The Relation of Washed Granules From Commercial Vaccine to the Virus

Abstract

The work of MacCallum and Oppenheimer 1 and of Craciun and Oppenheimer 2 offered at least the hope that the “washed granules” prepared from commercial calf vaccine might represent purified vaccinia virus. We have accordingly investigated further the nature of the washed granular material obtained by the method of Craciun and Oppenheimer. 2

In confirmation of the earlier work we have found that the granular centrifugalization sediments after repeated washings in Ringer's solution were infectious even in high dilution; characteristic lesions of vaccinia resulted from intradermal injection into rabbits; the supernatant fluids were infectious only in low dilution. When mixed with the sera of rabbits recently recovered from vaccinia the granules were rendered non-infectious; the infectivity of the granules was not neutralized by normal rabbit sera. Consideration of the results of previous work 1 , 2 , 3 and of this work leaves no doubt in our minds that the property of infectivity is borne by some of the particles in the washed granular material.

The washed granules have been found to become non-infectious at hydrogen ion concentrations more acid than pH = 5.2 or 5.3 (See Table I). This is in sufficient agreement with the results of Douglas and Smith, 4 who found that “diffusates” of vaccine virus from infected rabbits' testes were rapidly inactivated at reactions more acid than pH = 5.5.

We have found that infectivity could be restored to non-infectious mixtures of granules and immune serum by washing the serum-treated granules in saline or Ringer's solution. 5 , 6 , 7 Yet recovery of infectivity on washing was not complete; the infecting power of the rewashed granules treated with immune sera was considerably inferior to that of granules similarly treated with normal sera.