A Study On Preparation Technology Of Haemophilus Influenzae Type B Antigen (Oral Bacterial Extract) Preparation Process

Oral bacterial extract is an immunomodulatory agent for the prevention and treatment of respiratory tract infection. It is able to stimulate the body to produce non-specific and specific immune response. Oral bacterial extract is made of a certain percentage of mixed bacterial antigens that are dissolved by chemical or mechanical methods and extracted. Many domestic and international research results have showed that oral bacterial extract has a good clinical effect on the prevention and treatment of child and adult respiratory tract infections. Products of oral bacterial extract have been listed at home and abroad. The most common products of oral bacterial extract abroad are Broncho Vaxom and Lantigen B. In China, the products of oral bacterial extract of are called bronchitis vaccines, which contain less types of pathogenic antigens and exhibit weak clinical efficacy, causing their less population and promotion.Haemophilus influenzae type b (Hib) is the main pathogen which cause human respiratory tract infections. Before Hib vaccine became available in western countries, more than50%of patients with Hib infection mainly manifested as meningitis characteristic of high incidence, high mortality and high morbidity. Hib vaccines include capsular polysaccharide vaccines and capsular polysaccharide-protein conjugate vaccines. With the worldwide production and application of Hib vaccines Hib infection rate decreases significantly. However, other types of Hi strains consequently become the main pathogens of Hi infection, and the virulence increases significantly. Many data have showed that the oral bacterial extract has a certain effect on the prevention and treatment of the other types of Hi infection.Using a Hib strain (CMCC58534), we obtained a large amount of inactivated bacterial cells by microbial culture. The cells were further lysed with with physical disruption methods to obtain soluble extract of Hib bacterial cells. The effective antigens were then purified and its validity was evaluate by animal experiments.By fermentation test, The fermentation medium formula and technology parameters of the Hib strain were optimized, as well as qualified bacterial cells. The cells were lysed by ultrasonic disruption and and high pressure homogenization. Different pretreatment conditions for ultrasonic disruption and different pressures and disrupting times for high pressure homogenization were applied to test their effects on the Hib cell disruption.The effectiveness of Hib bacterial extract was evaluated by NK cell activity and the hemolytic plaque assays. The experimental animals used in this study were BALB/C mice. We respectively evaluated the effects of Hib bacterial cell extract on the non-specific immunity and specific immunity of the mice. Pysilogical saline is used as negative control and Broncho Vaxom as positive control. The result indicated that Hib bacterial extract had no significant effect on the non-specific immune but had more significant effect on specific immune function in mice.