Antibody evasion by SARS-CoV-2 Omicron subvariants BA.2.12.1, BA.4 and BA.5.

SARS-CoV-2 Omicron subvariants BA.2.12.1 and BA.4/5 have surged notably to become dominant in the United States and South Africa, respectively1,2. These new subvariants carrying further mutations in their spike proteins raise concerns that they may further evade neutralizing antibodies, thereby further compromising the efficacy of COVID-19 vaccines and therapeutic monoclonals. We now report findings from a systematic antigenic analysis of these surging Omicron subvariants. BA.2.12.1 is only modestly (1.8-fold) more resistant to sera from vaccinated and boosted individuals than BA.2. However, BA.4/5 is substantially (4.2-fold) more resistant and thus more likely to lead to vaccine breakthrough infections. Mutation at spike residue L452 found in both BA.2.12.1 and BA.4/5 facilitates escape from some antibodies directed to the so-called class 2 and 3 regions of the receptor-binding domain3. The F486V mutation found in BA.4/5 facilitates escape from certain class 1 and 2 antibodies but compromises the spike affinity for the viral receptor. The R493Q reversion mutation, however, restores receptor affinity and consequently the fitness of BA.4/5. Among therapeutic antibodies authorized for clinical use, only bebtelovimab retains full potency against both BA.2.12.1 and BA.4/5. The Omicron lineage of SARS-CoV-2 continues to evolve, successively yielding subvariants that are not only more transmissible but also more evasive to antibodies.

Human Immunodeficiency Virus (HIV) and Menopause Are Independently Associated With Lower Bone Mineral Density: Results From the Women's Interagency HIV Study.

BACKGROUND: We previously reported lower bone mineral density (BMD) among premenopausal women with HIV (WWH) compared to women without HIV (HIV-). Rate of bone loss may be even greater for WWH during the menopausal transition. METHODS: Pre-, peri- and postmenopausal women in the Women\'s Interagency HIV Study (WIHS) underwent whole body DXA and central quantitative computed tomography to measure areal BMD (aBMD) and volumetric BMD (vBMD), respectively. Multivariable regression models with covariates associated with low aBMD (T score < -1.0) in univariate analyses (P≤.05) and known risk factors for low BMD assessed contributions of HIV and menopausal stage to the prediction of aBMD. RESULTS: Compared to HIV- women, in unadjusted analyses, WWH had 5-9% lower aBMD at the lumbar spine (P=.001), femoral neck (P=.04), total hip (P=.003) and the ultradistal radius (P=.004), and higher osteoporosis prevalence (T score<-2.5) at the ultradistal radius only (13.5% vs 0%, P=.0003). WWH also had lower vBMD at the spine and hip. In fully adjusted models, HIV independently predicted reduced aBMD at the lumbar spine, total hip, femoral neck, and ultradistal radius; menopausal stage remained a significant predictor of lumbar spine and ultradistal radius aBMD. CONCLUSIONS: HIV infection and menopausal stage were independent predictors of lower BMD, and had an additive effect on lumbar spine and total hip BMD. Additional research is needed to better understand underlying mechanisms by which HIV impacts BMD as women age and transition through menopause, and develop strategies to mitigate osteoporosis and fracture risk in this growing population.

Longitudinal Viral Load Monitoring Using Home-Collected Dried Blood Spot Specimens of MSM Living with HIV: Results from a Feasibility Pilot Study.

Novel viral load monitoring strategies are needed to help individuals maintain an undetectable viral load (UVL). In 2018, U.S. MSM living with HIV with a past detectable VL received a dried blood spot (DBS) kit at baseline and 3-month follow-up and returned specimens to a research laboratory. Of 56 consenting participants, 91% returned specimens at baseline and 77% at 3-month follow-up; 74% who returned two specimens had UVL at both time points. At-home DBS collection and longitudinal VL monitoring is feasible among U.S. MSM with fluctuating viral load. This complementary approach to clinical care could improve viral suppression maintenance.

