Immunity Against Mycobacterium Tuberculosis

Although the production of interferon gamma by CD4+ T lymphocytes may perform a central role in the development of the immunity against Mycobacterium tuberculosis; a subpopulation of T lymphocytes called Gamma-Delta (TCR-) also plays a significant role, not yet completely defined, in mycobacterial infections.

Empirical data support that these cells promote important effector functions; such as proliferation, release of T helper type 1 cytokines and cytotoxic activity; Experimentally, TCR- are capable of expression of the antigen; presenting phenotype characterized by the HLADR, CD80 and CD86 markers. The magnitude ofthis expression is comparable to that observed in dendritic cells, considered professional APCs (antigen presenting cells) standards.

Mycobacterium tuberculosis

Proteins such as perforin, granzyme B and granulisin have the property of lysing cells infecting by M. tuberculosis, or even directly lysing the bacilli; The coinfection of Human Immunodeficiency Virus (HIV) and tuberculosis results in the enhancement of the activity of both diseases.

But the overall ability to produce cytotoxic granules by CD8+ and TCR- cells of vertically HIV-infecting youth; under effective therapy, is comparable to that of healthy individuals in response to mycobacterial antigens; and lower, in TCR- cells, in response to a mitogen; The production of granules for other antigens, such as those derived from Varicella-Zoster virus, has been shown to be lower in infected children than in healthy controls.

Activation marker expression

Activation marker expression, either spontaneous or stimulating by mycobacterial antigen; was increasing in the HIV-infected youth. These results underscore the importance of the careful monitoring of this population, in order to evaluate their ability to respond to mycobacteria and the inflammatory state throughout life.

But in higher expression of CD107a by CD8+ T-lymphocytes in the group of patients in the immunological class 3 may suggest the therapeutic efficacy of cART; with immune restoration. The relevance of this function is potentially high; considering the epidemiological importance of HIV-tuberculosis coinfection. But this phenotype was describing in the professional APCs.