Chemical Composition of Electronic Vaping Products from School Grounds in California.

INTRODUCTION: The use of electronic vaping products (EVPs) containing nicotine, marijuana, and/or other substances remains prominent among youth; with EVPs containing nicotine being the most commonly used tobacco product among youth since 2014. However, a detailed understanding of the chemical composition of these products is limited. METHODS: During February 25th-March 15th, 2019, a total of 576 EVPs, including 233 e-cigarette devices (with 43 disposable vape pens) and 343 e-liquid cartridges/pods/bottled e-liquids, were found or confiscated from a convenience sample of 16 public high schools in California. Liquids inside 251 vape pens and cartridges/pods/bottled e-liquids were analyzed using a gas chromatography/mass spectrometry (GC/MS). For comparison, new JUUL pods, the most commonly used e-cigarette among youth during 2018-2019, with different flavorings and nicotine content were purchased and analyzed. RESULTS: For e-cigarette cartridges/pods/bottled e-liquids, nicotine was detected in 204 of 208 (98.1%) samples. Propylene glycol (PG) and vegetable glycerin (VG) were dominant solvents in nicotine-containing EVPs. Among 43 disposable vape pen devices, cannabinoids such as tetrahydrocannabinol (THC) or cannabidiol (CBD) were identified in 39 of 43 (90.1%) samples, of which 3 contained both nicotine and THC. Differences in chemical compositions were observed between confiscated or collected JUULs and purchased JUULs. Measured nicotine was inconsistent with labels on some confiscated or collected bottled e-liquids. CONCLUSIONS: EVPs from 16 participating schools were found to widely contain substances with known adverse health effects among youth, including nicotine and cannabinoids. There was inconsistency between labeled and measured nicotine on the products from schools. IMPLICATIONS: This study measured the main chemical compositions of EVPs found at 16 California public high schools. Continued efforts are warranted, including at the school-level, to educate, prevent and reduce youth use of EVPs.

Legionnaires' disease in transportation, construction and other occupations in 39 US jurisdictions, 2014-2016.

BACKGROUND: Certain workers are at increased risk for acquiring Legionnaires' disease compared with other workers. This study aims to identify occupations at increased risk for acquiring Legionnaires' disease. METHODS: Using data from the US Centers for Disease Control and Prevention's Supplemental Legionnaires' Disease Surveillance System, this study identified Legionnaires' disease confirmed patients ≥16 years of age in 39 states with reported symptom onset during 2014-2016. Age-adjusted and sex-adjusted incidence rate ratios (IRR) stratified by occupation group were calculated by comparing Legionnaires' disease patients in an occupation group (eg, transportation) to those in all other occupation groups (eg, non-transportation). RESULTS: A total of 2553 patients had a known occupation group. The two occupations with the highest burden were transportation (N=287; IRR=2.11) and construction (N=269; IRR=1.82). Truck drivers comprised the majority (69.7%) of the transportation occupation group and construction labourers comprised almost half (49%) of the construction occupation group. The healthcare support occupation had the highest IRR (N=75; IRR=2.16). CONCLUSION: Transportation and construction workers, who are generally not covered by guidance related to building water systems, have increased risk of Legionnaires' disease compared with other workers. One hypothesised risk factor for truck drivers is the use of non-genuine windshield cleaner in their vehicles. A simple intervention is to use genuine windshield cleaner with bactericidal properties (ie, includes isopropanol/methanol) which can reduce the risk of Legionella growth and transmission. To improve surveillance of Legionnaires' disease and identification of similar exposures, the authors encourage the collection of occupation and industry information for all patients with Legionnaires' disease.

Colonization With Antibiotic-Resistant Bacteria in a Hospital and Associated Communities in Guatemala: An Antibiotic Resistance in Communities and Hospitals (ARCH) Study.

