PREPARATION OF SOLUBLE PERTUSSIS VACCINE

Multiple discontinuity as a remarkable feature of the development of acellular pertussis vaccines

Development of the Japanese acellular pertussis vaccines (APVs) of the 1980s involved six procedural or conceptual features that were discontinuous with the then-accepted views of how pertussis vaccines should be made and tested. These discontinuities were: modification of the standard intracerebral mouse test for protective potency; use of culture supernates, rather than cells, of Bordetella pertussis as the feedstock for antigen purification; use of haemagglutination as a measure of protective antigen(s); identification of pertussis toxin (PT) as the main protective antigen; complete inactivation of the biological activities of PT by formalin; and the use of a single strain of B. pertussis. Several of these discontinuities had long precedence in the pertussis literature, but the original observations had not been incorporated into the mainstream of pertussis vaccinology and were therefore 'premature'. The APVs, purified from culture-supernates, emerged after a long period of unsuccessful research on the split-cell pertussis vaccines, i.e. those derived from the bacterial cells themselves. There is a brief discussion of why APVs have taken so long to obtain acceptance outside Japan, and of how the listed discontinuities may be explicable in terms of antigen processing by the immune system. General lessions, applicable to vaccines for other infectious diseases, may be learned from this account of how APVs have evolved from whole-cell pertussis vaccines.

Pertussis vaccine: present status and future prospects

Use of killed whole-cell Bordetella pertussis vaccines has been a major factor in control of symptomatic whooping cough (pertussis). In the UK, diminished public confidence in the safety of this vaccine led to a reduction in vaccine acceptance which correlated with an increase in the incidence of pertussis. There is a need for acellular pertussis vaccines of low toxicity which, ideally, will prevent colonization and also protect against the disease symptoms. Vaccine design can rely increasingly on knowledge of the roles of individual bacterial components in the pathogenesis of pertussis. Serotype-specific agglutinogens 2 and 3 (fimbriae) and filamentous haemagglutinin are among surface components of B. pertussis which probably mediate adhesion to the respiratory mucosa. Systemic effects of pertussis can largely be attributed to the lymphocytosis promoting factor (pertussis toxin). Vaccines containing detoxified toxin plus one or more purified adhesins are envisaged at present.

Comparison of seven isolates of Mycoplasma meleagridis

A comparative study of seven isolates of Mycoplasma meleagridis indicated that they were indistinguishable morphologically. Two isolates, E2 and 8M92, induced hemagglutination of red blood cells of several different species while the others did not. Metabolic inhibition, growth inhibition and growth precipitation tests revealed minor differences among the seven isolates. According to these differences, isolates were divided into three groups: antiserum-sensitive isolate 1466, less sensitive isolates N, 8M92, RY3, 529 and E2 and insensitive isolate 1940. One dimensional polyacrylamide gel electrophoresis of cell proteins revealed that all isolates of M. meleagridis had virtually identical patterns and that they were electrophoretically distinct from Mycoplasma gallisepticum and Mycoplasma synoviae. When nonhemagglutinating isolate N, and hemagglutinating isolate E2 were examined by simple immunoelectrophoresis, no differences were detected. However, minor antigenic differences were detected between the two strains by means of two dimensional immunoelectrophoresis.

Studies on respiratory immunization with tetanus toxoid: the role of adjuvants

Aerosol vaccination of mice with purified plain tetanus toxoid does not induce an immune response unless a suitable adjuvant is added.Aluminium phosphate is without effect by aerosol treatment. Killed cells of Klebsiella pneumoniae, although effective, are unsatisfactory owing to the long inhalation period needed.Killed Bordetella perussis cells were found to be an excellent adjuvant. A single aerosol treatment with a toxoid-B. pertussis mixture during a moderate exposure period evoked a considerable immune response. With repeated aerosol treatment of primed mice the addition of adjuvant is not required; booster treatment with plain toxoid is at least as effective.Extracts from B. pertussis cells exert as good an adjuvant effect as the whole-cell vaccine. The remaining cell-wall debris also appears to be an active adjuvant.In combination with constant doses of adjuvant (10(8)B. pertussis cells), the 50% protective doses (ED 50) of toxoid were determined by inhalation and by s.c. injection and were found to be 0.1875 and 0.0625 LFU respectively. This would imply that, as a result of the adjuvant action, the s.c. ED 50 is reduced by approximately a factor of 20; whereas the respiratory ED 50 is decreased by at least a factor of 100.It is suggested that the much more pronounced adjuvant activity in aerosol immunization is associated with the induction of strong cell-mediated hypersensitivity in the respiratory tract.

