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The IL-2/IL-2R signaling pathway has an important role in autoimmunity. Several genes identified in genome-wide association (GWA) studies encode proteins in the IL-2/IL-2R signaling cascade that are associated with autoimmune diseases. One of these, PTPN2, encodes a protein tyrosine phosphatase that is highly expressed in T cells and regulates cytokine signaling. An intronic risk allele in PTPN2, rs1893217(C), correlated with decreased IL-2R signaling in CD4+ T cells as measured by phosphorylation of STAT5 (phosphorylated STAT5 (pSTAT5)). We modeled an additive single nucleotide polymorphism (SNP) genotype, in which each copy of the risk allele conferred a decrease in IL-2R signaling (P=4.4 × 10−8). Decreased pSTAT5 impacted IL-2Rβ chain signaling resulting in reduced FOXP3 expression in activated cells. This phenotype was not due to overt differences in expression of the IL-2R, molecules in the IL-2R signaling cascade or defects in STAT5. However, the rs1893217(C) risk variant did correlate with decreased PTPN2 expression in CD4+CD45RO T cells (P=0.0002). Thus, the PTPN2rs1893217(C) risk allele associated with reduced pSTAT5 in response to IL-2 and reduced PTPN2 expression. Together, these data suggest that decreased expression of PTPN2 may indirectly modulate IL-2 responsiveness. These findings, identified through genotype/phenotype relationships, may lead to identification of novel mechanisms underlying dysregulation of cytokine signaling in autoimmunity. [ABSTRACT FROM AUTHOR]

Objective: In humans, multiple genes in the interleukin (IL)-2/IL-2 receptor (IL-2R) pathway are associated with type 1 diabetes. However, no link between IL-2 responsiveness and CD4(+)CD25(+)FOXP3(+) regulatory T-cells (Tregs) has been demonstrated in type 1 diabetic subjects despite the role of these IL-2-dependent cells in controlling autoimmunity. Here, we address whether altered IL-2 responsiveness impacts persistence of FOXP3 expression in Tregs of type 1 diabetic subjects.Research Design and Methods: Persistence of Tregs was assessed by culturing sorted CD4(+)CD25(hi) natural Tregs with IL-2 and measuring FOXP3 expression over time by flow cytometry for control and type 1 diabetic populations. The effects of IL-2 on FOXP3 induction were assessed 48 h after activation of CD4(+)CD25(-) T-cells with anti-CD3 antibody. Cytokine receptor expression and signaling upon exposure to IL-2, IL-7, and IL-15 were determined by flow cytometry and Western blot analysis.Results: Maintenance of FOXP3 expression in CD4(+)CD25(+) Tregs of type 1 diabetic subjects was diminished in the presence of IL-2, but not IL-7. Impaired responsiveness was not linked to altered expression of the IL-2R complex. Instead, IL-2R signaling was reduced in Tregs and total CD4(+) T-cells of type 1 diabetic subjects. In some individuals, decreased signal transducer and activator of transcription 5 phosphorylation correlated with significantly higher expression of protein tyrosine phosphatase N2, a negative regulator of IL-2R signaling.Conclusions: Aberrant IL-2R signaling in CD4(+) T-cells of type 1 diabetic subjects contributes to decreased persistence of FOXP3 expression that may impact establishment of tolerance. These findings suggest novel targets for treatment of type 1 diabetes within the IL-2R pathway and suggest that an altered IL-2R signaling signature may be a biomarker for type 1 diabetes. [ABSTRACT FROM AUTHOR]

