Definition: Organisms or complex pharmaceutical substances, preparations, or agents of organic origin, usually obtained by biological methods or assay. Biological agents are differentiated from BIOLOGICAL FACTORS in that the latter are compounds with biological or physiological activity made by living organisms. (From Webster's 3d ed).
differentiate from BIOLOGICAL FACTORS; /ther use: coordinate with disease /drug ther
ImuVert labile preparation of natural membrane vesicles associated with RIBOSOMES which is derived from ther bacteria Serratia marcescens and used for ALOPECIA