The preparation and efficacy of manually emulsified Newcastle disease oil-emulsion vaccines.
Experimental Newcastle disease oil-emulsion vaccines were prepared by manually shaking small quantities of antigen, surfactant, and mineral oil and compared with oil-emulsion vaccines made by the more conventional mechanical methods. Emulsion stability (prolonged emulsification of aqueous antigen) of the manually prepared vaccines was achieved by four different processes and tested for efficacy in broilers. White rock broilers were vaccinated at 3-5 weeks of age and bled at 1- to 2 week intervals thereafter for 8 weeks. Cumulative 8-week hemagglutination-inhibition (HI) mean titers (reciprocals) ranged from 15 to 250 for manually emulsified vaccines and from 18 to 240 for mechanically emulsified vaccines. Eight-week cumulative mean HI responses induced by manually emulsified vaccines were never significantly (P less than 0.05) lower than their specific mechanically emulsified comparison vaccines and were occasionally significantly higher. Highest HI titers were induced when hydrophile-lipophile balances of 7, 9, and 6 were used for the preparation of manually emulsified vaccines. In general, most of the vaccine emulsions were stable for more than 30 days. Vaccine efficacy, however, was not always diminished by poor emulsion stability. These results indicate that manual emulsification can be used for the production of oil-emulsion vaccines of high efficacy that can provide benefits over existing mechanical methods.
Stone
H D
HD
U.S. Department of Agriculture, Agricultural Research Service, Athens, Georgia 30605.
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D002645:Chickens; D004355:Drug Stability; D004655:Emulsions; D006385:Hemagglutination Inhibition Tests; D009521:Newcastle Disease / Q000517:prevention & control*; D009522:Newcastle disease virus / Q000276:immunology*; D013047:Specific Pathogen-Free Organisms; D014611:Vaccination / Q000662:veterinary*; D015164:Vaccines, Inactivated / Q000276:immunology / Q000592:standards; D014765:Viral Vaccines / Q000276:immunology / Q000592:standards*
D000914:Antibodies, Viral; D004655:Emulsions; D015164:Vaccines, Inactivated; D014765:Viral Vaccines