Background: Australia introduced a national human papillomavirus (HPV) vaccination program for girls in 2007 and boys in 2013, achieving high coverage. We assessed HPV prevalence among men who have sex with women (MSW) and men who have sex with men (MSM) aged 18-35 years and examined program effects., Methods: Between 2015-2018, men self-collected a penile or intra-anal swab for HPV genotyping. Vaccination status was confirmed with the National Register. HPV prevalence was examined by age groups and vaccination status., Results: Prevalence of quadrivalent vaccine-targeted HPV types (6, 11, 16, 18) was 10.6% (95% confidence interval [CI], 8.7%-12.8%) in unvaccinated MSW and 10.7% (95% CI, 5.7%-19.3%) in vaccinated MSW (P = .96). Prevalence was 40.3% (95% CI, 36.0%-44.8%) in unvaccinated MSM and 29.9% (95% CI, 23.1%-37.8%) in vaccinated MSM (P = .02). Among those with confirmed doses, quadrivalent types were detected in 0% (95% CI, 0%-7.7%; n = 46) of men who had their first dose at 13-19 years and 37.2% (95% CI, 27.5%-47.8%; n = 94) in those who received their first dose at 20 years or older., Conclusions: Our data demonstrate the importance of universal adolescent HPV vaccination to ensure MSM receive the same benefits as MSW., Competing Interests: Potential conflicts of interest. G. L. M. reports grant funding from the Australian Research Council. S. M. G. discloses consulting fees, payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from MSD consultancy; has received support for attending meetings and/or travel from the Global Advisory Board of MSD; and is an unpaid President of the International Papillomavirus Society. C. K. F. and J. M. own shares in CSL. J. S. H. reports funding for the present manuscript provided by the National Health and Medical Research Council (grant number GNT2025960) with payments made to her institution. J. M. also reports the following patents: Inactivation of papillomavirus (Australian Patent No. 2002331456; United States Patent application number 14/566956 [continuation of patent application 10/490609]), and Treatment of infection (Australia 2009900969; International PCT AU2010/000255). L. O. acknowledges support for attending ViiV or Gilead meetings including travel and accommodation (no personal payment). D. A. M. reports receiving grants from Seqirus, nonfinancial support and honoraria from MSD, and nonfinancial support from Roche Diagnostics. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objective: Parkinson disease (PD) is associated with a predictable decline in motor function and mobility that is commonly managed with exercise. There is a limited understanding of the effects of group exercise compared to individual exercise (IE) and usual care (UC) on motor function and mobility. Our purpose was to investigate the effects of group exercise compared to IE and UC on motor function and mobility for people with PD., Methods: A systematic review and meta-analysis was performed with randomized control trials that investigated the effects of group compared with IE and UC on motor function and mobility for people with PD. A systematic search was performed in PubMed, EBSCO, and Science Direct databases. Methodological quality was assessed using the Cochrane Grading of Recommendations Assessment, Development, and Evaluation approach., Results: Twenty-three studies assessed at least 1 mobility-related outcome measure, met our inclusion criteria, and were included in quantitative analysis. There was no significant difference on motor function and mobility between group exercise and IE for all standardized outcome assessment meta-analyses. Motor function and mobility were significantly improved with group exercise compared to UC in 9 of 11 standardized outcome assessment meta-analyses. Results were based upon low to moderate quality of evidence., Conclusion: Based upon low to moderate quality of evidence, group exercise has a similar to larger effect as IE and UC on improving motor function and mobility for people with PD. When used in combination with skilled physical therapy, group exercise may be an appropriate adjunct to individualized physical therapy to maximize mobility and function., Impact: Long-term adherence to exercise is essential to maintain mobility and motor function for people with PD. Our study suggests group exercise is as effective as IE and may be an appropriate option to encourage long-term adherence related to increased access, socialization, and accountability., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Physical Therapy Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

