Within the spleen, both susceptible C57BL/6J and resistant A/J mice produced similar frequencies of memory B cell CD73+ FCRL5- and atypical memory CD73+ FCRL5+ CD80+ populations during infection, however in A/J mice these compartments were significantly increased in their class-switch recombination frequencies during secondary infection (Fig 5D). This evidence concerns the gene FCRL5 and infection.