Biology subjects

Nazir, J.

Publications and source records attributed to Nazir, J..

4 recordsLinked to original sources

bioRxiv2026

Mucosal ACP subunit vaccine formulated with a small molecule STING agonist drives protective TH1/TH17 responses and serum bactericidal antibodies against Neisseria gonorrhoeae

STING agonists are emerging vaccine adjuvants; however, only cyclic dinucleotides (low permeability and stability) have been tested against pathogenic bacteria. We examined diABZI, a non-nucleotide STING agonist active in human and murine orthologs, combined with the Neisseria gonorrhoeae (Ng) Adhesin Complex Protein, a conserved adhesin and human lysozyme C inhibitor, as a gonococcal vaccine. Intranasal administration of recombinant ACP (rACP)+diABZI accelerated gonococcal clearance, in contrast to rACP or rACP+CpG+MPLA, despite comparable antibody responses. While both diABZI and CpG+MPLA induced TH1, diABZI also induced TH17 polarization. Peptide mapping localized the immunodominant T cell epitopes to the ACP-lysozyme C interface. rACP+diABZI elicited higher human serum bactericidal activity (hSBA), that correlated with Ng clearance, and antibodies that reversed human lysozyme C inhibition and interfered with Ng adhesion and invasion in 3D human vaginal/urethral mucosal models. Passive serum transfer did not recapitulate protection, implicating mucosal antibodies and cellular immunity over circulating IgG.

microbiology↗

bioRxiv2026

An mRNA-Lipid Nanoparticle Platform Encoding the Conserved Outer Membrane Protein BamA Elicits Broadly Cross-Reactive Systemic and Mucosal Antibodies Against Antimicrobial-Resistant Neisseria gonorrhoeae

Neisseria gonorrhoeae (Ng) is the causative agent of gonorrhea, and the global spread of antimicrobial-resistant strains makes vaccine development a public health priority. Although messenger RNA (mRNA) vaccines have transformed protection against viral diseases, the platform remains in its infancy against pathogenic bacteria. Here, we evaluated the immunogenicity and protective efficacy of an mRNA-lipid nanoparticle (LNP) vaccine encoding the highly conserved outer membrane antigen BamA in the female mouse model of lower genital tract infection. We delivered BamA mRNA-LNPs via intramuscular (IM) or intranasal (IN) routes, with or without CpG ODN 2395, and measured antigen-specific antibody responses in serum and vaginal lavage samples. Both routes elicited robust BamA-specific antibodies that recognized diverse Ng isolates, including ceftriaxone-resistant strains. However, neither route accelerated bacterial clearance nor reduced bioburden, nor did either generate serum bactericidal activity. These findings show that BamA mRNA-LNPs are immunogenic but, as formulated, are not protective, and they pave the way for modifications to the construct, adjuvant, and route. To our knowledge, this is the first evaluation of an mRNA vaccine against Ng, establishing the platform as an amenable approach for gonococcal antigen testing. ImportanceNeisseria gonorrhoeae is a high-priority public health threat, and no licensed gonococcal vaccine exists. mRNA-lipid nanoparticle vaccines have transformed antiviral immunization but remain largely untested against bacterial pathogens. This study is the first to evaluate an mRNA vaccine against N. gonorrhoeae, using the conserved, essential outer membrane antigen BamA. We show that BamA mRNA-LNPs delivered by intramuscular or intranasal routes elicit robust, broadly cross-reactive antibodies that recognize diverse isolates, including ceftriaxone-resistant strains, even though the tested formulations did not confer protection in mice. By establishing mRNA-LNPs as a viable platform for gonococcal antigen testing, this work lays the foundation for optimizing constructs, adjuvants, and routes for developing mRNA-based vaccines against gonorrhea and other antimicrobial-resistant bacteria.

microbiology↗

bioRxiv2025

Bridging Gaps in Antibody Responses and Animal Welfare: Assessing Blood Collection Methods and Vaginal Immunity in Mice Immunized with Intranasal Gonococcal Vaccines

Assessing antibody titers and functional responses is essential for evaluating vaccine efficacy, yet the impact of blood collection methods on these immunological assessments remains unclear. Retro-orbital (RO) blood collection is commonly used but significant complications can occur. Increasingly, investigators have adopted alternative blood collection approaches, such as saphenous vein (SV) sampling to improve laboratory animal welfare. This study compared RO and SV sampling in the development of a Neisseria gonorrhoeae (Ng) vaccine, evaluating Adhesin Complex Protein (ACP) and multiple transferable resistance (Mtr) E protein (MtrE) as antigen candidates. Epitope mapping revealed that ACP and MtrE possess multiple, highly accessible B-cell and T-cell epitope clusters, reinforcing their immunological potential. Following intranasal immunization with rACP, rACP+CpG, and rMtrE+CpG, we assessed the specificity, magnitude, kinetics, and functional quality of immune responses elicited by the immunization regimens. Out of 45 comparisons, only eight significant differences were detected in antibody titers, while the human serum bactericidal assays revealed no differences between RO and SV in antigen-immunized groups. However, antibodies elicited by rACP alone or ACP+CpG in SV samples restored 30.05% and 75.2% of human lysozyme hydrolytic activity compared to 19.3 and 59.9 % in RO, respectively suggesting that SV sampling may be more reliable for assessing functional antibody responses. Beyond its immunological advantages, SV sampling reduces stress, minimizes ocular trauma, and improves animal welfare, making it a viable alternative to RO collection. Given its widespread use in vaccine research, standardizing SV sampling could improve data reliability, ethical compliance, and translational relevance in preclinical studies.

microbiology↗

bioRxiv2025

Competence of DNA Tetrahedron and Exosomes as Nanocarriers for Epirubicin drug delivery in Breast Cancer Cells

Epirubicin, a chemotherapeutic agent, is used in treatment of metastatic breast cancer treatment. However, poor intracellular delivery and systemic toxicity are its major limitations. Our study evaluates the use of DNA tetrahedron (TD) structures and exosomes for targeted delivery of epirubicin to enhance its therapeutic efficacy. Increased intracellular concentration of epirubicin was observed in Flow cytometer when delivered via the TD: Epi system compared to free epirubicin. Cell viability assays using Annexin V-FITC and propidium iodide staining revealed higher apoptosis rates in the TD: Epi system. Exosomes, primarily 100 {+/-} 20 nm in size (99% of particles), exhibit a - 28.5 mV zeta potential, ensuring colloidal stability. SEM and TEM confirm their spherical shape, uniform size, and double membrane structure. The TD: Epi system showed the highest efficacy in RT-qPCR analysis, followed by Epirubicin + Exosomes systems and epirubicin alone, further corroborated with western blot results. While exosomes also provided improved delivery and therapeutic outcomes compared to free epirubicin, they were less effective than the TD: Epi system. These results suggest that the TD carrier significantly enhances the delivery and apoptotic efficacy of epirubicin when compared to exosome-based delivery or epirubicin alone offering a promising strategy for improving treatment outcomes. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=178 HEIGHT=200 SRC="FIGDIR/small/637654v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@10e0393org.highwire.dtl.DTLVardef@10ce3eeorg.highwire.dtl.DTLVardef@148552aorg.highwire.dtl.DTLVardef@1cf4664_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