Biology subjects

Lofgren, M.

Publications and source records attributed to Lofgren, M..

5 recordsLinked to original sources

bioRxiv2026

Mannosylated nanoparticle immunogens enhance the circumsporozoite protein-specific B cell response and improve protection against sporozoite challenge

Underprocessed oligomannose glycans on protein nanoparticle immunogens engage the innate immune system through mannose-binding lectin and complement, enhancing immunogen trafficking and B cell responses. However, the extent to which oligomannose glycans directly improve protective immunity has remained unclear. Here we generate a series of CSP-bearing I53-50 nanoparticle malaria vaccine candidates with defined numbers and types of engineered N-linked glycans and systematically evaluate their immunogenicity and protective efficacy. Oligomannose display enhanced early plasmablast and germinal center B cell responses, leading to increased CSP-specific memory B cells, long-lived plasma cells, and durable serum antibody titers. Furthermore, nanoparticles bearing oligomannose glycans conferred the strongest protection against sporozoite challenge. By comparing immunogens with defined glycoforms, we attribute improved immune responses and protection specifically to oligomannose rather than complex or truncated glycans. These results will help guide the development of general strategies for glycan engineering aimed at enhancing the protective efficacy of nanoparticle vaccines.

immunology↗

bioRxiv2025

Exploring the neuroimmune cellular landscape in the skin of subjects with fibromyalgia.

Fibromyalgia (FM) is a chronic disorder involving widespread pain, fatigue, and cognitive impairment. Although its pathogenesis remains uncertain, FM patients exhibit hypersensitivity, reduced intraepidermal nerve fiber density (IENFD), and more recently shown, skin immune dysregulation, possibly manifesting in cutaneous alterations in various cell populations. To characterize the cutaneous cellular landscape in FM, we assessed the sensory profile and skin cell populations across different layers within the same cohort. FM patients, compared to healthy controls (HC), showed lower pain thresholds across multiple body areas, with no differences in thermal detection. While our findings confirm previous reports for reduced PGP9.5+ IENF and increased density in mast cells in FM, we also identified novel changes, particularly in the dermis. We observed elongated thinly myelinated NF200+ fibers and reduced density in non-nerve-associated S100B+ Schwann cells in FM compared to HC. Notably, dermal CD68+ and CD163+ populations were significantly reduced in FM, accompanied by morphological changes. The CD163+ population correlated negatively and significantly against IENFD. These findings suggest that, beyond intraepidermal nerve loss, FM involves broader neuroimmune alterations in the skin, particularly within the dermis, offering new insights into its pathophysiology and establishing a foundation for future studies exploring the functional implications of these changes. SUMMARYAmong the alterations observed in patients with fibromyalgia (FM) are changes in skin innervation and differences in the density of certain immune cell populations. To better characterize FM from an integral perspective, we examined both the sensory profile and the cutaneous cellular landscape of FM patients in comparison with healthy controls (HC). FM patients exhibited lower pain thresholds across multiple body areas, with no differences in thermal detection. Consistent with previous findings, FM skin biopsies revealed reduced intraepidermal nerve fiber density and increased mast cell numbers. Beyond these known alterations, our study identified novel dermal changes, including elongated thinly myelinated NF200+ fibers, reduced density of non-nerve-associated S100B+ Schwann cells, and decreased CD68+ and CD163+ macrophage populations exhibiting morphological alterations. Notably, CD163+ cell density correlated negatively with intraepidermal nerve fiber density, highlighting potential neuroimmune mechanisms underlying the pathophysiology of FM.

immunology↗

bioRxiv2025

Protective immunity against malaria by a nanoparticle CIS43-based junctional vaccine alone or in combination with R21

