Active Mouse Protection Test Research Articles

Effect of vitamin AD3E supplementation for haemorrhagic septicaemia vaccine in laboratory mice

Haemorrhagic septicemia is a fatal disease in tropical countries and annual vaccination is carried out in endemic areas. It is a killed vaccine with mineral oil as the adjuvant. The protection level of animal against infectious agent can be improved by the maintenance of proper nutrient status and vitamin supplementation. This method is followed by many vaccines both in animal and human medicine to enhance both cell mediated and humoral immunity. The objective of this study was to evaluate the logarithmic protection values of haemorrhagic septicaemia (HS) vaccine by vitamin AD3E supplementation in laboratory mice model. Active mouse protection test was performed by Reed and Muench’s method to calculate the logarithmic protection value in HS vaccine using mice model. The logarithmic protection value of non-supplemented group was 6.33 and supplemented groups were 6.73 and 6.75; and were found to be significant in treatment. It was concluded that the logarithmic protection level of vaccine can be significantly improved by the addition of vitamin AD3E in mice and presumption may be the same with livestock in field situation.

Study on Immunity of an Experimental Oil Adjuvant Haemorrhagic Septicaemia Vaccine in Cattle.

An oil adjuvant vaccine (OAV) was prepared from a local strain of Pasteurella multocida. Strain 6:B was cultured and inactivated by formalin. Bacterial pellet was prepared by centrifugation and subsequently adjuvanted by Montannide oil ISA-70. A dose of prepared vaccine containing 3ml (2mg dry weight/ml) was injected into five calves by IM route. Animals were bled before and at 24, 90, 150, and 200 days post-vaccination. Collected sera were used in passive mouse protection test (PMPT). Active mouse protection test (AMPT) was carried out for OAV according to standard method. Results of PMPT showed 100% protection up to 150 days and 66-83% up to 200 days post-vaccination. In AMPT, 4 log of protection was gained. In this experiment the immunity induced by OAV adjuvanted by ISA-70 could protect the calves.

Approaches to the Control of Acellular Pertussis Vaccines

The quality control of acellular pertussis vaccines presents particular problems related to the differences in composition and method of detoxification used in the various type of preparation. These vaccines are not amenable to potency assay by the active mouse protection test used for whole-cell pertussis vaccines and assurance of protective activity is problematic.In contrast, monitoring of these vaccines for safety is relatively straightforward and is centred on assays for the lipooligosaccharide endotoxin, active pertussis toxin and absence of reversion to toxicity of detoxified product. The absence of heat-labile toxin, tracheal cytotoxin and adenyl cyclase toxin is assumed provided that adequate validation of the process has been performed.Confirmation of the antigenic content of the detoxified bulk components is difficult to achieve by conventional binding assays based on monoclonal antibodies because of changes in accessibility of reactive sites post-toxoiding. However, single radial diffusion assay using polyclonal antisera permits estimation of pertussis toxoid (PT), filamentous haemagglutinin (FHA) and pertactin (P69). Dot blot immunoassay can be used for the fimbrial agglutinogens 2 and 3 (Fim 2 and 3) and potentially could also be used to check the composition of final filling lots for PT, FHA, P69 and Fim 2 and 3.Gel electrophoresis and immunoblotting can be applied to monitor purity of purified bulk components and the characteristics of these change after chemical detoxification. Electron microscopy provides a useful semi-quantitative supporting method for checking purity of bulk components. Physico-chemical examination, particularly CD and fluorescence spectroscopy, offer a means of monitoring the consistency of detoxified bulk components.No completely satisfactory method is available for monitoring potency. Immunogenicity assays may be useful for checking consistency but do not necessarily correlate with protection. At present, active protection against aerosol challenge offers the best prospect of a functional assay.

Adjuvant effect of DEAE-dextran on cholera vaccines

Investigations into the effectiveness of DEAE-dextran as an adjuvant of whole cell cholera vaccines (Vibrio cholerae Inaba and Ogawa serotypes) were conducted using two methods: (a) the active mouse protection test, (b) the determination of antibody production in the sera of immunized mice by measuring the level of vibriocidal antibodies, and by an enzyme-linked immunosorbent assay (ELISA). In all tests, the DEAE-dextran-adjuvanted vaccine showed an antigenicity substantially superior to that achieved without adjuvants.

Vaccines against Pseudomonas aeruginosa infection: 1. Experimental studies

An experimental study of several types of vaccines against Pseudomonas aeruginosa has been carried out. Pyoimmunogen, a multi-component vaccine consisting mainly of heat-stable proteins (or polypeptides) with a molecular weight of 20 000 to 60 000, was prepared both by laboratory and production techniques using three or five selected strains of P. aeruginosa. The preparations obtained by both methods were found to be of low toxicity and to induce in mice and rats active immunity against challenge with homologous and some heterologous strains of P. aeruginosa, including the toxigenic PA-103 strain. The Pseudomonas vaccine (PV) was prepared from partly purified water-soluble protein antigens (molecular weight ranging from 10 000 to 100 000) obtained from one (mono-PV) or three (tri-PV) selected strains. Mono-PV was prepared by the method of ultrafiltration and tri-PV — by differential centrifugation. Both types of vaccines proved effective in active mouse protection tests after challenge with homologous as well as with heterologous P. aeruginosa strains. Mono-PV is supposed to induce species-specific immunity against P. aeruginosa infection in mice.

Serum antibody responses to the outer membrane proteins of Bordetella pertussis.

