ABSTRACT
Potent broad-spectrum antiviral agents are urgently needed to combat existing and emerging viral infections. This is particularly important considering that vaccine development is a costly and time consuming process and that viruses constantly mutate and render the vaccine ineffective. Antimicrobial peptides (AMP), such as bacteriocins, are attractive candidates as antiviral agents against enveloped viruses. One of these bacteriocins is PLNC8 αß, which consists of amphipathic peptides with positive net charges that display high affinity for negatively charged pathogen membrane structures, including phosphatidylserine rich lipid membranes of viral envelopes. Due to the morphological and physiological differences between viral envelopes and host cell plasma membranes, PLNC8 αß is thought to have high safety profile by specifically targeting viral envelopes without effecting host cell membranes. In this study, we have tested the antiviral effects of PLNC8 αß against the flaviviruses Langat and Kunjin, coronavirus SARS-CoV-2, influenza A virus (IAV), and human immunodeficiency virus-1 (HIV-1). The concentration of PLNC8 αß that is required to eliminate all the infective virus particles is in the range of nanomolar (nM) to micromolar (µM), which is surprisingly efficient considering the high content of cholesterol (8-35%) in their lipid envelopes. We found that viruses replicating in the endoplasmic reticulum (ER)/Golgi complex, e.g. SARS-CoV-2 and flaviviruses, are considerably more susceptible to PLNC8 αß, compared to viruses that acquire their lipid envelope from the plasma membrane, such as IAV and HIV-1. Development of novel broad-spectrum antiviral agents can significantly benefit human health by rapidly and efficiently eliminating infectious virions and thereby limit virus dissemination and spreading between individuals. PLNC8 αß can potentially be developed into an effective and safe antiviral agent that targets the lipid compartments of viral envelopes of extracellular virions, more or less independent of virus antigenic mutations, which faces many antiviral drugs and vaccines.
Subject(s)
Bacteriocins , COVID-19 , Encephalitis Viruses, Tick-Borne , HIV-1 , Influenza A virus , Humans , Antiviral Agents/pharmacology , Bacteriocins/pharmacology , Lipids , SARS-CoV-2ABSTRACT
Longitudinal serum samples, nasopharyngeal/nasal swabs and rectal swab samples were collected from eighty-nine individuals (median age 66 y) with SARS-CoV-2 PCR-positive test results at Linköping University Hospital. Samples were collected from the initial visit and thereafter for up to 2 years of follow-up. The presence of serum IgG and IgA against SARS-CoV-2 antigens (S1-spike, nucleocapsid, and NSP3) was analysed. Nasal and rectal swabs were tested for the presence of mucosal IgA against the outer envelope S1 spike and the nucleocapsid protein. Ninety percent of the participants were seropositive for SARS-CoV-2 recombinant proteins on Day 28 after study entry, and all (100%) were seropositive based on samples collected 2 months or later. Almost all (95%) developed serum SARS-CoV-2-neutralizing antibodies that were measurable from 6 to 24 months. The most common antibody responses (both serum IgG, mainly IgG1, and in nasal mucosa IgA) reacted with the S1-spike protein and the nucleoprotein. In samples collected from nasal tissues, IgA anti-S1 spike protein was mainly observed during 2 months of follow-up. In a subpopulation (18% of tested individuals), rectal IgA swabs showed the presence of anti-S1 spike IgA for 1 month of follow-up among the participants studied. .
Subject(s)
COVID-19ABSTRACT
In this preclinical two-dose mucosal immunization study, using a combination of S1 spike and nucleocapsid proteins with cationic (N3)/or anionic (L3) lipids were investigated using an intranasal delivery route. The study showed that nasal administration of low amounts of antigens/adjuvants induced a primary and secondary immune response in systemic IgG, mIL-5, and IFN-gamma secreting T lymphocytes, as well as humoral IgA in nasal and intestinal mucosal compartments. It is believed that recipients will benefit from receiving a combination of viral antigens in promoting a border immune response against present and evolving contagious viruses. Lipid adjuvants demonstrated an enhanced response in the vaccine effect. This was seen in the significant immunogenicity effect when using the cationic lipid N3. Unlike L3, which showed a recognizable effect when administrated at a slightly higher concentration. Moreover, the findings of the study proved the efficiency of an intranasally mucosal immunization strategy, which can be less painful and more effective in enhancing the respiratory tract immunity against respiratory infectious diseases.
ABSTRACT
In this preclinical two-dose mucosal immunization study, using a combination of S1 spike and nucleocapsid proteins with cationic (N3)/or anionic (L3) lipids were investigated using an intranasal delivery route. The study showed that nasal administration of low amounts of antigens/adjuvants induced a primary and secondary immune response in systemic IgG, mIL-5, and IFN-gamma secreting T lymphocytes, as well as humoral IgA in nasal and intestinal mucosal compartments. It is believed that recipients will benefit from receiving a combination of viral antigens in promoting a border immune response against present and evolving contagious viruses. Lipid adjuvants demonstrated an enhanced response in the vaccine effect. This was seen in the significant immunogenicity effect when using the cationic lipid N3. Unlike L3, which showed a recognizable effect when administrated at a slightly higher concentration. Moreover, the findings of the study proved the efficiency of an intranasally mucosal immunization strategy, which can be less painful and more effective in enhancing the respiratory tract immunity against respiratory infectious diseases.