fatty acid nitro-alkene derivative that, under hypoxic conditions, induces angiogenesis. This scaffold was utilized to repair a rat abdominal wall partial thickness defect, hypothesizing that the nitro-fatty acid release would facilitate increased angiogenesis at the 8-week endpoint. The quantification of neovascularization was conducted by novel methodologies to assess vessel morphology and spatial distribution. The repaired abdominal wall defects were evaluated by histopathologic methods, including quantification of the foreign body response and cellular ingrowth. The results showed that NO₂-OA release was associated with significantly improved regional angiogenesis. The combined biohybrid scaffold and NO₂-OA-controlled release strategy also reduced scaffold encapsulation, increased wall thickness, and enhanced cellular infiltration. More broadly, the three components of the composite scaffold design (ECM gel, polymeric fibers, and PLGA microparticles) enable the tuning of performance characteristics, including scaffold bioactivity, degradation, mechanics, and drug release profile, all decisive factors to better address current limitations in abdominal wall repair or other soft tissue augmentation procedures.

Sustained viral gene delivery from a micro-fibrous, elastomeric cardiac patch to the ischemic rat heart

Biodegradable and elastomeric patches have been applied to the surface of infarcted hearts as temporary mechanical supports to effectively alter adverse left ventricular remodeling processes. In this report, recombinant adeno-associated virus (AAV), known for its persistent transgene expression and low pathogenicity, was incorporated into elastomeric polyester urethane urea (PEUU) and polyester ether urethane urea (PEEUU) and processed by electrospinning into two formats (solid fibers and core-sheath fibers) designed to influence the controlled release behavior. The extended release of AAV encoding green fluorescent protein (GFP) was assessed in vitro. Sustained and localized viral particle delivery was achieved over 2 months in vitro. The biodegradable cardiac patches with or without AAV-GFP were implanted over rat left ventricular lesions three days following myocardial infarction to evaluate the transduction effect of released viral vectors. AAV particles were directly injected into the infarcted hearts as a control. Cardiac function and remodeling were significantly improved for 12 weeks after patch implantation compared to AAV injection. More GFP genes was expressed in the AAV patch group than AAV injection group, with both α-SMA positive cells and cardiac troponin T positive cells transduced in the patch group. Overall, the extended release behavior, prolonged transgene expression, and elastomeric mechanical properties make the AAV-loaded scaffold an attractive option for cardiac tissue engineering where both gene delivery and appropriate mechanical support are desired.

Abstract P1-09-06: Prognostic and predictive relevance of cell cycle progression (CCP) score in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial

Background: The prognostic abilities of most gene expression signatures in breast cancer are often due to detection of proliferative activity measured from expression of genes regulated as a function of cell cycle progression. Cell Cycle Progression (CCP) score is an important prognostic factor in prostate cancer, and has shown promising results for renal and lung cancer; its role in ductal carcinoma in situ (DCIS) has not been explored. We investigated the prognostic and predictive relevance of CCP Score in DCIS using material from UK/ANZ DCIS trial.

Methods: Formalin-fixed paraffin embedded tissues were collected from patients enrolled in the UK/ANZ DCIS trial, a randomised 2X2 factorial design trial investigating role of tamoxifen, radiotherapy (RT) or both as adjuvant treatment in DCIS. mRNA expression of 25 S- and M-phase CCP genes was evaluated by reverse transcription followed by PCR on customized Taqman low-density arrays. CCP score is an un-weighted average of the expression values of CCP genes after normalisation with 14 housekeeping genes. CCP score was analysed as a continuous variable and also as an ordinal variable using tertile-based cut-offs. Exploratory analyses with subgroups defined by HER2 status by immunohistochemistry were performed.

Results: CCP scores were evaluable in 521 (134 recurrence events) of 704 available samples (DCIS absent or insufficient RNA in 51, assay failure in 132). Increase in CCP score (median 1.15; IQR 0.71-1.74) was associated with increased risk of ipsilateral breast event (IBE) [Hazard ratio (HR) = 1.28; 95% Confidence Interval (95%CI) 1.08-1.51; p = 0.0049]. CCP score however was not an independent predictor in multivariate analyses [HR = 1.16; 95%CI 0.95-1.42; p = 0.14].

CCP scores were categorised as CCP low (<0.87), CCP intermediate (>/= 0.87 to < 1.52) and CCP high (>/= 1.52) by tertiles. The benefit of RT in reducing IBE was significant when CCP score was low [HR = 0.35; 95%CI 0.14-0.87; p = 0.024] or intermediate [HR = 0.23; 95%CI 0.09-0.59; p = 0.0023], however, those with high CCP score did not derive significant RT benefit [HR = 0.59; 95%CI 0.31-1.13; p = 0.11].

In exploratory subgroup analyses, HER2 negative DCIS with high CCP score (20.9% of all DCIS cases) did not derive RT benefit and the largest RT benefit was seen for DCIS that expressed HER2 and did not have a high CCP score (23.2% of all DCIS cases).

