Yong Gao

Elite controllers (ECs) are rare human immunodeficiency virus (HIV)-infected individuals who manage viral replication without antiretroviral therapy. While

Kaposi’s sarcoma–associated herpesvirus (KSHV/HHV-8) infects more than 140 million people worldwide, with transmission occurring mainly through saliva, blood transfusion, and sexual contact. Despite its global burden, especially in HIV-endemic regions, KSHV-related diseases remain underdiagnosed and poorly managed. This review highlights current knowledge on KSHV pathogenesis with emphasis on latency, immune evasion, and oncogenesis. We summarize how viral proteins such as latency-associated nuclear antigen (LANA) and viral interleukin-6 (vIL-6) manipulate host cell survival pathways, including PI3-K signaling and Rho GTPase regulation, to drive Kaposi’s sarcoma, multicentric Castleman disease, and primary effusion lymphoma. Advances in diagnostics (PCR, serology, immunohistochemistry) and targeted therapies, particularly rituximab, have improved patient outcomes, although treatment challenges remain. Ongoing efforts in vaccine development and immune-based interventions hold promise for controlling viral persistence and preventing cancer progression. A deeper understanding of KSHV–host interactions will be crucial for designing next-generation therapies and guiding future public health strategies.

Elite controllers (ECs) are rare human immunodeficiency virus (HIV) infected individuals who manage viral replication without antiretroviral therapy. While their cellular immunity is well-characterized, humoral responses remain limited. Using single-cell functional screening, this study aimed to isolate and characterize HIV-1 envelope (Env) specific monoclonal antibodies (mAbs) from an EC. The Beacon® platform helped in enrichment, activation, and screening of cluster of differentiation 27+ (CD27⁺) memory B cells. Out of ~12,000 single B cells, we identified 40 Env-specific IgG-secreting cells. Although 18 mAbs were recovered, six showed high-affinity binding to multiple Env trimers (average EC50 < 100 ng/mL). Notably, one mAb (2#) neutralized 15 of 17 pseudoviruses with a geometric mean half maximal inhibitory concentration (IC50) of 46.53 μg/mL. Sequence analysis revealed a predominant usage of IGHV1-69 and varied somatic hypermutation levels. However, the high binding affinity could not consistently predict neutralization potency. This study demonstrated the utility of integrated single-cell screening for rapid antibody discovery from rare donors. It also highlighted the need for functional assessment in HIV-1 antibody development and identifying an mAb candidate with moderate breadth and potency for potential therapeutic or vaccine applications.

Monitoring variations in the virus genome to understand the SARS‐CoV‐2 evolution and spread of the virus is extremely important. Seven early SARS‐CoV‐2 isolates in China were cultured in vitro and were analyzed for their viral infectivity through viral growth assay, tissue culture infectious dose (TCID₅₀) assay, spike protein quantification, and next generation sequencing analysis, and the resultant mutations in spike protein were used to generate the corresponding pseudoviruses for analysis of immune escape from vaccination and postinfection immunity. The results revealed that in vitro cultured SARS‐CoV‐2 virus had much higher mutation frequency (up to ~20 times) than that in infected patients, suggesting that SARS‐CoV‐2 diversify under favorable conditions. Monitoring viral mutations is not only helpful for better understanding of virus evolution and virulence change, but also the key to prevent virus transmission and disease progression. Compared with the D614G reference strain, a pseudovirus strain of SARS‐CoV‐2 was constructed with a high mutation rate site on the spike protein. We found some novel spike mutations during in vitro culture, such as E868Q, conferred further immune escape ability.

Accurate detection of SARS-CoV-2 neutralizing antibody (nAb) is critical for assessing the immunity levels after virus infection or vaccination. As fast, cost-effective alternatives to viral infection-based assays, competitive binding (CB) assays were developed to quantitate nAb by monitoring the ability of sera to inhibit the binding of viral spike (S) protein to the angiotensin converting enzyme 2 (ACE2) receptor. Herein, we established a bead-based flow cytometric CB assay and tested the detection performance of six combination models, i.e. immobilized ACE2 and soluble Fc-tagged S1 subunit of S protein (iACE2/S1-Fc), immobilized ACE2 and soluble Fc-tagged receptor binding domain (RBD) of S protein (iACE2/RBD-Fc), immobilized S1 and soluble Fc-tagged ACE2 (iS1/ACE2-Fc), immobilized S1 and soluble His-tagged ACE2 (iS1/ACE2-His), immobilized RBD and soluble Fc-tagged ACE2 (iRBD/ACE2-Fc), and immobilized RBD and soluble His-tagged ACE2 (iRBD/ACE2-His). Using SARS-CoV-2 monoclonal antibodies and sera of convalescent COVID-19 patients and vaccinated subjects, the combination models iACE2/RBD-Fc, iACE2/S1-Fc and iS1/ACE2-His were identified to be able to specifically detect SARS-CoV-2 nAb, among which iACE2/RBD-Fc model showed the highest sensitivity, superior to a commercial SARS-CoV-2 surrogate virus neutralization test (sVNT) ELISA kit. Further studies demonstrated that the sensitivity and specificity of CB assays were affected by the tag of ACE2, type of spike and method of measuring binding rate between ACE2 and spike. Moreover, the iACE2/RBD-Fc model showed good performance in detecting kinetic development of nAb against both the prototype SARS-CoV-2 strain and an omicron variant of SARS-CoV-2 in people immunized by an inactivated SARS-CoV-2 vaccine, and the results of iACE2/RBD-Fc model are correlated well with those of live virus-based and pseudovirus-based neutralization tests, demonstrating the potential to be developed into a highly sensitive, specific, versatile and high-throughput method for detecting SARS-CoV-2 nAb in clinical practice.