immunology of infectious and parasitic diseases - XXXVII Congress ...

LYMPHOID ORGANS BEHAVIOR AND DINAMIC OF LYMPHOCYTE
POPULATIONS IN EXPERIMENTAL TRYPANOSOMA CRUZI ORAL
INFECTION
JULIANA BARRETO DE ALBUQUERQUE (PG)1; DÉSIO AURÉLIO FARIAS
DE OLIVEIRA1; DANIELLE SILVA DOS SANTOS1; LUIZ RICARDO
BERBERT1; CARLA EPONINA DE CARVALHO PINTO2; JOSÉ JURBERG1;
VANDA CUNHA1; WILSON SAVINO1; JULIANA DE MEIS1
1Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Brazil;
2Immunobiology Institute, Federal Fluminense University, Brazil
Introduction: Trypanosoma cruzi (T. cruzi), the causative agent of Chagas´
disease, infects about 10 million of people worldwide (WHO, 2010). The oral
transmission by ingestion of contaminated food is causing outbreaks in several
Brazilian states and other Latin America countries, and is potentially
unrestricted to endemic regions (Int J Parasitol 39:615-623, 2009). Although we
have previously described regional immune response in lymphoid organs in
intraperitoneal (IP) murine infection (PLoS Negl Trop Dis 3(7):e417, 2009),
there is a lack of data in oral infection/intragastric (IG). Here we analyze
peripheral lymphoid organs behavior and dinamic of lymphocyte subpopulations
in mice infected by IG or IP route. Methods and Results: BALB/c mice were
infected with 5x104 T. cruzi trypomastigotes IP or IG and parasitemia was
followed. After 9 (IP:n=8, IG:n=8), 12 (IP:n=3, IG:n=5), 15 (IP:n=1, IG:n=2), 17
(IP:n=1, IG:n=3) and 27 days (IG:n=3), subcutaneous (SCLN) and mesenteric
lymph nodes (MLN), spleen (Sp) and Peyer patches (PP) were harvested for
cell counting and flow cytometry. Hearts were harvested at 15 dpi (IP:n=3,
IG:n=2) and sections stained with Hematoxilin and Eosin. IG infected mice
presented lower parasitemia and mortality than IP infected mice. In IP infection,
95% of mice died before 18 dpi, while in IG group, 90% were still alive 27 dpi.
SCLN (controls=19,5x106±2,9 cells; IP=57,6x106±9,1 cells; IG =31,8x106±3,2
cells) and Sp (controls=239,1x106±49,7 cells; IP=776,3x106±180,9 cells;
IG=307,5x106±80,3 cells) showed increased number of cells in both groups 9
dpi and similar profile in later days; however, hypertrophy of these tissues as
well as T and CD19+ cells expansion was less evident IG mice than IP. In
mucosal-associated lymphoid tissues, such as PP, after 9 dpi the atrophy was
more evident in IP mice than IG (controls=1,5x106±0,4 cells; IP=0,5 x 106±0,2
cells; IG=0,8x106±0,1 cells), due to decrease in CD19+ and CD4+ cells. MLN
atrophy was only observed in after 15 dpi (controls= 40,1x106±4,5 cells; IP
=11x 106 cells; IG=19,3x106±9,3 cells), due to depletion of CD19+ cells. Heart
histological analysis showed similar alterations in 15 dpi (parasite nests,
inflammatory infiltrate and tissue damage) in both groups, even with the lower