Human immune response mechanisms to TB infection,This work elaborates on the e?ects of cytotoxic lymphocytes (CTLs)
and other immune mechanisms in determining whether a TB-infected individ-
ual will develop active or latent TB. It answers one intriguing question: why
do individuals infected with Mycobacterium tuberculosis (Mtb) experience dif-
ferent clinical outcomes? In addressing this question, we have developed a
model that captures the e?ects of CTLs and the combined e?ects of CD4+
helper T cells (Th1 and Th2) immune response mechanisms to TB infection.
The occurrence of active or latent infection is shown to depend on a number of
factors that include e?ector function and levels of CTLs. We use the model to
predict disease progression scenarios, including primary, latency or clearance.
Model analysis shows that occurrence of active disease is much attributed
to the Mtb pathogen ability to persist outside the intracellular environment
and that high levels of CTLs result in latent TB, while low levels of CTLs
result in active TB. This is attributed to the CTLs' ability to directly kill
infected macrophages and the bacteria inside the infected macrophages. The
study suggests directions for further basic studies and potential new treatment
strategies