BACKGROUND: We estimated the prevalence of colonization with extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) and carbapenem-resistant Enterobacterales (CRE) from a hospital and associated communities in western Guatemala. METHODS: Randomly selected infants, children, and adults (<1, 1-17, and ≥18 years, respectively) were enrolled from the hospital (n = 641) during the coronavirus disease 2019 (COVID-19) pandemic, March to September 2021. Community participants were enrolled using a 3-stage cluster design between November 2019 and March 2020 (phase 1, n = 381) and between July 2020 and May 2021 (phase 2, with COVID-19 pandemic restrictions, n = 538). Stool samples were streaked onto selective chromogenic agar, and a Vitek 2 instrument was used to verify ESCrE or CRE classification. Prevalence estimates were weighted to account for sampling design. RESULTS: The prevalence of colonization with ESCrE and CRE was higher among hospital patients compared to community participants (ESCrE: 67% vs 46%, P < .01; CRE: 37% vs 1%, P < .01). Hospital ESCrE colonization was higher for adults (72%) compared with children (65%) and infants (60%) (P < .05). Colonization was higher for adults (50%) than children (40%) in the community (P < .05). There was no difference in ESCrE colonization between phase 1 and 2 (45% and 47%, respectively, P > .05), although reported use of antibiotics among households declined (23% and 7%, respectively, P < .001). CONCLUSIONS: While hospitals remain foci for ESCrE and CRE colonization, consistent with the need for infection control programs, community prevalence of ESCrE in this study was high, potentially adding to colonization pressure and transmission in healthcare settings. Better understanding of transmission dynamics and age-related factors is needed.

Assessment of School Staff Knowledge and Perceptions of Student E-cigarette Use and Resource Needs, and E-cigarettes Confiscated at 12 North Carolina High Schools - 2019.

BACKGROUND: E-cigarettes are the most commonly used tobacco product among US youth and are regularly used on school grounds. We assessed school staff's awareness of students' e-cigarette use, response by schools, and resources needed to address use, and examined e-cigarettes confiscated by school staff in North Carolina to guide prevention and identify needed resources. METHODS: In May 2019, staff from a random sample of 25 of 451 North Carolina public and charter high schools were invited to complete an online survey and semistructured interview; 12 schools consented to ≥ 1 component (survey, N = 514; interviews, N = 35). Staff knowledge and perceptions of students' e-cigarette use and school tobacco policies were assessed, including school efforts to address e-cigarette use. E-cigarette products confiscated by nine schools from students during the 2018-2019 school year were collected. LIMITATIONS: Only 12 public high schools participated, and these schools might not be representative of all North Carolina high schools. Quantitative surveys were not collected from all staff at participating schools; however, the response rate was 62% and included different staff positions and both urban and rural schools. Finally, e-cigarette products collected by schools might not be representative of all devices used by students. RESULTS: Among surveyed staff, 33% observed students using e-cigarettes on school grounds; 86% believed e-cigarette use somewhat or largely contributes to learning disruptions. Overall, 94% of respondents knew their school's policy prohibits student e-cigarette use on school grounds, and 57% were not confident their school has resources to help students quit. From 35 interviews, themes included concern that schools' tobacco-free policies do not deter use and additional resources are needed to address e-cigarette use in schools. Of 336 collected devices, there were different e-cigarette types and most (65%) e-liquid bottles were flavored. CONCLUSION: Efforts are warranted to incorporate evidence-based curricula; educate staff, parents, and youth regarding health risks of e-cigarette use; and help youth quit e-cigarettes.

Coronavirus Disease 2019 (COVID-19) in Americans Aboard the Diamond Princess Cruise Ship.