Benefit of RT and 10-year IBE rates by CCP score (categorised) and HER2 status subgroups.SubgroupneventsHR (95%CI)p10-year IBE rates (%) - No RT10-year IBE rates (%) - RTCCP-high & HER2 neg106220.83 (0.35-1.97)0.6722.5 (14.0-35.0)20.0 (10.5-36.0)CCP-high & HER2 pos67210.43 (0.16-1.17)0.09840.6 (27.1-57.6)20.4 (8.9-42.9)CCP-non-High & HER2 neg217300.43 (0.18-0.99)0.04816.2 (10.7-24.0)8.1 (4.0-16.3)CCP- non-High & HER2 pos118330.14 (0.04-0.46)0.001239.5 (29.3-51.6)7.1 (2.3-20.4)CCP-non-High = low or intermediate CCP score

Conclusions: CCP score is not independently associated with the risk of IBE but appears to be a predictor of RT benefit. Exploratory analyses suggest that combined with HER2 status, it may help in identifying a large DCIS subgroup where RT is highly indicated and another large subgroup where mastectomy may be merited.

Citation Format: Thorat MA, Wagner S, Jones LJ, Levey PM, Bulka K, Hoff R, Sangale Z, Flake II DD, Bundred NJ, Fentiman IS, Forbes JF, Lanchbury JS, Cuzick J. Prognostic and predictive relevance of cell cycle progression (CCP) score in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-09-06.

Bi-layered polyurethane - Extracellular matrix cardiac patch improves ischemic ventricular wall remodeling in a rat model

As an intervention to abrogate ischemic cardiomyopathy, the concept of applying a temporary, local patch to the surface of the recently infarcted ventricle has been explored from a number of design perspectives. Two important features considered for such a cardiac patch include the provision of appropriate mechanical support and the capacity to influence the remodeling pathway by providing cellular or biomolecule delivery. The objective of this report was to focus on these two features by first evaluating the incorporation of a cardiac extracellular matrix (ECM) component, and second by evaluating the impact of patch anisotropy on the pathological remodeling process initiated by myocardial infarction. The functional outcomes of microfibrous, elastomeric, biodegradable cardiac patches have been evaluated in a rat chronic infarction model. Ten weeks after infarction and 8 wk after patch epicardial placement, echocardiographic function, tissue-level structural remodeling (e.g., biaxial mechanical response and microstructural analysis), and cellular level remodeling were assessed. The results showed that the incorporation of a cardiac ECM altered the progression of several keys aspects of maladaptive remodeling following myocardial infarction. This included decreasing LV global mechanical compliance, inhibiting echocardiographically-measured functional deterioration, mitigating scar formation and LV wall thinning, and promoting angiogenesis. In evaluating the impact of patch anisotropy, no effects from the altered patch mechanics were detected after 8 wk, possibly due to patch fibrous encapsulation. Overall, this study demonstrates the benefit of a cardiac patch design that combines both ventricle mechanical support, through a biodegradable, fibrillary elastomeric component, and the incorporation of ECM-based hydrogel components.

Abstract P3-07-02: Prognostic and predictive relevance of HER2 status in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial

Background:

As compared to invasive breast cancer (IBC), HER2 is much more frequently overexpressed in ductal carcinoma in situ (DCIS). Unlike IBC, the prognostic significance of HER2 overexpression remains to be established in DCIS and large studies to investigate its predictive role are lacking. We investigated the prognostic and predictive relevance of HER2 protein and ERBB2 mRNA expression in DCIS using material from UK/ANZ DCIS trial.

Methods:

Formalin-fixed paraffin embedded tissues (FFPETs) were collected from patients enrolled in the UK/ANZ DCIS trial, a randomised 2X2 factorial design trial investigating role of tamoxifen, radiotherapy or both as adjuvant treatment in DCIS. ERBB2 mRNA expression was evaluated by reverse transcription followed by PCR on customized Taqman low-density arrays. ERBB2 mRNA expression was analysed as a continuous variable and also as a binary variable using a cut-off to reproduce HER2 expression distribution similar to that observed with immunohistochemistry (IHC). HER2 protein expression was evaluated by IHC using HercepTest™ and scored as per ASCO-CAP 2013 recommendations; HER2 equivocal (IHC2+) were grouped with HER2 negative (IHC 0 or 1+) for main analyses. Additional analyses using binary ERBB2 mRNA expression as a reflex test for HER2 IHC2+ were also performed.

Results:

HER2 protein expression was evaluable in 713 (181 events) of 755 available samples (DCIS absent or lost during assay in 42). ERBB2 mRNA expression was evaluable in 521 (134 events) of 704 available samples (DCIS absent or insufficient RNA in 51, assay failure in 132). Both results were available in 508 cases (130 events). Increase in ERBB2 mRNA expression (median 0.62; range 0.07-36.76) was associated with increased risk of in situ ipsilateral breast event (DCIS-IBE) [Hazard ratio (HR) = 1.07; 95% Confidence Interval (95%CI) 1.04-1.10; p < 0.0001] but not with increased risk of invasive ipsilateral breast event (I-IBE) [HR = 1.03; 95%CI 0.97-1.10; p = 0.3209]. HER2 positivity by IHC was similarly associated with increased risk of DCIS-IBE [HR = 2.90; 95%CI 1.91-4.40; p < 0.0001] but not with increased risk of I-IBE [HR = 1.40; 95%CI 0. 0.81-2.42; p = 0.2313]. Reclassification of HER2 IHC2+ cases using binary ERBB2 mRNA expression (46 as negative, 16 as positive; 18 expression data unavailable) further improved prognostic discrimination of HER2 IHC [ΔX2 (1d.f.) 5.51; p = 0.0189] for any recurrence. The effect of radiotherapy (RT) for reducing I-IBE was greater in HER2 positive (by ERBB2 mRNA expression) cases [HR = 0.24; 95%CI 0.07-0.83; p = 0.0237] as compared with HER2 negative cases [HR = 0.60; 95%CI 0.23-1.55; p = 0.2925]. Kaplan-Meier estimates of 10-year I-IBE rates with and without RT were 4.5% (2.5%-1.4%) and 15.8% (9.6%-25.3%) in HER2 positive DCIS; rates in HER negative DCIS were 5.2% (2.1%-2.4%) and 7.3% (4.3%-12.2%) respectively. The differential benefit of RT by HER2 status was also seen for reduction in DCIS-IBE.

