Precision biologics – The catalysts of change in disease prevention

Emerging protein technologies, like precision biologics, have the potential to provide targeted disease prevention against costly pathogens. Precision biologics will be best delivered by their incorporation with other feed additives, such as alternative proteins or probiotics. This takes a synergistic approach to combating disease while meeting the growing demand for protein sources.

Dr. Sarah Zaytsoff
Poultry Scientist
NovoBind Livestock Therapeutics

Industry and researchers continue to discover and invest in the development of alternatives to antibiotics. The best solutions for livestock and aquaculture production in the absence of antibiotics will be a combination of varying strategies, from management to feed additives that strengthen gut health. Yeast extract, probiotics, and algae are examples of these feed additives that indirectly prevent diseases by improving gut health and intestinal immune function. However, many health enhancing feed additives lack specificity for particular pathogens when considered as antibiotic alternatives. This underscores the need for targeted solutions that not only prevent diseases but also uphold sustainability without posing risks of spreading antimicrobial resistance.

Antibodies are proteins produced by organisms with adaptive immune systems in response to an infection. These protective proteins have the ability to bind specifically to a component of a pathogen. Similarly, NovoBind’s precision biologics (NBXs) are small proteins that are derived from the binding region of a unique single-domain antibody type found in camels and llamas and are also known as nanobodies. Like conventional antibodies, NBXs bind in a specific and strong manner to its target to neutralize their function. NovoBind pioneers groundbreaking technology in the development of unique nanobodies designed to target the virulence factors found in pathogens. These virulence factors are crucial components that pathogens employ to initiate and promote infections. The company’s innovative approach encompasses a meticulous process that begins with the immunization of a llama using a purified virulence factor. Over time, blood samples are collected, and proprietary phage display technology comes into play, generating a multitude of NBX sequences. Top performing NBXs are then selected for clinical studies by screening for binding strength, stability in gut fluid, and functionality in in vitro assays.

Traditional antibiotics frequently kill or impair bacterial growth, which puts pressure on the development of resistance. This occurs when certain bacteria naturally acquire mutations that enable them to survive exposure to antibiotics. These resistant bacteria then become dominant in the environment and outcompete bacteria that are still susceptible to antibiotics. Thus, it is critical that a sustainable alternative to antibiotics must limit selective pressure for resistance to develop. NBXs are an ideal alternative because they function by disrupting the host-pathogen relationship, rather than killing or preventing bacterial growth. This limits the development of resistant pathogens and creates a sustainable platform as a targeted antimicrobial.

For a pathogen to successfully incite an infection, it must have the ability to move closer to host, colonize, and either release toxins or invade host cells. NBXs function by targeting and binding to virulence factors of pathogens, ultimately disrupting the host-pathogen interaction. Pathogens utilize various virulence factors to incite infection, including flagella, adhesins, toxins, or enzymes. Flagella and adhesins are important tools for pathogens to move in the intestine and approach the targeted host cells. Once near the host, pathogens can release toxins, infiltrate tissue damage, and initiate inflammation through interactions with host receptors. Pathogens can also secrete enzymes that may degrade components in the gut and subsequently utilize it as an energy source to grow and colonize. Collectively, NBXs work by strategically limiting a pathogens ability to colonize, interact with host, and ultimately prevent the onset of infection.

NovoBind is exploring various methods for delivering NBXs in-feed for livestock and aquaculture.

1. Semi-purified yeast extract.
The production of NBXs is streamlined and cost effective through the use of a conventional yeast system. From these yeasts, NBXs are extracellularly expressed, semi-purified from culture supernatant, and freeze-dried into a powder. The protein-rich powder is further microencapsulated to protect it during feed production and facilitates targeted delivery to a specific region of the intestine. This strategy further minimizes cost as the dose required is reduced.

2. Delivery by a probiotic.
Probiotics have been shown to provide tremendous health benefits to both livestock and aquaculture production. NovoBind has engineered a probiotic strain to produce, secrete and deliver a NBX at the potential infection site, providing synergistic impacts to producers without additional costs.

3. Combine with alternative protein sources.
The NBXs can be seamlessly integrated into existing feed additives or protein sources already used in animal feed. These can include yeast cell-wall extracts, algae, or plant material, such as corn or wheat.

Studies have been conducted with Southern Poultry Research Group to test the efficacy of NBXs against necrotic enteritis caused by Clostridium perfringens. NovoBind has evaluated the virulence factors of C. perfringens and selected two antigens for our NBXs to target. These antigens are well described in the literature to be critical in the manifestation of disease. Two formulations of NBXs were tested in the study: (1) a microencapsulated nanobody (ME-NBX) and (2) a probiotic secreting NBX (PB-NBX) (Table 1).

Figure 1. Bird mortality due to necrotic enteritis from Days 0-28.

The ME-NBXs from semi-purified yeast supernatant showed a 53% reduction in necrotic enteritis caused mortality (Figure 1). Additionally, the ME-NBX showed equal efficacy as the antibiotic growth promoter (AGP) control, signifying oral delivery of NBXs is an effective alternative.

Strikingly, the probiotic secreting NBX showed superior performance. While the probiotic alone (PB) with no NBX showed a 37% reduction to necrotic enteritis caused mortality, the probiotic secreting NBX (PB-NBX) reduced death by necrotic enteritis by an impressive 68%, outperforming the AGP treatment. This validates the synergistic potential of combining the NBXs with a probiotic. Therefore, for farmers already using probiotics in practice, there would be no extra cost to achieve an additional 50% reduction in mortality when switching to a probiotic that delivers NBXs.

The efficacy findings are not only encouraging but also highlight the potential of the NBX technology. Looking forward, more clinical trials are crucial to refine the application of NovoBind’s precision biologics against necrotic enteritis in poultry. As demonstrated, NovoBind’s NBXs are most effective when combined with other health promoting feed additives, as there is no magic bullet in reducing disease. Collaboration across industry is essential to ensure we continue to meet the worlds demand for protein sources.

About Sarah Zaytsoff
Sarah Zaytsoff obtained her PhD in poultry intestinal health from the University of Alberta. Her doctoral research focused on how stress can influence the onset of necrotic enteritis in poultry and worked on microbial based alternatives to antibiotic growth promoters. Since graduating, Zaytsoff has been working as a Poultry Scientist at NovoBind Livestock Therapeutics. Her role involves running the probiotic department and managing innovation projects related to nanobody delivery.