For many years, innate immunity has been considered as a separate enti
ty from the adaptive immune response and has been regarded to beef sec
ondary importance in the hierarchy of immune functions. For the past f
ew years, however, interest in innate immunity has grown enormously, s
o that now it is studied intensively in many laboratories that seek to
integrate these two distinct types of immune function. Our intent in
this review is to point out the similarities and differences in these
two types of host response to infection, and to indicate our present l
evel of understanding of how these can be integrated into a more compl
ete description of the immune response.