[Behaviour of gamma delta TCR+ T cells during the course of nontuberculous mycobacterial infections and proliferative response of host lymphocytes to 65kD heat shock protein].

In order to know the possibility that gamma delta TCR+ T cells induced by Mycobacterium avium complex (MAC) infections participate in the expression of host resistance and in the occurrence of Behçet disease, we examined the behaviour of them in MAC-infected host mice. In both BALB/c (Bcgs; MAC-susceptible) and CBA/JN (Bcgr; MAC-resistant) strain mice, a transient but appreciable increase in the number of gamma delta TCR+ T cells in the host peritoneal lymphocytes was noted around week 1 to 2 after M. intracellulare infection via ip. route. The degree of induction of gamma delta TCR+ T cells was somewhat higher in CBA/JN mice than in BALB/c mice. Therefore, gamma delta TCR+ T cells are partly responsible for the expression of host resistance against the MAC in the early phase of infection. However, the subsequent decrease in the level of gamma delta TCR+ T cells was observed by week 5. Thus, in the case of chronic state of MAC infection, the size of gamma delta TCR+ T cell-pool seems to be in normal level. This suggests that per cell activity of gamma delta TCR+ T cells rather than mobilizing number of them is important factor in the mechanisms for occurrence of allergic diseases including Behçet disease. Although, the early increase in gamma delta TCR+ T cells of peritoneal cells was also observed during the course of M. fortuitum infection, the degree of induction of gamma delta TCR+ T cells in A/J mice (M. fortuitum-susceptible) was in similar level as that in BALB/c mice (M. fortuitum-resistant).(ABSTRACT TRUNCATED AT 250 WORDS)