Conclusions:

HER2 overexpression is associated with increased risk of DCIS-IBE but not of I-IBE. HER2 status is predictive of radiotherapy response with larger reductions in both I-IBE and DCIS-IBE seen in HER2 positive DCIS.

Citation Format: Thorat MA, Wagner S, Jones LJ, Levey PM, Bulka K, Hoff R, Sangale Z, Flake II DD, Bundred NJ, Fentiman IS, Forbes JF, Lanchbury JS, Cuzick J. Prognostic and predictive relevance of HER2 status in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-02.

A systematic review of the effect of thermal processing on the allergenicity of tree nuts

BACKGROUND

Allergenicity of foods can be influenced by processing. Tree nuts are an important source of nutrition and increasingly consumed; however, processing methods are quite variable and data are currently lacking on the effects of processing on allergenicity.

OBJECTIVE

To perform a systematic literature review on the effects of food processing on the allergenicity of tree nuts.

METHODS

A systematic literature search of PubMed and Embase databases was performed, with screening of references, related articles and citations. Studies were included if they assessed the allergenicity or immunogenicity of processed nuts.

RESULTS

The search resulted in 32 articles suitable for analysis. Clinical studies indicate that roasting reduces the allergenicity of hazelnut in individuals with a birch pollen allergy and reactivity to raw hazelnut. Thermal processing may reduce the allergenicity of the PR-10 protein in hazelnut and almond in vitro. The majority of the in vitro studies investigating the allergenicity of nonspecific lipid transfer proteins (nsLTPs) and seed storage proteins in hazelnut, almond, cashew nut, Brazil nut, walnut, pecan nut and pistachio nut show heat stability towards different thermal processing methods.

CONCLUSION

Thermal processing may reduce allergenicity of PR-10 proteins in hazelnut and almond, in contrast to nsLTPs and seed storage proteins. This has important implications for source materials used for IgE testing and food challenges and diet advice.

[Off-label prescriptions in acute psychiatry: a practice-based evaluation]

BACKGROUND

In acute psychiatry the prescribed medication is frequently off-label.

AIM

To investigate the indications for off-label prescriptions described in the literature and to evaluate the use of off-label medication in the emergency service of Altrecht, Utrecht, The Netherlands.

METHOD

We performed a systematic search of the PubMed database and we evaluated all the records of patients examined by the emergency service during two assessment periods (April 2009 and November 2010).

RESULTS

The literature makes no mention of the prescribing of off-label medication in acute psychiatry. In general psychiatry, however, off-label medication is reported mainly for atypical antipsychotics. In the emergency service 41% of the medication prescribed during first contacts with patients was off-label. These prescriptions were most often for antipsychotics (54%) and benzodiazepines (38%) . The most important indications were aggression, agitation and sleep problems. If the term ‘off-label’ is interpreted in a broader sense with respect to antipsychotics for psychosis and hypomania, then 33% of the prescriptions appeared to be off-label. If benzodiazepines prescribed for aggression/agitation were not taken into account, then the proportion of off-label prescriptions decreased to 21%.

CONCLUSION

We consider it advisable that the reason for prescribing off-label medication should be clearly documented. New medical guidelines could help by summarising current views on the use of off-label medication.

Bed closures and incarceration rates among users of Veterans Affairs mental health services

OBJECTIVE

This study examined incarceration rates of users of Department of Veterans Affairs (VA) mental health services in 16 northeastern New York State counties between 1994 and 1997-a time of extensive bed closures in the VA system-to determine whether incarceration rates changed during this period.

METHODS

Data were obtained for male patients who used inpatient and outpatient VA mental health services between 1994 and 1997 and for men incarcerated in local jails during this period. For comparison, services use and incarceration data were obtained for all men who received inpatient behavioral health care at community general hospitals and state mental hospitals between 1994 and 1996 in the same counties. Probabilistic population estimation, a novel statistical technique, was employed to evaluate the degree of overlap between clinical and incarceration populations without relying on person-specific identifiers.

RESULTS

Of all male users of VA mental health services between 1994 and 1997, a total of 15.7 percent-39.6 percent of those age 18 to 39 years and 9.1 percent of those age 40 years and older-were incarcerated at some time during that period. Dual diagnosis patients had the highest rate of incarceration (25 percent), followed by patients with substance abuse problems only (21 percent) and those with mental health problems only (11 percent). The rate of incarceration among male patients hospitalized in VA facilities was lower than among men in general hospitals or state hospitals (11.6 percent, 23 percent, and 21.7 percent, respectively), but was not significantly different. No significant increase occurred in the annual rate of incarceration among VA patients from 1994 to 1997 (3.7 percent to 4 percent), despite extensive VA bed closures during these years.