In this study, we aimed to document stakeholders' experiences of implementing Australia's renewed National Cervical Screening Program. In December 2017, the program changed from 2nd yearly cytology for 20-69 year olds to 5 yearly human papillomavirus (HPV) screening for women 25-74 years. We undertook semi-structured interviews with key stakeholders including government, program administrators, register staff, clinicians and health care workers, non-government organisations, professional bodies, and pathology laboratories from across Australia between Nov 2018 - Aug 2019. Response rate to emailed invitations was 49/85 (58%). We used Proctor et al's (2011) implementation outcomes framework to guide our questions and thematic analysis. We found that stakeholders were evenly divided over whether implementation was successful. There was strong support for change, but concern over aspects of the implementation. There was some frustration related to the delayed start, timeliness of communication and education, shortcomings in change management, lack of inclusion of Aboriginal and Torres Strait Islander people in planning and implementation, failure to make self-collection widely available, and delays in the National Cancer Screening Register. Barriers centred around a perceived failure to appreciate the enormity of the change and register build, and consequent failure to resource, project manage and communicate effectively. Facilitators included the good will and dedication of stakeholders, strong evidence base for change and the support of jurisdictions during the delay. We documented substantial implementation challenges, offering learnings for other countries transitioning to HPV screening. Sufficient planning, significant and transparent engagement and communication with stakeholders, and change management are critical., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The CRE is a collaboration led by the Daffodil Centre (Cancer Council NSW and University of Sydney), the Australian Centre for the Prevention of Cervical Cancer (ACPCC), the University of Melbourne and the Kirby Institute, University of NSW. Both Cancer Council NSW and ACPCC participated in the implementation of the rNCSP and employees/representatives of these organisations were represented on the research team and invited to participate as stakeholders in the interviews. Where such potential conflict of interests could have arisen between interviewer/interviewee, interviews were conducted by people who were not conflicted and all interviews were analysed deidentified and consistently through thematic, coded analysis. The study was overseen by a scientific advisory committee.Box 1Facilitators and barriers to the implementation of Renewal identified by 49 stakeholders, 2018-2019 Facilitators to date1)Strong evidence base for change2)Goodwill and dedication of stakeholders, including ongoing advice and support from committees and advisory groups3)Ability of State and Territory programs to continue/ resume pre-Renewal operations (eg ongoing registry functions, program management and communications) during delay in transition and national registry operations Perceived future facilitators1)Clear communications to participants and providers, including data to show the program is working2)Getting the National Register up to full functionality, including:a.invitations, reminders, follow-up, and ready access to screening historiesb.improving data completeness and qualityc.using it to monitor and drive improvementd.moving away from paper-based communications and faxese.improving integration with laboratory and practice management systemsf.ensuring its algorithms provide clinical safety3)Good governance and planning, with sufficient capacity and dedicated resources.4)Specific improvements suggested included:a.simplifying some processes (such as colposcopy data collection and the layout of the guidelines)b.providing more support and information for practitionersc.timely guideline updatesd.continuous education and raising awareness in the population, including targeted campaigns for Aboriginal and Torres Strait Islander peoplee.expanding who can provide cervical screening, especially in rural and remote areas Barriers1.Failure to appreciate the enormity of the change and register build2.Importance of change management not acknowledged early enough3.Expertise of States and Territories not utilised adequately4.Absence of consistent central oversight, leadership and project management5.Workload of those responsible for implementing change was very high, with staff turnover and loss of knowledge6.Human cost of stress across all stakeholder groups7.Delays and issues with Register meant other important aspects of the rNCSP were insufficiently addressed8.Suboptimal communication, consultation, and transparency9.Late communication, particularly the announcement to delay the program. a.Program delay created operational issues, due to staff redundancies for State registers and cytologists in pathology labs, which happened too earlyb.Delay commonly conflated by the public with the belief that the program itself was flawed, creating mistrustc.Some practitioners had already told patients that their next screen would be the new test, or had patients hold off screening for the new test, only to have to explain to them on their return that it was not yet available10.Insufficient education for providers and the public.a.Not consistent or well-timed communication or education to support practitioners implementing the programb.Lack of clear and timely communication with the public11.Other practitioner level barriers included:a.Insufficient time to discuss cervical screening in consultationsb.Loss of the nurse led cervical screening MBS numberc.Difficulties implementing new clinical guidelines when providers and laboratories were not yet familiar with the detail and complexity (especially for people with previous abnormalities)d.Errors and frustrations with incorrect Register correspondence chasing colposcopy results12.Lack of a registered on-label indication for HPV testing on self-collected samples, creating lack of test availability which limited access13.Length of colposcopy waiting lists and associated delays in women being seen at colposcopy, (© 2023 The Authors.)

