rabies antiserum

Metabolic Footprint of Drosophila S2 Cells: Findings During the Production of a Recombinant Rabies Virus Glycoprotein.

Decarli Monize Caiado MC, Dos Santos Diogo Peres DP, Correia Daniela Matilde DM, de Azevedo Amadeus Gomes AG et al.

Over the past 50 years, the Drosophila melanogaster S2 cells have been valued for their ability to synthesize therapeutic molecules at high yield. To further increase protein expression, it is imperative to improve cellular performance, which is intrinsically linked to cell metabolism. Nevertheless, information on S2 metabolism, including pathways, components, and cellular compartments, remains limited, hindering advances in S2 cellular performance. Herein, using a genetically modified S2 cell line expressing the recombinant rabies virus glycoprotein (RVGP), we investigated the stress caused by RVGP production on S2 cells. Batch cultures using wild- and rec-types were performed, and 27 compounds were quantified over 192 h. The extracellular metabolome affected the rec-S2 growth kinetics after RVGP expression was activated. Although RVGP was produced in high amounts, we identified a substrate limitation for rec-S2 cell growth (glutamine), changes in amino acid routes due to RVGP biosynthesis (leucine, serine, glycine, and valine), and metabolites that might be affecting rec-S2 cell growth (acetate, pyruvate, citrate, and malate). Organic acid analysis indicated that malate and acetate production are correlated with RVGP production. This work revealed metabolic correlations in S2 cells that may have direct implications for media optimization and yield maximization, thereby improving S2 performance for scale-up.

Immunogenicity of Single-visit, Two-site Intradermal Pre-exposure Rabies Prophylaxis in Children: A Prospective Interventional Study.

Agarwal Anurag A, Sharma Kanvi K, Mathur Surendra Bahadur SB, Manchanda Vikas V et al.

Rabies remains a major public health concern in endemic countries, particularly among children. Simplified pre-exposure prophylaxis (PrEP) schedules may improve feasibility and access in resource-limited settings and facilitate the integration of rabies vaccination into routine childhood immunization, school-based and community-based vaccination programs in rabies-endemic regions. However, pediatric data on single-visit, 2-site intradermal PrEP regimens remain limited. This study evaluated the immunogenicity and safety of a single-visit, 2-site intradermal rabies PrEP regimen in children 1-18 years of age on days 28 and 180. This prospective single-arm study enrolled healthy children 1-18 years old at a tertiary care center. Participants received a single-visit, 2-site intradermal rabies PrEP regimen with a Vero cell culture rabies vaccine (RABIVAX-S®). Anti-rabies glycoprotein immuglobulin G antibody concentrations were measured using enzyme-linked immunosorbent assay, and rabies virus neutralizing antibody concentrations were estimated by Rapid Fluorescent Focus Inhibition Test at baseline, day 28 and day 180. Participants with rabies virus neutralizing antibody concentrations <0.5 IU/mL at day 28 or day 180 received 2 intradermal booster doses on days 0 and 3 after laboratory results became available and participants returned for follow-up, followed by repeat antibody assessment 7 days after the first booster dose. The primary outcome was seroprotection (≥0.5 IU/mL). Forty-eight children were enrolled, of whom 44 were evaluated on day 28. The enrolled cohort comprised participants 2-15 years old. On day 28, 40/44 (90.9%) achieved protective antibody concentrations (≥0.5 IU/mL). Among 40 participants included in the day 180 analysis, 27 (67.5%) maintained protective concentrations. All participants with insufficient concentrations (n = 4 on day 28, n = 13 on day 180) demonstrated robust anamnestic responses following booster administration, achieving 100% seroprotection within 7 days. The regimen was well tolerated, with only mild local adverse events reported. Single-visit, 2-site intradermal rabies PrEP demonstrated high early seroprotection and preserved immunologic priming despite declining antibody concentrations at 6 months. These findings support further evaluation of simplified pediatric PrEP regimens in larger controlled studies.

CorrespondenceA technique for periocular administration of rabies immunoglobulin.

Kryshtalskyj Michael T MT, Balaguer Arturo A, Morgenstern Kenneth E KE, Burkat Cat N CN et al.

Development and Epitope Characterization of Monoclonal Antibodies Targeting the Rabies Virus P Protein.

Liang Chao C, Chen Yanhui Y, Liu Hongliang H, Zhou Jingming J et al.

Rabies is a fatal zoonotic disease caused by rabies virus (RABV), resulting in approximately 59,000 deaths annually worldwide and posing a serious threat to public health. The RABV phosphoprotein (P protein) plays crucial roles in viral replication, transcription, and immune antagonism; however, its immunogenic properties have not been fully characterized. In this study, the RABV P protein was expressed in an Escherichia coli expression system and used to immunize mice, resulting in the generation of six P protein-specific monoclonal antibodies (mAbs). Using an overlapping peptide-based truncation strategy, two linear B-cell epitopes were identified: 52DMKRLHLDDEKSSNL66 and 177VAPGPPALEWSATNE191. Alanine-scanning mutagenesis revealed that residues D52, M53, R55, L56, and L58 were critical for the recognition of epitope 52DMKRLHLDDEKSSNL66 by mAbs 2D2 and 18G7. Residues G180, P181, and W186 were essential for recognition of epitope 177VAPGPPALEWSATNE191 by mAbs 3D7, 15D8, 16D3, and 16C6. Notably, although some amino acid residues within epitopes P1-5 and P4-2 exhibited high variability among representative RABV strains, the critical residues recognized by these monoclonal antibodies were highly conserved. These findings provide new insights into the antigenic structure of the RABV P protein and may contribute to future studies on its functional characterization, as well as the development of P protein-based diagnostic reagents and subunit vaccines.