Limiting dilution analysis of T cell unresponsiveness to mycobacteria in advanced disseminated tuberculosis.

Peripheral blood mononuclear cells from patients with advanced disseminated tuberculosis (Dis-TB) do not respond to purified protein derivative (PPD) measured as cell proliferation, lymphokine production and interleukin (IL)-2 receptor (Tac antigen) expression. Limiting dilution analysis revealed "multi-hit" curves and low frequencies of PPD-reactive T cells in cultures of Dis-TB, and "single-hit" curves and high frequencies of PPD-reactive T cells in cultures of patients with localized form of pulmonary tuberculosis. Moreover, a strict relationship between Tac antigen expression and ability of exogenous IL-2 to enhance bulk culture cell proliferation was observed in Dis-TB patients.