Neisseria gonorrhoeae (Ng) is the causative agent of the sexually transmitted infection, gonorrhea. Gonorrhea causes over 100 million new cases worldwide annually and adversely affects the reproductive health of women. Ng has become resistant to almost every antibiotic that has been used and has now achieved "superbug" status. Novel vaccines and therapies against this infection are urgently needed. Complement (C) is a critical arm of innate immune defenses against Ng. Ng possesses several mechanisms to subvert C activation and function, including binding of C inhibitors such as factor H (fH) and C4b-binding protein (C4BP) and blocking antibody (Ab) directed against a ubiquitous conserved outer membrane protein called reduction modifiable protein (Rmp). Gonorrhea is characterized by an influx of polymorphonuclear leukocytes (PMNs) into the genital tract, which in concert with Ab and C may facilitate clearance of infection.
In Specific Aim 1 a, we will elucidate the roles of PMNs, C and C receptors in vaccine efficacy. Our vaccine candidate is a peptide mimic (mimitope) of a Ng lipooligosaccharide epitope that elicits bactericidal and opsonophagocytic Ab in mice. Because binding of fH and C4BP to gonococci is human-specific, experiments will be carried out in human fH+/C4BP+ Tg mice, which we believe will more faithfully simulate protection in humans. Vaccine Ab efficacy will be evaluated in fH+/C4BP+ Tg mice that lack either PMNs, C3 (opsonin) or C5a (chemotaxin) receptor.
In Specific Aim 1 b, we will compare temporal changes in the vaginal transcriptome of immunized mice with unimmunized control mice (both infected with Ng) to define transcriptional profiles associated with vaccine- mediated bacterial clearance. Vaccine development against Ng has been hindered by lack of knowledge of the correlates of protection and these data using an unbiased genome-wide approach will inform rational vaccine development.
In Specific Aim 2, we will test the efficacy of a novel immunotherapeutic that binds to and kills Ng by Fc-mediated C activation. We developed the therapeutic based our studies that showed binding of the 3 C-terminal domains of fH to Ng. These domains were fused to IgG Fc to create the therapeutic molecule. Because the C-terminus of native fH binds to host glycosminoglycans (and limits toxic C activation on host cells), we created a mutation in the fH portion of the fH/Fc molecule that abrogates binding to the host, but not to the gonococcal surface thereby maintaining full C-mediated killing of Ng. We will test our lead fH/Fc molecule against antibiotic-resistant Ng in a murine vaginal infection model using fH+/C4BP+ Tg mice. Mice will also be evaluated for renal, ocular and hematologic toxicity.
In Specific Aim 3 we will determine how Abs directed against Ng Rmp that blocks C-dependent Ab killing of gonococci and negatively impact the efficacy of vaccine Ab subverts complement-mediated bactericidal function by vaccine Ab. The molecular basis of blocking of C-mediated killing of Ng will be elucidated. Completion of the proposed studies will represent an important step forward in the development of novel vaccines and therapies against gonorrhea.
Gonorrhea is a major public health problem worldwide that adversely affects the reproductive health of women. Gonococcal isolates that are resistant to almost every antibiotic in clinical use have heralded an era of untreatable gonorrhea - the CDC has conferred superbug status to Neisseria gonorrhoeae. Vaccines and novel treatments for this disease are badly needed. Using the knowledge that we have gained from our studies on complement interactions with N. gonorrhoeae, we have designed a vaccine candidate and an immunotherapeutic against gonorrhea. Studies in this application seek to understand how this vaccine and immunotherapeutic work in animal models. We also aim to define the fundamental host response that clears gonococcal infection (in this instance a mouse model, as a prelude to human studies), which will inform rational vaccine design and evaluation
|Shaughnessy, Jutamas; Gulati, Sunita; Agarwal, Sarika et al. (2016) A Novel Factor H-Fc Chimeric Immunotherapeutic Molecule against Neisseria gonorrhoeae. J Immunol 196:1732-40|
|Gulati, Sunita; Schoenhofen, Ian C; Whitfield, Dennis M et al. (2015) Utilizing CMP-Sialic Acid Analogs to Unravel Neisseria gonorrhoeae Lipooligosaccharide-Mediated Complement Resistance and Design Novel Therapeutics. PLoS Pathog 11:e1005290|
|Gulati, Sunita; Mu, Xin; Zheng, Bo et al. (2015) Antibody to reduction modifiable protein increases the bacterial burden and the duration of gonococcal infection in a mouse model. J Infect Dis 212:311-5|
|Lewis, Lisa A; Gulati, Sunita; Burrowes, Elizabeth et al. (2015) Î±-2,3-sialyltransferase expression level impacts the kinetics of lipooligosaccharide sialylation, complement resistance, and the ability of Neisseria gonorrhoeae to colonize the murine genital tract. MBio 6:|
|Beernink, Peter T; Shaughnessy, Jutamas; Stefek, Heather et al. (2014) Heterogeneity in rhesus macaque complement factor H binding to meningococcal factor H binding protein (FHbp) informs selection of primates to assess immunogenicity of FHbp-based vaccines. Clin Vaccine Immunol 21:1505-11|
|Agarwal, Sarika; Vasudhev, Shreekant; DeOliveira, Rosane B et al. (2014) Inhibition of the classical pathway of complement by meningococcal capsular polysaccharides. J Immunol 193:1855-63|
|Lewis, Lisa A; Vu, David M; Granoff, Dan M et al. (2014) Inhibition of the alternative pathway of nonhuman infant complement by porin B2 contributes to virulence of Neisseria meningitidis in the infant rat model. Infect Immun 82:2574-84|
|Shaughnessy, Jutamas; Vu, David M; Punjabi, Rahi et al. (2014) Fusion protein comprising factor H domains 6 and 7 and human IgG1 Fc as an antibacterial immunotherapeutic. Clin Vaccine Immunol 21:1452-9|
|Lewis, Lisa A; Ram, Sanjay (2014) Meningococcal disease and the complement system. Virulence 5:98-126|
|Lewis, Lisa A; Vu, David M; Vasudhev, Shreekant et al. (2013) Factor H-dependent alternative pathway inhibition mediated by porin B contributes to virulence of Neisseria meningitidis. MBio 4:e00339-13|
Showing the most recent 10 out of 15 publications