TNFRSF4 and infection: That ‘late’ variants of GL8 should be sensitive to inhibition by anti-CD134 antibody is intriguing and may be significant, given that autoantibodies against CD134 have been detected in a proportion of FIV-infected cats [24•] and these autoantibodies were capable of blocking infection with the CRD2-independent PPR strain of FIV [24•].