Abstract: Disclosed and claimed is an adjuvant for immunogenic, immunological, antigenic or vaccine compositions. The adjuvant is composed of insect cells or fractions thereof. Disclosed and claimed are also methods for preparing and using the adjuvant and compositions containing the adjuvant. Advantageously, a recombinant baculovirus containing DNA encoding and expressing an epitope of interest or antigen can be infected into insect cells such as insect cells derived from a Lepidopteran species such as S. frugiperda for expression, and the infected insect cells or a fraction thereof can be used with the expressed epitope of interest or antigen as an inventive antigen or in an inventive immunological, antigen or vaccine composition.