Abstract
Malaria disease is a major global health and economic development threat. It
results in approximately 2.7 million deaths annually. There is currently no
vaccine that has been licensed for use against malaria. Studies in animal
models, especially non-human primates can lead to the revelation of possible
immunological mechanisms that can lead to protection or predisposition of the
host to malaria. Plasmodium knowlesi, a simian and human malaria parasite, is
an attractive experimental parasite for malaria research since it can infect
olive baboons (Papio anubis), non-human primates that have similar
host-pathogen interactions to humans. This study was carried out to determine
host immunological profiles provoked in olive baboons during the course of an
infection with Plasmodium knowlesi. A total of eight adult baboons were
intravenously inoculated with overnight cultured blood stage P. knowlesi H
strain parasites. Five of these baboons became acutely infected while the other
three became chronically infected. The immunological basis of this dual outcome
of the infection was determined by measuring circulating cytokine (T helper 1
and T helper 2) and antibody (immunoglobulin G and immunoglobulin M) responses
elicited in the infected baboons on a weekly basis by Enzyme Linked
Immunosorbent Assay (ELISA) for up to six weeks post infection. Generated data
for the first time indicated that acute P. knowlesi malaria is accompanied by
increased concentrations of interferon gamma (IFN gamma), tumour necrosis
factor alpha (TNF alpha) and IL 6 and reduced levels of circulating interleukin
10 (IL 10), IL 4, IL 12, immunoglobulin G (IgG) and IgM in the baboon host.
These results are largely agreeable with data from human studies, thereby
increasing the relevance of the olive baboon - P. knowlesi experimental
infection system for future malaria studies.
Citation
ID:
283584
Ref Key:
michael2012immunity