Haemophilus influenzae Protein D antibody suppression in a multi‐component vaccine formulation

Abstract

Nontypeable Haemophilus influenzae (NTHi) has emerged as a dominant mucosal pathogen causing acute otitis media (AOM) in children, acute sinusitis in children and adults, and acute exacerbations of chronic bronchitis in adults. Consequently, there is an urgent need to develop a vaccine to protect against NTHi infection. A multi-component vaccine will be desirable to avoid emergence of strains expressing modified proteins allowing vaccine escape. Protein D (PD), outer membrane protein (OMP) 26, and Protein 6 (P6) are leading protein vaccine candidates against NTHi. In pre-clinical research using mouse models, we found that recombinantly expressed PD, OMP26, and P6 induce robust antibody responses after vaccination as individual vaccines, but when PD and OMP26 were combined into a single vaccine formulation, PD antibody levels were significantly lower. We postulated that PD and OMP26 physiochemically interacted to mask PD antigenic epitopes resulting in the observed effect on antibody response. However, column chromatography and mass spectrometry analysis did not support our hypothesis. We postulated that the effect might be in vivo through the mechanism of protein vaccine immunologic antigenic competition. We found when PD and OMP26 were injected into the same leg or separate legs of mice, so that antigens were immunologically processed at the same or different regional lymph nodes, respectively, antibody levels to PD were significantly lower with same leg vaccination. Different leg vaccination produced PD antibody levels quantitatively similar to vaccination with PD alone. We conclude that mixing PD and OMP26 into a single vaccine formulation requires further formulation studies.Nontypeable Haemophilus influenzae (NTHi) has become the most common cause of acute otitis media (AOM) in children in the US, persistent AOM, and recurrent AOM [1][2][3][4][5]. Treatment of AOM in children has an annual cost of over $6 billion in the US [6,7].NTHi also causes acute sinusitis and conjunctivitis in children and adults and acute exacerbations of chronic obstructive pulmonary disease (COPD) in adults [8][9][10][11]. COPD is the third leading cause of death in the US, affecting at least 24 million people, and US

Expression conditions and characterization of a novelly constructed lipoprotein intended as a vaccine to prevent human Haemophilus influenzae infections

“…Blood was also drawn at week 5. At week 5, mice were challenged by H. influenzae strains as previously described ( 26 , 39 , 40 ). No additional adjuvant was used in immunization as we recently showed that the studied lipidated proteins were self-adjuvanting ( 26 ).…”

Otitis media: recent advances in otitis media vaccine development and model systems

“…The development of multi-protein vaccines is becoming increasingly recognized as necessary for pathogens with highly variable antigens between and within strains ( Watson et al, 2019 ). However, such formulations can lead to antigenic competition, or masking of key antigenic epitopes leading to compromised immune responses to one or more antigens ( Michel et al, 2022 ). This requires analysis of antigens and responses in animal and human trials.…”

“…Given these observations, a vaccine formulated with HMW1/HMW2 and Hia proteins may protect against a broader range of NTHi strains. Pre-clinical studies with these proteins revealed that PD immunization with OMP26 produced lowered antibody responses against PD, however, PD immunization with P6 did not mask PD immune responses ( Michel et al, 2022 ), emphasizing the necessity of compatibility studies when combining antigens. Mice immunized with a truncated adhesin protein F (PF) showed faster clearance of NTHi infections compared to mice immunized with a control peptide ( Jalalvand et al, 2014 ).…”

Epidemic Trends and Biofilm Formation Mechanisms of Haemophilus influenzae: Insights into Clinical Implications and Prevention Strategies

“… 128 Recombinantly expressed protein D and outer membrane protein 26 could induce a robust antibody response after vaccination as a separate vaccine in a mouse model. 129 The fusion protein of E protein and PilA also expressed certain vaccine potential against NTHi biofilm in vitro mouse models. 130 The cationic cholesterol pullulan based (cCHP) - P6 nasal vaccine in the mouse model could also induce effective protective effect in the airway mucosa.…”