Humoral immune response profiling is a valuable tool for the identification of potential targets for vaccine development. Immunogenicity studies in clinical trials are usually performed by ELISA assay. However, technical constraints limit the number of antigens that can be simultaneously analyzed.
These limitations can be overcome by employing microarray technology, where antigenic reactivity can be evaluated for a large panel of potential antigens.
For instance, in this study, a Plasmodium Falciparum (Pf) protein microarray was used to analyze the immune response to attenuated active Pf sporozoites vaccine. The Pf protein microarray featured 7455 full-length or fragmented Pf proteins, representing 4805 protein-coding genes and covering 91% of the sporozoite proteome. The His- and NA- tagged proteins were printed on ONCYTE® AVID slides and incubated with serum samples obtained from volunteers enrolled in a double-blind, randomized, controlled trial conducted in Tanzania. Fluorescently-labeled secondary antibodies were used for detection.
The results indicated that a large proportion of the proteome was immunogenic in this study population, with profiles only moderately altered in response to Pf Vaccine immunization. Interestingly, the majority of the immunogenic targets are predicted to be intracellular proteins. This is in stark contrast with similar studies conducted for other parasitic infections and with the widespread assumption that surface proteins, the first point of contact with the host, elicit the strongest immune reaction.
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