BACKGROUND: The Diamond Princess cruise ship was the site of a large outbreak of coronavirus disease 2019 (COVID-19). Of 437 Americans and their travel companions on the ship, 114 (26%) tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We interviewed 229 American passengers and crew after disembarkation following a ship-based quarantine to identify risk factors for infection and characterize transmission onboard the ship. RESULTS: The attack rate for passengers in single-person cabins or without infected cabinmates was 18% (58/329), compared with 63% (27/43) for those sharing a cabin with an asymptomatic infected cabinmate, and 81% (25/31) for those with a symptomatic infected cabinmate. Whole genome sequences from specimens from passengers who shared cabins clustered together. Of 66 SARS-CoV-2-positive American travelers with complete symptom information, 14 (21%) were asymptomatic while on the ship. Among SARS-CoV-2-positive Americans, 10 (9%) required intensive care, of whom 7 were ≥70 years. CONCLUSIONS: Our findings highlight the high risk of SARS-CoV-2 transmission on cruise ships. High rates of SARS-CoV-2 positivity in cabinmates of individuals with asymptomatic infections suggest that triage by symptom status in shared quarters is insufficient to halt transmission. A high rate of intensive care unit admission among older individuals complicates the prospect of future cruise travel during the pandemic, given typical cruise passenger demographics. The magnitude and severe outcomes of this outbreak were major factors contributing to the Centers for Disease Control and Prevention's decision to halt cruise ship travel in US waters in March 2020.

Nursing Home Infection Control Program Characteristics, CMS Citations, and Implementation of Antibiotic Stewardship Policies: A National Study.

Recently, the Centers for Medicare & Medicaid Services (CMS) final rule required that nursing homes (NHs) develop an infection control program that includes an antibiotic stewardship component and employs a trained infection preventionist (IP). The objectives of this study were to provide a baseline assessment of (1) NH facility and infection control program characteristics associated with having an infection control deficiency citation and (2) associations between IP training and the presence of antibiotic stewardship policies, controlling for NH characteristics. A cross-sectional survey of 2514 randomly sampled US NHs was conducted to assess IP training, staff turnover, and infection control program characteristics (ie, frequency of infection control committee meetings and the presence of 7 antibiotic stewardship policies). Responses were linked to concurrent Certification and Survey Provider Enhanced Reporting data, which contain information about NH facility characteristics and citations. Descriptive statistics and multivariable regression analyses were conducted to account for NH characteristics. Surveys were received from 990 NHs; 922 had complete data. One-third of NHs in this sample received an infection control deficiency citation. The NHs that received deficiency citations were more likely to have committees that met weekly/monthly versus quarterly ( P < .01). The IPs in 39% of facilities had received specialized training. Less than 3% of trained IPs were certified in infection control. The NHs with trained IPs were more likely to have 5 of the 7 components of antibiotic stewardship in place (all P < .05). The IP training, although infrequent, was associated with the presence of antibiotic stewardship policies. Receiving an infection control citation was associated with more frequent infection control committee meetings. Training and support of IPs is needed to ensure infection control and antibiotic stewardship in NHs. As the CMS rule becomes implemented, more research is warranted. There is a need for increase in trained IPs in US NHs. These data can be used to evaluate the effectiveness of the CMS final rule on infection management processes in US NHs.

Implementation of Electronic Health Records in US Nursing Homes.

While electronic health records have emerged as promising tools to help improve quality of care, nursing homes have lagged behind in implementation. This study assessed electronic health records implementation, associated facility characteristics, and potential impact on quality indicators in nursing homes. Using national Centers for Medicare & Medicaid Services and survey data for nursing homes, a cross-sectional analysis was conducted to identify variations between nursing homes that had and had not implemented electronic health records. A difference-in-differences analysis was used to estimate the longitudinal effect of electronic health records on commonly used quality indicators. Data from 927 nursing homes were examined, 49.1% of which had implemented electronic health records. Nursing homes with electronic health records were more likely to be nonprofit/government owned (P = .04) and had a lower percentage of Medicaid residents (P = .02) and higher certified nursing assistant and registered nurse staffing levels (P = .002 and .02, respectively). Difference-in-differences analysis showed greater quality improvements after implementation for five long-stay and two short-stay quality measures (P = .001 and .01, respectively) compared with those who did not implement electronic health records. Implementation rates in nursing homes are low compared with other settings, and better-resourced facilities are more likely to have implemented electronic health records. Consistent with other settings, electronic health records implementation improves quality in nursing homes, but further research is needed to better understand the mechanism for improvement and how it can best be supported.

