An understanding of T cell responses that are crucial for control of Mycobacterium tuberculosis (MTB) has major implications for the development of immune-based interventions. We studied the frequency of purified
protein derivative (
PPD)-specific CD3) cells expressing
interleukin-2 (IL)-2,
gamma interferon (IFN)-gamma,
tumor necrosis factor (
TNF)-alpha and IL-10 in HIV-negative
pulmonary tuberculosis patients (TB,
n=30) as well as in healthy individuals (controls, n=21) from Central Africa. Increased frequencies of
PPD-stimulated CD3+ cells expressing IL-2, IFN-gamma, and
TNF-alpha in TB were seen when compared with frequencies of controls. The presence of type 1
cytokine biased responses in TB patients was supported by a shift in the distribution pattern of
cytokine expression from exclusively IL-2 or
TNF-alpha expression seen in controls towards an increased frequency of IFN-gamma/IL-2 or IFN-gamma/
TNF-alpha co-expression in TB. Higher levels of
PPD-induced IFN-gamma in the supernatants from TB patients than from controls were found, which correlated with its intracellular expression.
PPD was a weak inducer of IL-10 in T cells and insufficient in promoting
cytokine production in TCRgammadelta+CD3+ cells. Non-specific stimulation with PMA and
ionomycin revealed increased frequencies of CD4+ cells expressing IFN-gamma in controls, while expression of IL-2, IL-4, IL-10,
IL-13, and
TNF-alpha was not different. Non-specific
cytokine responses of TCRgammadelta+CD3+ cells were similar in all groups. Pulmonary TB in Central Africa is associated with enhanced expression and secretion of specifically induced
cytokines that are frequently implicated in host defense against MTB.