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SHORT COMMUNICATION - Kinetics of T Cell-activation Molecules in Response to Mycobacterium tuberculosis Antigens
Paulo RZ Antas; Eliane B Oliveira; Alexandre S Milagres; Kees C Franken; Tom HM Ottenhoff; Paul Klatser; Euzenir N Sarno & Elizabeth P Sampaio
Abstract
The phenotypic
features acquired subsequent to antigen-specific stimulation in vitro were evaluated
by means of the kinetic expressions of CD69 and CD25 activation molecules on T
lymphocytes and assayed by flow cytometry in response to PPD, Ag85B, and ferritin
in PPD-positive healthy control individuals. In response to PHA, CD69 staining
on both CD4+ and CD8+ T cells became initially marked after 4 h, peaked at 24
h, and quickly decreased after 120 h. For CD25, a latter expression was detected
around 8 h, having increased after 96 h. As expected, the response rate to the
mycobacterial antigens was much lower than that to the mitogen. Positive staining
was high after 96 h for CD25 and after 24 h for CD69. CD69 expression was significantly
enhanced (p < 0.05) on CD8+ as compared to CD4+ T cells. High levels were also
found between 96-120 h. Regarding Ag85B, CD25+ cells were mostly CD4+ instead
of CD8+ T cells. Moreover, in response to ferritin, a lower CD25 expression was
noted. The present data will allow further characterization of the immune response
to new mycobacterial-specific antigens and their evaluation for possible inclusion
in developing new diagnostic techniques for tuberculosis as well in a new vaccine
to prevent the disease.
Keywords
activation markers - CD69 - CD25 - flow cytometry
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