B cell memory responses induced by foot-and-mouth disease virus-like particles in BALB/c mice.

A challenging but critical question is that new foot-and-mouth disease (FMD) vaccines should be to induce B cell memory to provide antibodies for long-term protection. The maintenance of B cell memory is dependent on long-lived plasma cells (LLPCs) and memory B cells. We developed a chimeric FMDV virus-like particles (FMDV-VLPs), fusing VP1-VP4 into HBcAg. In our study, we investigated if or how long B cell memory was induced by FMDV-VLPs in mice. The data showed that FMDV-VLPs can induce memory humoral responses with a high level of total IgG1, IgG2a, IgA, and FMDV-specific IgG antibodies in serum. The persistence of antibody levels in serum could depend on LLPCs. The proportion of LLPCs in CD19+ cells in bone marrow exhibited a dynamic trend with two peaks at 28 days post-immunization (dpi) and 72 dpi, respectively. Additionally, the proportion of memory B cells in CD19+ cells in the spleen increased significantly both at 7 days post primary immunization and at 7 days post -boost immunization. Of note, LLPCs together with memory B cells contribute to the production of FMDV-specific IgG and IgG1. The changes of LLPCs and memory B cells may be related to TNF-α, IL-6 and, CXCL12. Taken together, FMDV-VLPs could induce B cells memory responses. A further understanding of the mechanisms that FMDV-VLPs how we can manipulate the induction and maintenance of memory B cells and LLPCs will promote vaccine design and likely address several challenges to develop FMDV new vaccines in the future.

Synthesis of soluble poly-yne polymers containing zirconium and silicon and corresponding conversion to nanosized ZrC/SiC composite ceramics.

Soluble organometallic polymers containing zirconium and silicon were synthesized by a salt metathesis reaction. The molecular weight of the polymers was measured by GPC and the corresponding structures were identified by (13)C NMR and FT-IR. After heat treatment of the polymers under argon at 1400 °C for 2 h, ZrC/SiC composites with different molar ratios of crystalline phases were obtained and characterized by XRD, elemental analysis, SEM and Raman spectroscopy. The crystalline size of the composites was approximately 100 nm-200 nm and the elements were well distributed at the different sites in the ceramics. The Raman results indicated that the ceramic residue could be considered as ZrC/SiC/C ternary composites.