Abstract While wild-type measles virus (WT MeV) was demonstrated to induce immune amnesia, it paradoxically still elicited high titers of measles-specific antibodies longitudinally; and much higher than the live-attenuated measles vaccine (LAMV). In order to further understand the longitudinal B and T repertoires, clonotype evolution and gene expression difference in WT MeV and LAMV, we conducted longitudinal single-cell RNA/VDJ sequencing of peripheral blood mononuclear cells (PBMC) from WT MeV and LAMV-infected rhesus macaques (RMs) (n = 3 in each WT MeV and LAMV groups, with 4 timepoints at D0, D11, D42/56, D168/176). Firstly, B cell subtypes (e.g. naïve, memory, activated and antibody-secreting B cells) were successfully annotated in PBMC based on key gene markers and immunogenetic information. Furthermore, preliminary analysis of 1 WT MeV and 1 LAMV revealed interesting differences in the B cell repertoire, including a more diverse usage of IGHV genes, greater isotype switching from IgD/M to IgGs, higher level of somatic hypermutation and later B cell clonal expansion peak in LAMV than WT-MeV infected RMs longitudinally. Interestingly, there was greater T cell clonotype expansion in the WT MeV than LAMV RMs. Our study highlights the differential humoral and adaptive immune responses between LAMV and WT MeV infections, uncovering important immunogenetic understanding in natural infection and vaccination.
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