Asymptomatic plasmodial infection is associated with increased tumor necrosis factor receptor II-expressing regulatory T cells and suppressed type 2 immune responses.

BACKGROUND: In malaria-endemic areas, a proportion of individuals becomes chronic carriers of parasites with few or no clinical signs. There is little information on cellular immune responses in asymptomatic parasite carriers. METHODS: In 80 schoolchildren residing in a malaria-endemic area of Flores Island, Indonesia, T-helper subsets, regulatory T-cell (Treg) frequencies, tumor necrosis factor receptor type II (TNFRII) expression on Tregs, and cytokine responses induced by Plasmodium falciparum-infected red blood cells (RBCs) were measured, and values for asymptomatic infected subjects were compared to those for uninfected controls. To ascertain that alterations found were due to the presence of malaria parasites, the immune responses were analyzed in 16 children before and 1 month after antimalarial treatment. RESULTS: TNFRII expression, a marker of activation on Tregs, was higher during infection but decreased upon treatment. GATA3-positive cells and the level of interleukin 13 secretion in response to P. falciparum-infected RBCs appeared to be suppressed by plasmodial infection, as both increased after antimalarial treatment. TNFRII expression on Tregs correlated positively with TNF in response to P. falciparum-infected RBCs, but this association disappeared following treatment. CONCLUSIONS: Malaria parasites associated with asymptomatic infections seem to result in increased TNFRII expression on Tregs, as well as suppressed Th2 cytokine responses, features that might be important for survival of the parasites in asymptomatic carriers.

Morphometric characterization of Kacang goats raised in lowland and highland areas of Jambi Province, Indonesia.

OBJECTIVE: The objective of this study was to characterize Kacang goats (aged 1-2 years) in the highland (group 1) and lowland (group 2) areas of Jambi Province based on their body measurements and body indices. MATERIALS AND METHODS: A total of 320 goats were collected from lowland (n = 160), and highland (n = 160) areas with sex proportions of 80 bucks and 80 does for each area. Eight body measurements and 12 body indices were used to characterize the Kacang goats from different areas. RESULTS: The research showed that each animal group had one principal component (PC) for body measurements and four PCs for body indices. Thus, the body measurement of rump height (RH) and the body indices of area index, weight index, and thoracic development were suggested as the variables to distinguish the Kacang goats from different areas. However, the canonical correlation (rc) value in the study was approximately 0.30 (low). Therefore, about 59.4% (lowland) and 60.6% (highland) of Kacang goats were characterized by the body measurements, and the body indices were indicated approximately 48.8% (lowland) and 61.2% (highland) of Kacang goats. A cluster analysis of the four Kacang populations revealed that Kacang goats in this study were grouped into a first cluster (Kerinci) and a second cluster (Muaro Jambi, Batanghari, and Sungai Penuh). CONCLUSION: It is concluded that body measurements and body indices cannot characterize the Kacang goats from lowland and highland areas.