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From Natural Polyreactive Autoantibodies to À La Carte Monoreactive Antibodies to Infectious Agents: Is It a Small World after All?

1998; American Society for Microbiology; Volume: 66; Issue: 1 Linguagem: Inglês

10.1128/iai.66.1.1-4.1998

1098-5522

Jean‐Pierre Bouvet, Guillaume Dighiero,

Immunotherapy and Immune Responses

Induction of antibodies (Abs) to infectious agents requires the help of many different genes involved in selection and regulation processes. It is thus unlikely that a direct development of conventional humoral immunity has occurred in the absence of preliminary simple immune mechanisms. The germinal structure of the polyreactive Ab system is in agreement with its involvement in the intermediate steps. Polyreactive auto-Abs have been evidenced in the serum of all healthy subjects and in myeloma proteins, and a high frequency of precursor B cells displaying this auto-Ab activity has been shown elsewhere (13, 14, 20). These data were further confirmed and expanded by multiple functional and structural studies (3). Natural Abs predominate early in life and are observed even in species only distantly related to humans, such as fish and amphibians (19). They are currently encoded by variable (V) genes under their germinal configuration (4), and they bind well-conserved epitopes even from different species. A feature of major interest is the ability of polyreactive auto-Abs to bind both self and nonself antigens such as microbial molecules. This specificity can be associated with the immune defenses against infection, especially in lower vertebrates. The antimicrobial functions of natural Abs lead us to discuss the advantages of the further development of the conventional Ab system in higher vertebrates and to suggest a scenario involving a successive evolution of these two Ab systems and their final coexistence as complementary mechanisms of protection against pathogens.