Genetic variation that determines TAPBP expression levels associates with the course of malaria in an HLA allotype-dependent manner

The Transformative Impact of the African Cohort Study (AFRICOS) Toward Reaching HIV 95-95-95 Goals in Sub-Saharan Africa

Over the last 20 years, the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) has rapidly expanded and made remarkable progress toward the UNAIDS 95-95-95 targets to end the HIV epidemic. Nevertheless, HIV continues to pose a significant health challenge globally, with a particular impact on the African continent. Funded by PEPFAR, the African Cohort Study (AFRICOS) has served as a monitoring and evaluation tool for PEPFAR to help guide HIV policy and PEPFAR programming for the last 10 years since its inception and offers a compelling example of how PEPFAR's investment in science continues to reap dividends. This paper details and critically reviews the transformative research AFRICOS has had on helping to end the HIV epidemic as a public health threat by 2030.

CD16 and CD57 expressing gamma delta T cells in acute HIV-1 infection are associated with the development of neutralization breadth

New HIV vaccine approaches are focused on eliciting broadly neutralizing antibodies. We characterized early gamma-delta (γδ) T cell responses starting from pre-acquisition and during acute HIV infection (AHI) in participants previously characterized for neutralization breadth development. We found significant differences in γδ T cell surface marker expression in participants that developed neutralization breadth compared to those that did not. Activation of γδ T cells occurred within the first weeks of HIV acquisition and associated with viral load. Expression of CD16 on Vδ1 T cells and CD57 on Vδ2 T cells were found to be significantly higher in broad neutralizers during AHI, and associated with the development of neutralization breadth years later. In addition, the levels of CD16 on Vδ1 T cells was associated with early production of founder virus Env-specific IgM. Thus, γδ T cells may promote development of neutralization breadth, which has implications for HIV vaccine strategies.

PD-1 blockade plus COX inhibitors in dMMR metastatic colorectal cancer: Clinical, genomic, and immunologic analyses from the PCOX trial

BACKGROUND

Approximately 20% of patients with DNA mismatch repair deficiency (dMMR) metastatic colorectal cancer do not respond to anti-programmed death-1 (PD-1) ligand therapy, and baseline biomarkers of response are lacking.

METHODS

We conducted a phase 2 study to evaluate the efficacy of cyclooxygenase (COX) inhibitors in combination with anti-PD-1 therapy in patients with dMMR metastatic colorectal cancer. The primary endpoint was objective response rate. The secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate, duration of response, and safety.

FINDINGS

A total of 30 patients were enrolled, and the objective response rate was 73.3%, meeting the predefined endpoint of 68%. The median PFS and median OS were not reached at a median follow-up period of 50.8 months. Disease control was achieved in 28 patients (93.3%). The median duration of response was not reached. The combination was well tolerated. Multiomics analysis revealed that the antigen processing and presentation pathway was positively associated with treatment response and PFS. Higher TAPBP expression was predictive of better PFS (log-rank p = 0.003), and this prognostic significance was confirmed in an immunotherapy validation cohort.

CONCLUSIONS

Thus, COX inhibitors combined with PD-1 blockade may be effective and safe treatment options for patients with dMMR metastatic colorectal cancer, and TAPBP may serve as a biomarker for immune checkpoint inhibitor therapy (this study was registered at ClinicalTrials.gov: NCT03638297).

FUNDING

Funded by the National Natural Science Foundation of China (81974369) and the program of Guangdong Provincial Clinical Research Center for Digestive Diseases (2020B1111170004).

HLA-DQ2/8 and COVID-19 in Celiac Disease: Boon or Bane

The SARS-CoV-2 pandemic continues to pose a global threat. While its virulence has subsided, it has persisted due to the continual emergence of new mutations. Although many high-risk conditions related to COVID-19 have been identified, the understanding of protective factors remains limited. Intriguingly, epidemiological evidence suggests a low incidence of COVID-19-infected CD patients. The present study explores whether their genetic background, namely, the associated HLA-DQs, offers protection against severe COVID-19 outcomes. We hypothesize that the HLA-DQ2/8 alleles may shield CD patients from SARS-CoV-2 and its subsequent effects, possibly due to memory CD4 T cells primed by previous exposure to human-associated common cold coronaviruses (CCC) and higher affinity to those allele's groove. In this context, we examined potential cross-reactivity between SARS-CoV-2 epitopes and human-associated CCC and assessed the binding affinity (BA) of these epitopes to HLA-DQ2/8. Using computational methods, we analyzed sequence similarity between SARS-CoV-2 and four distinct CCC. Of 924 unique immunodominant 15-mer epitopes with at least 67% identity, 37 exhibited significant BA to HLA-DQ2/8, suggesting a protective effect. We present various mechanisms that might explain the protective role of HLA-DQ2/8 in COVID-19-afflicted CD patients. If substantiated, these insights could enhance our understanding of the gene-environment enigma and viral-host relationship, guiding potential therapeutic innovations against the ongoing SARS-CoV-2 pandemic.

Visualising tapasin- and TAPBPR-assisted editing of major histocompatibility complex class-I immunopeptidomes

Which peptides are selected for presentation by major histocompatibility complex class-I (MHC-I) molecules is a key determinant of successful immune responses. Peptide selection is co-ordinated by the tapasin and TAP Binding PRotein (TAPBPR) proteins, which ensure MHC-I molecules preferentially acquire high-affinity-binding peptides. New structural analyses have offered insight into how tapasin achieves this function within the peptide-loading complex (PLC) (comprising the Transporter associated with Antigen Presentation (TAP) peptide transporter, tapasin-ERp57, MHC-I and calreticulin), and how TAPBPR performs a peptide editing function independently of other molecules. The new structures reveal nuances in how tapasin and TAPBPR interact with MHC-I, and how calreticulin and ERp57 complement tapasin to exploit the plasticity of MHC-I molecules to achieve peptide editing.