The Influence of Environment on Antigen Production by Pasteurella pestis Studied by Means of the Continuous Flow Culture Technique

Abstract

The yields of three antigens of Pasteurella pestis (fraction I, antigen 4, V antigen) in continuous flow culture over a range of temperature and pH values have been determined quantitatively. The production of some other antigens was followed qualitatively. The production of fraction I, V antigen and antigen 4 was greatest at 37[degree] and little or none at 28[degree]. The production of antigen 4 required an environmental pH below 69. The production of antigen 5 showed oxygen dependence at 28[degree] but not at 37[degree]. In transitions from one antigenic state to another the amounts of some antigens in the organism passed through maxima. Selection against types with the V and fraction I antigens occurred during growth at 37[degree], but not at 28[degree]. Selection against types with antigen 4 did not occur.