ABSTRACTS – ORAL PRESENTATIONS - AMCA, spol. s r.o.

could be achieved via the activation of Treg‘s suppressive function.
Here we report a more than tenfold increase in the frequency of Tregs following CD3/
CD28 co-stimulation within a week of in vitro cultivation of human Tregs, irrespective
of their genotype. Somewhat decreased kinetics of Treg expansion were observed on
day 5 in CD4 + T cells in the person homozygous for the CCR5 gene variant D32 (21.5%
versus 74.7% in wt) (Fig. 1). Importantly, similar the treatments, which lead to the
activation of Treg function in humans – e.g. anti-CD3/CD2/CD28 stimulation (Hagness
et al. 2012) simultaneously drove expansion of Tregs e.g. using anti-CD3/CD28 and/
or IL-2 (see Fig.1). Our study demonstrates a useful tool for in vitro evaluation of Treg
function and facilitates further understanding of the mechanisms of immunological selftolerance,
which may also provide insights into how strong immune responses, such as
graft rejection, can be restrained and engraftment of HIV resistant cells in HIV patients
with AIDS lymphoma or leukemia can be augmented.
References
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T.: Evidence for the cure of HIV infection by CCR5 D32/ D32 stem cell transplantation. -
Blood 117: 2791-2799, 2011.
Hagness, M., et al.: Kinetics and activation requirements of contact-dependent immune
suppression by human regulatory T cells. – The Journal of Immunology 188: 5459-5466,
2012.
McNutt, M.: News of the Week, Evidence mounts for two more HIV cures. Science 341:
114, 2013.
Peterson, C.W., Younan, P., Jerome, K.R., and Kiem, H.P.: Combinatorial anti-HIV gene
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702, 2013.
Wing, K., Sakaguchi, S.: Regulatory T cells exert checks and balances on self tolerance
and autoimmunity. Nature Immunology 11: 7-13, 2010.
Caption to figure
Fig. 1. Tregs homozygous for the CCR5 gene variant
D32 were expanded in vitro tenfold after CD3/
CD28 activation in the presence of exogenously
added recombinant IL-2. CD4 + T-cell expression
of the activation marker CD25 and lack of CD127
expression was evaluated by flow cytometry in
cells homozygous in the CCR5 gene variant D32
(CCR5 D32/ D32) or wt (wt/wt) and activated in
vitro by CD3/CD28 mAbs coated on plastic in the
presence of exogenously added IL-2. In vitro expansion of Tregs lead to an approximately
tenfold enrichment, irrespective of genotype, under the conditions mentioned above as
monitored after seven days of cultivation.
150 Analytical Cytometry VII