Antibody affinity maturation: the role of CD8+ cells.

The cellular control of antibody affinity maturation has been studied in mice genetically selected for their failure to demonstrate an increase in affinity following immunization (low-affinity N/M mice). Depletion of CD8+ cells in low N/M mice by thymectomy and/or anti-CD8 antibody treatment resulted in these animals acquiring the ability to mount an anti-DNP response of progressively increasing affinity. This indicates that CD8+ cells play an important regulatory role in the cellular interactions underlying the process of affinity maturation. In addition, evidence is presented which suggests that the route of immunization may also be critical in determining the affinity of antibody produced.