SH2D1A and infection: Since previous studies have shown that infection of SAP-deficient mice with MHV68 results in reduced viral load in spleens [35], [36], we infected mice with a recombinant MHV68 that expresses yellow fluorescent protein (MHV68-H2bYFP) [31] to compare the infected B cell populations in these mice with those seen in wild type mice.