Heterogeneity among strains of Mycoplasma granularum and identification of Mycoplasma hyosynoviae, sp. n

Twelve filtrable, pleomorphic organisms isolated from swine joints and respiratory tracts had typical colonial and microscopic characteristics of mycoplasmas. They resisted penicillin and did not revert to cell wall-producing bacterial forms in media devoid of bacterial inhibitors. The morphological and growth characteristics of these mycoplasmas were similar to those described previously for Mycoplasma granularum. However, a new name, M. hyosynoviae, is proposed for them since they differed biologically, serologically, and electrophoretically from the prototype strain of M. granularum. M. hyosynoviae required sterols, was stimulated by gastric mucin, and metabolized arginine; however, it did not metabolize urea, ferment glucose, or reduce tetrazolium. The organism produced "film and spots" on horse serum-supplemented medium and produced alpha hemolysis of guinea pig and sheep erythrocytes; however, it did not digest serum, produce phosphatase, or hemadsorb guinea pig or swine erythrocytes. M. hyosynoviae was distinguished from three other swine mycoplasmas, M. granularum, M. hyorhinis, and M. laidlawii, by means of acrylamide gel electrophoresis, growth inhibition, metabolic inhibition, and immunodiffusion techniques. It was also serologically and electrophoretically distinct from 13 additional non-swine mycoplasmas which require sterols and metabolize arginine.

Histamine-sensitizing factor, mouse-protective antigens, and other antigens of some members of the genus Bordetella

The three species of the genus Bordetella-B. pertussis, B. parapertussis, and B. bronchiseptica-have many antigens in common. Studies on representative strains of these species have shown that there are only a few specific antigens in each species. Whole-cell vaccines and extracts from B. pertussis contained specific mouse-protective antigen and a histamine-sensitizing factor. In addition, whole-cell vaccines and some saline extracts protected mice against intracranial challenge with B. bronchiseptica. Cells and a saline extract of B. parapertussis also protected against B. bronchiseptica but not against B. pertussis. Whole cells of B. bronchiseptica protected against B. bronchiseptica, but only one of three saline extracts protected against this challenge. Neither whole cells nor saline extracts from B. bronchiseptica protected against B. pertussis. The antigen in B. pertussis responsible for cross-protection against B. bronchiseptica was less resistant to heat than the protective antigen in B. bronchiseptica. Since histamine-sensitizing factor was not detected in B. bronchiseptica or B. parapertussis cells or extracts, this factor is not required to protect mice against B. bronchiseptica challenge. Whether B. pertussis vaccines protected against B. bronchiseptica by a nonspecific mechanism was not established, but it is clear that the specific antigen responsible for protection against B. pertussis was found only in B. pertussis and not in B. bronchiseptica or B. parapertussis.

Histamine-sensitizing factors from microbial agents, with special reference to Bordetella pertussis

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Endotoxin-induced hypersensitivity to histamine in mice. I. Contrasting effects of bacterial lipopolysaccharides and the classical histamine-sensitizing factor of Bordetella pertussis

Pieroni, Robert E. (Massachusetts Department of Public Health, Boston), Edward J. Broderick, and Leo Levine. Endotoxin-induced hypersensitivity to histamine in mice. I. Contrasting effects of bacterial lipopolysaccharides and the classical histamine-sensitizing factor of Bordetella pertussis. J. Bacteriol. 91:2169-2174. 1966.-The capacity of typhoid and possibly of pertussis endotoxins to induce histamine-shock susceptibility in some of the mice that survive graded doses of these endotoxins was confirmed. It was demonstrated, however, that pertussis endotoxin cannot be the main source of the typical histamine sensitization of pertussis vaccine. The following points are made. (i) With typhoid and pertussis endotoxins as inducers of histamine shock, no systematic relation between deaths and induction dose could be found, and 100% mortality could not be achieved. In contrast, with pertussis protective fraction as inducer, there was clear dose-response regression, with 100% mortality possible. (ii) The major part of the histamine-sensitizing activity of pertussis vaccine or its extracts was destroyed by trypsinization or by heating for 30 min at 100 C. These processes do not affect the histamine-sensitizing activity of the endotoxins. The implication for purified pertussis vaccine with high histamine-sensitization capacity is that endotoxin need not necessarily be present. The significance and possible mechanisms of action of endotoxin-induced histamine sensitivity are briefly discussed.