Abstract
We have dealt 1 with the enhancement of virulence of meningococci and typhoid bacilli for mice, and the effect of both active and passive immunization upon resistance of mice to infection with mucin-coated cultures. This work followed that of Nungester, Wolf and Jourdonais, 2 Miller 3 and Rake, 4 and in turn was followed by a similar report by Mishulow and Melman. 5 These reports show that the intraperitoneal mouse-virulence of certain strains of meningococci and typhoid bacilli may be multiplied a thousand- to a million-fold through the use of the proper gastric mucin, and that this procedure may be of use in the selection of bacterial vaccine strains and in turn in the evaluation of antiserum.
Subsequently we have found the “mucin-coating” technic applicable to B. coli, gonococci, and Streptococcus viridans. 6 In the following experiments we applied similar methods of virulence-enhancement to H. pertussis.
We have utilized 41 freshly isolated smooth strains, as described by Shibley and Hœlscher, 7 which fulfill Phase 1 characteristics as stated by Leslie and Gardner. 8 Twenty-four-hour growths on Bordet-agar slants enriched with 25% human or sheep blood, planted from the second of a series of two 48-hour transplants, were washed off with 1 cc. of infusion broth and further dilutions prepared from this as indicated.
Mucin-virulence: The mucin-coating technic has been applied with several minor variations to 36 pertussis cultures injected into 530 mice. None of the changes in technic affected the outcome of the tests. Only an occasional mouse died, and these few deaths bore little or no relation to the dose of mucin-coated culture injected. Similar results were obtained in 2 series of tests in 12 guinea pigs. Obviously mucin is of relatively little use in attempts to enhance the virulence of H. pertussis.
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