Background: Neutralizing antibodies toward FVIII replacement therapy (inhibitors) are the most serious treatment-related complication in hemophilia A (HA). A rat model of severe HA (F8(-/-) ) has recently been developed, but an immunological characterization is needed to determine the value of using the model for research into inhibitor development.
Objectives: Characterize the antibody response towards recombinant human coagulation factor VIII (rhFVIII) in the HA rat, following a human prophylactic dosing regimen.
Methods: Two identical studies were performed, which included a total of 17 homozygous HA rats (F8(-/-) , 0% FVIII activity), 12 heterozygous rats (F8(+/-) ), and 12 wild-type (F8(+/+) ) rats. All rats received intravenous injections of rhFVIII at 50 IU kg(-1) twice weekly for 4 weeks. Predosing blood samples were analyzed for binding and neutralizing anti-rhFVIII antibodies at weeks 1-7.
Results: In both studies, antibodies developed after 4-6 administrations of rhFVIII, and neutralizing antibodies reached levels similar to human patients (range 1-111 BU, median 6.0 BU) at the end of the study. There was no significant difference between the two studies or between genotypes in time to response or levels reached for binding and neutralizing antibodies. Interestingly, early spontaneous bleeds were associated with a faster antibody response.
Conclusions: Following intravenous administration of human FVIII, according to a clinical prophylaxis regimen, a robust and reproducible antibody response is seen in this HA rat model, suggesting that the model is useful for intervention studies with the aim of suppressing, delaying, or preventing the inhibitor response. Also, bleeds seem to have an adjuvant effect on the immune response.
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http://dx.doi.org/10.1111/jth.13259 | DOI Listing |
Front Immunol
January 2025
Laboratory of Molecular Cell Biology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
OX40, a member of the tumor necrosis factor (TNF) receptor superfamily, is expressed on the surface of activated T cells. Upon interaction with its cognate ligand, OX40L, OX40 transmits costimulatory signals to antigen-primed T cells, promoting their activation, differentiation, and survivalprocesses essential for the establishment of adaptive immunity. Although the OX40-OX40L interaction has been extensively studied in the context of disease treatment, developing a substitute for the naturally expressed membrane-bound OX40L, particularly a multimerized OX40L trimers, that effectively regulates OX40-driven T cell responses remains a significant challenge.
View Article and Find Full Text PDFFront Immunol
January 2025
Division of Allergy, Immunology and Rheumatology, University of Rochester Medical Center, Rochester, NY, United States.
While durable antibody responses from long-lived plasma cell (LLPC) populations are important for protection against pathogens, LLPC may be harmful if they produce antibodies against self-proteins or self-nuclear antigens as occurs in autoimmune diseases such as systemic lupus erythematosus (SLE). Thus, the elimination of autoreactive LLPC may improve the treatment of antibody-driven autoimmune diseases. However, LLPC remain a challenging therapeutic target.
View Article and Find Full Text PDFFront Immunol
January 2025
Laboratorio de Pediatria Clinica (LIM36), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil.
Introduction: Chemokines and their receptors are essential for leukocyte migration to several tissues, including human milk. Here, we evaluated the homing of T and B lymphocyte subsets to breast milk in response to ongoing respiratory infections in the nursing infant.
Methods: Blood and mature milk were collected from healthy mothers of nurslings with respiratory infections (Group I) and from healthy mothers of healthy nurslings (Group C).
Mol Ther Methods Clin Dev
March 2025
Department of Medicine, Division of Infectious Diseases, Mayo Clinic, Rochester, MN 55902, USA.
Lipid nanoparticles (LNPs) are often liver tropic, presenting challenges for LNP-delivered mRNA therapeutics intended for other tissues, as off-target expression in the liver may increase side effects and modulate immune responses. To avoid off-target expression in the liver, miR-122 binding sites have been used by others in viral and non-viral therapeutics. Here, we use a luciferase reporter system to compare different copy numbers and insertion locations of miR-122 binding sequences to restrict liver expression.
View Article and Find Full Text PDFSudan J Paediatr
January 2024
Department of Pediatrics, Manipal Tata Medical College and Tata Main Hospital, Jamshedpur, India.
Scrub typhus is an acute febrile illness caused by . It usually presents with high fever, lymphadenopathy, rash, organomegaly and an eschar formation at the site of the bite. Doxycycline is the drug of choice usually showing rapid defervescence, but rarely some cases does not respond.
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