Michael GicheruJoshua MutisoSimon KariukiMbayaki, Nelly2024-05-312024-05-312023-11https://ir-library.ku.ac.ke/handle/123456789/27983A 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 2023Plasmodium 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.enPrevalenceAntibodiesMalaria Vaccine CandidateAntigensAdult ResidentsWesternKenyaThesis