Study human antibody repertoire in malaria using ultra accurate immune repertoire sequencing

Recently developed Immune repertoire sequencing (IR-seq) has become a useful tool to quantify the composition of the various antigen receptor repertoires, such as antibody and T cell receptor. However, early versions of IR-seq suffer significantly from high amplification bias and high sequencing errors. In this study, we developed an improved IR-seq method that clusters antibody sequences within each molecular identifier group to further separate different Ig transcripts that have been tagged with the same molecular identifier. We first validated this method by using naive B cells sorted to different amounts. Analysis showed that our methods has significantly improved the sequence accuracy and diversity coverage. In addition, it enables us to examine small number of cells, such as memory and plasmablasts. We used this method to study antibody repertoire in children who experienced malaria in Africa. Epidemiology studies showed that children under 5 are most vulnerable to malaria with more than 460,000 cases of malaria caused death in children younger than 5 in Africa in 2012. However, little is known on how immunity toward malaria is established. We sequenced children from as young as 3 month to 10 year old and observed many traits in antibody diversity and mutations that correlate with age and confer protection, demonstrating the power of systems immunology approach to study infection.