NRSN1 and infection: Serum samples were collected from all 24 animals at 4 weeks post-infection, to compare the degree of antibody response the mice produced as a result of their infection with either Vmp−, wild-type or Vmp+R. The serum samples from mice that relapsed during their infection (i.e. those infected with wild-type and Vmp+R) reacted to multiple proteins (representative samples for each group are shown in Fig. 4).