Preparation of noninfectious arbovirus antigens

Noninfectious arbovirus antigens were prepared from borate-saline suspensions of infected suckling mouse brain buffered with tris(hydroxmethyl)aminomethane and treated with beta-propiolactone (BPL). The activity and stability of these antigens were enhanced by altering the buffering system, by passing the virus seed through a series of four or more continuous passages in the brains of suckling mice, or by a combination of these procedures. The titers of group A and B arbovirus antigens were comparable to titers of antigens extracted by the conventional sucroseacetone-BPL (SA-BPL) method. Antigens prepared from some ungrouped and Bunyamwera arboviruses by either the borate-saline-BPL or SA-BPL method produced inconsistent results and will require the development of more unique procedures to obtain suitable hemagglutinating antigens.