RAG1 and infection: Infection of T-cell deficient (Tcr α/βnull, Tcr γ/δ-null), but not B-cell deficient (Igh6-null) or severe combined immunodeficient (SCID) or Rag1-null mice follows a course of resolution that is similar to fully immunocompetent mice [5], and passive transfer of serum from actively infected immunocompetent mice that have undergone disease resolution (immune serum) into infected SCID mice results in complete resolution of arthritis and carditis, but not clearance of infection [6-8].