Abstract
We discuss the suitability of innate immune stimulation in acute respiratory infection post-exposure prophylaxis. The induction of innate immunity can be used to reduce susceptibility to immune-evasive pathogens (coronavirus, influenza virus, respiratory syncytial virus and rhinovirus). After the emergence of multiple SARS-CoV-2 variants, scientists are debating whether new variants could affect vaccine efficacy and how antigens could be redesigned to compensate. In addition, there is insufficient vaccine production to cover universal demand, and equitable vaccine distribution is a global challenge. Given these factors, non-specific immune stimulators may be suitable for a quick first response in the case of a suspected or early respiratory infection. Our group completed several HeberNasvac studies in healthy volunteers and patients with respiratory infections, and is currently starting large clinical trials in patients with early SARS-CoV-2 infections. This nasal formulation of hepatitis B vaccine has demonstrated its capacity to stimulate innate immunity markers (TLR3, TLR7 and TLR8 in tonsils) at the virus' entry site, in systemic compartments (HLA class II in monocytes and lymphocytes) and in the activation of dendritic cells, lymphocytes and other cell lines in vitro and ex vivo. In addition, research generated by the current pandemic may obtain results useful for treating other acute respiratory infections, which have long been main drivers of mortality among older adults and in early childhood.
Highlights
Innate immunity plays a key role in shaping antiviral defenses
RNA viruses are detected by toll-like receptors (TLR), among other innate immune receptors, TLR7 and TLR8, while TLR3 recognizes double-stranded RNA intermediates formed during viral replication
We explored its effect on the local RNA receptor expression (TLR3, TLR7 and TLR8) and other innate immunity markers (Table 1)
Summary
Innate (or nonspecific) immunity plays a key role in shaping antiviral defenses. RNA viruses are detected by toll-like receptors (TLR), among other innate immune receptors, TLR7 and TLR8, while TLR3 recognizes double-stranded RNA (dsRNA) intermediates formed during viral replication. HeberNasvac (coded CIGB2020 when used as a non-specific immune stimulator) is a mucosal and parenteral therapeutic vaccine; a liquid formulation containing a recombinant hepatitis B core and surface antigens HBcAg and HBsAg, produced at the Genetic Engineering and Biotechnology Center (CIGB) in Havana, Cuba. It contains 100 μg of each antigen in 1.0 mL of saline-phosphate buffer. A phase 1/2 open-label, randomized clinical trial was conducted in 46 hospitalized patients ≥60 years old, of both sexes, with symptoms of respiratory infection (78.3%), or asymptomatic, Evidence (Ref. or RPCEC id.) Study design
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