Detection of Recent HIV-1 Infection Using a New Limiting-Antigen Avidity Assay: Potential for HIV-1 Incidence Estimates and Avidity Maturation Studies

Background: Accurate and reliable laboratory methods are needed for estimation of HIV-1 incidence to identify the highrisk populations and target and monitor prevention efforts. We previously described a single-well limiting-antigen avidity enzyme immunoassay (LAg-Avidity EIA) to detect recent HIV-1 infection. Methods: We describe here further optimization and characterization of LAg-Avidity EIA, comparing it to the BED assay and a two-well avidity-index (AI) EIA. Specimen sets included longitudinal sera (n = 393), collected from 89 seroconverting individuals from 4 cohorts representing 4 HIV-1 subtypes, and sera from AIDS patients (n = 488) with or without TB coinfections from 3 different cohorts. Ninety seven HIV-1 positive specimens were purchased commercially. The BED assay, LAg-Avidity EIA, AI-EIA and HIV serology were performed, as needed. Results: Monitoring quality control specimens indicated high reproducibility of the LAg-Avidity EIA with coefficient of variation of,10 % in the dynamic range. The LAg-Avidity EIA has an overall mean duration of recency (v) of 141 days (95% CI 119–160) at normalized optical density (ODn) cutoff of 1.0, with similar v in different HIV-1 subtypes and populations (132 to 143 days). Antibody avidity kinetics were similar among individuals and subtypes by both the LAg-Avidity EIA and AI-EIA compared to the HIV-IgG levels measured by the BED assay. The false recent rate among individuals with AIDS was 0.2% with the LAg-Avidity EIA, compared to 2.9 % with the BED assay. Western blot profiles of specimens with increasing avidit

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Complicating Culturally Relevant Pedagogy: Unpacking African Immigrants' Cultural Identities

This study presents findings from a case study of 18 second- and 1.5-generation West African immigrants. We draw upon notions of elusive culture and indigenous knowledges to highlight participants’ complex cultural identities and respond to anti-immigration discourses through positioning West African immigrant students as assets in American classrooms.  We extend culturally relevant theory in order to reflect the heterogeneity of Black immigrant experiences in challenging simultaneously invisible and stereotypical views of African values, knowledges, and ideologies. We call for practitioners and researchers to attend to Black immigrant youth’s hybrid identities, indigenous knowledges, and enactments of cultural competence and socio-political consciousness within curriculum

Performance evaluation of the Asante Rapid Recency Assay for verification of HIV diagnosis and detection of recent HIV-1 infections: Implications for epidemic control.

We previously described development of a rapid test for recent infection (RTRI) that can diagnose HIV infection and detect HIV-1 recent infections in a single device. This technology was transferred to a commercial partner as Asante Rapid Recency Assay (ARRA). We evaluated performance of the ARRA kits in the laboratory using a well-characterized panel of specimens. The plasma specimen panel (N = 1500) included HIV-1 (N = 570), HIV-2 (N = 10), and HIV-negatives (N = 920) representing multiple subtypes and geographic locations. Reference diagnostic data were generated using the Bio-Rad HIV-1-2-O EIA/Western blot algorithm with further serotyping performed using the Multispot HIV-1/2 assay. The LAg-Avidity EIA was used to generate reference data on recent and long-term infection for HIV-1 positive specimens at a normalized optical density (ODn) cutoff of 2.0 corresponding to a mean duration of about 6 months. All specimens were tested with ARRA according to the manufacturer's recommendations. Test strips were also read for line intensities using a reader and results were correlated with visual interpretation. ARRA's positive verification line (PVL) correctly classified 575 of 580 HIV-positive and 910 of 920 negative specimens resulting in a sensitivity of 99.1% (95% CI: 98.0-99.6) and specificity of 98.9% (95% CI: 98.1-99.4), respectively. The reader-based classification was similar for PVL with sensitivity of 99.3% (576/580) and specificity of 98.8% (909/920). ARRA's long-term line (LTL) classified 109 of 565 HIV-1 specimens as recent and 456 as long-term compared to 98 as recent and 467 as long-term (LT) by LAg-Avidity EIA (cutoff ODn = 2.0), suggesting a mean duration of recent infection (MDRI) close to 6 months. Agreement of ARRA with LAg recent cases was 81.6% (80/98) and LT cases was 93.8% (438/467), with an overall agreement of 91.7% (kappa = 0.72). The reader (cutoff 2.9) classified 109/566 specimens as recent infections compared to 99 by the LAg-Avidity EIA for recency agreement of 81.8% (81/99), LT agreement of 9% (439/467) with overall agreement of 91.9% (kappa = 0.72). The agreement between visual interpretation and strip reader was 99.9% (95% CI: 99.6-99.9) for the PVL and 98.1% (95% CI: 96.6-98.9) for the LTL. ARRA performed well with HIV diagnostic sensitivity >99% and specificity >98%. Its ability to identify recent infections is comparable to the LA-Avidity EIA corresponding to an MDRI of about 6 months. This point-of-care assay has implications for real-time surveillance of new infections among newly diagnosed individuals for targeted prevention and interrupting ongoing transmission thus accelerating epidemic control

Summary of mean recency period (in days) for LAg-Avidity EIA at cutoff of 1.0 by cohort and prevalent HIV-1 subtype(s).

<p>Summary of mean recency period (in days) for LAg-Avidity EIA at cutoff of 1.0 by cohort and prevalent HIV-1 subtype(s).</p

A) Comparative OD or ODn values of a cross-sectional specimen set tested with Genetics Systems HIV-1/HIV-2 Plus O EIA and LAg-Avidity EIA.

<p>Specimens are arranged in ascending ODn on LAg-Avidity EIA to represent avidity maturation since seroconversion; a horizintal line at 1.0 indicates cut-off for recent and long-term classification. Only first 35 specimens are shown for clarity. B) Corresponding HIV-1 Western blot banding profile of first 32 specimens showing increase in number and intensity of bands typical of antibody maturation. For the purpose of incidence estimation, vertical arrow indicates cutoff; recent infections = left of the arrow, long-term infections = right of the arrow.</p

Comparative HIV antibody kinetics following seroconversion as detected by the BED assay (left), LAg-Avidity EIA (middle), and Avidity Index-EIA (right) among 89 seroconverting individuals (subtypes A ,B, C & D).

<p>The BED assay measures increasing proportion of HIV-specific IgG in total IgG, while LAg-Avidity EIA and AI-EIA measure increasing avidity of HIV antibody. Both LAg-Avidity EIA and AI-EIA use multi-subtype gp41 recombinant protein, rIDR-M, and pH 3.0 dissociation buffer to distinguish recent and long-term HIV infections.</p

Antibody avidity maturation post-seroconversion as measured by LAg-Avidity EIA in individuals from 4 cohorts representing different geographic locations and subtype infections: Amsterdam and Trinidad cohorts (subtype B; left), Kenya cohort (subtypes A and D; middle), and Ethiopia cohort (subtype C; right).

<p>Each line represents a single individual with sequential specimens collected over time post-seroconversion (X-axis; note that scale is different in panel C due to longer follow up).</p

Mean OD and ODn values for CAL and controls, including standard deviation (SD) and coefficient of variation (%CV) from 94 runs.

<p>NC-negative control, CAL = calibrator, LPC = low positive control and HPC = high positive control specimens.</p