Pectinaria gouldii and Phragmatopoma lapidosa are marine polychaetes that reside in protective structures built from sand grains bound together using proteinaceous cement secreted from specialized glands. P. gouldii constructs a solitary, ice-cream-cone-like structure. The smaller, gregarious P. lapidosa forms a large, reef-like mound. This study investigates the physical features of these two polychaete biocements, linking structure and function in two marine environments.      The surface structures of hydrated biocement samples were analyzed using atomic force microscopy (AFM), and the surface structures and composition of dehydrated biocement samples were analyzed using scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). Atomic force analyses indicate that (in their native states) the surface roughness, adhesion, and stiffness of P. gouldii biocement are greater than P. lapidosa biocement. The surface of P. gouldii resembled “cottage cheese,” while the surface of P. lapidosa had smoother features. SEM revealed “popped bubble” features that indicated a solid foam-like material for both biocements. EDS confirmed the presence of calcium, magnesium, and phosphorous in both biocements, with varying amounts of these three elements at different locations on the same sample.

Background Live attenuated (LA) vaccines alter immune functions and are associated with beneficial outcomes. We previously demonstrated that yellow fever virus vaccine (LA-YF-Vax) dampens T cell receptor (TCR) signaling in vitro via an RNA-based mechanism. We examined subjects before and after LA-YF-Vax to assess TCR-mediated functions in vivo. Methods Sera and peripheral blood mononuclear cells (PBMCs) were obtained before and after LA-YF-Vax (+/-additional vaccines) or quadrivalent influenza vaccine (QIV). TCR-mediated activation was determined by IL-2 release or phosphorylation of the lymphocyte-specific-Src-kinase. TCR-regulating phosphatase (PTPRE) expression was also measured. Results Compared to pre-vaccination, LA-YF-Vax recipient PBMCs demonstrated transient reduction in IL-2 release following TCR-stimulation and PTPRE levels, unlike QIV control subjects. YFV was detected in (8/14) following LA-YF-Vax. Following incubation of healthy donor PBMCs in serum-derived extracellular vesicles (EVs) prepared from LA-YF-Vax recipients, TCR signaling and PTPRE levels were reduced post-vaccination, even in subjects without detectable YFV RNA. Conclusions LA-YF-Vax reduces TCR functions and PTPRE levels following vaccination. EVs from serum recapitulated this effect in healthy cells. This likely contributes to the reduced immunogenicity for heterologous vaccines following LA-YF-Vax administration. Identification of specific immune mechanisms related to vaccines should contribute to understanding of the “off target”, beneficial effects of live vaccines.