Rapidly identifying and isolating people with acute SARS-CoV-2 infection has been a core strategy to contain COVID-19 in Australia, but a proportion of infections go undetected. We estimated SARS-CoV-2 specific antibody prevalence (seroprevalence) among blood donors in metropolitan Melbourne following a COVID-19 outbreak in the city between June and September 2020. The aim was to determine the extent of infection spread and whether seroprevalence varied demographically in proportion to reported cases of infection. The design involved stratified sampling of residual specimens from blood donors (aged 20-69 years) in three postcode groups defined by low (<3 cases/1,000 population), medium (3-7 cases/1,000 population) and high (>7 cases/1,000 population) COVID-19 incidence based on case notification data. All specimens were tested using the Wantai SARS-CoV-2 total antibody assay. Seroprevalence was estimated with adjustment for test sensitivity and specificity for the Melbourne metropolitan blood donor and residential populations, using multilevel regression and poststratification. Overall, 4,799 specimens were collected between 23 November and 17 December 2020. Seroprevalence for blood donors was 0.87% (90% credible interval: 0.25-1.49%). The highest estimates, of 1.13% (0.25-2.15%) and 1.11% (0.28-1.95%), respectively, were observed among donors living in the lowest socioeconomic areas (Quintiles 1 and 2) and lowest at 0.69% (0.14-1.39%) among donors living in the highest socioeconomic areas (Quintile 5). When extrapolated to the Melbourne residential population, overall seroprevalence was 0.90% (0.26-1.51%), with estimates by demography groups similar to those for the blood donors. The results suggest a lack of extensive community transmission and good COVID-19 case ascertainment based on routine testing during Victoria's second epidemic wave. Residual blood donor samples provide a practical epidemiological tool for estimating seroprevalence and information on population patterns of infection, against which the effectiveness of ongoing responses to the pandemic can be assessed., Competing Interests: The authors have declared that no competing interests exist.

Background: As of mid-2021, Australia's only nationwide coronavirus disease 2019 (COVID-19) epidemic occurred in the first 6 months of the pandemic. Subsequently, there has been limited transmission in most states and territories. Understanding community spread during the first wave was hampered by initial limitations on testing and surveillance. To characterize the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody seroprevalence generated during this time, we undertook Australia's largest national SARS-CoV-2 serosurvey., Methods: Between June 19 and August 6, 2020, residual specimens were sampled from people undergoing general pathology testing (all ages), women attending antenatal screening (20-39 years), and blood donors (20-69 years) based on the Australian population's age and geographic distributions. Specimens were tested by Wantai total SARS-CoV-2-antibody assay. Seroprevalence estimates adjusted for test performance were produced. The SARS-CoV-2 antibody-positive specimens were characterized with microneutralization assays., Results: Of 11 317 specimens (5132 general pathology; 2972 antenatal; 3213 blood-donors), 71 were positive for SARS-CoV-2-specific antibodies. Seroprevalence estimates were 0.47% (95% credible interval [CrI], 0.04%-0.89%), 0.25% (CrI, 0.03%-0.54%), and 0.23% (CrI, 0.04%-0.54%), respectively. No seropositive specimens had neutralizing antibodies., Conclusions: Australia's seroprevalence was extremely low (<0.5%) after the only national COVID-19 wave thus far. These data and the subsequent limited community transmission highlight the population's naivety to SARS-CoV-2 and the urgency of increasing vaccine-derived protection., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: In Australia, high and widespread uptake of the quadrivalent human papillomavirus (HPV) vaccine has led to substantial population-level reductions in the prevalence of quadrivalent vaccine targeted HPV genotypes 6/11/16/18 in women aged ≤ 35 years. We assessed risk factors for HPV detection among 18-35 year old women, 9-12 years after vaccine program introduction., Methods: Women attending health services between 2015 and 2018 provided a self-collected vaginal specimen for HPV genotyping (Roche Linear Array) and completed a questionnaire. HPV vaccination status was validated against the National Register. Adjusted odds ratios (aORs) and 95% confidence intervals (CI) were calculated for factors associated with HPV detection., Results: Among 1564 women (median age 24 years; IQR 21-27 years), Register-confirmed ≥ 1-dose vaccine coverage was highest at 69.3% and 68.1% among women aged 18-21 and 22-24 years respectively, decreasing to 42.9% among those aged 30-35 years. Overall prevalence of quadrivalent vaccine-targeted HPV types was very low (2.0%; 95% CI: 1.4-2.8%) and influenced only by vaccination status (5.5% among unvaccinated compared with 0.7% among vaccinated women; aOR = 0.13 (95% CI: 0.05-0.30)). Prevalence of remaining HPV types, at 40.4% (95% CI: 38.0-42.9%), was influenced by established risk factors for HPV infection; younger age-group (p-trend < 0.001), more recent (p < 0.001) and lifetime sexual partners (p-trend < 0.001), but not vaccination status. Prevalence of HPV31/33/45, which shared risk factors with that of non-vaccine targeted HPV types, was also lower among vaccinated (4%) compared with unvaccinated (7%) women (aOR = 0.51; 95% CI: 0.29-0.89), indicative of cross-protection., Conclusion: Vaccination has changed the epidemiology of HPV infection in Australian women, having markedly reduced the prevalence of vaccine-targeted types, including amongst women with known risk factors for infection. Vaccinated women appear to be benefiting from modest cross-protection against types 31/33/45 afforded by the quadrivalent HPV vaccine. These results reinforce the importance of HPV vaccination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Ltd.)

