Prevalence and Levels of Antibodies to Malaria Vaccine Candidate Antigens in Adult Residents of Western Kenya
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Date
2023-11
Authors
Mbayaki, Nelly
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Plasmodium falciparum remains a leading parasite of great public health concern
in sub-Saharan Africa where it is associated with malaria with high morbidity and
mortality cases. Communities in malaria endemic regions are frequently exposed
to plasmodial infections and gradually develop protective immunity which has
been shown in several studies to be mediated in part by antibodies to merozoite
antigens. However, poor understanding of the role of these anti-Plasmodium
antibodies and their contribution to protective immunity against malaria has
hindered the development of an effective vaccine. In addition, few studies have
compared antibody levels in immune adults in different regions which have
different malaria intensities. The current study aimed at determining anti-malarial
[mmunoglobulin gamma (IgG) responses to four P. falciparum merozoite
antigens: merozoite-induced surface protein 1 (MSP-1), ‘merozoite-synthesized
surface protein 3 (MSP-3), merozoite’s glutamate-rich protein (GLURP) and 2
combination of MSP-3+GLURP in the highland and lowland regions of western
Kenya that differ in malaria endemicity. Whole blood samples were collected
from 159 immune adults agaed 15 years and above participating in the ongoing
blood donation conducted by the Kisumu blood bank. Plasma was separated from
whole blood by use of ficoll-paque technique. The prevalence and levels of
specific IgG antibodies against the four antigens were established using enzymeimmunoassay (ELISA). Analysis of various data sets was done using the
statistical package for social sciences (SPSS) software version 21 software and a
P-value less than 0.035 was considered specifically significant. The results showed
that the prevalence of IgG antibodies against MSP-1 was significantly higher
compared to MSP-3, GLURP or MSP-3+GLURP in Western Kenya (p<0.05).
The highest antibody levels were against MSP-3 (p<0.001) which was
significantly higher compared to MSP-1, GLURP or MSP-3+GLURP. There was
no significance difference in the prevalence and levels of antibodies between
individuals residing in the lowland and highland areas in the four antigen groups
(P > 0.05). Based on these findings, this study concludes that there was high
prevalence levels of IgG antibodies against the Plasmodium merozoite antigens,
MSP-3 and MSP-3 + GLURP, in both Jowland and highland regions in Western
Kenya. Future vaccine development therefore, should consider using MSP-3 or
MSP-3 + GLURP, as candidate antigens for malaria vaccines development.
Description
A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Immunology) in the School of Pure and Applied Sciences of Kenyatta University, November 2023
Keywords
Prevalence, Antibodies, Malaria Vaccine Candidate, Antigens, Adult Residents, Western, Kenya