Impact of malnutrition on plasmodium falciparum specific IgG antibody and T cell responses in malaria infected children in Kilifi County, Kenya
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Date
2016-10
Authors
Waithaka, Albina Thira
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
In Africa, overlap between malaria and under-nutrition results in high child
mortality and morbidity and this is potentially due to immune dysfunction.
Antibody and T cell responses playa major role in malaria immunity, however
the impact of malnutrition on these responses is poorly understood. The
objective of this study was to evaluate the effect of malnutrition on
Plasmodium falciparum specific antibody and T cell responses in malaria
infected children in Kilifi County, Kenya. The study was conducted in Kilifi
County where malnutrition and malaria co-morbidity is prevalent. The study
used 240 archived plasma samples collected from children admitted at Kilifi
County Hospital with malaria. IgG responses to malaria antigens (AMA1,
MSP2, MSP3 and schizont extract) were compared between 120 malnourished
malaria infected and 120 age-matched well-nourished malaria infected
children. To test if soluble proteins present in malnourished children plasma
alter T cell function, peripheral blood mononuclear cells from a healthy adult
were cultured using either plasma from malnourished malaria-infected children
or well-nourished malaria infected children. Proteins in the plasma used in the
T cell culture experiment were identified using liquid chromatography tandem
mass spectrometry Results obtained showed that except for AMAl (p > 0.05)
the proportion of IgG responders to MSP2, MSP3 and schizont extract was
significantly higher in malnourished children (p :s 0.05). The levels of
antimalarial IgG for all the antigens were comparable (p > 0.05). T cells
cultured using plasma from malnourished children had higher proliferative
capacity than T cells cultured using plasma from well-nourished children (p <
0.05). Plasma proteomic profiling also demonstrated that malnourished
children had differentially expressed proteins in comparison to well-nourished
childreri, with notable up regulation. of the inflammatory proteins; ficolin 1,
CIq and lipopolysaccharide binding protein. In conclusion, malnourished
malaria infected children make adequate responses against malaria antigens,
however this may be dependent on the target P. falciparum antigen.
Malnutrition leads to "differential expression of various plasma proteins. Some
of these proteins are involved in inflammation and could be responsible for
promoting non-specific T cell proliferation. Given the presence of CIq, ficolin
and lipopolysaccharide binding protein in malnourished children, the role of
innate immunity in malaria and malnutrition should be considered. The
relationship b~tween various micronutrient deficiencies and protective
antibody. responses an.d T cell function should also be determined.
Description
A thesis submitted in partial fulfillment of the requirements for the award of the degree of Master of Science (Biochemistry) in
the School of Pure and Applied Sciences of Kenyatta University. October 2016