The effect of delayed addition of antigen and 'E' rosetting on the proliferative response to mycobacterial antigens of peripheral blood lymphocytes from normal individuals or from patients with tuberculosis or leprosy.

Some suppressor cells are reported to lose their activity when precultured without stimulus in vitro. We have investigated the role of such suppressors in responsiveness to mycobacterial antigens of peripheral blood mononuclear cells (PBMNC) from patients with leprosy or tuberculosis, or from normal donors. Delayed addition of mycobacterial antigens (Mycobacterium leprae, Mycobacterium vaccae and Mycobacterium tuberculosis), but not of a fungal antigen (Candida albicans) caused enhanced responses using PBMNC from most normal donors, or tuberculoid leprosy (TT/BT) patients. However, the effect was less common using PBMNC from the lepromatous leprosy (BL/LL) group. (P less than 01.01, using M. leprae, relative to the TT/BT group), suggesting that this type of suppression reflects a normal mechanism, which is diminished rather than increased in anergic patients. Delayed addition of antigens to 'E'-rosetting cells did not result in enhanced responses. However, the different effects of 'E'-rosetting on the responses to the mycobacterial antigens of cells from normals, TT/BT and BL/LL patients, suggested that there may be two types of proliferative response to these antigens.