Biology subjects

Whaley, K. J.

Publications and source records attributed to Whaley, K. J..

5 recordsLinked to original sources

bioRxiv2026

The Human Contraceptive Antibody Targets A Semenogelin Galectin-3 N-Linked Glycan Complex on the Sperm Surface

The human contraception antibody (HCA) is a non-hormonal topical contraceptive entering Phase II clinical trials that functions by agglutinating and immobilizing sperm. To date, the HCA epitope has been described as an N-linked polylactosamine glycan motif on CD52, but this assignment has been inferred only by colocalization with anti-CD52 and S19 antibodies in western blots. Here, we report that HCA may instead bind semenogelin-galectin-3 complexes associated with the sperm surface. Semenogelins are gel forming, highly glycosylated proteins, with molecular weights of 50-70 kDa that are cleaved into smaller segments that adhere to sperm during semen liquefaction. In this study, we isolated the HCA antigen from seminal plasma and sperm using an HCA affinity column and identified semenogelin by mass spectrometry. Western blot analysis of seminal plasma showed that HCA binds to a large smear of proteins with a higher apparent molecular mass than CD52, and that these may correspond to semenogelin sequences. Flow cytometric analysis of enzymatically deglycosylated sperm demonstrated that HCA binding requires sperm surface N-linked glycans. However, despite this apparent glycan dependence, HCA failed to bind any glycans represented on a comprehensive glycan microarray. In addition to semenogelin, Galectin-3 was identified in the HCA purified sperm lysates, supporting a model in which HCA recognizes semenogelin-derived glycopeptides that are tethered to the sperm surface via a galectin mediated interaction with an N-linked glycan. We found that O-linked glycan modifications on the semenogelin proteins contain LacNAc motifs that can bind to galectins. Finally, we found that depletion of galectins bound to the sperm surface by competitive inhibitors reduced HCA-mediated agglutination, and this could be rescued by addition of recombinant galectin-3/semenogelin-2 complexes to sperm cultures. Collectively, our findings suggest that HCA's binding site involves a semenogelin-galectin-3 complex anchored to the sperm surface via an N-linked glycan.

immunology↗

bioRxiv2026

Pre-clinical efficacy of a C4BP hexameric IgG Fc fusion protein against Neisseria gonorrhoeae

Gonorrhea is the second most common bacterial sexually transmitted infection and affects about 80 million people worldwide annually. The causative agent, Neisseria gonorrhoeae, has become resistant to almost every antibiotic used for its treatment. There is no licensed vaccine against gonorrhea. Therefore, there is an urgent need to develop novel prevention and treatment strategies to curb the spread of gonorrhea. The gonococcus has evolved several mechanisms to evade complement, a key arm of immune defenses against this pathogen, including binding of the human complement inhibitors Factor H (FH) and C4b-binding protein (C4BP). We previously showed that chimeric molecules fusing the gonococcal binding domains of FH and C4BP to IgG Fc and IgM Fc, respectively, mediate complement-dependent killing of gonococci in vitro and attenuate gonococcal colonization of mouse vaginas when administered topically. Here, we fused C4BP domains 1 and 2, which contain the gonococcal binding region, to IgG Fc bearing the IgM tail-piece to facilitate Fc hexamerization. This molecule, called C4BP-Hexa IgG Fc, showed [~]650-fold greater complement-dependent bactericidal activity on a molar basis than monomeric C4BP-IgG1 Fc. C4BP-Hexa IgG Fc enhanced association with and uptake by human neutrophils in a complement-independent manner. Despite off-target complement activation in solution, C4BP-Hexa IgG Fc reduced both the duration and the bacterial burden of gonococcal vaginal colonization in human FH and C4BP transgenic mice when administered intravaginally daily. In conclusion, we show proof-of-concept of the efficacy of a hexameric C4BP IgG Fc fusion molecule against N. gonorrhoeae, which could aid in the fight against this multidrug-resistant pathogen.

immunology↗

bioRxiv2021

Hexavalent Sperm-Binding IgG Antibody Released from Self-Dissolving Vaginal Film Enables Potent, On-Demand Non-Hormonal Female Contraception

