HIV-1 broadly neutralizing antibodies (bnAbs) develop in a subset of infected adults and exhibit high levels of somatic hypermutation (SHM) due to years of affinity maturation. There is no precedent for eliciting highly mutated antibodies by vaccination, nor is it practical to wait years for a desired response. Infants develop broad responses early, which may suggest a more direct path to generating bnAbs. Here, we isolated ten neutralizing antibodies (nAbs) contributing to plasma breadth of an infant at ∼1 year post-infection, including one with cross-clade breadth. The nAbs bind to envelope trimer from the transmitted virus, suggesting that this interaction may have initiated development of the infant nAbs. The infant cross-clade bnAb targets the N332 supersite on envelope but, unlike adult bnAbs targeting this site, lacks indels and has low SHM. The identification of this infant bnAb illustrates that HIV-1-specific neutralization breadth can develop without prolonged affinity maturation and extensive SHM.
In nonhealthcare settings, widespread screening for acute human immunodeficiency virus (HIV) infection (AHI) is limited by cost and decision algorithms to better prioritize use of resources. Comparative cost analyses for available strategies are lacking.
To determine cost-effectiveness of community-based testing strategies, we evaluated annual costs of 3 algorithms that detect AHI based on HIV nucleic acid amplification testing (EarlyTest algorithm) or on HIV p24 antigen (Ag) detection via Architect (Architect algorithm) or Determine (Determine algorithm) as well as 1 algorithm that relies on HIV antibody testing alone (Antibody algorithm). The cost model used data on men who have sex with men (MSM) undergoing community-based AHI screening in San Diego, California. Incremental cost-effectiveness ratios (ICERs) per diagnosis of AHI were calculated for programs with HIV prevalence rates between 0.1% and 2.9%.
Among MSM in San Diego, EarlyTest was cost-savings (ie, ICERs per AHI diagnosis less than $13.000) when compared with the 3 other algorithms. Cost analyses relative to regional HIV prevalence showed that EarlyTest was cost-effective (ie, ICERs less than $69.547) for similar populations of MSM with an HIV prevalence rate >0.4%; Architect was the second best alternative for HIV prevalence rates >0.6%.
Identification of AHI by the dual EarlyTest screening algorithm is likely to be cost-effective not only among at-risk MSM in San Diego but also among similar populations of MSM with HIV prevalence rates >0.4%.
HIV cure efforts are hampered by limited characterization of the cells supporting HIV replication in vivo and inadequate methods for quantifying the latent viral reservoir in patients receiving antiretroviral therapy. We combine fluorescent in situ RNA hybridization with detection of HIV protein and flow cytometry, enabling detection of 0.5-1 gag-pol mRNA(+)/Gag protein(+)-infected cells per million. In the peripheral blood of untreated persons, active HIV replication correlated with viremia and occurred in CD4 T cells expressing T follicular helper cell markers and inhibitory co-receptors. In virally suppressed subjects, the approach identified latently infected cells capable of producing HIV mRNA and protein after stimulation with PMA/ionomycin and latency-reversing agents (LRAs). While ingenol-induced reactivation mirrored the effector and central/transitional memory CD4 T cell contribution to the pool of integrated HIV DNA, bryostatin-induced reactivation occurred predominantly in cells expressing effector memory markers. This indicates that CD4 T cell differentiation status differentially affects LRA effectiveness.
Housing instability has been linked to HIV risk behaviors. Many studies have focused on the implications of one's housing structure or lack thereof. This study focuses on residential transience as an additional dimension of housing instability. Specifically, we assessed the associations between transience and four HIV risk behaviors. Transience was defined as moving twice or more in the past six months. Multivariate analyses of a sample of current injectors (n = 807) indicated that transience had an independent effect on HIV risk behaviors. Transient individuals were more likely to share needles and go to a shooting gallery than non-transient individuals. Transience was not associated with exchanging sex or having multiple sex partners when homelessness was included in the models. Further examination of the association between housing and HIV should consider the role of transience. Interventions that promote housing stability among IDUs and address HIV risk during times of instability are needed.
