Distinct repertoire expansion patterns during affinity maturation of antigen responding camelid-derived single-domain VHH antibody

It is difficult to link antibody repertoire expansion with changes in the physical characteristics of antigen-responding antibodies as correct light-chain and heavy-chain matching and conventional antibody production are laborious. Utilization of single-domain antibody solved these problems. A blood of immunized alpaca was collected weekly for three months for antibody repertoire analysis. The sequences processed to cluster and recombinant antibodies were generated to determine whether the clusters respond to antigens. The repertoire expansion in most of the antigen-responding clusters exhibited distinct patterns as compared to that of antigen irrelevant clusters. In addition, the sequences at the tips and root in the molecular phylogenetic cluster tree have strong and weak antigen affinity, respectively. These features may be utilized to predict clusters of antigen-binding antibodies and physical characteristics of antibodies. One-Sentence SummaryThe clusters of antigen responding single-domain antibodies exhibited distinct repertoire expansion patterns.