Epidemiological and biological determinants of Staphylococcus aureus clinical infection in New York State maximum security prisons.

BACKGROUND: Large outbreaks of Staphylococcus aureus (SA) infections have occurred in correctional facilities across the country. We aimed to define the epidemiological and microbiological determinants of SA infection in prisons to facilitate development of prevention strategies for this underserved population. METHODS: We conducted a case-control study of SA infection at 2 New York State maximum security prisons. SA-infected inmates were matched with 3 uninfected controls. Subjects had cultures taken from sites of infection and colonization (nose and throat) and were interviewed via structured questionnaire. SA isolates were characterized by spa typing. Bivariate and multivariable analyses were conducted using conditional logistic regression. RESULTS: Between March 2011 and January 2013, 82 cases were enrolled and matched with 246 controls. On bivariate analysis, the use of oral and topical antibiotics over the preceding 6 months was strongly associated with clinical infection (OR, 2.52; P < .001 and 4.38, P < .001, respectively). Inmates with clinical infection had 3.16 times the odds of being diabetic compared with inmates who did not have clinical infection (P < .001). Concurrent nasal and/or oropharyngeal colonization was also associated with an increased odds of infection (OR, 1.46; P = .002). Among colonized inmates, cases were significantly more likely to carry the SA clone spa t008 (usually representing the epidemic strain USA300) compared to controls (OR, 2.52; P = .01). CONCLUSIONS: Several inmate characteristics were strongly associated with SA infection in the prison setting. Although many of these factors were likely present prior to incarceration, they may help medical staff identify prisoners for targeted prevention strategies.

Obesity as a Determinant of Staphylococcus aureus Colonization Among Inmates in Maximum-Security Prisons in New York State.

Obesity increases a person's susceptibility to a variety of infections, including Staphylococcus aureus infections, which is an important cause of morbidity in correctional settings. Using a cross-sectional design, we assessed the association between obesity and S. aureus colonization, a risk factor for subsequent infection, in New York State maximum-security prisons (2011-2013). Anterior nares and oropharyngeal cultures were collected. Structured interviews and medical records were used to collect demographic, behavioral, and medical data. Body mass index (BMI; weight (kg)/height (m(2))) was categorized as 18.5-24.9, 25-29.9, 30-34.9, or ≥35. The association between BMI and S. aureus colonization was assessed using log-binomial regression. Thirty-eight percent of 638 female inmates and 26% of 794 male inmates had a BMI of 30 or higher. More than 40% of inmates were colonized. Female inmates with a BMI of 25-29.9 (prevalence ratio (PR) = 1.37, 95% confidence interval (CI): 1.06, 1.76), 30-34.9 (PR = 1.52, 95% CI: 1.17, 1.98), or ≥35 (PR = 1.49, 95% CI: 1.13, 1.96) had a higher likelihood of colonization than did those with a BMI of 18.5-24.9 after we controlled for age, educational level, smoking status, diabetes status, and presence of human immunodeficiency virus. Colonization was higher among male inmates with a BMI of 30-34.9 (PR = 1.27, 95% CI: 1.01, 1.61). Our findings demonstrate an association between BMI and S. aureus colonization among female prisoners. Potential contributory biologic and behavioral factors should be explored.

Spectratype analysis of the T cell receptor δ CDR3 region of bovine γδ T cells responding to leptospira.