Non-hormonal products for on-demand contraception are a global health technology gap, motivating us to pursue the use of sperm-binding monoclonal antibodies as a strategy to enable safe, effective, desirable, on-demand contraception. Here, using cGMP-compliant Nicotiana-expression system, we produce an ultra-potent sperm-binding IgG antibody possessing 6 Fab arms per molecule that bind a well-established contraceptive antigen target, CD52g. We term this hexavalent antibody "Fab-IgG-Fab" (FIF) to reflect its molecular orientation. The Nicotiana-produced FIF exhibits at least 10-fold greater sperm agglutination potency and kinetics than the parent IgG, while preserving Fc-mediated trapping of individual spermatozoa in mucus. We formulate the Nicotiana-produced FIF into a polyvinyl alcohol-based water-soluble contraceptive film, and evaluate its potency in reducing progressively motile sperm in the sheep vagina. Two minutes after vaginal instillation of human semen, no progressively motile sperm are recovered from the vaginas of sheep receiving FIF-Film. In contrast, high numbers of progressively motile sperm are recovered from sheep receiving a placebo film control. Our work supports the potential of highly multivalent contraceptive antibodies to provide safe, effective, on-demand non-hormonal contraception.

bioengineering↗

bioRxiv2018

Human antibody cocktail deploys multiple functions to confer pan-ebolavirus protection

During the unprecedented 2013-2016 Ebola virus disease (EVD) epidemic in Western Africa and in its aftermath, the passive administration of monoclonal antibodies (mAbs) emerged as a promising treatment approach1-7. However, all antibody-based therapeutics currently in advanced development are specific for a single member of the Ebolavirus genus, Ebola virus (EBOV), and ineffective against divergent outbreak-causing ebolaviruses, including Bundibugyo virus (BDBV) and Sudan virus (SUDV)2,3,5,7. Here we advance MBP134, a cocktail of two broadly neutralizing human mAbs targeting the filovirus surface glycoprotein, GP, as a candidate pan-ebolavirus therapeutic. One component of this cocktail is a pan-ebolavirus neutralizing mAb, ADI-15878, isolated from a human EVD survivor8,9. The second, ADI-23774, was derived by affinity maturation of a human mAb8,9 via yeast display to enhance its potency against SUDV. MBP134 afforded exceptionally potent pan-ebolavirus neutralization in vitro and demonstrated greater protective efficacy than ADI-15878 alone in the guinea pig model of lethal EBOV challenge. A second-generation cocktail, MBP134AF, engineered to effectively harness natural killer (NK) cells afforded additional, unprecedented improvements in protective efficacy against EBOV and SUDV in guinea pigs relative to both its precursor and to any mAbs or mAb cocktails tested previously. MBP134AF is a best-in-class mAb cocktail suitable for evaluation as a pan-ebolavirus therapeutic in nonhuman primates.

microbiology↗

bioRxiv2018

Two-antibody pan-ebolavirus cocktail confers broad therapeutic protection in ferrets and nonhuman primates

All available experimental vaccines and immunotherapeutics1,2 against Ebola virus (EBOV), including rVSV-ZEBOV3 and ZMappTM4, lack activity against other ebolaviruses associated with human disease outbreaks. This year, two separate outbreaks of EBOV in the Democratic Republic of Congo underscored the unpredictable nature of ebolavirus reemergence in a region that has historically experienced outbreaks of the divergent ebolaviruses Sudan virus (SUDV) and Bundibugyo virus (BDBV)5. Here we show that MBP134AF, a pan-ebolavirus therapeutic comprising two broadly neutralizing human antibodies (bNAbs)6,7(see companion manuscript, Wec et al.) could protect against lethal EBOV, SUDV, and BDBV infection in ferrets and nonhuman primates (NHPs). MBP134AF not only not only establishes a viable therapeutic countermeasure to outbreaks caused by antigenically diverse ebolaviruses but also affords unprecedented effectiveness and potency--a single 25-mg/kg dose was fully protective in NHPs. This best-in-class antibody cocktail is the culmination of an intensive collaboration spanning academia, industry and government in response to the 2013-2016 EBOV epidemic6,7 and provides a translational research model for the rapid development of immunotherapeutics targeting emerging infectious diseases.

microbiology↗