Repetitive display of the major repeats of the Plasmodium falciparum circumsporozoite protein (PfCSP) is the basis for two WHO-recommended vaccines: RTS,S/AS01 and R21/Matrix-M. Recently, however, the CIS43 monoclonal antibody that preferentially targets the junctional region of PfCSP has been shown to be highly protective in humans, highlighting its junctional epitope as a key vaccine target. Here, we develop a vaccine based on the tandem repeats of the junctional epitope displayed on a self-assembling nanoparticle, and compare this CIS43-based junctional vaccine alone or in combination with the benchmark R21 vaccine, using both B cell analysis and monoclonal antibody isolation to define targeting of the immune response. Comparable reduction in liver burden was observed following vaccination with junctional and R21 vaccines at a dose of 1 g. At a dose of 0.25 g, a modest reduction of malaria-liver burden with the junctional vaccine was observed compared to R21. Further, combining junctional and R21 vaccines induced modestly enhanced protection compared to either vaccine alone. While the R21 vaccine elicited antibodies primarily against the major repeats, the junctional vaccine elicited antibodies against both junctional and major repeat regions. In vivo-B cell analysis and isolation of monoclonal antibodies confirmed differences in vaccine-induced antibody specificities. Altogether, these data suggest the nanoparticle-formatted tandem-repeated CIS43-junctional vaccine to be a promising approach to broaden immunity against malaria, either as a standalone intervention or in combination with R21. HIGHLIGHTSO_LIDeveloped a self-assembling nanoparticle-displayed junctional vaccine of PfCSP based on tandem repeats of the epitope preferentially targeted by the highly protective CIS43 antibody C_LIO_LIThe CIS43-based junctional vaccine at low doses significantly reduced liver burden following malaria challenge in mice C_LIO_LIFollowing either low or high doses of the junctional vaccine in naive mice, adoptively transferred B cells expressing the CIS43 inferred germline sequence yielded a high frequency of germinal center and ASC responses C_LIO_LIThe CIS43-based junctional vaccine elicits antibodies against junctional and major repeat regions whereas the R21 vaccine elicits responses primarily against the major repeat region C_LIO_LIAt low dose, the CIS43-based junctional vaccine given together with the R21 vaccine showed modestly improved control of liver burden compared to either vaccine alone C_LI

immunology↗

bioRxiv2025

Conformation-gated binding drives negative cooperativity in ATP:cob(I)alamin Adenosyltransferase for optimized cobalamin handling

Vitamin B12 (cobalamin) is a high-value yet scarce cofactor required for various metabolic processes, making its efficient handling important for maintaining metabolic homeostasis. While the involvement of ATP:cob(I)alamin adenosyltransferases (MMAB) in the synthesis, delivery, and repair of 5-deoxyadenosylcobalamin (AdoCbl) is well established, the kinetic mechanisms that regulate this process, particularly its negative cooperativity, remain poorly understood. Understanding these mechanisms is key to clarifying how MMAB efficiently uses AdoCbl, prevents resource wastage, and supports bacterial survival in nutrient-limited environments. Using single-molecule relative fluorescence (SRF) spectroscopy, we found that conformation-gated binding is the driving force behind MMABs preference for AdoCbl over hydroxocobalamin and is the underlying mechanism for negative cooperativity. This mechanism significantly slows down the binding of the second equivalent of AdoCbl, favoring the singly bound state. Our findings indicate that MMAB predominantly binds a single AdoCbl, optimizing the AdoCbl loading to methylmalonyl-CoA mutase. Additionally, our SRF approach also serves as a tool to explore other cofactor interactions, such as those between riboswitches and cobalamin derivatives, to provide insights into regulatory mechanisms of cobalamin sensing and gene regulation, which are crucial for bacterial adaptation to changing nutrient conditions. Significance StatementMMAB is important for B12-dependent propionate metabolism in bacteria. Our findings reveal that conformation-driven binding mechanism underlines the negative cooperativity of MMAB, as it favors the binding of the first AdoCbl while limiting further binding. The larger kon for the first site, combined with similar unbinding rates for both sites, could provide a solution for optimizing cobalamin handling and minimize unnecessary waste. Our single-molecule fluorescence approach offers a powerful tool for investigating other dynamic cofactor interactions, providing new insights into regulatory mechanisms in bacterial metabolism.

biophysics↗

bioRxiv2023

Plasma cells are formed in waning germinal centers via an affinity-independent process

Long-lived plasma cells (PCs) secrete antibodies that can provide sustained immunity against infection. It has been proposed that high affinity cells are preferentially selected into this compartment, potentiating the immune response. Here we used single cell RNA-seq to track the development of Ighg2A10 cells, specific for the Plasmodium falciparum circumsporozoite protein (PfCSP) within the germinal center (GC). We identified cells differentiating into memory B cells (MBC) or PCs and estimated their affinity by V(D)J sequencing. While pre-memory cells were of lower affinity than GC B cells generally, the affinity of pre-PC cells was indistinguishable. Rather, a larger proportion of cells differentiated into PCs in waning GCs. These later emigrants replaced early arrivals in the bone marrow allowing the development of a high affinity PC compartment.

immunology↗