Background: Mycoplasma genitalium is now recognised as an important bacterial sexually transmitted infection. We summarised data from studies of mutations associated with macrolide and fluoroquinolone resistance in M genitalium to establish the prevalence of resistance. We also investigated temporal trends in resistance and aimed to establish the association between resistance and geographical location., Methods: In this systematic review and meta-analysis, we searched PubMed, Embase, and MEDLINE for studies that included data for the prevalence of mutations associated with macrolide and fluoroquinolone resistance in M genitalium published in any language up to Jan 7, 2019. We defined prevalence as the proportion of M genitalium samples positive for key mutations associated with azithromycin resistance (23S rRNA gene, position 2058 or 2059) or moxifloxacin resistance (S83R, S83I, D87N, or D87Y in parC), or both, among all M genitalium samples that were successfully characterised. We used random-effects meta-analyses to calculate summary estimates of prevalence. Subgroup and meta-regression analyses by WHO region and time period were done. This study was registered with PROSPERO, number CRD42016050370., Results: Overall, 59 studies from 21 countries met the inclusion criteria for our study: 57 studies of macrolide resistance (8966 samples), 25 of fluoroquinolone resistance (4003 samples), and 22 of dual resistance to macrolides and fluoroquinolones (3280 samples). The summary prevalence of mutations associated with macrolide resistance among M genitalium samples was 35·5% (95% CI 28·8-42·5); prevalence increased from 10·0% (95% CI 2·6-20·1%) before 2010, to 51·4% (40·3-62·4%) in 2016-17 (p<0·0001). Prevalence of mutations associated with macrolide resistance was significantly greater in samples in the WHO Western Pacific and Americas regions than in those from the WHO European region. The overall prevalence of mutations associated with fluoroquinolone resistance in M genitalium samples was 7·7% (95% CI 4·5-11·4%). Prevalence did not change significantly over time, but was significantly higher in the Western Pacific region than in the European region. Overall, the prevalence of both mutations associated with macrolide resistance and those associated with fluoroquinolone resistance among M genitalium samples was 2·8% (1·3-4·7%). The prevalence of dual resistance did not change significantly over time, and did not vary significantly by geographical region., Interpretation: Global surveillance and measures to optimise the efficacy of treatments-including resistance-guided strategies, new antimicrobials, and antimicrobial combination approaches-are urgently needed to ensure cure in a high proportion of M genitalium infections and to prevent further spread of resistant strains., Funding: Australian National Health and Medical Research Council., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Introduction: Australia has recently implemented major changes in cervical cancer prevention policies including introduction of primary human papillomavirus (HPV) screening starting at age 25, and replacement of the quadrivalent HPV vaccine with the nonavalent vaccine in the national school-based program. We assessed the feasibility and utility of conducting HPV testing in residual clinical specimens submitted for routine Chlamydia trachomatis screening, as a means of tracking HPV vaccine program impact among young sexually active women., Methods: De-identified residual specimens from women aged 16-24 years submitted for chlamydia testing were collected from three pathology laboratories in Victoria and New South Wales. Limited demographic information, and chlamydia test results were also collected. Patient identifiers were sent directly from the laboratories to the National HPV Vaccination Program Register, to obtain HPV vaccination histories. Samples underwent HPV genotyping using Seegene Anyplex II HPV 28 assay., Results: Between April and July 2018, 362 residual samples were collected, the majority (60.2%) of which were cervical swabs. Demographic data and vaccination histories were received for 357 (98.6%) women (mean age 21.8, SD 2.0). Overall, 65.6% of women were fully vaccinated, 9.8% partially, and 24.7% unvaccinated. The majority (86.0%) resided in a major city, 35.9% were classified in the upper quintile of socioeconomic advantage and chlamydia positivity was 7.8%.The prevalence of quadrivalent vaccine-targeted types (HPV6/11/16/18) was 2.8% (1.5-5.1%) overall with no differences by vaccination status (p = 0.729). The prevalence of additional nonavalent vaccine-targeted types (HPV31/33/45/52/58) was 19.3% (15.6-23.8%). One or more oncogenic HPV types were detected in 46.8% (95% CI 41.6-52.0%) of women., Conclusions: HPV testing of residual chlamydia specimens provides a simple, feasible method for monitoring circulating genotypes. Applied on a larger scale this method can be utilised to obtain a timely assessment of nonavalent vaccine impact among young women not yet eligible for cervical screening., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: DAM reports travel grants from Seqirus, travel funding and honoraria to her institute from Merck Sharp & Dohme (MSD), outside the submitted work. JMLB, MS and DH are investigators on the Compass trial for which VCS Foundation has received kits and partial funding from Roche. VCS Pathology has also received free test kits from Roche, Seegene, Cepheid, and Becton Dickinson. JMLB, MS and SMG were investigators on a cervical cancer typing study with laboratory testing funded by Seqirus more than three years ago. JMLB and SMG were investigators on a recurrent respiratory papillomatosis surveillance study partially funded by an investigator initiated grant from MSD more than three years ago. SMG has received grants to her institution from Merck and GSK (GlaxoSmithKline) to perform phase 3 clinical vaccine trials. She has received speaking fees from MSD for work performed in her personal time and Merck paid for travel and accommodation to present at Global HPV Advisory board meetings. DAM, JMK and RG are investigators on a genital warts surveillance grant funded by Sequiris. All other authors declare no conflicts of interest., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

