CONCENTRATION AND PURIFICATIONOF VIRUSESWITH SPECIALREFERENCE TO REOVIRUSES

INTRODUCrION Amongthepowerful tools employed byvirolo- gists andtheir colleagues, molecular biologists, arethose acquired fromphysical andbiological chemists, whichallow isolation ofmacromole- cules intheir active forms. Thesetechniques, namely, ultracentrifugation, adsorption chroma- tography, electrophoresis, andpartition inliquid phases, haveseparated complete virus particles (virions) fromincomplete fragments (protein capsomeres andnucleic acid) andother sub- fractions ofcells. Concentration ofviruses has beennecessary toobtain themultiplicity of virus tocell needed forcareful study ofvirus synthesis within cells. Ithaspermitted extra- polation ofevents measured inaculture of108 cells toevents inasingle cell. Ithas, moreover, beenvital tobiochemical study, andwill prob- ablybecomeincreasingly important inproduc- tion ofvaccines free frommaterials withpossible harmful effects. Thesetechniques andaselected fewoftheir applications will bereviewed. Someofmywork withreoviruses will bereported.