CONCLUSIONS

Substantial proportions of mental health system users were incarcerated during the study period, especially younger men and those with both substance use and mental health disorders. Rates of incarceration were similar across health care systems. The closure of a substantial number of VA mental health inpatient beds did not seem to affect the rate of incarceration among VA service users.

Trends in antiretroviral therapy and mother-infant transmission of HIV. The Women and Infants Transmission Study Group

Trends in the vertical transmission rate of HIV and evolving antiretroviral usage between 1990 and 1998 within the Women and Infants Transmission Study were evaluated. A decline in mother-infant transmission was temporally associated with advances in therapy, especially when regimens including a protease inhibitor were included in the analysis.

Intermediate-size trials for the evaluation of HIV vaccine candidates: a workshop summary

There has been considerable debate over what evidence from preclinical and clinical studies is required to advance an HIV vaccine candidate to phase III efficacy testing. Given this situation, conduct of intermediate-size trials is proposed as a method for assessing the plausibility that a vaccine candidate would prevent chronic HIV infection. Designed to observe 45 incident infections in the control group, these preliminary efficacy trials could rule out candidates with low or no efficacy while advancing those candidates with some evidence of protection to definitive trials. In addition, these trials could provide clues about correlates of immunity. A threefold or greater difference in the postvaccination geometric mean titer of neutralizing antibody can be readily detected between infected and uninfected vaccinees. Differences in CD8+ cytotoxic T lymphocytes, however, are more difficult to detect. Intermediate-size trials could also discern a 0.5 log10 or greater difference in plasma HIV-1 RNA levels between infected vaccinees and infected controls. Such differences in viral load might suggest disease amelioration or reduction in infectiousness. Given the large variability in CD4 count and its relatively modest average decline in the year after infection, a slower decline in CD4 count among infected vaccinees would not be detectable. With limited resources, intermediate-size trials could contribute significantly to HIV vaccine development.

Diagnosis of infection with human immunodeficiency virus type 1 by a DNA polymerase chain reaction assay among infants enrolled in the Women and Infants' Transmission Study

Early diagnosis of infection with human immunodeficiency virus type 1 (HIV- 1) in young infants is essential to decisions on their medical and social care. Whereas studies have suggested that polymerase chain reaction (PCR) is a sensitive and timely method of diagnosing HIV infection in children, these evaluations have been limited by the number of specimens studied. Recently, Roche Molecular Systems developed a complete HIV-1 DNA PCR testing kit (from specimen preparation to detection). In this study, use of this PCR test kit was evaluated for the detection of HIV infection in infants of seropositive mothers who were enrolled in the longitudinal, multicenter Women and Infants' Transmission Study. A total of 1209 blood specimens from 483 infants were tested and analyzed. The overall sensitivity and specificity of a single PCR test in determining HIV infection status in infants more than 1 but less than 36 months of age were 95% and 97%, respectively. For infected infants 1 to 6 months of age the sensitivity of the DNA-PCR test was 90% to 100%. In a direct comparison with coculture, the Roche DNA-PCR test was significantly more sensitive than coculture in the detection of HIV-1 in infected infants and was equivalent to coculture for the diagnosis of HIV in infants when a standardized algorithm was used to define infection status.

Trial objectives and end points for measuring the efficacy of HIV vaccines

In order to prove the efficacy of human immunodeficiency virus (HIV) vaccines, it will be necessary to do large-scale trials in populations at high risk of acquiring HIV infection. The choice of objectives and end points and their measurement will be key to the design of efficacy trials. To address these issues, the National Institute of Allergy and Infectious Diseases convened several workshops and discussions at national meetings. These discussions have concluded that many factors will contribute to the selection of practical primary objectives and end points for efficacy trials of HIV vaccines. For initial trials the objective of preventing the establishment of chronic infection is a reasonable choice, given the current state of knowledge. However, given the complexities of HIV and the acquired immunodeficiency syndrome, it will be important to collect data and evaluate other potential objectives and end points as well.

Extreme thermostability of tarantula hemocyanin

Biotops with extreme temperatures such as deserts force animals to avoid or escape high temperatures by biochemical, behavioural or morphological adaptation. In this context we tested the resistance to heat of the oxygen carrier hemocyanin from the ancient tarantula Eurypelma californicum, which is found in arid zones of North America. Differential scanning calorimetry, light scattering, crossed immunogelelectrophoresis and oxygen binding experiments show that the 24-meric hemocyanin is conformationally stable and fully functioning at temperatures up to 90 degrees C. Our results demonstrate that the cation-mediated state of oligomerization is not only crucial for the high cooperativity of oxygen binding of this hemocyanin, but also for its extreme stability in the physiological temperature and pH range.

HIV vaccine development and clinical trials

The magnitude of HIV pandemic has made the development of HIV vaccines an urgent biomedical research priority. Although the biologic problems in designing a vaccine for a chronic viral infection like HIV are formidable, there has been encouraging progress. More than a dozen first generation prophylactic HIV vaccine candidates have completed phase I human trials that have established the safety and immunogenicity of these products in adults. A phase II trial of two HIV subunit envelope vaccines in adults at high risk of HIV infection is underway in the United States, and preparations for phase III efficacy trials have begun. Preliminary studies are under way to evaluate the potential application of active and passive immunization for preventing vertical transmission of HIV. Because of the higher rate of HIV transmission and a more abbreviated time course to disease, it may be more efficient to evaluate the efficacy of HIV vaccines in HIV infected pregnant women and their offspring than in adults who are exposed sexually to HIV.

