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|Title:||Purification and Characterization of Soluble Antigens From the Human Malaria Parasite, Plasmodium Falciparum|
|Author(s):||Shamansky, Lisa Marie|
|Department / Program:||Biochemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Plasmodium falciparum is one of four species of protozoa that cause malaria in humans. It is the most lethal and studies on the immune response to malaria and the development of effective vaccines are crucial.
The research presented here focuses on the blood stage of the parasite life cycle, which is responsible for the clinical manifestations of malaria. It has been shown that immunizing experimental monkeys with in vitro culture medium or partially pure fractions of culture medium can protect them from malaria. The goal of this research was to isolate and characterize some of the parasite antigens being released into the culture medium (exoantigens) that are capable of eliciting protective antibodies.
Two exoantigens were purified from a strain of P. falciparum isolated in Senegal (Geneve SGE-1) of apparent molecular weight 83,000 (83K) and 100,000 (100K). The pure exoantigens were sequenced and found to have homologous N-termini. These exoantigens were glycoproteins and using antibodies raised against the individual pure proteins, were found to be cross-reactive and located on the parasite surface at all developmental stages.
The analogous exoantigen of apparent molecular weight 77,000 (77K) was purified from another strain of P. falciparum isolated in Vietnam (Indochina I). The 77K Indochina I exoantigen was also found to be a glycoprotein on the parasite surface. The 83K Geneve and 77K Indochina I exoantigens share common epitopes by virtue of their cross-reactivity but their N-termini showed no homology. Therefore, the antigen from these two geographically distant strains shows antigenic diversity and common epitopes. These exoantigens meet the criteria for good vaccine candidates and will be tested in vivo.
A third exoantigen of apparent molecular weight 70,000 (70K) was also isolated from the Indochina I strain but it was identified to be human serum albumin. It remains unclear as to whether there is a parasite antigen copurifying with albumin, but this fraction looks promising in a preliminary in vivo protection experiment utilizing experimental monkeys. It needs further investigating.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-15|