Gamma delta T cells comprise the majority of blood T cells in ruminants at birth and remain at high levels for several years with most expressing the WC1 co-receptor. A subpopulation of Bos taurus WC1(+) cells expressing a restricted set of WC1 molecules respond immediately by proliferation and interferon-γ production to leptospira following vaccination, preceding the response by CD4 T cells. Our goal is to define the γδ T cell recognition elements involved. Previously, we showed that the responding cells employed a variety of TRDV genes indicating that the CDR1 and CDR2 of TCRδ could vary and may not be principally involved in antigen specificity. Murine and human γδ T cells bind T22 and self lipids through their CDR3δ. Like mice, cattle use up to five TRDD genes in a single CDR3δ adding flexibility to length and configuration for antigen binding. Here, we used spectratyping to evaluate the CDR3δ of leptospira-responsive cells. Little or no compartmentalization of CDR3δ was found for antigen-responsive cells that incorporated TRDV1, TRDV2, or TRDV3 even though they comprise the majority of the leptospira-responding population. Compartmentalization occurred for TRDV4-containing transcripts and was maintained over time and among cattle. However, no common amino acid motif was apparent in those CDR3δ sequences, although a bias in D gene usage occurred. We hypothesize that the restricted set of WC1 co-receptors expressed by the responding cells may lend specificity to the response through their ability to bind bacteria facilitating interaction of various TCRs with bacterial components resulting in cross-linking and activation.

"Striving for Excellence": Minimum Data Set Coordinators' Perceptions of Their Role in the Nursing Home.

The purpose of the current study was to explore how Minimum Data Set (MDS) coordinators perceive their role and the assessment process. Eleven MDS coordinators from 10 geographically dispersed nursing homes (NHs) were interviewed between May and September 2013. Four broad themes emerged from content analysis: (a) information gathering, (b) interdisciplinary coordination, (c) role challenges, and (d) resources. The first two themes referred to key components and competencies in the MDS coordinators' role, the third theme dealt with certain challenges inherent in the role, and the fourth theme highlighted resources that helped address these challenges. The current study provides insight into how MDS coordinators perceive their role, as well as some of the challenges they face to successfully enact that role. The current findings can help inform NH management staff, such as directors of nursing and NH administrators, and policy makers, on how best to support MDS coordinators' work to enable efficient and accurate resident assessment processes.

Perceived barriers to infection prevention and control for nursing home certified nursing assistants: a qualitative study.

Healthcare-associated infections, while preventable, result in increased morbidity and mortality in nursing home (NH) residents. Frontline personnel, such as certified nursing assistants (CNAs), are crucial to successful implementation of infection prevention and control (IPC) practices. The purpose of this study was to explore barriers to implementing and maintaining IPC practices for NH CNAs as well as to describe strategies used to overcome these barriers. We conducted a multi-site qualitative study of NH personnel important to infection control. Audio-recorded interviews were transcribed verbatim and transcripts were analyzed using conventional content analysis. Five key themes emerged as perceived barriers to effective IPC for CNAs: 1) language/culture; 2) knowledge/training; 3) per-diem/part-time staff; 4) workload; and 5) accountability. Strategies used to overcome these barriers included: translating in-services, hands on training, on-the-spot training for per-diem/part-time staff, increased staffing ratios, and inclusion/empowerment of CNAs. Understanding IPC barriers and strategies to overcome these barriers may better enable NHs to achieve infection reduction goals.

Understanding infection prevention and control in nursing homes: A qualitative study.

Infections have been identified as a priority issue in nursing homes (NHs). We conducted a qualitative study purposively sampling 10 NHs across the country where 6-8 employees were recruited (N = 73). Semi-structured, open-ended guides were used to conduct in-depth interviews. Data were audiotaped, transcribed and a content analysis was performed. Five themes emerged: 'Residents' Needs', 'Roles and Training' 'Using Infection Data,' 'External Resources' and 'Focus on Hand Hygiene.' Infection prevention was a priority in the NHs visited. While all sites had hand hygiene programs, other recommended areas were not a focus and many sites were not aware of available resources. Developing ways to ensure effective, efficient and standardized infection prevention and control in NHs continues to be a national priority.

Molecular characterization of methicillin-resistant Staphylococcus aureus clinical isolates obtained from the Rikers Island Jail System from 2009 to 2013.

Inmates of Rikers Island jail potentially introduce Staphylococcus aureus into New York State prisons upon transfer. In this study, methicillin-resistant Staphylococcus aureus isolates (n = 452), collected from infected inmates (2009 to 2013), were characterized. spa type t008 was the predominant clone identified, accounting for 82.3% of the isolates, with no evidence of mupirocin or chlorhexidine resistance.