We investigated whether single nucleotide polymorphisms in genes related to glucose metabolism correlate with insulin secretion in type 1 diabetes patients. A cohort of 49 type 1 diabetes patients underwent serial mixed meal tolerance tests to assess insulin secretion. Patients were genotyped for SNPs related to glucose metabolism: CDKAL1 rs7754840, G6PC2 rs560887, HHEX rs1111875, KCNJ11 rs5215. Recently diagnosed patients (<100 days) homozygous for the G allele of G6PC2 had higher area under the curve C-peptide on mixed meal tolerance tests compared to non-homozygous patients (344.8 ± 203.2 vs. 167.9 ± 131.5, p = 0.04). Other SNPs did not correlate with insulin secretion in the new onset period. In a longitudinal survival analysis, homozygosity for the minor allele (A) in G6PC2 predicted more rapid loss of insulin secretion over time. A SNP in the beta cell gene G6PC2 may correlate with preserved insulin secretion in type 1 diabetes.

A unified, bioinformatics-driven, single nucleotide polymorphism (SNP)-based approach to microbial genotyping has been developed. Multilocus sequence typing (MLST) databases consist of known variants of standardized housekeeping genes. Normally, seven fragments are defined; a sequence type (ST) consists of the variants of these fragments that are found in a particular isolate. A computer program that can identify highly informative sets of SNPs in entire MLST databases has been constructed. The SNPs either define a particular user-specified ST or provide a high value for Simpson's index of diversity (D), and may thus be generally applicable to that species. SNP sets that are diagnostic for Neisseria meningitidis ST-11 and ST-42, and high-D SNP sets for N. meningitidis and Staphylococcus aureus, were identified and real-time PCR methods to interrogate these SNPs were demonstrated. High-D SNP sets were also identified in other MLST databases. This widely applicable approach allows rapid genetic fingerprinting of infectious agents.

