Immunological memory: stable IgG patterns determine in vivo responsiveness at the clonal level.

Immune responsiveness to the streptococcal group polysaccharides at the clonal level can conveniently be monitored by analytical isoelectric focusing combined with autoradiography. The parameters investigated in this paper can be summarized as follows: [1] Within the first week after injection antistreptococcal p0lysaccharide responses are characterized by IgM antibodies, followed by subclass restriction in Balb/c mice to IgG2a antibodies. [2] The clonal pattern of specific IgG2a antibodies established in the second week after immunization does not change within the following 6 weeks. [3] Persistence of a specific response pattern established within a primary immunization course holds for Balb/c mice and rabbits for as long as 12 to 13 months. [4] Repeated immunization courses in mice and rabbits maintain established clonal antibody patterns in toto. Temporal variations of clonal expression are generally quantitative rather than qualitative. B-cell memory within this system is therefore stable and long-lived.