The arrest of T cell maturation in spontaneously hypertensive rats with a deficient production of thymic factors.

Abstract

Spontaneously hypertensive rats (SHR) which regularly develop hypertension and periarteritis nodosa showed a progressive loss of T cell numbers and functions early in life. When six months old and compared with W rats, the original strain of SHR, they were found to possess a reduced number of thymocytes that formed rosettes with guinea pig erythrocytes and that reacted to anti-Thy1. 1 and anti-T (W3/13) sera. The number of spleen and lymph node cells which reacted to anti-T (W3/13) and anti-helper T (W3/25) sera also decreased. The antibody response of 3-month-old SHR spleen cells to SRBC was about one-fifth that of Wistar rats and progressively declined with age. Subcutaneous grafting of 3-month-old SHR thymus tissues failed to promote differentiation and functions of T cells in the spleen of nude mice, whereas 3-month-old W thymus tissues showed significant recovery of T cell generation and functions. The T cell functions of old SHR was completely restored by grafting adult W thymus tissues but was not restored by grafting adult SHR thymus tissues. Similar recovery was also obtained by the injection of thymus extracts from W thymus tissues. These results suggest that thymic epithelial cell products regulating T cell maturation may decrease in SHR with increasing age.