Search

SARS-CoV-2 mRNA booster vaccines provide protection from severe disease, eliciting strong immunity that is further boosted by previous infection. However, it is unclear whether these immune responses are affected by the interval between infection and vaccination. Over a 2-month period, we evaluated antibody and B cell responses to a third-dose mRNA vaccine in 66 individuals with different infection histories. Uninfected and post-boost but not previously infected individuals mounted robust ancestral and variant spike-binding and neutralizing antibodies and memory B cells. Spike-specific B cell responses from recent infection (<180 days) were elevated at pre-boost but comparatively less so at 60 days post-boost compared with uninfected individuals, and these differences were linked to baseline frequencies of CD27 lo B cells. Day 60 to baseline ratio of BCR signaling measured by phosphorylation of Syk was inversely correlated to days between infection and vaccination. Thus, B cell responses to booster vaccines are impeded by recent infection., Competing Interests: Declaration of interests The authors declare no competing interests., (Published by Elsevier Inc.)

Messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are highly effective at inducing protective immunity. However, weak antibody responses are seen in some individuals, and cellular correlates of immunity remain poorly defined, especially for B cells. Here we used unbiased approaches to longitudinally dissect primary antibody, plasmablast, and memory B cell (MBC) responses to the two-dose mRNA-1273 vaccine in SARS-CoV-2-naive adults. Coordinated immunoglobulin A (IgA) and IgG antibody responses were preceded by bursts of spike-specific plasmablasts after both doses but earlier and more intensely after dose 2. While antibody and B cell cellular responses were generally robust, they also varied within the cohort and decreased over time after a dose-2 peak. Both antigen-nonspecific postvaccination plasmablast frequency after dose 1 and their spike-specific counterparts early after dose 2 correlated with subsequent antibody levels. This correlation between early plasmablasts and antibodies remained for titers measured at 6 months after vaccination. Several distinct antigen-specific MBC populations emerged postvaccination with varying kinetics, including two MBC populations that correlated with 2- and 6-month antibody titers. Both were IgG-expressing MBCs: one less mature, appearing as a correlate after the first dose, while the other MBC correlate showed a more mature and resting phenotype, emerging as a correlate later after dose 2. This latter MBC was also a major contributor to the sustained spike-specific MBC response observed at month 6. Thus, these plasmablasts and MBCs that emerged after both the first and second doses with distinct kinetics are potential determinants of the magnitude and durability of antibodies in response to mRNA-based vaccination.

The role of commensurability and the interplay of correlated disorder and interactions on vortex dynamics in the presence of columnar pins is studied via molecular dynamics simulations. Simulations of dynamics reveal substantial caging effects and a nonmonotonic dependence of the critical current with enhancements near integer values of the matching field Bphi and 3Bphi in agreement with experiments on the cuprates. We find qualitative differences in the phase diagram for small and large values of the matching field.

We calculate the inelastic light scattering from x rays, which allows the photon to transfer both energy and momentum to the strongly correlated charge excitations. We find that the charge-transfer peak and the low-energy peak both broaden and disperse through the Brillouin zone similar to what is seen in experiments in materials such as Ca2CuO2Cl2.