The present invention relates to a protein comprising a truncated version of the HSV-2 protein mg G-2, said protein comprising: (i) an extracellular region of mg G-2 (EX-mg G-2), or a truncated version thereof, of at least 285 amino acids； said extracellular region or truncated version thereof having at least 90%, 95%, 96%, 97%, 98% or 99% sequence identity (% SI) to a peptide fragment of the corresponding length present in SEQ ID NO: 3； (ii) a truncated transmembrane region of mg G-2 (t-TMR-mg G-2) of 2 to 15 amino acids； said truncated transmembrane region having at least 90% sequence identity (% SI) to a peptide fragment of the corresponding length present in SEQ ID NO: 6； and (iii) an intracellular region of mg G-2 (IC-mg G-2), or a truncated version thereof, of at least 18 amino acids； said intracellular region or truncated version thereof having at least 90% or 95% sequence identity (% SI) to a peptide fragment of the corresponding length present in SEQ ID NO: 8.
