Mouse Protection Tests in the Study of Pertussis Vaccine A Comparative Series Using the Intracerebral Route for Challenge * Affiliation P. L. Kendrick, Grace Eldering, M. K. Dixon, and J. Misner CopyRight*Presented before the Laboratory Section of the American Public Health Association at the Seventy-fourth Annual Meeting in Cleveland, Ohio, November 13, 1946. https://doi.org/10.2105/AJPH.37.7.803-b Published Online: August 29, 2011

N early 1943, in connection with an investigation of the antigenicity of pertussis vaccines, particularly as measured by animal protection, a cooperative study was undertaken with a group of interested manufacturing laboratories. As a starting point, samples of vaccine were submitted for comparative density determinations. The findings indicated that a photometric method was reasonably. reliable and reproducible, under properly controlled conditions." For example, the calibration chart for each particular instrument should be based on a series of graded dilutions of a suspension of organisms having the size and morphology of smooth Hemophilus pertussis; the suspension must be of known density based on a series of di-