RESUMEN: Se necesitan nuevas estrategias para evaluar los niveles de la carga viral para ayudar a las personas viviendo con VIH a mantener una carga viral indetectable (CVI). En 2018, hombres viviendo con VIH, que reportaron sexo con hombres y una carga viral detectable, recibieron dos paquetes de materiales para colectar muestras de sangre seca después de completar una evaluación basal y después de tres meses de seguimiento. Participantes devolvieron las muestras de sangre seca a un laboratorio. De 56 participantes que dieron su consentimiento a participar en el estudio, el 91% devolvió una muestra de sangre seca al inicio del estudio y el 77% a los 3 meses de seguimiento. Además, el 74% que devolvió dos muestras de sangre seca tenían CVI en ambos puntos de tiempo. La colección de sangre seca en el hogar y el monitoreo longitudinal de la carga viral de VIH es factible entre los hombres viviendo con el VIH y que tienen sexo con hombres. Los resultados de este estudio pueden proporcionar un enfoque complementario a la atención clínica para mejorar la supresión viral del VIH.

Small intestinal CD8+TCRgammadelta+NKG2A+ intraepithelial lymphocytes have attributes of regulatory cells in patients with celiac disease.

Intraepithelial lymphocytes (IELs) bearing the gammadelta TCR are more abundant in the small intestinal mucosa of patients with celiac disease (CD) compared with healthy individuals. However, their role in disease pathogenesis is not well understood. Here, we investigated the functional attributes of TCRgammadelta+ IELs isolated from intestinal biopsies of patients with either active celiac disease (ACD) or those on a gluten-free diet (GFD). We found that compared with individuals with ACD, individuals on GFD have a higher frequency of CD8+TCRgammadelta+ IELs that express the inhibitory NK receptor NKG2A and intracellular TGF-beta1. TCR triggering as well as cross-linking of NKG2A increased both TGF-beta1 intracellular expression and secretion in vitro. Coculture of sorted TCRgammadelta+NKG2A+ IELs, IL-15-stimulated TCRalphabeta+ IELs, and HLA-E+ enterocytes resulted in a decreased percentage of cytotoxic CD8+TCRalphabeta+ IELs expressing intracellular IFN-gamma and granzyme-B and surface NKG2D. This inhibition was partially abrogated by blocking either TGF-beta alone or both NKG2A and HLA-E. Thus, our data indicate that suppression was at least partially mediated by TGF-beta secretion as a result of engagement of NKG2A with its ligand, HLA-E, on enterocytes and/or TCRalphabeta+ IELs. These findings demonstrate that human small intestinal CD8+TCRgammadelta+ IELs may have regulatory potential in celiac disease.

The combined effects of age and HIV on the anatomic distribution of cortical and cancellous bone in the femoral neck among men and women.

OBJECTIVE: To investigate HIV-related and age-related differences in hip bone structure in men and women. DESIGN: Cross sectional study of bone structure and HIV serostatus. METHODS: We used Quantitative Computed Tomography (QCT) data from the Multicenter AIDS Cohort Study (MACS) and Women's Interagency HIV Study (WIHS) to examine cortical thickness (CT) and cortical (CBMD), trabecular (TBMD), and integral (IBMD) bone mineral density across anatomic quadrants of the femoral neck in older adult MSM and women with (PWH) and without (PWOH) HIV infection. The percentage difference (%diff) in the means for CT and BMD overall and by quadrant between PWH and PWOH were estimated. RESULTS: Among 322 MSM (median age 60 years) with bone measures, distributions were similar between HIV serostatus groups with %diff in the quadrant means ranging from -7 to -1% for CT and from -1 to 4% for BMD, and overall lower hip cortical thickness than expected. In contrast, in 113 women (median age 51 years), PWH had lower CT, IBMD and TBMD consistently across all quadrants, with differences ranging from -10 to -20% for CT, -6 to -11% for IBMD and -3 to -6% for TBMD. Estimates reached statistical significance in superoanterior quadrant for CT and IBMD and inferoposterior for CT. CONCLUSION: Among women, PWH appear to have a thinner cortex and less dense integral bone compared with PWOH, particularly in the superior quadrants whereas MSM overall had a thinner than expected hip cortex.