Risk factors for colonization with extended-spectrum cephalosporin-resistant and carbapenem-resistant Enterobacterales among hospitalized patients in Guatemala: An Antibiotic Resistance in Communities and Hospitals (ARCH) study.

Objectives: The spread of extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) and carbapenem-resistant Enterobacterales (CRE) has resulted in increased morbidity, mortality, and health care costs worldwide. To identify the factors associated with ESCrE and CRE colonization within hospitals, we enrolled hospitalized patients at a regional hospital located in Guatemala. Methods: Stool samples were collected from randomly selected patients using a cross-sectional study design (March-September, 2021), and samples were tested for the presence of ESCrE and CRE. Hospital-based and household variables were examined for associations with ESCrE and CRE colonization using lasso regression models, clustered by ward (n = 21). Results: A total of 641 patients were enrolled, of whom complete data sets were available for 593. Colonization with ESCrE (72.3%, n = 429/593) was negatively associated with carbapenem administration (odds ratio [OR] 0.21, 95% confidence interval [CI] 0.11-0.42) and positively associated with ceftriaxone administration (OR 1.61, 95% CI 1.02-2.53), as was reported hospital admission within 30 days of the current hospitalization (OR 2.84, 95% CI 1.19-6.80). Colonization with CRE (34.6%, n = 205 of 593) was associated with carbapenem administration (OR 2.62, 95% CI 1.39-4.97), reported previous hospital admission within 30 days of current hospitalization (OR 2.58, 95% CI 1.17-5.72), hospitalization in wards with more patients (OR 1.05, 95% CI 1.02-1.08), hospitalization for ≥4 days (OR 3.07, 95% CI 1.72-5.46), and intubation (OR 2.51, 95% CI 1.13-5.59). No household-based variables were associated with ESCrE or CRE colonization in hospitalized patients. Conclusion: The hospital-based risk factors identified in this study are similar to what has been reported for risk of health care-associated infections, consistent with colonization being driven by hospital settings rather than community factors. This also suggests that colonization with ESCrE and CRE could be a useful metric to evaluate the efficacy of infection and prevention control programs in clinics and hospitals.

Gene number determination and genetic polymorphism of the gamma delta T cell co-receptor WC1 genes.

BACKGROUND: WC1 co-receptors belong to the scavenger receptor cysteine-rich (SRCR) superfamily and are encoded by a multi-gene family. Expression of particular WC1 genes defines functional subpopulations of WC1(+) γδ T cells. We have previously identified partial or complete genomic sequences for thirteen different WC1 genes through annotation of the bovine genome Btau_3.1 build. We also identified two WC1 cDNA sequences from other cattle that did not correspond to sequences in the Btau_3.1 build. Their absence in the Btau_3.1 build may have reflected gaps in the genome assembly or polymorphisms among animals. Since the response of γδ T cells to bacterial challenge is determined by WC1 gene expression, it was critical to understand whether individual cattle or breeds differ in the number of WC1 genes or display polymorphisms. RESULTS: Real-time quantitative PCR using DNA from the animal whose genome was sequenced ("Dominette") and sixteen other animals representing ten breeds of cattle, showed that the number of genes coding for WC1 co-receptors is thirteen. The complete coding sequences of those thirteen WC1 genes is presented, including the correction of an error in the WC1-2 gene due to mis-assembly in the Btau_3.1 build. All other cDNA sequences were found to agree with the previous annotation of complete or partial WC1 genes. PCR amplification and sequencing of the most variable N-terminal SRCR domain (domain 1 which has the SRCR "a" pattern) of each of the thirteen WC1 genes showed that the sequences are highly conserved among individuals and breeds. Of 160 sequences of domain 1 from three breeds of cattle, no additional sequences beyond the thirteen described WC1 genes were found. Analysis of the complete WC1 cDNA sequences indicated that the thirteen WC1 genes code for three distinct WC1 molecular forms. CONCLUSION: The bovine WC1 multi-gene family is composed of thirteen genes coding for three structural forms whose sequences are highly conserved among individual cattle and breeds. The sequence diversity necessary for WC1 genes to function as a multi-genic pattern recognition receptor array is encoded in the genome, rather than generated by recombinatorial diversity or hypermutation.

