The therapeutic efficacy of granulocyte colony-stimulating factor (G-CSF) against an experimental intramuscular infection induced by Pseudomonas aeruginosa in mice was confirmed. Bacterial growth in the infected thigh muscle was suppressed by G-CSF treatment. The change in the number of peripheral blood polymorphonuclear leukocytes (PMN) after bacterial challenge was investigated. The results showed that G-CSF could stimulate stronger defense mechanisms after stimulation by bacterial challenge. In the G-CSF-treated group, more clusters of matured PMN were observed in the infected thigh muscle 6 h after bacterial challenge. Next, the correlation between the number of PMN in the blood at the time of infection and the therapeutic efficacy of antibiotics was investigated. The therapeutic efficacy of ceftazidime, a P-lactam antibiotic, was affected by the number of blood PMN at the time of infection. In particular, a decrease of peripheral blood PMN at the time of infection resulted in a dramatic decrease in the efficacy of ceftazidime. The reduction in leukopenia by G-CSF remarkably strengthened the therapeutic effect of antibiotics in mice.

In the chick tracheal organ culture of Bordetella pertussis phase I organisms, marked bacterial growths were observed in the culture medium and on the tracheal fragments.However, serum-free fresh or conditioned medium alone as well as an emulsion of tracheal tissues prepared in the conditioned medium supported little growth of the bacteria.The need for the existence of the organ fragment was inevitable.Fluorescence microscopy of the infected tracheal fragment and a time course study of bacterial growth in the medium with the organ culture suggested that the principal site of bacterial growth appeared to be on the surface of the tracheal fragments and the increase in the culture medium might be brought about mainly by the release of bacteria therefrom.Although the histopathological findings of whooping cough [15] and the growth requirements of Bordetella pertussis in artificial media are well known [20], little is documented about its pathogenesis. The bacteria initially grow on the mucous membranes of the respiratory tract of patients, displaying a characteristic localization on the ciliae of epithelial cells [17]. Subsequent invasion of the bacteria into the alveoli may result in the development of the disease.The experimental infection with this organism has been studied most extensively in the mouse. Bacterial growth can be demonstrated in mucous secretions on the surface of the ciliated epithelium of the respiratory tract following an intranasal inoculation [2]. For rather practical reasons, however, the intracerebral infection route with B. pertussis 18-323 strain [13] is commonly used for assaying the pertussis vaccine. In the brain, the bacteria grow and localize on the ciliated ependymal cell layer of the ventricle wall [1,[10][11][12], again demonstrating that the localization of bacterial growth is quite similar with that observed in the respiratory tract in the natural infection. Substantiation of such an affinity of the bacteria, for the ciliated epithelial layers offers an important problem for further investigation through which the mode of infection or peculiarity of the infection with B. pertussis could be elucidated.The organ culture technique might be useful for this purpose as frequently used in studies of the respiratory viral disease agents. The growth characteristics of B. pertussis observed in the chick tracheal organ culture system will be described in this paper.

Among various metabolic inhibitors tested, only 2, 4-dinitrophenol inhibited the growth of Bordetella pertussis in chick tracheal organ culture at concentrations nontoxic both for bacterial organisms and for ciliary motility of the tracheal fragments. Although this effect of 2, 4-dinitrophenol was reversible in its early stage, longer treatment with this inhibitor resulted in an irreversible inhibition of bacterial growth due to secondary damage of the tracheal fragments. From these observations, it was postulated that the energy required for bacterial growth might be derived from cellular metabolism sensitive to inhibition with 2, 4-dinitrophenol.

The effects of four kinds of human immunoglobulin preparations for intravenous use [pH-4-treated (IG-100), polyethyleneglycol-treated (PEG-G), sulfonated (S-G) and pepsin-treated (Pep-G)] on intracerebral (i.c.) Bordetella pertussis infection in mice, and on B. pertussis vaccine-induced leukocytosis-promoting factor (LPF) and histamine-sensitizing factor (HSF) were compared with those of human immunoglobulin preparation for intramuscular use (GGN). A prophylactic potential against i.c. B. pertussis challenge was demonstrated in IG-100, PEG-G and GGN. A prophylactic potential was also demonstrated in S-G and Pep-G, although to a lesser extent. Neutralizing activity for LPF was in the following order: GGN = IG-100 = PEG-G greater than S-G = Pep-G; for HSF it was as follows: IG-100 greater than PEG-G greater than GGN = S-G greater than Pep-G. There were no significant differences in antibody titers of the various preparations against B. pertussis antigens. These results suggest that the Fc part of the immunoglobulin molecule is important for protecting against i.c. B. pertussis infection and for neutralizing B. pertussis toxins.