Mannheimia haemolytica vector
Inventors
Briggs, Robert E. • Tatum, Fred M.
Assignees
US Department of Agriculture USDA
Publication Number
US-12214031-B2
Publication Date
2025-02-04
Expiration Date
2041-03-02
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Abstract
The present invention relates to modified Mannheimia haemolytica (M. haemolytica) lktCA gene cluster cassettes, compositions comprising such cassettes, methods of using such cassettes and compositions, and kits comprising such cassettes and compositions. Also described herein are Mycoplasma bovis (M. bovis) protective antigens, compositions comprising such antigens, methods of using such antigens and compositions, and kits comprising such antigens and compositions. Also described herein are modified M. haemolytica lktCA gene cluster cassettes engineered to express M. bovis protective antigens, compositions comprising such cassettes, methods of using such cassettes and compositions, and kits comprising such cassettes and compositions.
Core Innovation
The invention relates to modified Mannheimia haemolytica (M. haemolytica) lktCA gene cluster cassettes comprising an insertion of a polynucleotide encoding an additional M. haemolytica leukotoxin neutralizing epitope. These modified cassettes encode two leukotoxin neutralizing epitopes and are useful for the expression of bacterial or viral antigens. The invention also encompasses modified M. haemolytica lktCA gene cluster cassettes engineered to express Mycoplasma bovis (M. bovis) antigens, as well as compositions, vaccines, immunogenic compositions, vectors, bacterial or fungal strains containing these cassettes, and kits comprising such materials. Methods of vaccination using these cassettes and compositions are described.
The problem being addressed is the difficulty in controlling Mycoplasma bovis disease in cattle and other animals. M. bovis causes pneumonia, otitis media, polyarthritis, and mastitis, leading to significant economic losses in dairy, beef, and bison producers. Treatment with antimicrobials is often unrewarding due to late diagnosis and slow progression of symptoms, while current vaccines have yielded mixed results and there is no widely effective commercial product universally available. Additionally, there is a need for improved vaccine platforms that can provide protection against M. bovis, potentially through expression of conserved protective antigens.
Prior art includes use of attenuated M. haemolytica strains with modified leukotoxin gene clusters that are protective against M. haemolytica infection. The innovation here is to create modified M. haemolytica lktCA gene cluster cassettes with an additional leukotoxin neutralizing epitope and to insert polynucleotides encoding M. bovis protective antigens such as EF-Tu and DnaK, either individually or as a chimera. This approach allows the modified M. haemolytica strains to serve as live vectors expressing M. bovis antigens, eliciting immune responses protective against both pathogens when administered as vaccines to animals.
Claims Coverage
The patent contains multiple independent claims covering the modified gene cassette, compositions, and kits involving the modified cassettes.
Modified M. haemolytica lktCA gene cluster cassette with dual leukotoxin neutralizing epitopes
A cassette comprising a modified Mannheimia haemolytica lktCA gene cluster that comprises two polynucleotides encoding leukotoxin neutralizing epitopes: a native leukotoxin neutralizing epitope and an additional leukotoxin neutralizing epitope inserted immediately downstream of the native leukotoxin A start codon.
Compositions comprising the modified cassette
Compositions comprising the modified Mannheimia haemolytica lktCA gene cluster cassette, wherein the composition may be a polynucleotide, plasmid, expression vector, host cell, vaccine, or immunogenic composition, including replacement plasmids and attenuated M. haemolytica strain A1 or A6 bacteria.
Modified cassette further comprising heterologous antigen polynucleotide
The modified Mannheimia haemolytica lktCA gene cluster cassette further comprising at least one polynucleotide encoding a heterologous antigen, which may be inserted upstream of the additional leukotoxin neutralizing epitope.
Modified cassette comprising Mycoplasma bovis antigen
The at least one polynucleotide encoding a heterologous antigen is an M. bovis antigen encoding polynucleotide included in the modified gene cassette.
Kits comprising the modified cassettes or compositions
Kits comprising the modified Mannheimia haemolytica lktCA gene cluster cassette alone or with heterologous antigen-encoding polynucleotides or compositions.
The independent claims cover the invention of a modified Mannheimia haemolytica lktCA gene cassette with two leukotoxin neutralizing epitopes, compositions and bacterial strains containing such cassettes possibly expressing heterologous antigens including M. bovis antigens, and kits containing these materials for vaccination and immunization.
Stated Advantages
The vaccine strains protect calves against virulent Mannheimia haemolytica and Mycoplasma bovis challenge with reduced lung lesions and bacterial load.
Attenuated strains expressing modified leukotoxin are less virulent but still colonize the upper respiratory tract and elicit neutralizing immune responses.
Modified M. haemolytica vectors expressing M. bovis antigens allow targeted immune responses at mucosal surfaces where both pathogens initiate colonization.
The bacterial vector platform allows controlled infectious power, multiple vaccine delivery routes, potent stimulation of innate and adaptive immunity, and relatively low manufacturing costs.
Documented Applications
Vaccines and immunogenic compositions for prevention and treatment of Mycoplasma bovis infection in animals including cattle, sheep, goats, pigs, bison, elk, camels, dogs, and deer.
Use of modified Mannheimia haemolytica strains expressing leukotoxin neutralizing epitopes and M. bovis antigens as live attenuated vaccines administered by oral, intranasal, parenteral, or other routes.
Combination vaccines comprising Mannheimia haemolytica components along with antigens from other respiratory pathogens such as Pasteurella multocida, Histophilus somni, Bovine herpes virus 1 (BHV-1), Parainfluenza virus 3 (PI3V), and Bovine respiratory syncytial virus (BRSV).
Kits comprising the modified Mannheimia haemolytica lktCA gene cluster cassettes, compositions, and bacterial strains for use in immunization protocols against respiratory diseases in ruminants and other mammals.
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