Challenges and strategies for research in prisons.

In this article, we discuss some of the challenges encountered while conducting research in two maximum security prisons and approaches we found helpful to facilitate the research process through the development of collaborative relationships, the establishment of prison contacts, and the implementation of rigorous research methods. As a result of our experiences, we have been successful at maintaining a high rate of inmate participation (>80%) and a well-functioning multidisciplinary team. The approaches described may be useful to other investigators planning to conduct research in a challenging setting such as prisons.

Evolution of the CD163 family and its relationship to the bovine gamma delta T cell co-receptor WC1.

BACKGROUND: The scavenger receptor cysteine rich (SRCR) domain is an ancient and conserved protein domain. CD163 and WC1 molecules are classed together as group B SRCR superfamily members, along with Spalpha, CD5 and CD6, all of which are expressed by immune system cells. There are three known types of CD163 molecules in mammals, CD163A (M130, coded for by CD163), CD163b (M160, coded for by CD163L1) and CD163c-alpha (CD163L1 or SCART), while their nearest relative, WC1, is encoded by a multigene family so far identified in the artiodactyl species of cattle, sheep, and pigs. RESULTS: We annotated the bovine genome and identified genes coding for bovine CD163A and CD163c-alpha but found no evidence for CD163b. Bovine CD163A is widely expressed in immune cells, whereas CD163c-alpha transcripts are enriched in the WC1+ gammadelta T cell population. Phylogenetic analyses of the CD163 family genes and WC1 showed that CD163c-alpha is most closely related to WC1 and that chicken and platypus have WC1 orthologous genes, previously classified as among their CD163 genes. CONCLUSION: Since it has been shown that WC1 plays an important role in the regulation of gammadelta T cell responses in cattle, which, like chickens, have a high percentage of gammadelta T cells in their peripheral blood, CD163c-alpha may play a similar role, especially in species lacking WC1 genes. Our results suggest that gene duplications resulted in the expansion of CD163c-alpha-like and WC1-like molecules. This expanded repertoire was retained by species known as "gammadelta T cell high", but homologous SRCR molecules were maintained by all mammals.

Annotation and classification of the bovine T cell receptor delta genes.

BACKGROUND: gammadelta T cells differ from alphabeta T cells with regard to the types of antigen with which their T cell receptors interact; gammadelta T cell antigens are not necessarily peptides nor are they presented on MHC. Cattle are considered a "gammadelta T cell high" species indicating they have an increased proportion of gammadelta T cells in circulation relative to that in "gammadelta T cell low" species such as humans and mice. Prior to the onset of the studies described here, there was limited information regarding the genes that code for the T cell receptor delta chains of this gammadelta T cell high species. RESULTS: By annotating the bovine (Bos taurus) genome Btau_3.1 assembly the presence of 56 distinct T cell receptor delta (TRD) variable (V) genes were found, 52 of which belong to the TRDV1 subgroup and were co-mingled with the T cell receptor alpha variable (TRAV) genes. In addition, two genes belonging to the TRDV2 subgroup and single TRDV3 and TRDV4 genes were found. We confirmed the presence of five diversity (D) genes, three junctional (J) genes and a single constant (C) gene and describe the organization of the TRD locus. The TRDV4 gene is found downstream of the C gene and in an inverted orientation of transcription, consistent with its orthologs in humans and mice. cDNA evidence was assessed to validate expression of the variable genes and showed that one to five D genes could be incorporated into a single transcript. Finally, we grouped the bovine and ovine TRDV1 genes into sets based on their relatedness. CONCLUSIONS: The bovine genome contains a large and diverse repertoire of TRD genes when compared to the genomes of "gammadelta T cell low" species. This suggests that in cattle gammadelta T cells play a more important role in immune function since they would be predicted to bind a greater variety of antigens.