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Lanzavecchia, Antonio

Publications and source records attributed to Lanzavecchia, Antonio.

Broad betacoronavirus neutralization by a stem helix–specific human antibody

Targeting a range of betacoranaviruses In the past 20 years, three highly pathogenic β-coronaviruses have crossed from animals to humans, including the most recent: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A spike protein that decorates these viruses has an S1 domain that binds host cell receptors and an S2 domain that fuses the viral and cell membranes to allow cell entry. The S1 domain is the target of many neutralizing antibodies but is more genetically variable than S2, and antibodies can exert selective pressure, leading to resistant variants. Pinto et al . identified five monoclonal antibodies that interact with a helix in the S2 domain. The most broadly neutralizing antibody inhibited all β-coronavirus subgenera and reduced viral burden in hamsters infected with SARS-CoV-2. —VV

59 BASIC BIOLOGICAL SCIENCES↗

A vision of immuno-oncology: the Siena think tank of the Italian Network for Tumor Biotherapy (NIBIT) foundation

The yearly Think Tank Meeting of the Italian Network for Tumor Biotherapy (NIBIT) Foundation, brings together in Siena, Tuscany (Italy), experts in immuno-oncology to review the learnings from current immunotherapy treatments, and to propose new pre-clinical and clinical investigations in selected research areas. While immunotherapies in non-small cell lung cancer and melanoma led to practice changing therapies, the same therapies had only modest benefit for patients with other malignancies, such as mesothelioma and glioblastoma. One way to improve on current immunotherapies is to alter the sequence of each combination agent. Matching the immunotherapy to the host’s immune response may thus improve the activity of the current treatments. A second approach is to combine current immunotherapies with novel agents targeting complementary mechanisms. Identifying the appropriate novel agents may require different approaches than the traditional laboratory-based discovery work. For example, artificial intelligence-based research may help focusing the search for innovative and most promising combination partners. Novel immunotherapies are needed in cancer patients with resistance to or relapse after current immunotherapeutic drugs. Such new treatments may include targeted agents or monoclonal antibodies to overcome the immune-suppressive tumor microenvironment. The mode of combining the novel treatments, including vaccines, needs to be matched to the patient’s immune status for achieving the maximum benefit. In this scenario, specific attention should be also paid nowadays to the immune intersection between COVID-19 and cancer.

60 APPLIED LIFE SCIENCES↗

Structural basis of LAIR1 targeting by polymorphic Plasmodium RIFINs

RIFIN, a large family of Plasmodium variant surface antigens, plays a crucial role in malaria pathogenesis by mediating immune suppression through activation of inhibitory receptors such as LAIR1, and antibodies with LAIR1 inserts have been identified that bind infected erythrocytes through RIFIN. However, details of RIFIN-mediated LAIR1 recognition and receptor activation have been unclear. Here, we use negative-stain EM to define the architecture of LAIR1-inserted antibodies and determine crystal structures of RIFIN-variable 2 (V2) domain in complex with a LAIR1 domain. These structures reveal the LAIR1-binding region of RIFIN to be hydrophobic and membrane-distal, to exhibit extensive structural diversity, and to interact with RIFIN-V2 in a one-to-one fashion. Through structural and sequence analysis of various LAIR1 constructs, we identify essential elements of RIFIN-binding on LAIR1. Furthermore, a structure-derived LAIR1-binding sequence signature ascertained >20 LAIR1-binding RIFINs, including some from P. falciparum field strains and Plasmodium species infecting gorillas and chimpanzees.

59 BASIC BIOLOGICAL SCIENCES↗

Mapping Neutralizing and Immunodominant Sites on the SARS-CoV-2 Spike Receptor-Binding Domain by Structure-Guided High-Resolution Serology

We report analysis of the specificity and kinetics of neutralizing antibodies (nAbs) elicited by SARS-CoV-2 infection is crucial for understanding immune protection and identifying targets for vaccine design. In a cohort of 647 SARS-CoV-2-infected subjects, we found that both the magnitude of Ab responses to SARS-CoV-2 spike (S) and nucleoprotein and nAb titers correlate with clinical scores. The receptor-binding domain (RBD) is immunodominant and the target of 90% of the neutralizing activity present in SARS-CoV-2 immune sera. Whereas overall RBD-specific serum IgG titers waned with a half-life of 49 days, nAb titers and avidity increased over time for some individuals, consistent with affinity maturation. We structurally defined an RBD antigenic map and serologically quantified serum Abs specific for distinct RBD epitopes leading to the identification of two major receptor-binding motif antigenic sites. Our results explain the immunodominance of the receptor-binding motif and will guide the design of COVID-19 vaccines and therapeutics.

59 BASIC BIOLOGICAL SCIENCES↗