Neonatal serologic screening and early treatment for congenital Toxoplasma gondii infection. The New England Regional Toxoplasma Working Group

BACKGROUND

Most infants with congenital Toxoplasma gondii infection have no symptoms at birth, but many will have retinal disease or neurologic abnormalities later in life. Early detection and treatment of congenital toxoplasmosis may reduce these sequelae.

METHODS

In Massachusetts since January 1986, and in New Hampshire since July 1988, newborns have been screened for intrauterine infection with T. gondii by means of an IgM capture immunoassay of blood specimens routinely collected for screening for metabolic disorders. Congenital infection is confirmed by assays for specific IgG and IgM antibodies in serum from infants and their mothers. For this study, infants with serologic evidence of infection underwent extensive clinical evaluation and received one year of treatment.

RESULTS

Through June 1992, 100 of 635,000 infants tested had positive screening tests. Congenital infection was confirmed in 52 infants, 50 of whom were identified only through neonatal screening and not through initial clinical examination. However, after the serologic results became available, more detailed examinations revealed abnormalities of either the central nervous system or the retina in 19 of 48 infants evaluated (40 percent). After treatment, only 1 of 46 children had a neurologic deficit (hemiplegia attributable to a cerebral lesion present at birth). Thirty-nine treated children had follow-up ophthalmologic examinations when one to six years old; four (10 percent) had eye lesions that may have developed postnatally (a macular lesion in one child and minor retinal scars in three).

CONCLUSIONS

Routine neonatal screening for toxoplasmosis identifies congenital infections that are subclinical, and early treatment may reduce the severe long-term sequelae.

Comparison of three nonradioisotopic polymerase chain reaction-based methods for detection of human immunodeficiency virus type 1

Three nonradioisotopic polymerase chain reaction (PCR)-based detection techniques were evaluated for sensitivity and specificity in detecting human immunodeficiency virus type 1 (HIV-1) proviral DNA in peripheral blood mononuclear cells. The Roche prototype HIV-1 PCR assay, the Du Pont enzyme-linked oligonucleotide sandwich assay (ELOSA), and the Gen-Probe hybridization protection assay (HPA) were compared with a standard radioisotopic oligonucleotide solution hybridization (OSH) technique. A panel of 111 well-characterized clinical samples that included peripheral blood mononuclear cells from 48 healthy, low-risk, HIV-1 antibody-negative subjects, 24 antibody-positive subjects with stable CD4 counts of less than 200/mm3, and 39 antibody-positive subjects with stable CD4 counts of greater than 800/mm3 were studied. Each method demonstrated good specificity, ranging between 96 and 100%; those of the OSH and ELOSA (Du Pont) were 100%, those of the HPA (Gen-Probe) were 100% with one probe and 96% with the other probe, and that of the HIV-1 PCR assay (Roche) was 96%. Sensitivities ranged from 96 to 100% for the low-CD4-count group, with the OSH, the HIV-1 PCR assay (Roche), and the HPA (Gen-Probe) all attaining a sensitivity of 100%. For the high-CD4-count group, sensitivities ranged from 69 to 97%, with the OSH attaining a sensitivity of 97% and the HPA attaining sensitivities of 97% with one probe and 95% with the other probe. These data indicate that the nonradioisotopic techniques are sensitive and specific for the detection of HIV-1 proviral DNA in clinical samples.

Evaluation of recombinant trypomastigote surface antigens of Trypanosoma cruzi in screening sera from a population in rural Northeastern Brazil endemic for chagas' disease

A perfect serologic test for infection with Trypanosoma cruzi does not exist. This study uses recombinant T. cruzi surface proteins in the antibody capture enzyme linked immunoabsorption assay (ELISA); and compares this approach to the more standard immunofluorescence assay (IFA). Three recombinant antigens are studied: F1-160 corresponding to the 160 kDa flagellar associated surface protein of trypomastigotes (the motile form of T. cruzi in mammalian infections); and SA 85-1.1 and 1.2 corresponding to different members of the 85 kDa family of surface proteins expressed by trypomastigotes and amastigotes (the replicative, non-motile form of T. cruzi in mammalian infections). Each recombinant antigen is found to be highly specific (range 86-94%) but relatively insensitive (range 36-52%) when used to screen for antibodies to T. cruzi. Defining seropositivity as reactivity to any of the three recombinant antigens markedly increases the sensitivity (72%) with only a minor reduction in specificity (82%). Thus, employing recombinant T. cruzi antigens to screen for T. cruzi infection has promise, but improvements in sensitivity must be made before widespread utilization is recommended.

Clinical utility of HIV-IgA immunoblot assay in the early diagnosis of perinatal HIV infection

OBJECTIVE

To ascertain the sensitivity, specificity, predictive value, and clinical use of a human immunodeficiency virus (HIV)-IgA immunoblot assay for diagnosing perinatal HIV infection in infants tested at birth to 1 month, 3 months, and 6 months of age.

