B.FLT.3007-Evaluation of mycobacterium cell wall fraction to reduce Bovine Respiratory Disease

Summary

This project investigated the potential of an innate immune stimulating compound, a Mycobacterium cell wall fraction, to provide short term, broad-based disease protection against bovine respiratory disease (BRD) until protective responses from vaccination develop.

Objectives

• Evaluate the preferred route of administration and safe dosage of the Mycobacterium cell wall fraction.
• Evaluate the ability of the Mycobacterium cell wall fraction to stimulate in-vivo and ex vivo cytokine production, cytokine gene expression, flow cytometry of immune cells and injection site histology.
• Assess the ability of the Mycobacterium cell wall fraction to reduce incidence and/or severity of BRD infections using an artificial infection model.
• Investigate the impacts of Mycobacterium cell wall fraction treatment on feed/water intake during the induction period during the artificial infection model.
• Assess the ability of Mycobacterium cell wall fraction to enhance responses to BRD vaccines when co‐administered at feedlot induction.

Key findings

• Results suggested that mycobacterium cell wall fraction, administered either subcutaneously or intramuscularly, at a dose rate of 2mL or 5mL is ‘safe’ to use in weaner cattle of approximately 220kg liveweight.
• Results from the mechanistic trial suggested that mycobacterium cell wall fraction has anti-inflammatory properties and created an environment conducive to stimulation of both innate and adaptive type responses, but no evidence of a strong pro-inflammatory mediator driven innate response was observed.
• The ability of the mycobacterium cell wall fraction to protect feedlot cattle against BRD either directly, by providing short term protection against the disease during the induction period, or indirectly, by improving the efficacy of BRD vaccination at the feedlot when co-administered at induction was not assessed here as the project was terminated by MLA.

Benefits to industry

This project investigated the efficacy of a mycobacterium cell wall fraction to act as immunostimulant. If demonstrated to be successful during this research project, further research will be required to confirm the value proposition for disease prevention.

MLA action

MLA terminated the research project given interactions between dose, time, and treatment making it difficult to determine a clear mode of action.