A ROLE FOR B-CELLS IN THE DEVELOPMENT OF T-CELL HELPER FUNCTION IN A MALARIA INFECTION IN MICE

B cell knockout mice are unable to clear a primary erythrocytic infect ion of Plasmodium chabaudi chabaudi. However, the early acute infectio n is controlled to some extent, giving rise to a chronic relapsing par asitemia that can be reduced either by drug treatment or by adoptive t ransfer of B cells, Similar to mice rendered B-cell deficient by lifel ong treatment with anti-mu antibodies, B cell knockout mice (mu MT) re tain a predominant CD4(+) Th1-like response to malarial antigens throu ghout a primary infection, This contrasts with the response seen in co ntrol C57BL/6 mice in which the CD4(+) T-cell response has switched to that characteristic of Th2 cells at the later stages of infection, ma nifesting efficient help for specific antibodies in vitro and interleu kin 4 production, Both chloroquine and adoptive transfer of immune B c ells reduced parasite load, However, the adoptive transfer of B cells resulted in a Th2 response in recipient mu MT mice, as indicated by a relative increase in the precursor frequency of helper cells for antib ody production. These data support the idea that B cells play a role i n the regulation of CD4(+) T subset responses.