KIR3DL1 and KIR3DL2 are NK cell receptors for polymorphic HLA-B and -A determinants. The proportion of NK cells that bind anti-KIR3DL1-specific Ab DX9 and their level of binding vary between individuals. To determine whether these differences are due to KIR polymorphism, we assessed KIR3D gene diversity in unrelated individuals and families. Both KIR3DL1 and KIR3DL2 are highly polymorphic genes, with KIR3DS1 segregating like an allele of KIR3DL1. A KIR haplotype lacking KIR3DL1 and KIR3DS1 was defined. The two KIR3DL1 alleles of a heterozygous donor were expressed by different, but overlapping, subsets of NK cell clones. Sequence variation in KIR3DL1 and KIR3DL2 appear distinct; recombination is more evident in KIR3DL1, and point mutation is more evident in KIR3DL2. The KIR3DL1 genotype correlates well with levels of DX9 binding by NK cells, but not with the frequency of DX9-binding cells. Different KIR3DL1 alleles determine high, low, and no binding of DX9 Ab. Consequently, heterozygotes for high and low binding KIR3DL1 alleles have distinct subpopulations of NK cells that bind DX9 at high and low levels, giving characteristic bimodal distributions in flow cytometry. The Z27 Ab gave binding patterns similar to those of DX9. Four KIR3DL1 alleles producing high DX9 binding phenotypes were distinguished from four alleles producing low or no binding phenotypes by substitution at one or more of four positions in the encoded protein: 182 and 283 in the extracellular Ig-like domains, 320 in the transmembrane region, and 373 in the cytoplasmic tail.

The presence and expression of killer inhibitory receptor (KIR) and CD94:NKG2 genes from 68 donors were analyzed using molecular typing techniques. The genes encoding CD94:NKG2 receptors were present in each person, but KIR gene possession varied. Most individuals expressed inhibitory KIR for the three well-defined HLA-B and -C ligands, but noninhibitory KIR genes were more variable. Twenty different KIR phenotypes were defined. Two groups of KIR haplotypes were distinguished and occurred at relatively even frequency. Group A KIR haplotypes consist of six genes: the main inhibitory KIR, one noninhibitory KIR, and a structurally divergent KIR. Allelic polymorphism within five KIR genes was detected. Group B comprises more noninhibitory KIR genes and contains at least one additional gene not represented in group A. The KIR locus therefore appears to be polygenic and polymorphic within the human population.

The expression of KIR and CD94:NKG2 receptors was determined for more than 100 natural killer (NK) cell clones obtained from two blood donors who differ in their HLA class I and KIR genes. More than 98% of the clones were inhibited by individual autologous class I allotypes, and every clone was inhibited by the combination of autologous allotypes. The patterns of inhibition correlate with expression of inhibitory receptors of defined specificity. One donor possesses three class I ligands for KIR, and a majority of NK cells use KIR as their inhibitory receptor; the second donor possesses only a single ligand for KIR, and a majority of NK cells use the more broadly reactive CD94:NKG2a as their inhibitory receptor. Because of these differences, the first donor has subpopulations of NK cells that kill cells of the second donor, whereas the NK cells of the second donor are universally tolerant of cells from the first donor.

NK cells express receptors that bind to polymorphic determinants of MHC class I heavy chains. MHC ligands vary greatly between mammalian species, and the use of distinct molecular families of NK cell receptors by humans and mice suggests that the receptors too can be evolving rapidly. The KIR (killer cell inhibitory receptor) family of receptors are found in primates and recognize class I epitopes that are of relatively recent origin in primate evolution. Therefore, KIR molecules have probably evolved class I receptor function more recently than C-type lectins, which are represented in both humans and mice. Individual humans express NK cell receptors for which they have no class I ligand, demonstrating a looseness in the coupling of expression between the receptors and their ligands. However, study of a single donor suggests that every NK cell expresses at least one inhibitory receptor for a self-HLA class I allotype, consistent with the missing self hypothesis. Thus the NK-cell receptor-class I interaction appears to control the NK-cell repertoire during ontogeny of the individual and has the potential to be a selective factor influencing both MHC class I and NK cell receptor diversity in the evolution of populations and species.

We have isolated and characterized cDNA clones that encode the rat homologue of a binding protein, LERK-2, for the receptor tyrosine kinase, elk. The cDNAs contain an open reading frame of 1527 nucleotides capable of encoding a protein 345 amino acid residues in length. The nucleotide sequence of the present clones is > 90% identical to the previously identified human LERK-2 cDNA, and the predicted proteins encoded by the rat and human clones are identical at 95% of amino acid residues. Recombinant proteins expressed from the rat cDNAs bind to elk with high affinity, similar to recombinant human LERK-2 and an endogenously-expressed rat elk-binding protein. Expression of the rat LERK-2 mRNA was detected in embryonic brain, kidney, lung, skeletal muscle, thymus, liver, and heart, and diminished in the early post-natal period. Significant LERK-2 mRNA expression in the young adult rat was restricted to the lung, kidney, heart and testes.