DESIGN

Prospective, longitudinal cohort study of children born to HIV-infected and noninfected women. The HIV-IgA immunoblot assays were performed at birth to 1 month, 3 months, and 6 months of age and compared with the Centers for Disease Control's classification system of HIV infection in the children. Children were followed up for at least 15 months to ensure accuracy of infection status.

SETTING

Municipal hospital in central Brooklyn, NY, where the prevalence of HIV infection is high.

PATIENTS

Serum samples from 58 children, 22 with documented HIV infection, 18 noninfected children born to seropositive women, and 18 children born to noninfected women, were studied.

MAIN OUTCOME MEASURE

Diagnosis of HIV infection using the Centers for Disease Control's classification scheme was compared with diagnosis using the HIV-IgA immunoblot assay for children 6 months of age or younger.

RESULTS

The HIV-IgA immunoblot assay yielded negative results at 3 and 6 months of age for all 18 infants born to seronegative women; for the 18 seroreverting, noninfected children born to infected women, the assay yielded negative results at 1 month, 3 months, and 6 months of age. The positive predictive value of the assay was 100%--no false-positive results were identified in the 88 serum samples obtained from noninfected infants. For the HIV-infected children, sensitivity was a function of age: one (5.9%) of 17 infants had an assay that yielded positive results at birth to 1 month of age, 13 (62%) of 21 infants had assays that yielded positive results at 3 months of age, and 17 (77%) of 22 infants had assays that yielded positive results at 6 months of age. The presence or absence of symptoms did not affect the sensitivity.

CONCLUSION

The HIV-IgA immunoblot assay can detect a significant proportion of infected children during an early asymptomatic period of their life. This relatively inexpensive, easily standardized assay may allow for institution of therapy before the onset of clinical symptoms.

Isocratic reversed-phase HPLC method to measure pyrimethamine extracted from plasma of infants treated for toxoplasmosis

An isocratic HPLC method for measuring pyrimethamine extracted from infant plasma is reported. The method is an improvement over previously published methods by requiring lower volumes of plasma (100 microL) and having increased sensitivity to pyrimethamine at 210 nm. The procedure, which entails a basic organic extraction and subsequent HPLC chromatography of the reconstituted extract, can detect 1.4 ng and quantify 4.0 ng of pyrimethamine per 40-microL injection, with two analyses per 100-microL sample. Analytical recovery of pyrimethamine added to plasma at 10, 50, and 125 ng/100 microL averaged 80%, 92%, and 101%, respectively (n = 20). Within- and between-day CVs were less than 7%. Studies of various plasma samples from adults and infants (n = 15) revealed no interference from other plasma peaks with the analyte of interest.

Isocratic reversed-phase HPLC method to measure pyrimethamine extracted from plasma of infants treated for toxoplasmosis

An isocratic HPLC method for measuring pyrimethamine extracted from infant plasma is reported. The method is an improvement over previously published methods by requiring lower volumes of plasma (100 microL) and having increased sensitivity to pyrimethamine at 210 nm. The procedure, which entails a basic organic extraction and subsequent HPLC chromatography of the reconstituted extract, can detect 1.4 ng and quantify 4.0 ng of pyrimethamine per 40-microL injection, with two analyses per 100-microL sample. Analytical recovery of pyrimethamine added to plasma at 10, 50, and 125 ng/100 microL averaged 80%, 92%, and 101%, respectively (n = 20). Within- and between-day CVs were less than 7%. Studies of various plasma samples from adults and infants (n = 15) revealed no interference from other plasma peaks with the analyte of interest.

IgA and IgM human immunodeficiency virus antibodies in weakly reactive or false-negative blood donors

Detection of antibodies to the human immunodeficiency virus (HIV) in recently infected donors is crucial to prevent the transmission of HIV infection via blood products. To determine whether specific antibodies of the IgA or IgM class are present as markers of recent infection in donor specimens that have borderline reactivity on routine enzyme immunoassay (EIA) screening, 15 specimens that were positive by immunoblot were tested for IgA and IgM HIV antibodies. All 15 had detectable IgA HIV antibodies, and 14 had IgM HIV antibodies. The 15 specimens were tested further, each by two independent laboratories, with nine licensed EIAs. Two of the nine EIAs found all 15 units positive in both laboratories; seven EIAs found 1 to 5 of the 15 units negative, for a total of 31 false-negative results. The results indicated a difference between the sensitivity of EIA kits using only anti-IgG reagents and of kits using multispecific reagents that react with IgG and other classes of antibody. In a modified procedure, the addition of enzyme-conjugated anti-IgA or anti-IgM to the kit's enzyme-conjugated reagent increased the optical density values of most false-negative specimens to the positive range. It was concluded that licensed kits vary in reactivity with IgA and IgM HIV antibodies and that sensitivity could be increased by improved detection of these classes of antibody.

Prevalence of HIV infection in childbearing women in the United States. Surveillance using newborn blood samples

A national, population-based survey was initiated in 1988 to measure the prevalence of human immunodeficiency virus (HIV) infection in women giving birth to infants in the United States. Following standardized procedures, residual dried-blood specimens collected on filter paper for newborn metabolic screening were tested anonymously in state public health laboratories for maternal antibody to HIV. As of September 1990, annual survey data were available from 38 states and the District of Columbia. The highest HIV seroprevalence rates were observed in New York (5.8 per 1000), the District of Columbia (5.5 per 1000), New Jersey (4.9 per 1000), and Florida (4.5 per 1000). Nationwide, an estimated 1.5 per 1000 women giving birth to infants in 1989 were infected with HIV. Assuming a perinatal transmission rate of 30%, we estimate that approximately 1800 newborns acquired HIV infection during one 12-month period. Preventing transmission of HIV infection to women and infants is an urgent public health priority.

