Neisserial surface protein a (NSPA) variants and methods of use thereof

A variant Neisserial surface protein (NspA), wherein the variant NspA comprises an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO:

• 1 and comprises at least one of:
• (a) an amino acid substitution of the lysine (K) at position 72 with an uncharged amino acid or a negatively charged amino acid;
• (b) an amino acid substitution of the aspartic acid (D) at position 77 with an uncharged amino acid or a positively charged amino acid;
• (c) an amino acid substitution of the aspartic acid (D) at position 113 with an uncharged amino acid or a positively charged amino acid, wherein when the amino acid substitution at position 113 is with histidine, the variant NspA does not comprise a substitution of valine at position 112 with alanine;
• and
• (d) an amino acid substitution of the aspartic acid (D) at position 118 with an uncharged amino acid or a positively charged amino acid, wherein the uncharged amino acid comprises:
• a non-polar side chain and is selected from the group consisting of glycine, alanine, valine, leucine, methionine and isoleucine;
• a polar side chain and is selected from the group consisting of serine, threonine, cysteine, proline, and glutamine;
• or a non-polar, aromatic side chain and is selected from the group consisting of phenylalanine, tyrosine, and tryptophan,
• wherein the amino acid substitutions are relative to the amino acid sequence of SEQ ID NO:1.