Abstract: A recombinant SARS-CoV-2 S glycoprotein ectodomain trimer is disclosed, including three recombinant protomers each containing at least the SARS-CoV-2 S glycoprotein ectodomain, and wherein: in each protomer, the furin cleavage site is inactivated/disrupted; Arg408 of one of the protomers is covalently linked to Lys378 of another one of the protomers; and Lys947 of one of the protomers is covalently linked to Arg1019 and/or to Lys776 of another one of the protomers.

Abstract: Fusion inhibitor peptides are provided comprising a sequence derived from an HR2 domain. In preferred embodiments, the peptides are capable of oligomerization. Also provided are nucleic acids encoding the peptides, vectors comprising the nucleic acids and host cells transformed with the vectors. The peptides may be used as medicaments. Also provided are methods for expressing a protein comprising one or more transmembrane domain(s) in an expression system. The methods comprise fusing a sequence encoding an 18-mer peptide, or a functional equivalent thereof, to a gene encoding the protein and expressing the resultant gene-fusion product in an expression system.

Abstract: The present invention provides a fusion protein construct (gp41HA) consisting of the ectodomain of the HIV-1IIIB envelope glycoprotein gp41 fused to a fragment of the influenza virus HA2 hemagglutinin protein. Immunization in-vivo via an intraperitoneal prime followed by intranasal or intragastric boosts with gp41HA induces high concentrations of serum IgG antibodies and fecal IgA antibodies that reacted with gp41 in HIV-1IIIB viral lysate and are cross-reactive with gp41 in HIV-1MN lysate. Followup analyses by indirect immunofluorescence showed that both serum IgG and fecal IgA recognized human peripheral blood mononuclear cells infected with either syncytium-inducing (SI) or non-syncytium-inducing (NSI) North American HIV-1 field isolates, but not uninfected cells.

Abstract: The present invention provides a fusion protein construct (gp41HA) consisting of the ectodomain of the HIV-1IIIB envelope glycoprotein gp41 fused to a fragment of the influenza virus HA2 hemagglutinin protein. Immunization in-vivo via an intraperitoneal prime followed by intranasal or intragastric boosts with gp41HA induces high concentrations of serum IgG antibodies and fecal IgA antibodies that reacted with gp41 in HIV-1IIIB viral lysate and are cross-reactive with gp41 in HIV-1MN lysate. Follow up analyses by indirect immunofluorescence showed that both serum IgG and fecal IgA recognized human peripheral blood mononuclear cells infected with either syncytium-inducing (SI) or non-syncytium-inducing (NSI) North American HIV-1 field isolates, but not uninfected cells.