Use of paper-absorbed fingerstick blood samples for studies of antibody to human immunodeficiency virus type 1 in intravenous drug users

The suitability of paper-absorbed (PA) fingerstick blood specimens for antibody testing of human immunodeficiency virus type 1 (HIV-1) was examined in two populations of intravenous drug users (IVDU): 393 persons from a drop-in counseling and testing clinic and 145 from a methadone treatment clinic. From the first group, the same 66 immunoblot-confirmed enzyme immunoassay (EIA)-positive specimens were identified in sera from venipuncture and parallel fingerstick PA specimens. The latter had slightly higher EIA mean background levels resulting in 10 immunoblot-negative EIA-positive samples versus 6 in the sera group. HIV-1 seroprevalence was 17% of 393 from the drop-in clinic. By category of IVDU, the rates were 34% and 14% for active and recovering IVDU, respectively (P less than .001), and 36% in black and Latino compared with 13% in white IVDU (P less than .002). Of the 145 participants in the methadone program, 39% had antibody to HIV-1: 49% for blacks and Latinos compared with 30% in whites (P less than .01). The data indicate that antibody testing for HIV-1 by PA is equivalent to the serum antibody assay of venipuncture specimens. The fingerstick method appears to have greater use for serosurveys and screening programs because of convenience, safety, and ease of storage, transport, and processing of samples.

A nine year prospective study of Chagas' disease in a defined rural population in northeast Brazil

The association between infection with Trypanosoma cruzi and the development of electrocardiographic alterations and mortality was studied longitudinally for 9 years in a population residing in an endemic area in Castro Alves, Bahia, Brazil. Annual censuses were begun in 1973. At 3 year intervals from 1974 to 1983, the population was examined serologically and subjected to electrocardiography using standardized techniques. Of 1,751 individuals registered during the 10 censuses, 1,541 (88%) were examined serologically at least once. Of 747 individuals in constant residence and originally seronegative, 24 were seropositive upon subsequent evaluation, giving a seroconversion rate of 4.92/1,000 person-years (PY). The overall rate of development of an abnormal ECG was 25.7/1,000 PY for seropositive individuals and 12.5/1,000 PY for seronegative individuals, a relative risk of 2. The 10-14-year-old seropositive group had the highest risk of developing ECG abnormalities (24.1/1,000 PY, relative risk = 3.5). The age-adjusted mortality rate of seropositive individuals was slightly higher than for seronegative individuals (8.9 vs. 7.8/1,000 PY). In sero-positive individuals, mortality was strongly associated with the presence of ventricular conduction defects and arrhythmias. Ventricular conduction defects appeared most frequently in younger individuals. Older individuals presented the highest risk of development of frequent and multifocal extrasystoles.

Detection of IgM and IgA HIV antibodies after removal of IgG with recombinant protein G

Indirect assays for IgM and IgA antibodies often lack sensitivity and specificity due to interference from IgG antibodies. To overcome this problem we have developed a simple procedure using recombinant protein G coupled to agarose beads to remove the interfering IgG. A series of HIV seroconversion panels was tested by IgM and IgA immunoblot after protein G treatment in order to evaluate IgG removal and to study appearance of IgM and IgA antibodies in early HIV infection. Protein G treatment removed 99.9% of the IgG and reduced IgG anti-HIV titers of over 1/100,000 to undetectable levels. Both IgM and IgA HIV antibodies were detected as early in seroconversion as were IgG HIV antibodies. IgA HIV antibodies persisted for a longer period of time, reacted with more HIV proteins, and showed more intense staining than IgM HIV antibodies.

HIV seroprevalence surveys of childbearing women--objectives, methods, and uses of the data

A seroprevalence survey of human immunodeficiency virus (HIV) among childbearing women is being conducted in 43 States and Territories as one of the family of HIV seroprevalence surveys. This blinded survey, in which serologic test results are not linked to identifiable persons, uses neonatal dried blood specimens on filter paper to test for maternal antibodies to HIV. This survey provides relatively unbiased estimates of prevalence of HIV infection in the population of women delivering live children during given survey periods, by month or quarter of delivery, geographic area, and demographic subgroup. This objective will be met while protecting the integrity and efficient conduct of neonatal screening programs and ensuring patient anonymity. Information from this survey will be used to (a) assess the levels and trends of HIV infection in women and infants, (b) help develop and evaluate prevention programs, and (c) project the number of women and children who will develop HIV infection and the acquired immunodeficiency syndrome (AIDS) and will require health care and social services in the future.