The serum antibody responses to the outer membrane proteins, purified filamentous hemagglutinin, and leukocytosis-promoting factor of Bordetella pertussis were examined in mice and children immunized with pertussis whole-cell vaccine. It was found that, although there were many similarities in the responses of mice and children, there were important differences. Sera from vaccinated mice reacted strongly with purified filamentous hemagglutinin and gave weak or undetectable responses to the components of purified leukocytosis-promoting factor. The converse was found with sera from vaccinated children. Antibodies to leukocytosis-promoting factor may thus be of importance in protecting children against pertussis, although they appear to play no role in the active mouse protection test for vaccine efficacy. These results cast doubt on the value of the mouse as an animal model for the potency testing of extracted acellular pertussis vaccines.

The mouse vibriocidal antibody test: A method for monitoring the potency of cholera vaccines

The mouse vibriocidal antibody test has been developed in order to compare the activities of cholera vaccines by the use of antibody levels induced in mice by vaccination. Antibody titres were measured by a new vibriocidal test in which tetrazolium salt was used to produce a colour change in growing bacteria and simplify the determination of the endpoint. The whole test was performed in microtitre plates. The mouse vibriocidal antibody test gave reproducible estimates of potency and was serotype specific. Potentcies estimated by the test were in agreement with those provided by the active mouse protection test, although both tests gave estimates with wide confidence intervals. The mouse vibriocidal antibody test was considered to be potentially useful in determining potencies of cholera vaccines and, in particular, as a screening test for vaccines with little or no activity.

A comparative study of gastric mucin and commercial baker's yeast as virulence-enhancing agents in the typhoid mouse protection test

The virulence-enhancing effects of gastric mucin and of commercial baker's yeast were compared by active mouse protection tests of two typhoid vaccines, one preparation serving as a reference preparation. The potencies of the two vaccines differed significantly, to a very similar degree, with both virulence-enhancing agents, indicating that under defined conditions commercial baker's yeast may be substituted for mucin in the active mouse protection test.

Stability of cholera and typhoid vaccines

Fluid plain and adsorbed and freeze-dried cholera and tyhpoid vaccines of different composition were examined for thermostability by potency testing (by active mouse protection tests) after exposure to 37 degrees C for 1, 2, 3, 4, 8 and 12 weeks. Loss of potency was evaluated by comparison with samples stored at 4 degrees C. The fluid plain cholera vaccine remained fully potent for 1--3 weeks, the adsorbed vaccine for at least 4 weeks. The fluid typhoid vaccines showed greater thermosensitivity than the fluid plain cholera vaccine. The freeze-dried cholera and typhoid vaccines were both very stable, retaining fully potency after at least 12 weeks' exposure to 37 degrees C. It should be emphasized that the above results apply exclusively to vaccines prepared by the methods used by the authors and formulated to identical compositions.

Comparative antigenicity testing of cholera vaccines by application of hog gastric mucin and ferric ammonium citrate

The antigencity of different cholera vaccines was compared by active mouse protection tests, using hog gastric mucin and ferric ammonium citrate as virulence-enhancing agents. The results were evaluated by analysis of variance (parallel line assay). No significant difference was found between the vaccines with either mucin or ferric ammonium citrate used as virulence-enhancing agents. However, the marked difference found in the relative potencies and, especially in the 95% fiducial limits, served as a reminder of the importance of careful checking and mathematical-statistical evaluation of all parameters in each case of vaccine standardization.

Assay of cholera vaccine potency

The Feeley-Pittman active mouse protection test was examined as a method of estimating the potency of cholera vaccines in the laboratory before their administration in the field. With strict standardization of conditions, it was found to give reproducible estimates both within and between laboratories. Ninety-one (79%) of the 115 assays performed gave statistically valid results according to the criteria of the authors, and the pooled valid results showed that it was possible to distinguish in the laboratory between a wide range of different vaccine potencies. The potency estimates of those cholera vaccines used in field trials correlated well with their ability to protect against the disease, and the commercially available vaccines tested were as potent as the international reference preparations. The Feeley-Pittman test was recommended for routine laboratory vaccine assay.

Vi-negative strains of Salmonella typhosa: attempts to induce W-V reversion and the use of non-Vi strains in evaluating typhoid vaccines.

Tully, Joseph G. (Walter Reed Army Institute of Research, Washington, D.C.) and Julius A. Currie. Vi-negative strains of Salmonella typhosa: attempts to induce W-V reversion and the use of non-Vi strains in evaluating typhoid vaccines. J. Bacteriol. 84:747-753. 1962.-Repeated attempts have been made to detect reversion of several W-form Salmonella typhosa strains to Vi antigen-containing cultures. Passage of the O-901, H-901, and Ty2W cultures through various mouse strains did not result in the recovery of V-form typhoid bacilli. Rabbits immunized repeatedly with non-Vi strains of typhoid bacilli, or with W cultures successively passed through mice, did not respond with Vi antibody formation. Attempts also were made to detect reversion of non-Vi strains passed in broth and plate cultures to which heat-killed Vi antigen-containing strains had been added. No evidence was obtained that the selection of Vi-containing cultures had been enhanced. The non-Vi typhoid strains employed in this study thus appeared to be stable W-form cultures. Viable-cell vaccines and acetone-killed and dried (AKD) vaccines of V- and W-form S. typhosa were compared in active mouse protection tests against intraperitoneal and intracerebral challenges with V- and W-form typhoid strains. Only Vi-containing cultures effectively protected mice against virulent V-form challenges, regardless of the route utilized. Greater quantities of both viable-cell and AKD vaccines prepared from non-Vi strains were required for protection against V- as well as W-form S. typhosa challenges.