Effect of histamine-sensitizing factor of Bordetella pertussis on pharmacologic response of rat atria

The effects of sensitization with the histamine-sensitizing factor (HSF) of Bordetella pertussis as well as Bordetella vaccines on a pharmacologic response in rat heart preparations were determined. In normal rats the spontaneous beating of atria in vitro through the positive inotropic action produced by the addition of epinephrine was inhibited immediately by addition of acetylcholine, whereas in the B. pertussis vaccine-treated rats the exciting atria were scarcely inhibited by acetylcholine. Neither B. parapertussis nor B. bronchiseptica vaccines induced such an altered atrial response in rats. Of the B. pertussis cell components purified HSF induced the altered response at the minimal dose of 0.1 microgram per rat, and a dose of 1 microgram or more produced the maximal change. This altered atrial-inducing activity of HSF was inactivated by heating at 63 C for 30 min, and was neutralized by anti-HSF rabbit serum. The altered response rose quickly in 1 day after i.v. injection of 1 microgram of HSF, reached a plateau in 3 to 5 days, which lasted at least 14 days, and disappeared completely 56 days later. HSF failed to produce directly any functional damage to the beating atria in vitro, and to induce the altered response of the normal rat atria by incubation with as much as 10 microgram of HSF per bath (50 ml) for 4 hr. A trace stimulation was found in the normal rat atria as well as in perfused frog hearts, if HSF was given directly at a dose of 20 microgram per bath.     

Correlation between growth rate and loss of histamine-sensitizing factor during antigenic modulation in Bordetella pertussis

The pattern of loss of histamine-sensitizing factor (HSF) during antigenic modulation of Bordetella pertussis in Hornibrook medium was examined. The aim was to determine the possible underlying mechanism involved in modulation. Normal (X-mode) B. pertussis cells were grown in Hornibrook medium in which 0.5% (w/v) NaCl had been replaced with 0.5% (w/v) MgSO4. 7H2O (C-medium). At various time intervals during growth, the viable cell numbers and optical densities of both cultures in the X- and C-media were estimated. Whole cells were harvested from the cultures at the same time intervals and aliquots from the cultures were assayed for the levels of their histamine-sensitizing properties. Correlation of the increase in viable cell numbers with rate of loss of histamine-sensitizing activity in both the cells and whole cultures indicated that components responsible for the histamine-sensitizing activity were not synthesized during modulation. Moreover, the loss of HSF from B. pertussis cells was faster than can be explained by dilution of the original factor in the inoculum among progeny cells. Modulation may involve cessation of synthesis and selective degradation or denaturation of some envelope polypeptides immediately upon inoculation of normal X-mode B. pertussis cells into C-medium.     

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.     

Antigens of Bordetella pertussis. IV. Effect of heat, merthiolate, and formaldehyde on histamine-sensitizing factor and protective activity of soluble extracts from Bordetella pertussi.s

Munoz, J. (Rocky Mountain Laboratory, Hamilton, Mont.), and B. M. Hestekin. Antigens of Bordetella pertussis. IV. Effect of heat, Merthiolate, and formaldehyde on histamine-sensitizing factor and protective activity of soluble extracts from Bordetella pertussis. J. Bacteriol. 91:2175-2179. 1966.-Both histamine-sensitizing and protective activities of soluble preparations from Bordetella pertussis cells are destroyed by heating at 80 C for 0.5 hr. The histamine-sensitizing activity appeared to be more susceptible to inactivation by heat than the protective activity. Formaldehyde in a final concentration of 0.5% rapidly diminished the histamine-sensitizing ability of saline extract (SE) held at 37 C. The protective activity was clearly more resistant to inactivation by formaldehyde at similar temperature. The inactivating action of formaldehyde was slower when the concentration of SE was increased or when the mixture was kept at 2 to 5 C. Merthiolate in a final concentration of 1:10,000 had no demonstrable deleterious effects on either protective or histamine-sensitizing activity of SE.     

Antibodies binding diverse pertactin epitopes protect mice from Bordetella pertussis infection

Infection by the bacterium Bordetella pertussis continues to cause considerable morbidity and mortality worldwide. Many current acellular pertussis vaccines include the antigen pertactin, which has presumptive adhesive and immunomodulatory activities, but is rapidly lost from clinical isolates after the introduction of these vaccines. To better understand the contributions of pertactin antibodies to protection and pertactin''s role in pathogenesis, we isolated and characterized recombinant antibodies binding four distinct epitopes on pertactin. We demonstrate that four of these antibodies bind epitopes that are conserved across all three classical Bordetella strains, and competition assays further showed that antibodies binding these epitopes are also elicited by B. pertussis infection of baboons. Surprisingly, we found that representative antibodies binding each epitope protected mice against experimental B. pertussis infection. A cocktail of antibodies from each epitope group protected mice against a subsequent lethal dose of B. pertussis and greatly reduced lung colonization levels after sublethal challenge. Each antibody reduced B. pertussis lung colonization levels up to 100-fold when administered individually, which was significantly reduced when antibody effector functions were impaired, with no antibody mediating antibody-dependent complement-induced lysis. These data suggest that antibodies binding multiple pertactin epitopes protect primarily by the same bactericidal mechanism, which overshadows contributions from blockade of other pertactin functions. These antibodies expand the available tools to further dissect pertactin''s role in infection and understand the impact of antipertactin antibodies on bacterial fitness.     

Failure to convert Bordetella parapertussis to Bordetella pertussis with a pertussis phage

To analyze the described lysogenic conversion of Bordetella parapertussis to a Bordetella pertussis-like form we used the phage 134 to lysogenize a B. parapertussis strain. Southern blot analysis of the isolated ‘lysogens’ showed that they were not true lysogens, but rather chronically infected strains. These pseudo-lysogens did not show any changes in virulence properties compared with the parental strain. The only difference we could show was a change in the LPS-structure: the pseudolysogens had a rough LPS, like B. pertussis, whereas the parental B. parapertussis strain was smooth.