Seroprevalence of human immunodeficiency virus among childbearing women. Estimation by testing samples of blood from newborns

Attempts to predict the course of the epidemic of acquired immunodeficiency syndrome (AIDS) have been hampered by the lack of an objective, practical way to estimate the prevalence of infection with the human immunodeficiency virus (HIV) in the general population. Testing for the prevalence of HIV infection in women should be a sensitive means to track the epidemic and to study the potential for perinatal transmission. Antibodies in maternal blood are contained in neonatal blood specimens routinely collected on absorbent paper for other purposes, such as screening for phenylketonuria; we therefore tested for HIV antibody in these specimens. Analysis of batches of individually blinded specimens from selected hospitals protected the anonymity of the mothers and babies and was cost efficient. Using the newborn's blood as an indicator of the mother's serologic status, we concluded that 1 of every 476 women (2.1 per 1000) giving birth in Massachusetts was positive for HIV antibody by immunofluorescence assay or enzyme-linked immunosorbent assay, both confirmed by immunoblot (Western blot) testing. The prevalence of HIV infection varied according to the type and location of the maternity hospitals; rates of seropositivity were highest in inner-city hospitals (8.0 per 1000), lower in mixed urban and suburban hospitals (2.5 per 1000), and lowest in suburban and rural hospitals (0.9 per 1000). This method is useful for collecting data needed to plan and evaluate prevention strategies and to predict the health care resources that will be needed to care for women and children who contract AIDS. Because other states have newborn screening programs similar to the Massachusetts program, this approach can be used for national surveillance of AIDS in women.

Frozen maternal platelets for neonatal thrombocytopenia

A case is reported of an alloimmunized, neonatal, thrombocytopenic patient who was successfully transfused with maternal platelets collected by cytapheresis and cryopreserved 3 months before delivery. Phlebotomy or cytapheresis of the mother immediately before delivery was avoided. Transfusion of maternal platelets over a 7-day period with aliquots containing an average of 7.1 X 10(10) platelets in 50 ml of plasma was possible. Satisfactory increases in platelet counts were sustained after transfusion.

Cardiac morbidity and mortality due to Chagas' disease: prospective electrocardiographic study of a Brazilian community

The evolution of Chagas' cardiomyopathy is poorly understood. We therefore examined the development of cardiac lesions in a rural Brazilian community for a period of 7 years. Initially, 42% of 1017 residents were seropositive for infection with Trypanosoma cruzi. Age-specific infection rates indicated that most had become infected before the age of 20 years. On follow-up, it appeared that those persons who developed cardiac lesions did so soon after infection, since the incidence of right bundle branch block and other ventricular conduction defects (VCDs) was also highest before age 20 years. The progressive nature of these lesions was demonstrated by frequent development of additional electrocardiographic abnormalities and high mortality among infected adults with VCDs. In contrast, mortality was low and approximately the same for seropositive and seronegative adults under 60 years who had normal electrocardiograms. Electrocardiography during the early asymptomatic stage of infection was able to distinguish persons with potentially lethal cardiac lesions from those with a benign prognosis.

Isolation and functional characterization of murine T cell lines and clones specific for the protozoan parasite Trypanosoma cruzi

Murine T cell lines responsive to the protozoan parasite Trypanosoma cruzi were generated in vitro by stimulating hyperimmune C57BL/6 lymphoid cells with trypomastigote stage antigen. A spleen-derived line designated ST1 and eight clones derived from ST1 were characterized. All lines bear the surface phenotype Thy-1.2+, Ly-1.2+, 2.2- and respond to T. cruzi antigen only in the presence of antigen-presenting cells matched at the I-A subregion of the H2 locus. Clonal specificity analyses indicated that these T. cruzi-selected T cells are species specific and recognize antigenic determinants that are expressed predominantly in the trypomastigote stage. On the basis of their distinct patterns of response to a panel of different T. cruzi strains, clones recognizing strain-specific, shared, or common determinants were identified. Functional studies indicated that ST1 and some but not all of the clones are capable of expressing antigen-specific T helper function in vitro and in vivo. In addition, co-incubation of T. cruzi-specific T cells with cultured T. cruzi-infected syngeneic macrophages led to the dose-dependent destruction of intracellular parasites. Most notably, ST1 and several of the cloned T. cruzi-specific T cell lines were able to passively protect syngeneic recipients from lethal T. cruzi challenge infection. Efforts to identify the parasite antigens recognized by these T cell lines, particularly the protective clones, are currently in progress.

Isolation and functional characterization of murine T cell lines and clones specific for the protozoan parasite Trypanosoma cruzi

Murine T cell lines responsive to the protozoan parasite Trypanosoma cruzi were generated in vitro by stimulating hyperimmune C57BL/6 lymphoid cells with trypomastigote stage antigen. A spleen-derived line designated ST1 and eight clones derived from ST1 were characterized. All lines bear the surface phenotype Thy-1.2+, Ly-1.2+, 2.2- and respond to T. cruzi antigen only in the presence of antigen-presenting cells matched at the I-A subregion of the H2 locus. Clonal specificity analyses indicated that these T. cruzi-selected T cells are species specific and recognize antigenic determinants that are expressed predominantly in the trypomastigote stage. On the basis of their distinct patterns of response to a panel of different T. cruzi strains, clones recognizing strain-specific, shared, or common determinants were identified. Functional studies indicated that ST1 and some but not all of the clones are capable of expressing antigen-specific T helper function in vitro and in vivo. In addition, co-incubation of T. cruzi-specific T cells with cultured T. cruzi-infected syngeneic macrophages led to the dose-dependent destruction of intracellular parasites. Most notably, ST1 and several of the cloned T. cruzi-specific T cell lines were able to passively protect syngeneic recipients from lethal T. cruzi challenge infection. Efforts to identify the parasite antigens recognized by these T cell lines, particularly the protective clones, are currently in progress.