Germinal centre and marginal zone B cells expand quickly in a second Plasmodium chabaudi malaria infection producing mature plasma cells.
Antibodies and B cells are critical in the protective immune response to the blood stage of the malaria parasite, Plasmodium chabaudi. However, little is known about the development of memory B cells and their differentiation into plasma cells during infection or after re-infection. Here we have shown that B cells with phenotypic characteristics of memory cells (CD19(+)IgD(-) CD38(+), IgG1(+)) are generated in a primary Plasmodium chabaudi chabaudi infection of mice. In addition, we observed that germinal centre cells (CD19(+), GL7(+), MHCII(hi)) and Marginal Zone B cells (CD19(+)CD23(-)IgD(-)) show faster expansion on re-infection than in the primary, though other subsets do not. Interestingly, though both IgM(-) and IgM(+) memory cells are produced, IgM(+) memory cells do not expand on second infection. The second infection quickly produced mature bone marrow plasma cells (intracellular Ig(hi), CD138(hi), CD9(+), B220(-)), compared to primary infection; which generates a very large population of immature splenic plasma cells (B220+). This analysis suggests that a memory B cell population is generated after a single infection of malaria, which on re-infection responds quickly producing germinal centres and generating long-lived plasma cells making the second encounter with parasite more efficient.
Stephens
R
R
National Institute for Medical Research, Division of Parasitology, London, UK.
Ndungu
F M
FM
Langhorne
J
J
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D018858:Germinal Center / Q000276:immunology; D007156:Immunologic Memory; D016131:Lymphocyte Subsets / Q000276:immunology; D008288:Malaria / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010950:Plasma Cells / Q000276:immunology*; D016788:Plasmodium chabaudi / Q000276:immunology*