Microbial parasitism cross-reactive with host antigen: implications concerning loss of "self" tolerance and development of autoimmune disease.

The implications of inserting eukaryotic genetic material coding for human "self" antigens into prokaryotic microbe vectors that parasitize humans are discussed against the background of contemporary concepts of immunologic tolerance to "self" constituents and the types of host autoreactive immune responses that might occur. The injurious potential of autoreactive immune responses elicited by infecting microbes which share antigenic constituents with host "self" antigens is carefully weighed. The risk of similar cross-reacting microbial vectors arising as a consequence of ongoing recombinant DNA technology and experimentation and posing public health concerns for humans is examined. On balance, the risk would appear to be extraordinarily low.