Functional impairment of T cells is characteristic of many chronic mouse and human viral infections. The inhibitory receptor programmed death 1 (PD-1; also known as PDCD1), a negative regulator of activated T cells, is markedly upregulated on the surface of exhausted virus-specific CD8 T cells in mice. Blockade of this pathway using antibodies against the PD ligand 1 (PD-L1, also known as CD274) restores CD8 T-cell function and reduces viral load. To investigate the role of PD-1 in a chronic human viral infection, we examined PD-1 expression on human immunodeficiency virus (HIV)-specific CD8 T cells in 71 clade-C-infected people who were naive to anti-HIV treatments, using ten major histocompatibility complex (MHC) class I tetramers specific for frequently targeted epitopes. Here we report that PD-1 is significantly upregulated on these cells, and expression correlates with impaired HIV-specific CD8 T-cell function as well as predictors of disease progression: positively with plasma viral load and inversely with CD4 T-cell count. PD-1 expression on CD4 T cells likewise showed a positive correlation with viral load and an inverse correlation with CD4 T-cell count, and blockade of the pathway augmented HIV-specific CD4 and CD8 T-cell function. These data indicate that the immunoregulatory PD-1/PD-L1 pathway is operative during a persistent viral infection in humans, and define a reversible defect in HIV-specific T-cell function. Moreover, this pathway of reversible T-cell impairment provides a potential target for enhancing the function of exhausted T cells in chronic HIV infection.
Inadequate local cell-mediated immunity appears crucial for the establishment of chronic HIV infection. Accumulation of regulatory T cells (Treg) at the site of HIV replication, the lymphoid organs, may influence the outcome of HIV infection. Our data provide the first evidence that chronic HIV infection changes Treg tissue distribution. Several molecules characteristics of Treg (FoxP3, CTLA-4, glucocorticoid-induced TNFR family-related receptor, and CD25) were expressed more in tonsils of untreated patients compared with antiretroviral-treated patients. Importantly, most FoxP3+ cells expressed CTLA-4, but not CD69. Furthermore, a direct correlation between FoxP3 levels and viral load was evident. In contrast, FoxP3 expression was decreased in circulating T cells from untreated patients, but normalized after initiation of treatment. Functional markers of Treg activity (indoleamine 2,3-dioxygenase, TGF-beta, and CD80) were markedly increased in the tonsils of untreated patients. Our data could provide a new basis for immune-based therapies that counteract in vivo Treg and thereby reinforce appropriate antiviral immunity.
Although antiretroviral therapy has the ability to fully restore a normal CD4(+) cell count (>500 cells/mm(3)) in most patients, it is not yet clear whether all patients can achieve normalization of their CD4(+) cell count, in part because no study has followed up patients for >7 years.
Three hundred sixty-six patients from 5 clinical cohorts who maintained a plasma human immunodeficiency virus (HIV) RNA level 1000 copies/mL for at least 4 years after initiation of antiretroviral therapy were included. Changes in CD4(+) cell count were evaluated using mixed-effects modeling, spline-smoothing regression, and Kaplan-Meier techniques.
The majority (83%) of the patients were men. The median CD4(+) cell count at the time of therapy initiation was 201 cells/mm(3) (interquartile range, 72-344 cells/mm(3)), and the median age was 47 years. The median follow-up period was 7.5 years (interquartile range, 5.5-9.7 years). CD4(+) cell counts continued to increase throughout the follow-up period, albeit slowly after year 4. Although almost all patients (95%) who started therapy with a CD4(+) cell count 300 cells/mm(3) were able to attain a CD4(+) cell count 500 cells/mm(3), 44% of patients who started therapy with a CD4(+) cell count <100 cells/mm(3) and 25% of patients who started therapy with a CD4(+) cell count of 100-200 cells/mm(3) were unable to achieve a CD4(+) cell count >500 cells/mm(3) over a mean duration of follow-up of 7.5 years; many did not reach this threshold by year 10. Twenty-four percent of individuals with a CD4(+) cell count <500 cells/mm(3) at year 4 had evidence of a CD4(+) cell count plateau after year 4. The frequency of detectable viremia ("blips") after year 4 was not associated with the magnitude of the CD4(+) cell count change.
A substantial proportion of patients who delay therapy until their CD4(+) cell count decreases to <200 cells/mm(3) do not achieve a normal CD4(+) cell count, even after a decade of otherwise effective antiretroviral therapy. Although the majority of patients have evidence of slow increases in their CD4(+) cell count over time, many do not. These individuals may have an elevated risk of non-AIDS-related morbidity and mortality.