IGF-1 Receptor Expression on Circulating Osteoblast Progenitor Cells Predicts Tissue-Based Bone Formation Rate and Response to Teriparatide in Premenopausal Women With Idiopathic Osteoporosis.

We have previously reported that premenopausal women with idiopathic osteoporosis (IOP) have profound microarchitectural deficiencies and heterogeneous bone remodeling. Those with the lowest bone formation rate have higher baseline serum insulin-like growth factor-1 (IGF-1) levels and less robust response to teriparatide. Because IGF-1 stimulates bone formation and is critical for teriparatide action on osteoblasts, these findings suggest a state of IGF-1 resistance in some IOP women. To further investigate the hypothesis that osteoblast and IGF-1-related mechanisms mediate differential responsiveness to teriparatide in IOP, we studied circulating osteoblast progenitor (COP) cells and their IGF-1 receptor (IGF-1R) expression. In premenopausal women with IOP, peripheral blood mononuclear cells (PBMCs) were obtained at baseline (n = 25) and over 24 months of teriparatide treatment (n = 11). Flow cytometry was used to identify and quantify COPs (non-hematopoetic lineage cells expressing osteocalcin and RUNX2) and to quantify IGF-1R expression levels. At baseline, both the percent of PBMCs that were COPs (%COP) and COP cell-surface IGF-1R expression correlated directly with several histomorphometric indices of bone formation in tetracycline-labeled transiliac biopsies. In treated subjects, both %COP and IGF-1R expression increased promptly after teriparatide, returning toward baseline by 18 months. Although neither baseline %COP nor increase in %COP after 3 months predicted the bone mineral density (BMD) response to teriparatide, the percent increase in IGF-1R expression on COPs at 3 months correlated directly with the BMD response to teriparatide. Additionally, lower IGF-1R expression after teriparatide was associated with higher body fat, suggesting links between teriparatide resistance, body composition, and the GH/IGF-1 axis. In conclusion, these assays may be useful to characterize bone remodeling noninvasively and may serve to predict early response to teriparatide and possibly other bone formation-stimulating medications. These new tools may also have utility in the mechanistic investigation of teriparatide resistance in premenopausal IOP and perhaps in other populations. © 2017 American Society for Bone and Mineral Research.

Repression by RB1 characterizes genes involved in the penultimate stage of erythroid development.

Retinoblastoma-1 (RB1), and the RB1-related proteins p107 and p130, are key regulators of the cell cycle. Although RB1 is required for normal erythroid development in vitro, it is largely dispensable for erythropoiesis in vivo. The modest phenotype caused by RB1 deficiency in mice raises questions about redundancy within the RB1 family, and the role of RB1 in erythroid differentiation. Here we show that RB1 is the major pocket protein that regulates terminal erythroid differentiation. Erythroid cells lacking all pocket proteins exhibit the same cell cycle defects as those deficient for RB1 alone. RB1 has broad repressive effects on gene transcription in erythroid cells. As a group, RB1-repressed genes are generally well expressed but downregulated at the final stage of erythroid development. Repression correlates with E2F binding, implicating E2Fs in the recruitment of RB1 to repressed genes. Merging differential and time-dependent changes in expression, we define a group of approximately 800 RB1-repressed genes. Bioinformatics analysis shows that this list is enriched for terms related to the cell cycle, but also for terms related to terminal differentiation. Some of these have not been previously linked to RB1. These results expand the range of processes potentially regulated by RB1, and suggest that a principal role of RB1 in development is coordinating the events required for terminal differentiation.