Nipah virus immunogens and their use

An immunogen, comprising:

• a recombinant Nipah virus (NiV) F ectodomain trimer stabilized in a prefusion conformation by one or more amino acid substitutions in protomers of the trimer, the amino acid substitutions comprising one or more of the following:
• cysteine substitutions at NiV F positions 104 and 114 that form a non-natural intra-protomer disulfide bond, or cysteine substitutions at NiV F positions 114 and 426 that form a non-natural intra-protomer disulfide bond;
• a proline substitution at NiV F position 191;
• a phenylalanine substitution at NiV F position 172;
• a glycine substitution at NiV F position 70;
• and
• a deletion of NiV F positions 102-113 with positions 101 and 114 linked by a glycine-serine linker;
• wherein the NiV F positions are according to the reference NiV F sequence set forth as SEQ ID NO:
• 52.